1

Introduction to LANIntroduction to LANTDC 363TDC 363

Week 2Week 2

Networking HardwareNetworking Hardware

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Networking HardwareNetworking HardwareBook: Chapter 5Book: Chapter 5

Topologies and Access MethodsTopologies and Access MethodsBook: Chapter 6Book: Chapter 6

Outline (Chap 5)Outline (Chap 5)

Network EquipmentNetwork EquipmentNICNICRepeater and HubRepeater and Hub

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Bridge and Ethernet SwitchBridge and Ethernet SwitchRouter Router

Network AdaptersNetwork Adapters

Also called network interface cards (NICs)Also called network interface cards (NICs)Connectivity devices enabling a workstation, Connectivity devices enabling a workstation, server, printer, or other node to receive and server, printer, or other node to receive and

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transmit data over the network mediatransmit data over the network mediaLayer 2 deviceLayer 2 device

Why is NIC a LayerWhy is NIC a Layer--2 device?2 device?

2

Types of Network AdaptersTypes of Network Adapters

Old DaysOld DaysIndustry Standard Architecture Industry Standard Architecture (ISA)(ISA)MicroChannel Architecture (MCA)MicroChannel Architecture (MCA)Extended Industry Standard Extended Industry Standard Architecture (EISA)Architecture (EISA)

P i h l C t I t tP i h l C t I t t

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Peripheral Component Interconnect Peripheral Component Interconnect (PCI)(PCI)PCI ExpressPCI ExpressPersonal Computer Memory Card Personal Computer Memory Card International Association (PCMCIA)International Association (PCMCIA)Universal Serial Bus (USB)Universal Serial Bus (USB)Compact Flash (CF) CardCompact Flash (CF) CardNIC on MotherboardNIC on Motherboard

Installing and Configuring Network Installing and Configuring Network Adapter HardwareAdapter Hardware

(a Historical Perspective)(a Historical Perspective)JumperJumper

Small, removable piece of plastic that contains a metal Small, removable piece of plastic that contains a metal receptaclereceptacle

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NIC Configuration Information

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Ref. p. 240

3

Hubs and RepeatersHubs and RepeatersLayerLayer--1 device1 deviceRepeater: 2Repeater: 2--port hubport hubHub: mutiHub: muti--port repeaterport repeaterConnectivity device that regenerates digital signalConnectivity device that regenerates digital signal

Eliminate Noise (Attenuation) Eliminate Noise (Attenuation) Signal received on one port is broadcast to all other portsSignal received on one port is broadcast to all other ports

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Network of HubsNetwork of Hubs

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BridgesBridges

Like a repeater, a bridge has a single Like a repeater, a bridge has a single input and single output portinput and single output portUnlike a repeater, it can interpret the Unlike a repeater, it can interpret the

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data it retransmitsdata it retransmitsLayerLayer--2 device2 device

4

Ethernet SwitchesEthernet Switchesswitch ::= multiswitch ::= multi--port bridgeport bridge

Divide a network into smaller logical pieces Divide a network into smaller logical pieces (multiple collision domains)(multiple collision domains)

desktop ormodular

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desktop orstackable

CutCut--Through Mode andThrough Mode andStore and Forward ModeStore and Forward Mode

CutCut--through modethrough modeSwitching mode in which switch reads a frame’s Switching mode in which switch reads a frame’s header and decides where to forward the data header and decides where to forward the data before it receives the entire packetbefore it receives the entire packet

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CutCut--through switches can detect through switches can detect runtsrunts, or packet , or packet fragmentsfragments

Store and forward modeStore and forward modeSwitching mode in which switch reads the entire Switching mode in which switch reads the entire data frame into its memory and checks it for data frame into its memory and checks it for accuracy before transmitting the informationaccuracy before transmitting the information

Delay in StoreDelay in Store--andand--ForwardForward

Max Frame Size 1500 bytes (12,000 bit)Max Frame Size 1500 bytes (12,000 bit)10BaseT Network (10M bps)10BaseT Network (10M bps)

12,000 12,000 ÷÷ 10M = 1,200 10M = 1,200 µµss100B TX N k (100M b )100B TX N k (100M b )

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100BaseTX Network (100M bps)100BaseTX Network (100M bps)12,000 12,000 ÷÷ 100M = 120 100M = 120 µµss

