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1

Chapter 6

High-SpeedLANs

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Chapter 6 High-Speed LANs2

Introduction

Fast Ethernet and Gigabit Ethernet Fibre Channel High-speed Wireless LANs

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Chapter 6 High-Speed LANs3

Characteristics of High-

Speed LANsFast Ethernet Gigabit Ethernet Fibre Channel Wireless LAN

Data Rate 100 Mbps 1 Gbps, 10 Gbps 100 Mbps 3.2Gbps1 Mbps 54

Mbps

TransmissionMode

UTP,STP,Optical Fiber

UTP, shieldedcable, optical

fiber

Optical fiber,coaxial cable,

STP

2.4 GHz, 5 GHzMicrowave

Access Method CSMA/CD CSMA/CD Switched CSMA/CAPolling

SupportingStandard IEEE 802.3 IEEE 802.3

Fibre ChannelAssociation IEEE 802.11

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Chapter 6 High-Speed LANs7

Frame Transmission on a Bus

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Chapter 6 High-Speed LANs9

CSMA/CD Operation

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Chapter 6 High-Speed LANs10

IEEE 802.3 Frame Format

Preamble 7 octets with pattern 10101010, followed by one

byte with pattern 10101011 (SFD) used to synchronize receiver, sender clock rates

Note: IEEE 802.3 specifies that frame length, excluding preamble andSFD, must be between 64 and 1518 bytes. Data is padded to 1500bytes, if necessary, to ensure that the minimum length is achieved.

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11

IEEE 802.3 Frame Format

Addresses:frame is received by all adapters on a

LAN and dropped if address does not match Length:indicates the length of data segment (min.

46 bytes, max. 1500 bytes). Note: in Ethernet thisis higher layer protocol, mostly IP but others maybe supported such as Novell IPX and AppleTalk)

LLC Data: data from next-higher layer protocol Pad: used to fill out data to minimum of 46 bytes FCS:CRC32checked at receiver, if error detected,

the frame is usually dropped

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Chapter 6 High-Speed LANs12

IP & IEEE 802.3 Framing

Frame Relay Frame Format

ATM Cell Format

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Chapter 6 High-Speed LANs16

Hubs and Switches

High-Speed Backplane or

Interconnection fabric

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Chapter 6 High-Speed LANs22

802.3 Ethernet CSMA/CD

Efficiency

Efficiency =1

1 + 6.44( )tpropttrans

the parameter a

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Chapter 6 High-Speed LANs24

Gigabit Ethernet Example(IEEE 802.3z)

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Chapter 6 High-Speed LANs 25

Gigabit Ethernet Media Options

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Chapter 6 High-Speed LANs 26

Ethernet Data Rate - Distance

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Chapter 6 High-Speed LANs 27

Benefits of 10 Gbps Ethernetover ATM No expensive, bandwidth consuming

conversionbetween Ethernet packetsand ATM cells

Network is Ethernet, end-to-end IP plus Ethernet offers QoS and

traffic policingcapabilities approaching

that of ATM Wide varietyof standard optical

interfaces for 10 Gbps Ethernet

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Chapter 6 High-Speed LANs 31

Switched Fibre ChannelNetwork

F_Ports

N_Ports

E_Ports

Also:L_Ports &G_Ports

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Chapter 6 High-Speed LANs 33

Fibre Channel Protocol

Architecture FC-4 Mapping: mappings to IEEE

802, ATM, IP, SCSI, etc.

FC-3 Common Services: multicasting

(multiple ports on one node), etc. FC-2 Framing Protocol: framing,

grouping, flow and error control

FC-1 Transmission Protocol: signal

encoding/decoding scheme FC-0 Physical Media: signaling for

optical fiber, coax, STP

Mapping

Common Services

Framing

Transmission

Physical

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Chapter 6 High-Speed LANs 34

Fibre Channel Protocol

Architecture

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Chapter 6 High-Speed LANs 35

Fibre Channel Topologies

Point-to-point no intervening fabricswitches

no routing

Arbitrated loop conceptually similar to

token ring up to 126 nodes SCSI

Fabric, or switched switched connection simple for nodes to manage IP

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Chapter 6 High-Speed LANs 36

Fibre Channel ApplicationExample

133 Mbps 1 Gbps

33 m 10 kmpoint-to-point

Fiber,video coax,STP

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Chapter 6 High-Speed LANs 38

IEEE 802.11 ProtocolArchitecture

(PCF)

(DCF)

(1997) (1999)

2.4 Ghz

orthogonal

FDM

6, 12, 24,

36, 48,

54 Mbps

(2003)

IEEE 802.11g)

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Chapter 6 High-Speed LANs 43

Performance Issues inWireless Networks Bandwidth limitation High relative bit error rate (BER) Higher latency User mobility (handoff)

Effects on TCP congestion mechanisms and,therefore, performance and throughput?