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Chapter 6 High-Speed LANs1

Chapter 6Chapter 6

High-Speed LANs

Chapter 6 High-Speed LANs2

Introduction Introduction

Fast Ethernet and Gigabit EthernetFibre ChannelHigh-speed Wireless LANs

Chapter 6 High-Speed LANs3

Table 6.1Table 6.1

Chapter 6 High-Speed LANs4

Emergence of High-Speed LANsEmergence of High-Speed LANs

2 Significant trends– Computing power of PCs continues to grow

rapidly– Network computing

Examples of requirements– Centralized server farms– Power workgroups– High-speed local backbone

Chapter 6 High-Speed LANs5

Classical EthernetClassical Ethernet

Bus topology LAN10 MbpsCSMA/CD medium access control

protocol2 problems:

– A transmission from any station can be received by all stations

– How to regulate transmission

Chapter 6 High-Speed LANs6

Solution to First ProblemSolution to First Problem

Data transmitted in blocks called frames:– User data– Frame header containing unique address of

destination station

Chapter 6 High-Speed LANs7

Figure 6.1Figure 6.1

Chapter 6 High-Speed LANs8

CSMA/CDCSMA/CD

Carrier Sense Multiple Access/ Carrier Detection

1. If the medium is idle, transmit.2. If the medium is busy, continue to listen until

the channel is idle, then transmit immediately.3. If a collision is detected during transmission,

immediately cease transmitting.4. After a collision, wait a random amount of

time, then attempt to transmit again (repeat from step 1).

Chapter 6 High-Speed LANs9

Figure 6.2Figure 6.2

Chapter 6 High-Speed LANs10

Figure 6.3Figure 6.3

Chapter 6 High-Speed LANs11

Medium Options at 10MbpsMedium Options at 10Mbps

<data rate> <signaling method> <max length> 10Base5

– 10 Mbps

– 50-ohm coaxial cable bus

– Maximum segment length 500 meters 10Base-T

– Twisted pair, maximum length 100 meters

– Star topology (hub or multipoint repeater at central point)

Chapter 6 High-Speed LANs12

Figure 6.4Figure 6.4

Chapter 6 High-Speed LANs13

Hubs and SwitchesHubs and Switches

Hub Transmission from a station received by central

hub and retransmitted on all outgoing lines Only one transmission at a time

Layer 2 Switch Incoming frame switched to one outgoing line Many transmissions at same time

Chapter 6 High-Speed LANs14

Figure 6.5Figure 6.5

Chapter 6 High-Speed LANs15

Bridge Frame handling done

in software Analyze and forward

one frame at a time Store-and-forward

Layer 2 Switch Frame handling done

in hardware Multiple data paths

and can handle multiple frames at a time

Can do cut-through

Chapter 6 High-Speed LANs16

Layer 2 SwitchesLayer 2 Switches

Flat address spaceBroadcast stormOnly one path between any 2 devices

Solution 1: subnetworks connected by routers

Solution 2: layer 3 switching, packet-forwarding logic in hardware

Chapter 6 High-Speed LANs17

Figure 6.6Figure 6.6

Chapter 6 High-Speed LANs18

Figure 6.7Figure 6.7

Chapter 6 High-Speed LANs19

Figure 6.8Figure 6.8

Chapter 6 High-Speed LANs20

Figure 6.9Figure 6.9

Chapter 6 High-Speed LANs21

Figure 6.10Figure 6.10

Chapter 6 High-Speed LANs22

Figure 6.11Figure 6.11

Chapter 6 High-Speed LANs23

Benefits of 10 Gbps Ethernet over Benefits of 10 Gbps Ethernet over ATMATMNo expensive, bandwidth consuming

conversion between Ethernet packets and ATM cells

Network is Ethernet, end to endIP plus Ethernet offers QoS and traffic

policing capabilities approach that of ATMWide variety of standard optical interfaces

for 10 Gbps Ethernet

Chapter 6 High-Speed LANs24

Fibre ChannelFibre Channel

2 methods of communication with processor:– I/O channel– Network communications

Fibre channel combines both– Simplicity and speed of channel

communications– Flexibility and interconnectivity of network

communications

Chapter 6 High-Speed LANs25

Figure 6.12Figure 6.12

Chapter 6 High-Speed LANs26

I/O channelI/O channelHardware based, high-speed, short

distanceDirect point-to-point or multipoint

communications linkData type qualifiers for routing payloadLink-level constructs for individual I/O

operationsProtocol specific specifications to support

e.g. SCSI

Chapter 6 High-Speed LANs27

Fibre Channel Network-Oriented Fibre Channel Network-Oriented FacilitiesFacilitiesFull multiplexing between multiple

destinationsPeer-to-peer connectivity between any pair

of portsInternetworking with other connection

technologies

Chapter 6 High-Speed LANs28

Fibre Channel RequirementsFibre Channel Requirements Full duplex links with 2 fibres/link 100 Mbps – 800 Mbps Distances up to 10 km Small connectors high-capacity Greater connectivity than existing multidrop

channels Broad availability Support for multiple cost/performance levels Support for multiple existing interface command

sets

Chapter 6 High-Speed LANs29

Figure 6.13Figure 6.13

Chapter 6 High-Speed LANs30

Fibre Channel Protocol Fibre Channel Protocol ArchitectureArchitectureFC-0 Physical MediaFC-1 Transmission ProtocolFC-2 Framing ProtocolFC-3 Common ServicesFC-4 Mapping

Chapter 6 High-Speed LANs31

Wireless LAN RequirementsWireless LAN RequirementsThroughputNumber of nodesConnection to backboneService areaBattery power consumptionTransmission robustness and securityCollocated network operationLicense-free operationHandoff/roamingDynamic configuration

Chapter 6 High-Speed LANs32

Figure 6.14Figure 6.14

Chapter 6 High-Speed LANs33

IEEE 802.11 ServicesIEEE 802.11 Services

Association ReassociationDisassociationAuthenticationPrivacy

Chapter 6 High-Speed LANs34

Figure 6.15Figure 6.15

Chapter 6 High-Speed LANs35

Figure 6.16Figure 6.16

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