Gigabit Ethernet (1G bps)Gigabit Ethernet (1G bps)12,000 12,000 ÷÷ 10M = 12 10M = 12 µµss

5

RoutersRouters

Multiport connectivity deviceMultiport connectivity deviceCan integrate LANs and WANs running at Can integrate LANs and WANs running at different transmission speeds and using a variety different transmission speeds and using a variety of protocolsof protocols

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of protocolsof protocolsRouters operate at the Network layer (Layer 3) Routers operate at the Network layer (Layer 3) of the OSI Modelof the OSI Model

RoutersRouters

Modular routerModular routerRouter with Router with multiple slots multiple slots that can hold that can hold differentdifferent

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different different interface cards interface cards or other or other devicesdevices

Router Features and FunctionsRouter Features and Functions

Filter out broadcast transmission to alleviate network Filter out broadcast transmission to alleviate network congestioncongestionPrevent certain types of traffic from getting to a networkPrevent certain types of traffic from getting to a networkSupport simultaneous local and remote activitySupport simultaneous local and remote activity

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Provide high network fault tolerance through redundant Provide high network fault tolerance through redundant componentscomponentsMonitor network traffic and report statistics to a MIBMonitor network traffic and report statistics to a MIBDiagnose internal or other connectivity problems and Diagnose internal or other connectivity problems and trigger alarmstrigger alarms

6

Router Features and FunctionsRouter Features and Functions

Static routingStatic routingTechnique in which a network administrator programs a Technique in which a network administrator programs a router to use a specified paths between nodesrouter to use a specified paths between nodes

Dynamic routingDynamic routing

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Automatically calculates best path between nodes and Automatically calculates best path between nodes and accumulates this information in a routing tableaccumulates this information in a routing table

HopHopTerm used in networking to describe each trip data take from Term used in networking to describe each trip data take from one connectivity device to anotherone connectivity device to another

Router Features and FunctionsRouter Features and Functions

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Routing ProtocolsRouting Protocols

To determine the To determine the best pathbest path, routers communicate , routers communicate with each other through with each other through routing protocolsrouting protocolsIn addition to its ability to find the best path, a routing In addition to its ability to find the best path, a routing protocol can be characterized according to its protocol can be characterized according to its

i d b d id h h di d b d id h h d

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convergence time and bandwidth overheadconvergence time and bandwidth overheadConvergence timeConvergence time

The time it takes for a router to recognize a best path in the event of The time it takes for a router to recognize a best path in the event of a change or outagea change or outage

Bandwidth overheadBandwidth overheadBurden placed on an underlying network to support the routing Burden placed on an underlying network to support the routing protocolprotocol

7

Routing ProtocolsRouting Protocols

The four most common routing protocols:The four most common routing protocols:RIP (Routing Information Protocol) for IPRIP (Routing Information Protocol) for IP

RIPRIP--IIII

OSPF (Open Shortest Path First) for IPOSPF (Open Shortest Path First) for IP

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OSPF (Open Shortest Path First) for IPOSPF (Open Shortest Path First) for IPEIGRP (Enhanced Interior Gateway Routing EIGRP (Enhanced Interior Gateway Routing Protocol) for IP, IPX, and AppleTalkProtocol) for IP, IPX, and AppleTalkBGP (Border Gateway Protocol) for IPBGP (Border Gateway Protocol) for IP

required for routing on the public Internetrequired for routing on the public Internet

Brouters and Routing SwitchesBrouters and Routing Switches

Bridge routerBridge routerAlso called a Also called a brouterbrouterIndustry term used to describe routers that take on Industry term used to describe routers that take on some characteristics of bridgessome characteristics of bridges

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some characteristics of bridgessome characteristics of bridgesRouting switchRouting switch

Router hybrid that combines a router and a switchRouter hybrid that combines a router and a switch

GatewaysGatewaysStandard definition: a layerStandard definition: a layer--7 device to interconnect two 7 device to interconnect two distinct networks.distinct networks.Practical definitionPractical definition: a device to interconnect two networks.: a device to interconnect two networks.Combination of networking hardware and software that Combination of networking hardware and software that connects two dissimilar kinds of networksconnects two dissimilar kinds of networks

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connects two dissimilar kinds of networksconnects two dissimilar kinds of networksPopular types of gateways include:Popular types of gateways include:

EE--mail gatewaysmail gatewaysIBM host gatewaysIBM host gatewaysInternet gatewaysInternet gatewaysLAN gatewaysLAN gateways

