11McGraw-Hill copyThe McGraw-Hill Companies Inc 2000

Data Communication amp Data Communication amp NetworkingNetworking DKT 224 DKT 224

Ir Anuar Mat Safar Ir Anuar Mat Safar

04-9851684 013-422324204-9851684 013-4223242

Puan Shahadah Bt AhmadPuan Shahadah Bt Ahmad

04-9854979 017-572233904-9854979 017-5722339

School of Computer amp Communication School of Computer amp Communication Engineering KUKUMEngineering KUKUM

anuarmsunimapedumyanuarmsunimapedumy

shahadahunimapedumyshahadahunimapedumy

22

Course OutcomesCourse Outcomes

11 Students will be able to understand the theory and Students will be able to understand the theory and basic of data communication and networkbasic of data communication and network

22 Able to identify network connection concept and Able to identify network connection concept and protocol usedprotocol used

33 Students be familiarize with the data communication Students be familiarize with the data communication network equipments and instruments to analyze network equipments and instruments to analyze network protocol and perform some troubleshootingnetwork protocol and perform some troubleshooting

44 Students be exposed to network architecture and new Students be exposed to network architecture and new technologies in data communication and networktechnologies in data communication and network

33

SyllabusSyllabus

StudStudyyWWeeeekk

Course ContentCourse Content

1212 INTRODUCTION INTRODUCTION Chapter 1Chapter 1Introduction to data communicationsIntroduction to data communications

- component data representation and data flowcomponent data representation and data flow Chapter 2Chapter 2

Introduction to data communication networks Introduction to data communication networks -network criteria physical structures network models categories of -network criteria physical structures network models categories of networks and Internet work networks and Internet work -protocols and standards-protocols and standards

(4 hours)(4 hours)

343455

PHYSICAL LAYER AND MEDIA (review)PHYSICAL LAYER AND MEDIA (review) Chapter 345Chapter 345 Data and signals Digital transmission and analog transmissionData and signals Digital transmission and analog transmission Chapter 6 7Chapter 6 7 Bandwidth utilization amp transmission mediaBandwidth utilization amp transmission media

(6 hours)(6 hours)

44

SyllabusSyllabus

Study Study WeekWeek Course ContentCourse Content

6767 DATA LINK LAYERDATA LINK LAYER Chapter 10Chapter 10 Error Detection and CorrectionError Detection and Correction

(4 hours)(4 hours)

910910 DATA LINK LAYER( cont)DATA LINK LAYER( cont) Chapter 1112Chapter 1112 Data link control amp Multiple accessData link control amp Multiple access

(4 hours)(4 hours)

55

Study WeekStudy WeekCourse ContentCourse Content

11121112

Chapter 1314Chapter 1314

Wired and wireless LANsWired and wireless LANs(4 hours)(4 hours)

13141314 SECURITYSECURITY

Chapter 3031Chapter 3031

Cryptography amp network SecurityCryptography amp network Security(4 hours)(4 hours)

SyllabusSyllabus

66McGraw-Hill copyThe McGraw-Hill Companies Inc 2000

AssessmentAssessment

Final Exam - 50 Final Exam - 50 Course Work ndash 50 Course Work ndash 50

Lab ndash 30 Lab ndash 30 Test Assigment ndash 10Test Assigment ndash 10Lab Project ndash 10Lab Project ndash 10

77

Lab experiment Lab experiment

LAB 1 - Introduction to LINUXLAB 1 - Introduction to LINUX

LAB 2 - LAB 2 - Network protocol analyzerNetwork protocol analyzer

LAB 3 - LAB 3 - Network setup 1Network setup 1

LAB 4 - Network setup 2LAB 4 - Network setup 2

LAB 5 - Wireless access point LAB 5 - Wireless access point configurationconfiguration

88McGraw-Hill copyThe McGraw-Hill Companies Inc 2000

ReferencesReferences1Behrouz A Forouzan Data Communications and 1Behrouz A Forouzan Data Communications and

Networking 4th Edition McGraw Hill 2007 Networking 4th Edition McGraw Hill 2007 (TEXT BOOK)(TEXT BOOK)

2 William Stalling Data and Computer 2 William Stalling Data and Computer

Communications 7th Edition Prentice Hall Communications 7th Edition Prentice Hall 2005 2005

3Wayne Tomasi Introduction to Data 3Wayne Tomasi Introduction to Data

Communications and Networking Communications and Networking

Prentice Hall2004Prentice Hall2004

99

Chapter 1

Introduction

Copyright copy The McGraw-Hill Companies Inc Permission required for reproduction or display

1010

1-1 DATA COMMUNICATIONS1-1 DATA COMMUNICATIONS

The term The term telecommunicationtelecommunication means communication at a means communication at a distance The word distance The word datadata refers to information presented refers to information presented in whatever form is agreed upon by the parties creating in whatever form is agreed upon by the parties creating and using the data and using the data Data communicationsData communications are the are the exchange of data between two devices via some form of exchange of data between two devices via some form of transmission medium such as a wire cable transmission medium such as a wire cable

ComponentsData RepresentationData Flow

Topics discussed in this sectionTopics discussed in this section

1111

Figure 11 Five components of data communication

1212

Data RepresentationData Representation

TEXTTEXT ndash unicode (32 bits to represent ndash unicode (32 bits to represent character)- ASCIIcharacter)- ASCII

NUMBERSNUMBERS

IMAGESIMAGES-composed of a matrix of pixel-composed of a matrix of pixel

AUDIOAUDIO- recording or broadcasting of - recording or broadcasting of sound or musicsound or music

VIDEOVIDEO- recording or broadcasting of a - recording or broadcasting of a picture or moviepicture or movie

1313

Figure 12 Data flow (simplex half-duplex and full-duplex)

1414

1-2 NETWORKS1-2 NETWORKS

A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) ) connected by communication connected by communication linkslinks A node can be a A node can be a computer printer or any other device capable of sending computer printer or any other device capable of sending andor receiving data generated by other nodes on the andor receiving data generated by other nodes on the networknetwork

Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork

Topics discussed in this sectionTopics discussed in this section

1515

NETWORKSNETWORKS

Set of nodes connected via physical links Set of nodes connected via physical links 1) Distributing Processing 1) Distributing Processing 2) Sharing Data and centralization 2) Sharing Data and centralization 3) Security and robustness 3) Security and robustness

1616

Network CriteriaNetwork Criteria

1) Performance Transmission and response timesrsquo throughput and delay 2) Reliability How often the networks fail

3) Security Privacy and integrity of communication Data recovery from breaches and data loss

1717

Physical Structures Physical Structures

Types of connectionsTypes of connections

1) Point to Point (P to P) Dedicated link to 1) Point to Point (P to P) Dedicated link to be utilized only by end devices be utilized only by end devices

2) Multipoint (Multidrop) Many end 2) Multipoint (Multidrop) Many end devices share the link capacitydevices share the link capacity

