unit 7, chapter 13 & 14 how do they talk to each other?

Wide Area Networking &Wide Area Networking &InternetworkingInternetworking

Unit 7, Chapter 13 & 14How do they talk to each other?

Objectives

Summarize the characteristics and capabilities of a wide area network (WAN).Identify distinguishing attributes of WANs as compared to LANs.Identify the devices that are used in constructing WANs.

Wide Area Networks

General Design hybrid of a star, hierarchical and mesh topologiesUsually lease or use from communication carriers– Provide plain circuits– Additional services packet switching, frame relay,

ATM, ISDN

Network Signaling

Signaling required to manage the network and perform certain functionsControl signals are sent as part of the protocolTone Signaling– Generation of tone or combination of tones which tell the CO

switch what number is being dialed

Signaling System 7 (SS7) – Used between switches– Carried over independent channels from the voice circuits– Common Channel Interoffice Signaling (CCIS)

• Carry multiple voice channel signaling– Optimized for digital networks

Packet Data Networks

Packet Data Networks – Packet Switching Networks or Packet NetworkDeveloped by Advanced Research Projects AgencyPackets sent through the network from source to destinationNo physical link is establishedPackets from other nodes is interspersed on the networkMessages are disassembled and reassembledDesigned with multiple high-speed paths

Packet Switching Techniques

2 Methods to handle stream of packets– Datagrams

• Connection-less circuit• Each packet handled independently by the network• No guarantee delivery

– Virtual Circuits• Connection Oriented circuit• Route established through the network• Call request packet sent first, route determined• Virtual circuit number is assigned, call accept is returned• Virtual circuit number used for communication• When communication is complete, clear packet request is sent

Routing Traffic

Routing – How to create the virtual circuit or route the individual packets to its destinationConnection Oriented Routing - VCConnectionless Routing – Packet SwitchingCentralized Routing – Simple– Usually used in a stat hierarchy– Static routes

Routing Traffic

Distributed Routing– Responsibility for building and maintaining routing tables on some nodes in

network– Avoids single point of failure

Static & Dynamic Routing– Static Routes are fixed– Dynamic Routes can change– Dynamic routing determines best path through network, difficult to

implement

Broadcast Routing– Used by CSMA/CD protocol– Broadcast all packets to all stations at all times– Not efficient and not useable on large networks

Congestion Control

Congestion – traffic arrives faster than it can be handledTransmission delay increases as well as retransmission of packetsManage by reducing flow of packets on the networkChoke Packet – sent to sources of traffic to tell them to slow the flow downQuality of Service (QOS) is a way to allow certain traffic to have priority over others

Delays & Queing

Propagation Delay – Time to get a signal from sender to receiver– LAN Delays usually about 1ms– WAN delay is longer due to distance and technology

Switching Delay – Delay moving data through switches and routersQueuing Delay – Too much too fastQueuing Theory – Analysis of queues and queuing

Specific WAN SystemsX.25

– Popular in Europe– Defines interface between computer and packet data network– 3 Standard Layers –

• Packet – VC Service, upto 4095 VCs on one physical network• Link • Physical (X.21)

Frame Relay– More efficient than X.25, for high speed networks– ¼ the overhead of a packet switching technology– Not as good at congestion control– Control Plane – Establish and terminate connections– User Plane – Data Transfer– 2 Separate channels for planes– Committed Information Rate (CIR): guaranteed throughput speed, vendor may

discard anything over CIR– Port Speed – Maximum speed that the circuit can communicate. 256KB Port

speed / 64KB CIR

Specific WAN SystemsAsynchronous Transfer Mode (ATM)

Developed to reduce delays that can occur on Frame RelayCell RelayEvolution of Frame Relay53 Byte Fixed Sized Cells (Thought to be the optimum size)Real Time Service (Voice & Video)– Constant Bit Rate (CBR) – Fixed and continuously available bandwidth– Real-Time Variable Bit Rate (rt-VBR) – Bursty communications

Non-real Time Services– Non-Real Time Variable Bit Rate Services (nrt-VBR)

• Fast Response Time Can Tolerate Some Delay– Available Bit Rate Service (ABR)

• Define Maximum Rate to be used and Minimum required, provide at least minimum

– Unspecified Bit Rate (UBR)• As available basis

Specific WAN SystemsAsynchronous Transfer Mode (ATM)