8

HigherHigher--Layer SwitchesLayer SwitchesSwitch capable of interpreting Layer 3 data is called a Switch capable of interpreting Layer 3 data is called a Layer 3 switchLayer 3 switch

What is the difference between a Layer 3 switch and a router?What is the difference between a Layer 3 switch and a router?Switch capable of interpreting Layer 4 data is called a Switch capable of interpreting Layer 4 data is called a Layer 4 switchLayer 4 switch

k d f d dk d f d d

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What kind of layer 4 data is used to switch?What kind of layer 4 data is used to switch?These higherThese higher--layer switches may also be called layer switches may also be called routing routing switchesswitches or or application switchesapplication switchesLayerLayer--7 switch ???7 switch ???Confusion in terminology???Confusion in terminology???

Chapter Outline (Chap. 6)Chapter Outline (Chap. 6)

LAN TopologyLAN TopologyWAN TopologyWAN TopologyEthernetEthernet

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Token RingToken RingOther LAN Technologies:Other LAN Technologies:

FDDI and ATMFDDI and ATM

Simple Physical TopologiesSimple Physical TopologiesPhysical topologyPhysical topology

Physical layout of a networkPhysical layout of a networkA A Bus topologyBus topology consists of a single cable, called a consists of a single cable, called a bus, bus, connecting all nodes on a network without connecting all nodes on a network without intervening connectivity devicesintervening connectivity devices

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Q: any problem with this topology?

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Ring TopologyRing Topology

Each node is Each node is connected to the connected to the two nearest nodes so two nearest nodes so the entire network the entire network

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forms a circleforms a circleOne method for One method for passing data on ring passing data on ring networks is networks is token token passingpassing

Star TopologyStar TopologyEvery node on the network is connected Every node on the network is connected through a central devicethrough a central device

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StarStar--wired Ring Topologywired Ring TopologyHybrid topologyHybrid topology

Complex combination of the simple physical topologiesComplex combination of the simple physical topologiesStarStar--wired ringwired ring

StarStar--wired topologieswired topologies use physical layout of a star in conjunction use physical layout of a star in conjunction with token ringwith token ring--passing data transmission methodpassing data transmission method

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10

StarStar--wired Bus Topologywired Bus Topology

In a In a starstar--wired bus topologywired bus topology, groups of workstations are , groups of workstations are starstar--connected to hubs and then networked via a single busconnected to hubs and then networked via a single bus

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EnterpriseEnterprise--Wide TopologiesWide Topologies

EnterpriseEnterpriseAn entire organizationAn entire organization

Backbone networksBackbone networksS i l b kbS i l b kb

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Serial backboneSerial backboneDistributed backboneDistributed backboneCollapsed backboneCollapsed backboneParallel backboneParallel backbone

Serial & Distributed BackboneSerial & Distributed BackboneSerial backboneSerial backbone

Two or more hubs connected to each other by a single cableTwo or more hubs connected to each other by a single cableDistributed backboneDistributed backbone

Hubs connected to a series of central hubs or routers in a hierarchyHubs connected to a series of central hubs or routers in a hierarchy

Serial

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SerialBackbone

11

Collapsed BackboneCollapsed BackboneCollapsedCollapsed ::= divide a single collision domain into multiple ones::= divide a single collision domain into multiple onesUses a router or switch as the single central connection point for multiple Uses a router or switch as the single central connection point for multiple subnetworkssubnetworks

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Parallel BackboneParallel BackboneCollapsed backbone arrangement that consists of more than Collapsed backbone arrangement that consists of more than one connection from central router or switch to each network one connection from central router or switch to each network segmentsegment

Ref: Figure 6-10: A parallel

backbone network

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Logical TopologiesLogical TopologiesRefer to the way in which data are transmitted Refer to the way in which data are transmitted between nodesbetween nodesDescribe the way:Describe the way:

Data are packaged in framesData are packaged in frames

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Electrical pulses are sent over network’s physical mediaElectrical pulses are sent over network’s physical media

Logical topology may also be called Logical topology may also be called network network transport systemtransport system

Communication at layer 2.Communication at layer 2.

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Switching

CircuitSwitching

MessageSwitching

PacketSwitching

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FrameSwitching

CellSwitching

Discussion: switching vs. transmission. What are the differences?Note: ATM is NOT a circuit switching technology.