1818

Figure 13 Types of connections point-to-point and multipoint

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

33

SyllabusSyllabus

StudStudyyWWeeeekk

Course ContentCourse Content

1212 INTRODUCTION INTRODUCTION Chapter 1Chapter 1Introduction to data communicationsIntroduction to data communications

- component data representation and data flowcomponent data representation and data flow Chapter 2Chapter 2

Introduction to data communication networks Introduction to data communication networks -network criteria physical structures network models categories of -network criteria physical structures network models categories of networks and Internet work networks and Internet work -protocols and standards-protocols and standards

(4 hours)(4 hours)

343455

PHYSICAL LAYER AND MEDIA (review)PHYSICAL LAYER AND MEDIA (review) Chapter 345Chapter 345 Data and signals Digital transmission and analog transmissionData and signals Digital transmission and analog transmission Chapter 6 7Chapter 6 7 Bandwidth utilization amp transmission mediaBandwidth utilization amp transmission media

(6 hours)(6 hours)

44

SyllabusSyllabus

Study Study WeekWeek Course ContentCourse Content

6767 DATA LINK LAYERDATA LINK LAYER Chapter 10Chapter 10 Error Detection and CorrectionError Detection and Correction

(4 hours)(4 hours)

910910 DATA LINK LAYER( cont)DATA LINK LAYER( cont) Chapter 1112Chapter 1112 Data link control amp Multiple accessData link control amp Multiple access

(4 hours)(4 hours)

55

Study WeekStudy WeekCourse ContentCourse Content

11121112

Chapter 1314Chapter 1314

Wired and wireless LANsWired and wireless LANs(4 hours)(4 hours)

13141314 SECURITYSECURITY

Chapter 3031Chapter 3031

Cryptography amp network SecurityCryptography amp network Security(4 hours)(4 hours)

SyllabusSyllabus

66McGraw-Hill copyThe McGraw-Hill Companies Inc 2000

AssessmentAssessment

Final Exam - 50 Final Exam - 50 Course Work ndash 50 Course Work ndash 50

Lab ndash 30 Lab ndash 30 Test Assigment ndash 10Test Assigment ndash 10Lab Project ndash 10Lab Project ndash 10

77

Lab experiment Lab experiment

LAB 1 - Introduction to LINUXLAB 1 - Introduction to LINUX

LAB 2 - LAB 2 - Network protocol analyzerNetwork protocol analyzer

LAB 3 - LAB 3 - Network setup 1Network setup 1

LAB 4 - Network setup 2LAB 4 - Network setup 2

LAB 5 - Wireless access point LAB 5 - Wireless access point configurationconfiguration

88McGraw-Hill copyThe McGraw-Hill Companies Inc 2000

ReferencesReferences1Behrouz A Forouzan Data Communications and 1Behrouz A Forouzan Data Communications and

Networking 4th Edition McGraw Hill 2007 Networking 4th Edition McGraw Hill 2007 (TEXT BOOK)(TEXT BOOK)

2 William Stalling Data and Computer 2 William Stalling Data and Computer

Communications 7th Edition Prentice Hall Communications 7th Edition Prentice Hall 2005 2005

3Wayne Tomasi Introduction to Data 3Wayne Tomasi Introduction to Data

Communications and Networking Communications and Networking

Prentice Hall2004Prentice Hall2004

99

Chapter 1

Introduction

Copyright copy The McGraw-Hill Companies Inc Permission required for reproduction or display

1010

1-1 DATA COMMUNICATIONS1-1 DATA COMMUNICATIONS

The term The term telecommunicationtelecommunication means communication at a means communication at a distance The word distance The word datadata refers to information presented refers to information presented in whatever form is agreed upon by the parties creating in whatever form is agreed upon by the parties creating and using the data and using the data Data communicationsData communications are the are the exchange of data between two devices via some form of exchange of data between two devices via some form of transmission medium such as a wire cable transmission medium such as a wire cable

ComponentsData RepresentationData Flow

Topics discussed in this sectionTopics discussed in this section

1111

Figure 11 Five components of data communication

1212

Data RepresentationData Representation

TEXTTEXT ndash unicode (32 bits to represent ndash unicode (32 bits to represent character)- ASCIIcharacter)- ASCII

NUMBERSNUMBERS

IMAGESIMAGES-composed of a matrix of pixel-composed of a matrix of pixel

AUDIOAUDIO- recording or broadcasting of - recording or broadcasting of sound or musicsound or music

VIDEOVIDEO- recording or broadcasting of a - recording or broadcasting of a picture or moviepicture or movie

1313

Figure 12 Data flow (simplex half-duplex and full-duplex)

1414

1-2 NETWORKS1-2 NETWORKS

A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) ) connected by communication connected by communication linkslinks A node can be a A node can be a computer printer or any other device capable of sending computer printer or any other device capable of sending andor receiving data generated by other nodes on the andor receiving data generated by other nodes on the networknetwork

Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork

Topics discussed in this sectionTopics discussed in this section

1515

NETWORKSNETWORKS

Set of nodes connected via physical links Set of nodes connected via physical links 1) Distributing Processing 1) Distributing Processing 2) Sharing Data and centralization 2) Sharing Data and centralization 3) Security and robustness 3) Security and robustness

1616

Network CriteriaNetwork Criteria

1) Performance Transmission and response timesrsquo throughput and delay 2) Reliability How often the networks fail

3) Security Privacy and integrity of communication Data recovery from breaches and data loss

1717

Physical Structures Physical Structures

Types of connectionsTypes of connections

1) Point to Point (P to P) Dedicated link to 1) Point to Point (P to P) Dedicated link to be utilized only by end devices be utilized only by end devices

2) Multipoint (Multidrop) Many end 2) Multipoint (Multidrop) Many end devices share the link capacitydevices share the link capacity

1818

Figure 13 Types of connections point-to-point and multipoint

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

44

SyllabusSyllabus

Study Study WeekWeek Course ContentCourse Content

6767 DATA LINK LAYERDATA LINK LAYER Chapter 10Chapter 10 Error Detection and CorrectionError Detection and Correction

(4 hours)(4 hours)

910910 DATA LINK LAYER( cont)DATA LINK LAYER( cont) Chapter 1112Chapter 1112 Data link control amp Multiple accessData link control amp Multiple access

(4 hours)(4 hours)

55

Study WeekStudy WeekCourse ContentCourse Content

11121112

Chapter 1314Chapter 1314

Wired and wireless LANsWired and wireless LANs(4 hours)(4 hours)

13141314 SECURITYSECURITY

Chapter 3031Chapter 3031

Cryptography amp network SecurityCryptography amp network Security(4 hours)(4 hours)

SyllabusSyllabus

66McGraw-Hill copyThe McGraw-Hill Companies Inc 2000

AssessmentAssessment

Final Exam - 50 Final Exam - 50 Course Work ndash 50 Course Work ndash 50

Lab ndash 30 Lab ndash 30 Test Assigment ndash 10Test Assigment ndash 10Lab Project ndash 10Lab Project ndash 10