Synchrounous Optical Network (SONET)– Standard for sending data on fiber between carriers– Optical Carrier LevelData Rate– OC-1 51.84 Mbps– OC-3 155.52 Mbps– OC-12 622.08 Mbps– OC-24 1.244 Gbps– OC-48 2.488 Gbps– OC-192 10 Gbps– OC-256 13.271 Gbps– OC-768 40 Gbps

Specific WAN Systems

Integrated Services Digital Network (ISDN)– “B” Type Channel : Carry up to 64Kbps Data– “D” Type Channel : Carry up to 16Kbps Signaling Data– Basic Rate Interface = 2B + 1D Channel for 128Kbps– Primary Rate Interface = 23B + 1D (all b&d are 64Kbps)

• Equal to the bandwidth of a T1 (24 channels)• Subdivide bandwidth as needed 10 Channels Voice, 13 Data

Broadband ISDN – Defined but not widely implemented– FDX Circuit 155.52 Mbps– FDX Circuit 622.08 Mbps– Asymmetrical Circuit with 2 simplex channels one at 155.52 Mbps and the

other at 622.08Mbps

Switched Multimegabit Data Services(SMDS)Virtual Private Networks (VPN)

Principles of Internetworking

TCP/IP packet switching networkVarious network technologies are employed – EthernetSubnetworks – Individual networks that are connected togetherEnd System – Device or computerIntermediate system – – Switches = Layer 2 or Layer 3– Bridge = Layer 2– Routers = Layer 3

Virtual Network – Subnets appear to be one large network

OSI –TCP/IP Models

OSI Model TCP/IP

L7 Application

Application

L6 Presentation

L5 Session

L5 Session

TransportL4 Transport

L3 Network

InternetL2 Data Link

L2 Data linkData link (Network

interface)

L1 Physical (Hardware)

TCP/IP Protocol Suite

Layer 1 = Physical Layer– Hardware (NIC)

Layer 2 = Network Interface– Split data into packets (frames) to be sent out– Sends frames and routes to devices on the network– Error detection and control for higher layers

Layer 3 = Internet Layer– IP and IP address are used to transmit data– No corresponding OSI layer

Layer 4 = Transport Layer– Ensures no errors and packets are in the correct order

Layer 5 = Application Layer

Internet Protocol Addressing

IP Address is uniqueIPV4 – 32 Bit Address, 4 Octets (xxx.xxx.xxx.xxx)– Host portion-Host_id (nnn.hhh.hhh.hhh)– Network portion-Network-id (nnn.hhh.hhh.hhh)– 5 Network classes

• Class A, starts with 0, range 0 – 126• Class B, starts with 10, range 128 – 191• Class C, starts with 110, range 192 – 223• Class D, starts with 1110, range 224 – 239 (multicast)• Class E, starts with 1111, range 240 – 255 (reserved)• Private address= 10.0.0.0,192.168.0.0,172.16.0.0

IP Classful Addressing

Address Classes:IP Address Rule I

Copyright ©2005 by Pearson Education, Inc.Upper Saddle River, New Jersey 07458

All rights reserved.

Address Classes:IP Address Rule II



Address Classes:IP Address Rule III

Cisco Learning InstituteNetwork+ Fundamentals and Certification



Subnets & Subnetting

Subnetwork or Subnet – separate part of an organizations network that is identifiableSecurity and traffic controlSubnet mask – 32 Bit number – ANDed with network portion of address(only 1+1=1)– 1’s = network and 0’s = host– Ex. Class A 255.0.0.0, network info is in the first octet

Default Subnet Masks– Class A = 255.0.0.0– Class B = 255.255.0.0– Class C = 255.255.255.0

Bits in the host octets are used to define subnet(pg 388)– Class C address 206.11.20.81– Subnet mask 255.255.255.224 or /27

• 11111111.11111111.11111111.11100000• 81 = 0101 0001

– Subnet Number 2– Host ID 17

Subnets & Subnetting

Classless Inter-Domain Routing:CIDR Address Prefix and Number of Class C

Addresses




Addressing Particulars

/nn Classless Internet Domain Routing– 204.11.20.16/19 or Subnet mask

11111111.11111111.11100000.00000000

Supernetting – several class C addresses into a contiguous address blockDynamic IP address – address assigned when neededStatic – address is configured and does not change(routers…infrastructure equipment)Private networks – 10.0.0.0, 172.16.0.0,192.168.0.0