Practical QuestionsPractical Questions

As a network engineer, you are assigned to design a As a network engineer, you are assigned to design a campus network.campus network.

What is the technology to be deployed at the entrance What is the technology to be deployed at the entrance facility?facility?

From carrier’s central officeFrom carrier’s central office

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From carrier s central officeFrom carrier s central officeFrom the main building of the campusFrom the main building of the campus

What is the technology to be deployed at the equipment What is the technology to be deployed at the equipment room?room?What is the technology to be deployed at the telecom closet?What is the technology to be deployed at the telecom closet?What is the technology to be deployed at the work area (i.e., What is the technology to be deployed at the work area (i.e., desktop)? desktop)?

What are my choices?What are my choices?

EthernetEthernet10BaseT, 10Base2, 10Base510BaseT, 10Base2, 10Base5Fast EthernetFast Ethernet1G and 10G Ethernet1G and 10G Ethernet

T k RiT k Ri

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Token RingToken Ring100BaseVG100BaseVGFDDIFDDIATMATM[Wireless][Wireless]

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EthernetEthernet

Most popular industry use and acceptanceMost popular industry use and acceptanceProduct availabilityProduct availabilityMany vendorsMany vendorsRelatively low costRelatively low cost

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High knowledge baseHigh knowledge base

Standardized for multiple media typesStandardized for multiple media typesTwisted pair (10M, 100M, and 1G)Twisted pair (10M, 100M, and 1G)Optical fiber (10M, 100M, 1G, and 10G)Optical fiber (10M, 100M, 1G, and 10G)Coaxial cable (10Base2, 10Base5)Coaxial cable (10Base2, 10Base5)

Ethernet StandardsEthernet Standards

SpecificationsSpecificationsEthernet standards define Physical and MAC layers of the OSI Ethernet standards define Physical and MAC layers of the OSI

model only. model only. Physical layerPhysical layer

Electrical characteristics of cable connectors, including maximumElectrical characteristics of cable connectors, including maximum

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Electrical characteristics of cable connectors, including maximum Electrical characteristics of cable connectors, including maximum lengthslengthsBit encoding (e.g., Manchester coding) and transmission rate Bit encoding (e.g., Manchester coding) and transmission rate (10/100/1000 Mbps)(10/100/1000 Mbps)

Medium Access Control (MAC) layerMedium Access Control (MAC) layerEthernet frame format and addressingEthernet frame format and addressingAccess protocol = Carrier Sense Multiple Access with Collision Access protocol = Carrier Sense Multiple Access with Collision Detection (CSMA/CD)Detection (CSMA/CD)

Ethernet Standards Ethernet Standards -- HistoryHistory

Early StandardsEarly StandardsDigital (DEC), Intel, and Xerox (DIX) published two Ethernet standards: Digital (DEC), Intel, and Xerox (DIX) published two Ethernet standards: Ethernet 1.0 (1980) and Ethernet 2.0 (1982). Ethernet 1.0 (1980) and Ethernet 2.0 (1982). DIX Ethernet 2.0 is compatible with IEEE 802.3 Ethernet. Ethernet 1.0 DIX Ethernet 2.0 is compatible with IEEE 802.3 Ethernet. Ethernet 1.0 is not compatible with modern systems.is not compatible with modern systems.

10Base5 (1985)10Base5 (1985)

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10Base5 (1985)10Base5 (1985)10Base2 (1988)10Base2 (1988)1Base5 (1988)1Base5 (1988)10BaseT (1990)10BaseT (1990)100BaseT / 100BaseF (1995)100BaseT / 100BaseF (1995)1000BaseX / 1000BaseT (1998/1999)1000BaseX / 1000BaseT (1998/1999)10GB Ethernet 10GB Ethernet –– 802.3ae (2002)802.3ae (2002)

14

EthernetEthernet

Carrier Sense Multiple Access with Collision Detection Carrier Sense Multiple Access with Collision Detection (CSMA/CD)(CSMA/CD)

The The access methodaccess method used in Ethernetused in EthernetCollisionCollision

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In Ethernet networks, the interference of one network node’s data In Ethernet networks, the interference of one network node’s data transmission with another network node’s data transmissiontransmission with another network node’s data transmission