77

Lab experiment Lab experiment

LAB 1 - Introduction to LINUXLAB 1 - Introduction to LINUX

LAB 2 - LAB 2 - Network protocol analyzerNetwork protocol analyzer

LAB 3 - LAB 3 - Network setup 1Network setup 1

LAB 4 - Network setup 2LAB 4 - Network setup 2

LAB 5 - Wireless access point LAB 5 - Wireless access point configurationconfiguration

88McGraw-Hill copyThe McGraw-Hill Companies Inc 2000

ReferencesReferences1Behrouz A Forouzan Data Communications and 1Behrouz A Forouzan Data Communications and

Networking 4th Edition McGraw Hill 2007 Networking 4th Edition McGraw Hill 2007 (TEXT BOOK)(TEXT BOOK)

2 William Stalling Data and Computer 2 William Stalling Data and Computer

Communications 7th Edition Prentice Hall Communications 7th Edition Prentice Hall 2005 2005

3Wayne Tomasi Introduction to Data 3Wayne Tomasi Introduction to Data

Communications and Networking Communications and Networking

Prentice Hall2004Prentice Hall2004

99

Chapter 1

Introduction

Copyright copy The McGraw-Hill Companies Inc Permission required for reproduction or display

1010

1-1 DATA COMMUNICATIONS1-1 DATA COMMUNICATIONS

The term The term telecommunicationtelecommunication means communication at a means communication at a distance The word distance The word datadata refers to information presented refers to information presented in whatever form is agreed upon by the parties creating in whatever form is agreed upon by the parties creating and using the data and using the data Data communicationsData communications are the are the exchange of data between two devices via some form of exchange of data between two devices via some form of transmission medium such as a wire cable transmission medium such as a wire cable

ComponentsData RepresentationData Flow

Topics discussed in this sectionTopics discussed in this section

1111

Figure 11 Five components of data communication

1212

Data RepresentationData Representation

TEXTTEXT ndash unicode (32 bits to represent ndash unicode (32 bits to represent character)- ASCIIcharacter)- ASCII

NUMBERSNUMBERS

IMAGESIMAGES-composed of a matrix of pixel-composed of a matrix of pixel

AUDIOAUDIO- recording or broadcasting of - recording or broadcasting of sound or musicsound or music

VIDEOVIDEO- recording or broadcasting of a - recording or broadcasting of a picture or moviepicture or movie

1313

Figure 12 Data flow (simplex half-duplex and full-duplex)

1414

1-2 NETWORKS1-2 NETWORKS

A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) ) connected by communication connected by communication linkslinks A node can be a A node can be a computer printer or any other device capable of sending computer printer or any other device capable of sending andor receiving data generated by other nodes on the andor receiving data generated by other nodes on the networknetwork

Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork

Topics discussed in this sectionTopics discussed in this section

1515

NETWORKSNETWORKS

Set of nodes connected via physical links Set of nodes connected via physical links 1) Distributing Processing 1) Distributing Processing 2) Sharing Data and centralization 2) Sharing Data and centralization 3) Security and robustness 3) Security and robustness

1616

Network CriteriaNetwork Criteria

1) Performance Transmission and response timesrsquo throughput and delay 2) Reliability How often the networks fail

3) Security Privacy and integrity of communication Data recovery from breaches and data loss

1717

Physical Structures Physical Structures

Types of connectionsTypes of connections

1) Point to Point (P to P) Dedicated link to 1) Point to Point (P to P) Dedicated link to be utilized only by end devices be utilized only by end devices

2) Multipoint (Multidrop) Many end 2) Multipoint (Multidrop) Many end devices share the link capacitydevices share the link capacity

1818

Figure 13 Types of connections point-to-point and multipoint

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

55

Study WeekStudy WeekCourse ContentCourse Content

11121112

Chapter 1314Chapter 1314

Wired and wireless LANsWired and wireless LANs(4 hours)(4 hours)

13141314 SECURITYSECURITY

Chapter 3031Chapter 3031

Cryptography amp network SecurityCryptography amp network Security(4 hours)(4 hours)

SyllabusSyllabus

66McGraw-Hill copyThe McGraw-Hill Companies Inc 2000

AssessmentAssessment

Final Exam - 50 Final Exam - 50 Course Work ndash 50 Course Work ndash 50

Lab ndash 30 Lab ndash 30 Test Assigment ndash 10Test Assigment ndash 10Lab Project ndash 10Lab Project ndash 10

77

Lab experiment Lab experiment

LAB 1 - Introduction to LINUXLAB 1 - Introduction to LINUX

LAB 2 - LAB 2 - Network protocol analyzerNetwork protocol analyzer

LAB 3 - LAB 3 - Network setup 1Network setup 1

LAB 4 - Network setup 2LAB 4 - Network setup 2

LAB 5 - Wireless access point LAB 5 - Wireless access point configurationconfiguration

88McGraw-Hill copyThe McGraw-Hill Companies Inc 2000

ReferencesReferences1Behrouz A Forouzan Data Communications and 1Behrouz A Forouzan Data Communications and

Networking 4th Edition McGraw Hill 2007 Networking 4th Edition McGraw Hill 2007 (TEXT BOOK)(TEXT BOOK)

2 William Stalling Data and Computer 2 William Stalling Data and Computer

Communications 7th Edition Prentice Hall Communications 7th Edition Prentice Hall 2005 2005

3Wayne Tomasi Introduction to Data 3Wayne Tomasi Introduction to Data

Communications and Networking Communications and Networking

Prentice Hall2004Prentice Hall2004

99

Chapter 1

Introduction

Copyright copy The McGraw-Hill Companies Inc Permission required for reproduction or display

1010

1-1 DATA COMMUNICATIONS1-1 DATA COMMUNICATIONS

The term The term telecommunicationtelecommunication means communication at a means communication at a distance The word distance The word datadata refers to information presented refers to information presented in whatever form is agreed upon by the parties creating in whatever form is agreed upon by the parties creating and using the data and using the data Data communicationsData communications are the are the exchange of data between two devices via some form of exchange of data between two devices via some form of transmission medium such as a wire cable transmission medium such as a wire cable

ComponentsData RepresentationData Flow

Topics discussed in this sectionTopics discussed in this section

1111

Figure 11 Five components of data communication

1212

Data RepresentationData Representation

TEXTTEXT ndash unicode (32 bits to represent ndash unicode (32 bits to represent character)- ASCIIcharacter)- ASCII

NUMBERSNUMBERS

IMAGESIMAGES-composed of a matrix of pixel-composed of a matrix of pixel

AUDIOAUDIO- recording or broadcasting of - recording or broadcasting of sound or musicsound or music

VIDEOVIDEO- recording or broadcasting of a - recording or broadcasting of a picture or moviepicture or movie

1313

Figure 12 Data flow (simplex half-duplex and full-duplex)