Subnetting Example

Step Example Rules

Address 8.1.4.5 None

Mask 255.255.0.0 None

Number of network bits 8 Always defined by Class A,B,C

Number of Host Bits 16Always defined by the number of binary 0s in the

mask

Number of Subnet Bits 8 32 - (Network size + host size)

Total 32 Network + Host + Subnet

Domain Names

Mnemonic for IP address (WWW.MSN.COM)Domain Name Services(DNS) used to translate or resolve name to addressHierarchical Structure– Local– Corporate– Global

Top Level Domain (.com,.edu,.net,.org….)Internet Corporation for Assigned Names and Numbers (ICAAN)Root Servers – Contain IP addresses of all TLD registries

Transmission Control Protocol

Can communicate between hosts with diverse hardware and operating systemsDeveloped by Defense Advanced Research Projects Agency (DARPA)Direct or point-to-point communicationsConnection oriented communicationFull Duplex – communication in both direction3 way hand shake to start communications & End Communications– Start:->SYN,<-SYN+ACK,->ACK – End: ->FIN+ACK,<-FIN+ACK,->ACK

TCP HEADER

TCP Header Information

TCP/IP Header:Stop-and-Go (left) versus Sliding Window Flow Control

(right)



TCP/IP Header:Sliding Window Flow Control in

Operation



User Datagram Protocol

Simple protocolConnectionlessNo error checkingNo sequencingNo HandshakingExamples: Ping, DNS, VOIP, TFTP

UDP Header:UDP Diagram Format




UDP Header:IP Header Field Information




Other Protocols

Address Resolution Protocol (ARP)Dynamic Host Configuration ProtocolFile Transfer Protocol/Trivial File Transfer ProtocolHypertext Transfer Protocol & Hypertext Transfer Protocol over Secure Sockets Layer or Transfer Layer SecurityPost Office Protocol v3 (POP3) & Internet Message Access Protocol v4 (IMAP4)Simple Mail Transfer Protocol

Internet Tools

Name Server Lookup (nslookup)– Determine IP address of a host system

Whois– Determine name from an IP address

Ping – Troubleshooting tool – Is the node there, is it alive, how much time ….

Traceroute– Determine route packet takes to remote host

Review Questions

1. A ___________ determines the best way to route to use when sending a message through a network and sends it on its way.a. switchb. routerc. d-slamd. packet

Review Questions

2. Routers are specialized computers that perform routing in a network.a. Trueb. False

Review Questions

3. Delays in networks can come from _____________________.a. propagationb. switchingc. queuingd. all of the above

Review Questions

4. Which of the following is not an Internet top level domain name?a. .bizb. .govc. .comd. None of the above

Review Questions

5. A queue is a ____________.a. billiard stickb. waiting linec. serverd. router

Review Questions

6. Which of the following is not a cost of network design and implementation?a. The time of the network designersb. The cost of consultants to assist with the designc. The cost of staff to test the new networkd. The cost of the network operations personnel to run

the network

Review Questions

7. When two stations on a circuit transmit at the same time, ______ occurs.a. an altercationb. a divisionc. pollingd. a collision

Review Questions

8. Which of the following routing techniques are used in WANs?a. dynamic routingb. distributed routingc. static routingd. All of the above

Review Questions

9. Which of the following was developed to overcome the overhead of packet switching and provide more efficient data transmission?

a. X.25b. Circuit switched systemsc. Frame relayd. RS-232e. X.21

Review Questions

10. VPNs ____________________a. Can send data through the Internetb. Can handle traffic relatively securelyc. Can restrict outside packets from entering the

VPNd. Are usually quite cost effectivee. All of the above

Homework

Assignment: Due Next Week– Review:

• Chapter 13, pp. 350-371• Chapter 14, pp. 378-411

– Read:• Chapter 15, pp. 416-445• Chapter 16, pp. 450-480

– Complete:• Multiple Choice Questions 1-10 on pp. 446-447

unit 7, chapter 13 & 14 how do they talk to each other?

Documents

packet networkdeveloped

circuiteach packet

networkchoke packet

clear packet request

networkcall request

packet data network3

routersqueuing delay

mswan delay