JammingJammingPart of CSMA/CD in which, upon detection of collision, station Part of CSMA/CD in which, upon detection of collision, station issues special 32issues special 32--bit sequence to indicate to all nodes on Ethernet bit sequence to indicate to all nodes on Ethernet segment that its previously transmitted frame has suffered a collision segment that its previously transmitted frame has suffered a collision and should be considered faultyand should be considered faulty

CSMA/CD AlgorithmCSMA/CD Algorithm

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Ethernet Collision DomainEthernet Collision Domain

On an Ethernet network, an individual network On an Ethernet network, an individual network segment is known as a segment is known as a collision domaincollision domain

Portion of network in which collisions will occur if Portion of network in which collisions will occur if two nodes transmit data at same timetwo nodes transmit data at same time

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Data propagation delayData propagation delayLength of time data take to travel from one point on Length of time data take to travel from one point on the segment to another pointthe segment to another pointThe last bit must be sent out before the first bit The last bit must be sent out before the first bit arrives at the farthest end of the networkarrives at the farthest end of the network

15

55--44--3 Rule (10Base#)3 Rule (10Base#)5 segments, 4 repeaters, 3 populated segments5 segments, 4 repeaters, 3 populated segments

10Base2

hub/repeater

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Ethernet FrameEthernet Frame

PaddingPaddingBytes added to data portion of an Ethernet frame to Bytes added to data portion of an Ethernet frame to make sure this field is at least make sure this field is at least 4646 bytes in sizebytes in size

Ethernet frame types (caveat)Ethernet frame types (caveat)

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yp ( )yp ( )IEEE 802.3 (“Ethernet 802.2” or “LLC”)IEEE 802.3 (“Ethernet 802.2” or “LLC”)Novell proprietary 802.3 frame (or “Ethernet Novell proprietary 802.3 frame (or “Ethernet 802.3”)802.3”)Ethernet II frameEthernet II frameIEEE 802.3 SNAP frameIEEE 802.3 SNAP frame

Ethernet FrameEthernet Frame

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Q1: What is the size of Ethernet address (known as MAC Address)?Q2: What is the minimum size of an Ethernet frame?

Note: the answer is NOT 72 (why?)

Preamble: for circuit synchronization SFD: Start of Frame Delimiter

16

Ethernet AddressEthernet Address

Also known as Media Access Control (MAC) addressAlso known as Media Access Control (MAC) addressSix bytesSix bytes

Block ID (3 bytes): unique to a vendorBlock ID (3 bytes): unique to a vendorDevice ID (3 bytes): unique to a deviceDevice ID (3 bytes): unique to a device

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Exercise:Exercise:How do you find the MAC address of your PC?How do you find the MAC address of your PC?How do you find the MAC address of the PC next to you?How do you find the MAC address of the PC next to you?If your PC has two Ethernet cards, do you have one MAC If your PC has two Ethernet cards, do you have one MAC address or two MAC address?address or two MAC address?

Switched EthernetSwitched Ethernet

Traditional Ethernet LANs, called Traditional Ethernet LANs, called shared Ethernetshared Ethernet, , supply fixed amount of bandwidth that must be shared supply fixed amount of bandwidth that must be shared by all devices on a segmentby all devices on a segmentSwitchSwitch

D i h k i llD i h k i ll

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Device that can separate network segments into smaller Device that can separate network segments into smaller segments, with each segment being independent of the others segments, with each segment being independent of the others and supporting its own trafficand supporting its own traffic

Switched EthernetSwitched EthernetNewer Ethernet model that enables multiple nodes to Newer Ethernet model that enables multiple nodes to simultaneously transmit and receive data over logical network simultaneously transmit and receive data over logical network segmentssegments

Switched EthernetSwitched Ethernet

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BridgesBridgesFiltering databaseFiltering database

Collection of data created and used by a bridge that correlates the MAC addresses of Collection of data created and used by a bridge that correlates the MAC addresses of connected workstations with their locationsconnected workstations with their locationsAlso known as a Also known as a Bridge Forwarding Table, MAC Address Table, MAC Bridge Forwarding Table, MAC Address Table, MAC Forwarding Table, Source Address Table, Content Address MemoryForwarding Table, Source Address Table, Content Address Memory

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Bridge Forwarding Table (I)Bridge Forwarding Table (I)P4