1414

1-2 NETWORKS1-2 NETWORKS

A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) ) connected by communication connected by communication linkslinks A node can be a A node can be a computer printer or any other device capable of sending computer printer or any other device capable of sending andor receiving data generated by other nodes on the andor receiving data generated by other nodes on the networknetwork

Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork

Topics discussed in this sectionTopics discussed in this section

1515

NETWORKSNETWORKS

Set of nodes connected via physical links Set of nodes connected via physical links 1) Distributing Processing 1) Distributing Processing 2) Sharing Data and centralization 2) Sharing Data and centralization 3) Security and robustness 3) Security and robustness

1616

Network CriteriaNetwork Criteria

1) Performance Transmission and response timesrsquo throughput and delay 2) Reliability How often the networks fail

3) Security Privacy and integrity of communication Data recovery from breaches and data loss

1717

Physical Structures Physical Structures

Types of connectionsTypes of connections

1) Point to Point (P to P) Dedicated link to 1) Point to Point (P to P) Dedicated link to be utilized only by end devices be utilized only by end devices

2) Multipoint (Multidrop) Many end 2) Multipoint (Multidrop) Many end devices share the link capacitydevices share the link capacity

1818

Figure 13 Types of connections point-to-point and multipoint

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

66McGraw-Hill copyThe McGraw-Hill Companies Inc 2000

AssessmentAssessment

Final Exam - 50 Final Exam - 50 Course Work ndash 50 Course Work ndash 50

Lab ndash 30 Lab ndash 30 Test Assigment ndash 10Test Assigment ndash 10Lab Project ndash 10Lab Project ndash 10

77

Lab experiment Lab experiment

LAB 1 - Introduction to LINUXLAB 1 - Introduction to LINUX

LAB 2 - LAB 2 - Network protocol analyzerNetwork protocol analyzer

LAB 3 - LAB 3 - Network setup 1Network setup 1

LAB 4 - Network setup 2LAB 4 - Network setup 2

LAB 5 - Wireless access point LAB 5 - Wireless access point configurationconfiguration

88McGraw-Hill copyThe McGraw-Hill Companies Inc 2000

ReferencesReferences1Behrouz A Forouzan Data Communications and 1Behrouz A Forouzan Data Communications and

Networking 4th Edition McGraw Hill 2007 Networking 4th Edition McGraw Hill 2007 (TEXT BOOK)(TEXT BOOK)

2 William Stalling Data and Computer 2 William Stalling Data and Computer

Communications 7th Edition Prentice Hall Communications 7th Edition Prentice Hall 2005 2005

3Wayne Tomasi Introduction to Data 3Wayne Tomasi Introduction to Data

Communications and Networking Communications and Networking

Prentice Hall2004Prentice Hall2004

99

Chapter 1

Introduction

Copyright copy The McGraw-Hill Companies Inc Permission required for reproduction or display

1010

1-1 DATA COMMUNICATIONS1-1 DATA COMMUNICATIONS

The term The term telecommunicationtelecommunication means communication at a means communication at a distance The word distance The word datadata refers to information presented refers to information presented in whatever form is agreed upon by the parties creating in whatever form is agreed upon by the parties creating and using the data and using the data Data communicationsData communications are the are the exchange of data between two devices via some form of exchange of data between two devices via some form of transmission medium such as a wire cable transmission medium such as a wire cable

ComponentsData RepresentationData Flow

Topics discussed in this sectionTopics discussed in this section

1111

Figure 11 Five components of data communication

1212

Data RepresentationData Representation

TEXTTEXT ndash unicode (32 bits to represent ndash unicode (32 bits to represent character)- ASCIIcharacter)- ASCII

NUMBERSNUMBERS

IMAGESIMAGES-composed of a matrix of pixel-composed of a matrix of pixel

AUDIOAUDIO- recording or broadcasting of - recording or broadcasting of sound or musicsound or music

VIDEOVIDEO- recording or broadcasting of a - recording or broadcasting of a picture or moviepicture or movie

1313

Figure 12 Data flow (simplex half-duplex and full-duplex)

1414

1-2 NETWORKS1-2 NETWORKS

A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) ) connected by communication connected by communication linkslinks A node can be a A node can be a computer printer or any other device capable of sending computer printer or any other device capable of sending andor receiving data generated by other nodes on the andor receiving data generated by other nodes on the networknetwork

Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork

Topics discussed in this sectionTopics discussed in this section

1515

NETWORKSNETWORKS

Set of nodes connected via physical links Set of nodes connected via physical links 1) Distributing Processing 1) Distributing Processing 2) Sharing Data and centralization 2) Sharing Data and centralization 3) Security and robustness 3) Security and robustness

1616

Network CriteriaNetwork Criteria

1) Performance Transmission and response timesrsquo throughput and delay 2) Reliability How often the networks fail

3) Security Privacy and integrity of communication Data recovery from breaches and data loss

1717

Physical Structures Physical Structures

Types of connectionsTypes of connections

1) Point to Point (P to P) Dedicated link to 1) Point to Point (P to P) Dedicated link to be utilized only by end devices be utilized only by end devices

2) Multipoint (Multidrop) Many end 2) Multipoint (Multidrop) Many end devices share the link capacitydevices share the link capacity

1818

Figure 13 Types of connections point-to-point and multipoint

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

77

Lab experiment Lab experiment

LAB 1 - Introduction to LINUXLAB 1 - Introduction to LINUX

LAB 2 - LAB 2 - Network protocol analyzerNetwork protocol analyzer

LAB 3 - LAB 3 - Network setup 1Network setup 1

LAB 4 - Network setup 2LAB 4 - Network setup 2

LAB 5 - Wireless access point LAB 5 - Wireless access point configurationconfiguration

88McGraw-Hill copyThe McGraw-Hill Companies Inc 2000

ReferencesReferences1Behrouz A Forouzan Data Communications and 1Behrouz A Forouzan Data Communications and

Networking 4th Edition McGraw Hill 2007 Networking 4th Edition McGraw Hill 2007 (TEXT BOOK)(TEXT BOOK)

2 William Stalling Data and Computer 2 William Stalling Data and Computer

Communications 7th Edition Prentice Hall Communications 7th Edition Prentice Hall 2005 2005

3Wayne Tomasi Introduction to Data 3Wayne Tomasi Introduction to Data

Communications and Networking Communications and Networking

Prentice Hall2004Prentice Hall2004

99

Chapter 1

Introduction

Copyright copy The McGraw-Hill Companies Inc Permission required for reproduction or display

1010

1-1 DATA COMMUNICATIONS1-1 DATA COMMUNICATIONS

The term The term telecommunicationtelecommunication means communication at a means communication at a distance The word distance The word datadata refers to information presented refers to information presented in whatever form is agreed upon by the parties creating in whatever form is agreed upon by the parties creating and using the data and using the data Data communicationsData communications are the are the exchange of data between two devices via some form of exchange of data between two devices via some form of transmission medium such as a wire cable transmission medium such as a wire cable