P3P2

P1

99 88 77 22 22 22

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99:88:77:11:11:11

99:88:77:22:22:22

99:88:77:33:33:33

99:88:77:44:44:44

99:88:77:55:55:55

99:88:77:66:66:66

P1P1 99:88:77:11:11:1199:88:77:11:11:11 P3P3 99:88:77:44:44:4499:88:77:44:44:44P1P1 99:88:77:22:22:2299:88:77:22:22:22 P4P4 99:88:77:55:55:5599:88:77:55:55:55P2P2 99:88:77:33:33:3399:88:77:33:33:33 P4P4 99:88:77:66:66:6699:88:77:66:66:66

Notes on Switch and MAC AddressNotes on Switch and MAC Address

MAC address is used for transmission within an MAC address is used for transmission within an IP subnet. When data is sent to another IP IP subnet. When data is sent to another IP subnet, IP address is needed. subnet, IP address is needed. A ro ter separates LAN into m ltiple IP s bnetA ro ter separates LAN into m ltiple IP s bnet

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A router separates LAN into multiple IP subnet, A router separates LAN into multiple IP subnet, and an Ethernet switch learns all MAC addresses and an Ethernet switch learns all MAC addresses of its own IP subnet.of its own IP subnet.Ethernet switch on one IP subnet does NOT Ethernet switch on one IP subnet does NOT learn MAC addresses of another IP subnet.learn MAC addresses of another IP subnet.

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Bridge Forwarding Tables (II)Bridge Forwarding Tables (II)Network

192.168.1.099:88:77:11:11:11

Network 192.168.2.0

99:88:77:22:22:22P1 P2

P11

P12

P21SW1 SW2

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192.168.1.1011:22:33:01:01:01

192.168.1.1111:22:33:02:02:02

192.168.1.1211:22:33:03:03:03

192.168.2.1011:22:33:04:04:04

192.168.2.1111:22:33:05:05:05

192.168.2.1211:22:33:06:06:06

P12 P13 P14 P22 P23 P24

Bridge Forwarding Table (IIBridge Forwarding Table (II--cont.)cont.)

Network 192.168.1.0

99:88:77:11:11:11

Network 192.168.2.0

99:88:77:22:22:22P1 P2

P11

P12

SW1

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192.168.1.1011:22:33:01:01:01

192.168.1.1111:22:33:02:02:02

192.168.1.1211:22:33:03:03:03

P12 P13 P14 PortPort MAC AddressMAC AddressP11P11 99:88:77:11:11:1199:88:77:11:11:11P12P12 11:22:33:01:01:0111:22:33:01:01:01P13P13 11:22:33:02:02:0211:22:33:02:02:02P14P14 11:22:33:03:03:0311:22:33:03:03:03

MAC Forwarding Table of SW2MAC Forwarding Table of SW2Network

192.168.1.099:88:77:11:11:11

Network 192.168.2.0

99:88:77:22:22:22P1 P2

P21

PP MAC AddMAC Add

SW2

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192.168.2.1011:22:33:04:04:04

192.168.2.1111:22:33:05:05:05

192.168.2.1211:22:33:06:06:06

P22 P23 P24PortPort MAC AddressMAC Address

P21P21 99:88:77:22:22:2299:88:77:22:22:22P22P22 11:22:33:04:04:0411:22:33:04:04:04P23P23 11:22:33:05:05:0511:22:33:05:05:05P24P24 11:22:33:06:06:0611:22:33:06:06:06

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Ethernet Ethernet –– problem with loopproblem with loop

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The network will be flooded with broadcast messages quickly.

IEEE 802.1DIEEE 802.1DSpanning Tree Algorithm and Protocol (STP)Spanning Tree Algorithm and Protocol (STP)

( )

Solution: STP blocks certain switch ports so that the network is transformed from a loop topology to a loop-free topology (or a tree topology). Also note that the connectivity must be maintained after the STP calculation.

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(root)

blocked port

New standard with faster failover time: RSTP (802.1w)

Using Switches to Create VLANsUsing Switches to Create VLANs

Virtual local area networks (VLANs)Virtual local area networks (VLANs)Network within a network that is logically defined by Network within a network that is logically defined by grouping its devices’ switch ports in the same grouping its devices’ switch ports in the same broadcast domainbroadcast domain

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Broadcast domainBroadcast domainCombination of ports that make up a Layer 2 Combination of ports that make up a Layer 2 segment and must be connected by a Layer 3 devicesegment and must be connected by a Layer 3 deviceCollision domain vs. Broadcast domainCollision domain vs. Broadcast domain

20

Using Switches to Create VLANsUsing Switches to Create VLANs

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VLAN ChallengeVLAN ChallengeSW1 SW2

SW3

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WS1 WS2 WS3 WS4 WS5 WS6

Solution Solution –– VLAN TrunkingVLAN TrunkingSW1 SW2

SW3

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WS1 WS2 WS3 WS4 WS5 WS6

VLAN Trunk: a physical link that carries Ethernet frames of multiple VLANsQuestion: how do we distinguish frames of different VLANs?