ComponentsData RepresentationData Flow

Topics discussed in this sectionTopics discussed in this section

1111

Figure 11 Five components of data communication

1212

Data RepresentationData Representation

TEXTTEXT ndash unicode (32 bits to represent ndash unicode (32 bits to represent character)- ASCIIcharacter)- ASCII

NUMBERSNUMBERS

IMAGESIMAGES-composed of a matrix of pixel-composed of a matrix of pixel

AUDIOAUDIO- recording or broadcasting of - recording or broadcasting of sound or musicsound or music

VIDEOVIDEO- recording or broadcasting of a - recording or broadcasting of a picture or moviepicture or movie

1313

Figure 12 Data flow (simplex half-duplex and full-duplex)

1414

1-2 NETWORKS1-2 NETWORKS

A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) ) connected by communication connected by communication linkslinks A node can be a A node can be a computer printer or any other device capable of sending computer printer or any other device capable of sending andor receiving data generated by other nodes on the andor receiving data generated by other nodes on the networknetwork

Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork

Topics discussed in this sectionTopics discussed in this section

1515

NETWORKSNETWORKS

Set of nodes connected via physical links Set of nodes connected via physical links 1) Distributing Processing 1) Distributing Processing 2) Sharing Data and centralization 2) Sharing Data and centralization 3) Security and robustness 3) Security and robustness

1616

Network CriteriaNetwork Criteria

1) Performance Transmission and response timesrsquo throughput and delay 2) Reliability How often the networks fail

3) Security Privacy and integrity of communication Data recovery from breaches and data loss

1717

Physical Structures Physical Structures

Types of connectionsTypes of connections

1) Point to Point (P to P) Dedicated link to 1) Point to Point (P to P) Dedicated link to be utilized only by end devices be utilized only by end devices

2) Multipoint (Multidrop) Many end 2) Multipoint (Multidrop) Many end devices share the link capacitydevices share the link capacity

1818

Figure 13 Types of connections point-to-point and multipoint

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

88McGraw-Hill copyThe McGraw-Hill Companies Inc 2000

ReferencesReferences1Behrouz A Forouzan Data Communications and 1Behrouz A Forouzan Data Communications and

Networking 4th Edition McGraw Hill 2007 Networking 4th Edition McGraw Hill 2007 (TEXT BOOK)(TEXT BOOK)

2 William Stalling Data and Computer 2 William Stalling Data and Computer

Communications 7th Edition Prentice Hall Communications 7th Edition Prentice Hall 2005 2005

3Wayne Tomasi Introduction to Data 3Wayne Tomasi Introduction to Data

Communications and Networking Communications and Networking

Prentice Hall2004Prentice Hall2004

99

Chapter 1

Introduction

Copyright copy The McGraw-Hill Companies Inc Permission required for reproduction or display

1010

1-1 DATA COMMUNICATIONS1-1 DATA COMMUNICATIONS

The term The term telecommunicationtelecommunication means communication at a means communication at a distance The word distance The word datadata refers to information presented refers to information presented in whatever form is agreed upon by the parties creating in whatever form is agreed upon by the parties creating and using the data and using the data Data communicationsData communications are the are the exchange of data between two devices via some form of exchange of data between two devices via some form of transmission medium such as a wire cable transmission medium such as a wire cable

ComponentsData RepresentationData Flow

Topics discussed in this sectionTopics discussed in this section

1111

Figure 11 Five components of data communication

1212

Data RepresentationData Representation

TEXTTEXT ndash unicode (32 bits to represent ndash unicode (32 bits to represent character)- ASCIIcharacter)- ASCII

NUMBERSNUMBERS

IMAGESIMAGES-composed of a matrix of pixel-composed of a matrix of pixel

AUDIOAUDIO- recording or broadcasting of - recording or broadcasting of sound or musicsound or music

VIDEOVIDEO- recording or broadcasting of a - recording or broadcasting of a picture or moviepicture or movie

1313

Figure 12 Data flow (simplex half-duplex and full-duplex)

1414

1-2 NETWORKS1-2 NETWORKS

A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) ) connected by communication connected by communication linkslinks A node can be a A node can be a computer printer or any other device capable of sending computer printer or any other device capable of sending andor receiving data generated by other nodes on the andor receiving data generated by other nodes on the networknetwork

Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork

Topics discussed in this sectionTopics discussed in this section

1515

NETWORKSNETWORKS

Set of nodes connected via physical links Set of nodes connected via physical links 1) Distributing Processing 1) Distributing Processing 2) Sharing Data and centralization 2) Sharing Data and centralization 3) Security and robustness 3) Security and robustness

1616

Network CriteriaNetwork Criteria

1) Performance Transmission and response timesrsquo throughput and delay 2) Reliability How often the networks fail

3) Security Privacy and integrity of communication Data recovery from breaches and data loss

1717

Physical Structures Physical Structures

Types of connectionsTypes of connections

1) Point to Point (P to P) Dedicated link to 1) Point to Point (P to P) Dedicated link to be utilized only by end devices be utilized only by end devices

2) Multipoint (Multidrop) Many end 2) Multipoint (Multidrop) Many end devices share the link capacitydevices share the link capacity

1818

Figure 13 Types of connections point-to-point and multipoint

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

99

Chapter 1

Introduction

Copyright copy The McGraw-Hill Companies Inc Permission required for reproduction or display

1010

1-1 DATA COMMUNICATIONS1-1 DATA COMMUNICATIONS

The term The term telecommunicationtelecommunication means communication at a means communication at a distance The word distance The word datadata refers to information presented refers to information presented in whatever form is agreed upon by the parties creating in whatever form is agreed upon by the parties creating and using the data and using the data Data communicationsData communications are the are the exchange of data between two devices via some form of exchange of data between two devices via some form of transmission medium such as a wire cable transmission medium such as a wire cable

ComponentsData RepresentationData Flow

Topics discussed in this sectionTopics discussed in this section

1111

Figure 11 Five components of data communication

1212

Data RepresentationData Representation

TEXTTEXT ndash unicode (32 bits to represent ndash unicode (32 bits to represent character)- ASCIIcharacter)- ASCII

NUMBERSNUMBERS

IMAGESIMAGES-composed of a matrix of pixel-composed of a matrix of pixel

AUDIOAUDIO- recording or broadcasting of - recording or broadcasting of sound or musicsound or music

VIDEOVIDEO- recording or broadcasting of a - recording or broadcasting of a picture or moviepicture or movie

1313

Figure 12 Data flow (simplex half-duplex and full-duplex)

1414

1-2 NETWORKS1-2 NETWORKS

A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) ) connected by communication connected by communication linkslinks A node can be a A node can be a computer printer or any other device capable of sending computer printer or any other device capable of sending andor receiving data generated by other nodes on the andor receiving data generated by other nodes on the networknetwork

Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork

Topics discussed in this sectionTopics discussed in this section

1515

NETWORKSNETWORKS

Set of nodes connected via physical links Set of nodes connected via physical links 1) Distributing Processing 1) Distributing Processing 2) Sharing Data and centralization 2) Sharing Data and centralization 3) Security and robustness 3) Security and robustness