21

Tagged MAC FrameTagged MAC Frame

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(IEEE 802.1Q standard)

VLANVLAN

trunk trunk

trunkSW1SW2 SW3

Router (R)

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WS1 WS2 WS3 WS4 WS5 WS6

WS1 => WS6 (L2 Comm): WS1 => SW1 => SW2 => SW3 => WS6WS1 => WS2 (L3 comm): WS1 => SW1 => SW2 => R => SW2 => SW1 => WS2

Competing LAN Competing LAN TechnologiesTechnologies

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However,However,there is really no competition there is really no competition

against Ethernet.against Ethernet.

22

Token RingToken RingStandard: IEEE 802.5Standard: IEEE 802.5Standard Speeds: 4M and 16M bps.Standard Speeds: 4M and 16M bps.Token Ring networks use the token passing Token Ring networks use the token passing routine and a starroutine and a star--ring hybrid physical topologyring hybrid physical topologyThe 100The 100 Mbps Token Ring standard is known asMbps Token Ring standard is known as

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The 100The 100--Mbps Token Ring standard is known as Mbps Token Ring standard is known as HighHigh--Speed Token Ring (HSTR)Speed Token Ring (HSTR)On a Token Ring network, one workstation, On a Token Ring network, one workstation, called the called the active monitoractive monitor, acts as the controller , acts as the controller for token passingfor token passing

Token Ring (w/ MAU)Token Ring (w/ MAU)Multistation Access Unit (MAU)Multistation Access Unit (MAU)

Regenerates signalsRegenerates signals

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Ethernet vs. Token RingEthernet vs. Token Ring

You may argue 1 or 2 advantages of token ring You may argue 1 or 2 advantages of token ring over over sharedshared Ethernet.Ethernet.

More efficient use of bandwidthMore efficient use of bandwidthFairness to each workstationFairness to each workstation

There are no arg ments hen comparing ithThere are no arg ments hen comparing ith

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There are no arguments when comparing with There are no arguments when comparing with switchedswitched Ethernet.Ethernet.You may still find token ring today, but it is very You may still find token ring today, but it is very unlikely to deploy a new network with token unlikely to deploy a new network with token ring.ring.

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Fiber Fiber Distributed Distributed

Logical topology whose standard was originally specified by ANSI in midLogical topology whose standard was originally specified by ANSI in mid--1980s and later refined by ISO1980s and later refined by ISO

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Data Interface Data Interface (FDDI)(FDDI)

Used to be a popular technology at the campus backbone, but not any more. Why?

Asynchronous Transfer Mode (ATM)Asynchronous Transfer Mode (ATM)

Logical topology that relies on a fixed packet size to Logical topology that relies on a fixed packet size to achieve high data transfer rates of DS3 (45M), OCachieve high data transfer rates of DS3 (45M), OC--3 (155M), OC3 (155M), OC--12 (622M), and more12 (622M), and moreThe fixed packet in ATM is called aThe fixed packet in ATM is called a cellcell (53 bytes)(53 bytes)

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The fixed packet in ATM is called a The fixed packet in ATM is called a cell cell (53 bytes)(53 bytes)A unique aspect of ATM technology is that it relies A unique aspect of ATM technology is that it relies on on virtual circuitsvirtual circuits

ATM uses circuit switching, which allows ATM to ATM uses circuit switching, which allows ATM to guarantee a specific guarantee a specific quality of service (QOS)quality of service (QOS)

IP/Ethernet over ATMIP/Ethernet over ATM

Multiple Encapsulation over ATM (RFC 2684)Multiple Encapsulation over ATM (RFC 2684)

RFC 2684Ethernet

IP

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Classical IP over ATM (RFC 1577)Classical IP over ATM (RFC 1577)ATM LAN Emulation (LANE)ATM LAN Emulation (LANE)Multiprotocol over ATM (MPOA)Multiprotocol over ATM (MPOA)

ATMRFC 2684

24

Review QuestionsReview QuestionsWhat is the OSI layer for the following networking device: NIC, What is the OSI layer for the following networking device: NIC, repeater, hub, bridge, Ethernet switch, routerrepeater, hub, bridge, Ethernet switch, routerWhat is the IRQ of your Ethernet PCI adapter?What is the IRQ of your Ethernet PCI adapter?Can you support full duplex with a hub? Why?Can you support full duplex with a hub? Why?What is the difference between a hub and an Ethernet switch?What is the difference between a hub and an Ethernet switch?What is the difference between an Ethernet frame and a tagged What is the difference between an Ethernet frame and a tagged E h f ?E h f ?

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Ethernet frame?Ethernet frame?What is a router? For a typical home network, do you need a What is a router? For a typical home network, do you need a router? Give an example that you will need one and another router? Give an example that you will need one and another example that you do not need one.example that you do not need one.Describe the difference between static routing and dynamic Describe the difference between static routing and dynamic routing. What are routing protocols? Given three examples of routing. What are routing protocols? Given three examples of routing protocols. What is the routing protocol used on THE routing protocols. What is the routing protocol used on THE INTERNET?INTERNET?

Review Questions (cont.)Review Questions (cont.)

Give an example for the following network Give an example for the following network topologies: bus, ring, and star.topologies: bus, ring, and star.Comparison of three switching Comparison of three switching t hn l i ir it m nd p k tt hn l i ir it m nd p k t

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technologies: circuit, message, and packet. technologies: circuit, message, and packet. Which one is used on the data networking Which one is used on the data networking today?today?Describe the process flow of CSMA/CD.Describe the process flow of CSMA/CD.

Chapter Summary (cont.)Chapter Summary (cont.)

Describe the differences (advantages and Describe the differences (advantages and disadvantages) of cutdisadvantages) of cut--through and storethrough and store--andand--forward modes employed in the Ethernet forward modes employed in the Ethernet switch.switch.S i T Al i h (STA) Wh i STA?S i T Al i h (STA) Wh i STA?

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Spanning Tree Algorithm (STA): What is STA? Spanning Tree Algorithm (STA): What is STA? Why do we need it? What will be the problems Why do we need it? What will be the problems if you do not apply STA? Can you draw two if you do not apply STA? Can you draw two diagrams showing a network (logical and diagrams showing a network (logical and physical) topology with and without STA? physical) topology with and without STA?

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Review Questions (cont.)Review Questions (cont.)What are the differences between What are the differences between shared shared Ethernet Ethernet and and switched switched Ethernet?Ethernet?Given a switched Ethernet network, populate Given a switched Ethernet network, populate the MAC forwarding table on each Ethernet the MAC forwarding table on each Ethernet switch.switch.

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List all Ethernet standards and their speed.List all Ethernet standards and their speed.What is the mix and max Ethernet frame size (802.3 What is the mix and max Ethernet frame size (802.3 and 802.1Q frame)?and 802.1Q frame)?Why is VLAN trunk and why is it needed? Draw a Why is VLAN trunk and why is it needed? Draw a diagram to show how VLAN tagging is used.diagram to show how VLAN tagging is used.

Review Questions (cont.)Review Questions (cont.)Token Ring:Token Ring:

What is a token?What is a token?Draw an example of network diagram for token ringDraw an example of network diagram for token ringWhat is the top speed of token ring?What is the top speed of token ring?

How is FDDI used on the network? Will you How is FDDI used on the network? Will you

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w w W yw w W yconsider FDDI for a new network deployment? consider FDDI for a new network deployment? Why?Why?ATM: Is ATM a viable technology for LAN ATM: Is ATM a viable technology for LAN deployment? Why?deployment? Why?

Lab ExerciseLab Exercise

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26

TDC363 TDC363 –– Lab01Lab01

LAN LabRouter

SW01 (192.168.1.1)

LAN Lab Core SW Internet

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140.192.40.5

140.192.40.7

192.168.1.5

192.168.1.7 Linux-05

Windows-07

SW02 (192.168.1.2)

Linux AccessLinux Access

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Ethernet Switch AccessEthernet Switch Access

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telnet 192.168.1.1 (SW01)telnet 192.168.1.2 (SW02)

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MACMAC--AddressAddress--TableTable

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show interface (physical port)show interface (physical port)

Note that each physical

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port (interface) has a MAC address.