1616

Network CriteriaNetwork Criteria

1) Performance Transmission and response timesrsquo throughput and delay 2) Reliability How often the networks fail

3) Security Privacy and integrity of communication Data recovery from breaches and data loss

1717

Physical Structures Physical Structures

Types of connectionsTypes of connections

1) Point to Point (P to P) Dedicated link to 1) Point to Point (P to P) Dedicated link to be utilized only by end devices be utilized only by end devices

2) Multipoint (Multidrop) Many end 2) Multipoint (Multidrop) Many end devices share the link capacitydevices share the link capacity

1818

Figure 13 Types of connections point-to-point and multipoint

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

1010

1-1 DATA COMMUNICATIONS1-1 DATA COMMUNICATIONS

The term The term telecommunicationtelecommunication means communication at a means communication at a distance The word distance The word datadata refers to information presented refers to information presented in whatever form is agreed upon by the parties creating in whatever form is agreed upon by the parties creating and using the data and using the data Data communicationsData communications are the are the exchange of data between two devices via some form of exchange of data between two devices via some form of transmission medium such as a wire cable transmission medium such as a wire cable

ComponentsData RepresentationData Flow

Topics discussed in this sectionTopics discussed in this section

1111

Figure 11 Five components of data communication

1212

Data RepresentationData Representation

TEXTTEXT ndash unicode (32 bits to represent ndash unicode (32 bits to represent character)- ASCIIcharacter)- ASCII

NUMBERSNUMBERS

IMAGESIMAGES-composed of a matrix of pixel-composed of a matrix of pixel

AUDIOAUDIO- recording or broadcasting of - recording or broadcasting of sound or musicsound or music

VIDEOVIDEO- recording or broadcasting of a - recording or broadcasting of a picture or moviepicture or movie

1313

Figure 12 Data flow (simplex half-duplex and full-duplex)

1414

1-2 NETWORKS1-2 NETWORKS

A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) ) connected by communication connected by communication linkslinks A node can be a A node can be a computer printer or any other device capable of sending computer printer or any other device capable of sending andor receiving data generated by other nodes on the andor receiving data generated by other nodes on the networknetwork

Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork

Topics discussed in this sectionTopics discussed in this section

1515

NETWORKSNETWORKS

Set of nodes connected via physical links Set of nodes connected via physical links 1) Distributing Processing 1) Distributing Processing 2) Sharing Data and centralization 2) Sharing Data and centralization 3) Security and robustness 3) Security and robustness

1616

Network CriteriaNetwork Criteria

1) Performance Transmission and response timesrsquo throughput and delay 2) Reliability How often the networks fail

3) Security Privacy and integrity of communication Data recovery from breaches and data loss

1717

Physical Structures Physical Structures

Types of connectionsTypes of connections

1) Point to Point (P to P) Dedicated link to 1) Point to Point (P to P) Dedicated link to be utilized only by end devices be utilized only by end devices

2) Multipoint (Multidrop) Many end 2) Multipoint (Multidrop) Many end devices share the link capacitydevices share the link capacity

1818

Figure 13 Types of connections point-to-point and multipoint

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

1111

Figure 11 Five components of data communication

1212

Data RepresentationData Representation

TEXTTEXT ndash unicode (32 bits to represent ndash unicode (32 bits to represent character)- ASCIIcharacter)- ASCII

NUMBERSNUMBERS

IMAGESIMAGES-composed of a matrix of pixel-composed of a matrix of pixel

AUDIOAUDIO- recording or broadcasting of - recording or broadcasting of sound or musicsound or music

VIDEOVIDEO- recording or broadcasting of a - recording or broadcasting of a picture or moviepicture or movie

1313

Figure 12 Data flow (simplex half-duplex and full-duplex)

1414

1-2 NETWORKS1-2 NETWORKS

A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) ) connected by communication connected by communication linkslinks A node can be a A node can be a computer printer or any other device capable of sending computer printer or any other device capable of sending andor receiving data generated by other nodes on the andor receiving data generated by other nodes on the networknetwork

Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork

Topics discussed in this sectionTopics discussed in this section

1515

NETWORKSNETWORKS

Set of nodes connected via physical links Set of nodes connected via physical links 1) Distributing Processing 1) Distributing Processing 2) Sharing Data and centralization 2) Sharing Data and centralization 3) Security and robustness 3) Security and robustness

1616

Network CriteriaNetwork Criteria

1) Performance Transmission and response timesrsquo throughput and delay 2) Reliability How often the networks fail

3) Security Privacy and integrity of communication Data recovery from breaches and data loss

1717

Physical Structures Physical Structures

Types of connectionsTypes of connections

1) Point to Point (P to P) Dedicated link to 1) Point to Point (P to P) Dedicated link to be utilized only by end devices be utilized only by end devices

2) Multipoint (Multidrop) Many end 2) Multipoint (Multidrop) Many end devices share the link capacitydevices share the link capacity

1818

Figure 13 Types of connections point-to-point and multipoint

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

1212

Data RepresentationData Representation

TEXTTEXT ndash unicode (32 bits to represent ndash unicode (32 bits to represent character)- ASCIIcharacter)- ASCII

NUMBERSNUMBERS

IMAGESIMAGES-composed of a matrix of pixel-composed of a matrix of pixel

AUDIOAUDIO- recording or broadcasting of - recording or broadcasting of sound or musicsound or music

VIDEOVIDEO- recording or broadcasting of a - recording or broadcasting of a picture or moviepicture or movie

1313

Figure 12 Data flow (simplex half-duplex and full-duplex)

1414

1-2 NETWORKS1-2 NETWORKS

A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) ) connected by communication connected by communication linkslinks A node can be a A node can be a computer printer or any other device capable of sending computer printer or any other device capable of sending andor receiving data generated by other nodes on the andor receiving data generated by other nodes on the networknetwork

Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork

Topics discussed in this sectionTopics discussed in this section

1515

NETWORKSNETWORKS

Set of nodes connected via physical links Set of nodes connected via physical links 1) Distributing Processing 1) Distributing Processing 2) Sharing Data and centralization 2) Sharing Data and centralization 3) Security and robustness 3) Security and robustness

1616

Network CriteriaNetwork Criteria

1) Performance Transmission and response timesrsquo throughput and delay 2) Reliability How often the networks fail

3) Security Privacy and integrity of communication Data recovery from breaches and data loss

1717

Physical Structures Physical Structures

Types of connectionsTypes of connections

1) Point to Point (P to P) Dedicated link to 1) Point to Point (P to P) Dedicated link to be utilized only by end devices be utilized only by end devices

2) Multipoint (Multidrop) Many end 2) Multipoint (Multidrop) Many end devices share the link capacitydevices share the link capacity

1818

Figure 13 Types of connections point-to-point and multipoint

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

1313

Figure 12 Data flow (simplex half-duplex and full-duplex)

1414

1-2 NETWORKS1-2 NETWORKS

A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) ) connected by communication connected by communication linkslinks A node can be a A node can be a computer printer or any other device capable of sending computer printer or any other device capable of sending andor receiving data generated by other nodes on the andor receiving data generated by other nodes on the networknetwork

Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork

Topics discussed in this sectionTopics discussed in this section

1515

NETWORKSNETWORKS

Set of nodes connected via physical links Set of nodes connected via physical links 1) Distributing Processing 1) Distributing Processing 2) Sharing Data and centralization 2) Sharing Data and centralization 3) Security and robustness 3) Security and robustness

1616

Network CriteriaNetwork Criteria

1) Performance Transmission and response timesrsquo throughput and delay 2) Reliability How often the networks fail

3) Security Privacy and integrity of communication Data recovery from breaches and data loss

1717

Physical Structures Physical Structures

Types of connectionsTypes of connections

1) Point to Point (P to P) Dedicated link to 1) Point to Point (P to P) Dedicated link to be utilized only by end devices be utilized only by end devices

2) Multipoint (Multidrop) Many end 2) Multipoint (Multidrop) Many end devices share the link capacitydevices share the link capacity

1818

Figure 13 Types of connections point-to-point and multipoint

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

1414

1-2 NETWORKS1-2 NETWORKS

A A networknetwork is a set of devices (often referred to as is a set of devices (often referred to as nodesnodes) ) connected by communication connected by communication linkslinks A node can be a A node can be a computer printer or any other device capable of sending computer printer or any other device capable of sending andor receiving data generated by other nodes on the andor receiving data generated by other nodes on the networknetwork

Distributed ProcessingNetwork CriteriaPhysical StructuresNetwork ModelsCategories of NetworksInterconnection of Networks Internetwork

Topics discussed in this sectionTopics discussed in this section

1515

NETWORKSNETWORKS

Set of nodes connected via physical links Set of nodes connected via physical links 1) Distributing Processing 1) Distributing Processing 2) Sharing Data and centralization 2) Sharing Data and centralization 3) Security and robustness 3) Security and robustness

1616

Network CriteriaNetwork Criteria

1) Performance Transmission and response timesrsquo throughput and delay 2) Reliability How often the networks fail

3) Security Privacy and integrity of communication Data recovery from breaches and data loss

1717

Physical Structures Physical Structures

Types of connectionsTypes of connections

1) Point to Point (P to P) Dedicated link to 1) Point to Point (P to P) Dedicated link to be utilized only by end devices be utilized only by end devices

2) Multipoint (Multidrop) Many end 2) Multipoint (Multidrop) Many end devices share the link capacitydevices share the link capacity

1818

Figure 13 Types of connections point-to-point and multipoint

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

1515

NETWORKSNETWORKS

Set of nodes connected via physical links Set of nodes connected via physical links 1) Distributing Processing 1) Distributing Processing 2) Sharing Data and centralization 2) Sharing Data and centralization 3) Security and robustness 3) Security and robustness

1616

Network CriteriaNetwork Criteria

1) Performance Transmission and response timesrsquo throughput and delay 2) Reliability How often the networks fail

3) Security Privacy and integrity of communication Data recovery from breaches and data loss

1717

Physical Structures Physical Structures

Types of connectionsTypes of connections

1) Point to Point (P to P) Dedicated link to 1) Point to Point (P to P) Dedicated link to be utilized only by end devices be utilized only by end devices

2) Multipoint (Multidrop) Many end 2) Multipoint (Multidrop) Many end devices share the link capacitydevices share the link capacity

1818

Figure 13 Types of connections point-to-point and multipoint

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

1616

Network CriteriaNetwork Criteria

1) Performance Transmission and response timesrsquo throughput and delay 2) Reliability How often the networks fail

3) Security Privacy and integrity of communication Data recovery from breaches and data loss

1717

Physical Structures Physical Structures

Types of connectionsTypes of connections

1) Point to Point (P to P) Dedicated link to 1) Point to Point (P to P) Dedicated link to be utilized only by end devices be utilized only by end devices

2) Multipoint (Multidrop) Many end 2) Multipoint (Multidrop) Many end devices share the link capacitydevices share the link capacity

1818

Figure 13 Types of connections point-to-point and multipoint

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

1717

Physical Structures Physical Structures

Types of connectionsTypes of connections

1) Point to Point (P to P) Dedicated link to 1) Point to Point (P to P) Dedicated link to be utilized only by end devices be utilized only by end devices

2) Multipoint (Multidrop) Many end 2) Multipoint (Multidrop) Many end devices share the link capacitydevices share the link capacity

1818

Figure 13 Types of connections point-to-point and multipoint

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

1818

Figure 13 Types of connections point-to-point and multipoint

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

1919

Physical TopologyPhysical Topology

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

2020

Figure 14 Categories of topology

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

2121

Physical TopologyPhysical Topology

A) Mesh A) Mesh

Each device has dedicated point-to-point Each device has dedicated point-to-point link to other devices Fully connected link to other devices Fully connected mesh will have n( n-1) 2 FD links mesh will have n( n-1) 2 FD links Where n = number of nodes Where n = number of nodes

Pros Fast communication Robust and Pros Fast communication Robust and Privacy (Security) Privacy (Security) Cons Cabling Space and cost Cons Cabling Space and cost

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

2222

Figure 15 A fully connected mesh topology (five devices)

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

2323

Physical Topology (cont)Physical Topology (cont)

B) Star B) Star

Devices are connected Point to Point to a Devices are connected Point to Point to a central ldquoHubrdquo (Controller Exchanger) central ldquoHubrdquo (Controller Exchanger)

Pros Less cabling and HW ports two Pros Less cabling and HW ports two hops only hops only

Cons Not robust Cons Not robust

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

2424

Figure 16 A star topology connecting four stations

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

2525

Figure 17 A bus topology connecting three stations

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

2626

C) Bus C) Bus

Multipoint link as ldquobackbonerdquo for a network Multipoint link as ldquobackbonerdquo for a network where devices have drop line to tap into where devices have drop line to tap into the bus the bus

Pros Less Cabling Pros Less Cabling Cons Topology dependent limit number Cons Topology dependent limit number of nodes on the bus due to signal power of nodes on the bus due to signal power loss with distance not so robust loss with distance not so robust

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

2727

Figure 18 A ring topology connecting six stations

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

2828

C) Ring Each device connects Point to C) Ring Each device connects Point to Point with only two other devices in a left Point with only two other devices in a left and right neighbors arrangement via a and right neighbors arrangement via a repeaterrepeater

Pros easy installation better fault Pros easy installation better fault isolation and robustness isolation and robustness

Cons N2 hops communicationCons N2 hops communication

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

2929

Figure 19 A hybrid topology a star backbone with three bus networks

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

3030

D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo D) Hybrid bull Pizza ldquostarrdquo inside a ldquo ringrdquo

Pros Better robustness still low cost Pros Better robustness still low cost Delay is 1 hop (until the star is not with a Delay is 1 hop (until the star is not with a ring cut max 2 bull Star of bussesring cut max 2 bull Star of busses

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

3131

Categories of NetworksCategories of Networks

Local Area Networks (LAN)Local Area Networks (LAN) Few Few Kilometers Connects devices (Pcs Kilometers Connects devices (Pcs printers servers) within the same room printers servers) within the same room building company and campus building company and campus

Topologies most used are bus ring and Topologies most used are bus ring and starstar

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

3232

Figure 110 An isolated LAN connecting 12 computers to a hub in a closet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

3333

Categories of Networks(cont)Categories of Networks(cont)

Wide Area Networks (WAN)Wide Area Networks (WAN)

span a large geographical area about span a large geographical area about 100rsquos ndash 1000rsquos of Km 100rsquos ndash 1000rsquos of Km

1) Switched End users connected via a 1) Switched End users connected via a cloud of switches (subnet) cloud of switches (subnet)

2) Point-to Point Line leased from 2) Point-to Point Line leased from telephone company TV connecting users telephone company TV connecting users to the ISP for Internet accessto the ISP for Internet access

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

3434

alternative technologies used includealternative technologies used include circuit switchingcircuit switching packet switchingpacket switching frame relayframe relay Asynchronous Transfer Mode (ATMAsynchronous Transfer Mode (ATM

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

3535

Circuit SwitchingCircuit Switching

uses a dedicated communications path uses a dedicated communications path established for duration of conversationestablished for duration of conversation

comprising a sequence of physical linkscomprising a sequence of physical links

with a dedicated logical channelwith a dedicated logical channel

eg telephone networkeg telephone network

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

3636

Packet SwitchingPacket Switching

data sent out of sequencedata sent out of sequence

small chunks (packets) of data at a timesmall chunks (packets) of data at a time

packets passed from node to node packets passed from node to node between source and destinationbetween source and destination

used for terminal to computer and used for terminal to computer and computer to computer communicationscomputer to computer communications

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

3737

Frame RelayFrame Relay

packet switching systems have large packet switching systems have large overheads to compensate for errorsoverheads to compensate for errors

modern systems are more reliablemodern systems are more reliable

errors can be caught in end systemerrors can be caught in end system

Frame Relay provides higher speedsFrame Relay provides higher speeds

with most error control overhead removedwith most error control overhead removed

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

3838

Asynchronous Transfer ModeAsynchronous Transfer Mode(ATM)(ATM)

evolution of frame relayevolution of frame relay

fixed packet (called cell) lengthfixed packet (called cell) length

with little overhead for error controlwith little overhead for error control

anything from 10Mbps to Gbpsanything from 10Mbps to Gbps

constant data rate using packet switching constant data rate using packet switching technique with multiple virtual circuitstechnique with multiple virtual circuits

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

3939

Figure 111 WANs a switched WAN and a point-to-point WAN

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

4040

Figure 112 A heterogeneous network made of four WANs and two LANs

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

4141

Categories of Networks(cont)Categories of Networks(cont)

Metropolitan Area NetworksMetropolitan Area Networks

MAN towncity MAN towncity

High-speed backbone linking multiple High-speed backbone linking multiple LANrsquos DSL TV cables LANrsquos DSL TV cables

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

4242

1-3 THE INTERNET1-3 THE INTERNET

The The InternetInternet has revolutionized many aspects of our daily has revolutionized many aspects of our daily lives It has affected the way we do business as well as the lives It has affected the way we do business as well as the way we spend our leisure time The Internet is a way we spend our leisure time The Internet is a communication system that has brought a wealth of communication system that has brought a wealth of information to our fingertips and organized it for our use information to our fingertips and organized it for our use

A Brief HistoryThe Internet Today (ISPs)

Topics discussed in this sectionTopics discussed in this section

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

4343

The InternetThe Internet

Internet evolved from ARPANETInternet evolved from ARPANET first operational packet networkfirst operational packet network applied to tactical radio amp satellite nets alsoapplied to tactical radio amp satellite nets also had a need for interoperabilityhad a need for interoperability led to standardized TCPIP protocolsled to standardized TCPIP protocols

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

4444

The InternetThe Internet

Huge number of interconnected Networks Huge number of interconnected Networks (100000rsquos) private organized egrsquo government (100000rsquos) private organized egrsquo government schools research facilities in many countries schools research facilities in many countries

Collection of LANrsquoS MANrsquoS and WANrsquos Collection of LANrsquoS MANrsquoS and WANrsquos 1048708 1048708 The internet protocol stack is the TCPIP The internet protocol stack is the TCPIP 1048708 1048708 End users use the internet via Internet Service End users use the internet via Internet Service

providers (ISPs) which are of the following providers (ISPs) which are of the following hierarchies hierarchies

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

4545

Figure 113 Hierarchical organization of the Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

4646

Internet ElementsInternet Elements

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

4747

Internet ArchitectureInternet Architecture

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

4848

Example ConfigurationExample Configuration

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

4949

1-4 PROTOCOLS AND STANDARDS1-4 PROTOCOLS AND STANDARDS

In this section we define two widely used terms In this section we define two widely used terms protocolsprotocols and and standardsstandards First we define protocol which is First we define protocol which is synonymous with rule Then we discuss standards which synonymous with rule Then we discuss standards which are agreed-upon rulesare agreed-upon rules

ProtocolsStandardsStandards OrganizationsInternet Standards

Topics discussed in this sectionTopics discussed in this section

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

5050

What is a protocolWhat is a protocol Communications between computers requires very specific unambiguous rules A protocol is a set of rules that governs how two or more communicating parties are to interactExamples

Internet Protocol (IP)Transmission Control Protocol (TCP)HyperText Transfer Protocol (HTTP)Simple Mail Transfer Protocol (SMTP)

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

5151

Elements Elements

1) Syntax PDU format 1) Syntax PDU format 2) Semantics The meaning of each PDUrsquos field 2) Semantics The meaning of each PDUrsquos field 3) Timing Synchronization of communication 3) Timing Synchronization of communication

when PDU is to be transferred and its data ratewhen PDU is to be transferred and its data rate

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

5252

What is a standardWhat is a standard

bull bull A ldquo standard is set of guidelinesrdquo to users A ldquo standard is set of guidelinesrdquo to users and manufactures to ensure interconnectivity and manufactures to ensure interconnectivity

1) ldquoDefactordquo not approved but widely used 1) ldquoDefactordquo not approved but widely used (TCPIP) (TCPIP)

2) ldquoDejurerdquo approved by recognized body 2) ldquoDejurerdquo approved by recognized body (IEEE 802X) (IEEE 802X)

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet

5353

SummarySummary

introduced data communications needsintroduced data communications needs

communications modelcommunications model

defined data communicationsdefined data communications

overview of networksoverview of networks

introduce Internetintroduce Internet