1 chapter 6 high-speed lans. chapter 6 high-speed lans 2 introduction fast ethernet and gigabit...

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Chapter 6Chapter 6

High-Speed High-Speed LANsLANs

Chapter 6 High-Speed LANs2

Introduction Introduction

Fast Ethernet and Gigabit Fast Ethernet and Gigabit EthernetEthernet

Fibre ChannelFibre ChannelHigh-speed Wireless LANsHigh-speed Wireless LANs


Characteristics of High-Characteristics of High-Speed LANsSpeed LANs

Fast EthernetFast Ethernet Gigabit Gigabit EthernetEthernet

Fibre ChannelFibre Channel Wireless LANWireless LAN

Data RateData Rate 100 Mbps100 Mbps 1 Gbps, 10 1 Gbps, 10 GbpsGbps

100 Mbps – 3.2 100 Mbps – 3.2 GbpsGbps

1 Mbps – 54 1 Mbps – 54 MbpsMbps

Transmission Transmission ModeMode

UTP,STP, UTP,STP, Optical FiberOptical Fiber

UTP, shielded UTP, shielded cable, optical cable, optical

fiberfiber

Optical fiber, Optical fiber, coaxial cable, coaxial cable,

STPSTP

2.4 GHz, 5 GHz 2.4 GHz, 5 GHz MicrowaveMicrowave

Access MethodAccess Method CSMA/CDCSMA/CD CSMA/CDCSMA/CD SwitchedSwitched CSMA/CA CSMA/CA PollingPolling

Supporting Supporting StandardStandard IEEE 802.3IEEE 802.3 IEEE 802.3IEEE 802.3 Fibre Channel Fibre Channel

AssociationAssociation IEEE 802.11IEEE 802.11


Frame Transmission on a Frame Transmission on a BusBus


CSMA/CD OperationCSMA/CD Operation


IEEE 802.3 Frame FormatIEEE 802.3 Frame Format

PreamblePreamble 7 octets with pattern 10101010, followed by 7 octets with pattern 10101010, followed by

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

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


IEEE 802.3 Frame FormatIEEE 802.3 Frame Format

Addresses:Addresses: frame is received by all adapters on frame is received by all adapters on a LAN and dropped if address does not matcha LAN and dropped if address does not match

Length:Length: indicates the length of data segment indicates the length of data segment (min. 46 bytes, max. 1500 bytes). Note: in (min. 46 bytes, max. 1500 bytes). Note: in Ethernet this is higher layer protocol, mostly IP Ethernet this is higher layer protocol, mostly IP but others may be supported such as Novell IPX but others may be supported such as Novell IPX and AppleTalk)and AppleTalk)

LLC Data:LLC Data: data from next-higher layer protocoldata from next-higher layer protocol Pad:Pad: used to fill out data to minimum of 46 used to fill out data to minimum of 46

bytesbytes FCS:FCS: CRCCRC3232 checked at receiver, if error checked at receiver, if error

detected, the frame is usually droppeddetected, the frame is usually dropped


IP & IEEE 802.3 FramingIP & IEEE 802.3 Framing

Frame Relay Frame Format

ATM Cell Format


Hubs and SwitchesHubs and SwitchesHubHub Physical amplification and Physical amplification and

retransmission of bits (repeater)retransmission of bits (repeater) Transmission from a station received by Transmission from a station received by

central hub and retransmitted on all central hub and retransmitted on all outgoing linesoutgoing lines

Only one transmission at a timeOnly one transmission at a time Logically, a busLogically, a bus

Layer 2 Hub (Switch)Layer 2 Hub (Switch) Incoming frame buffered and then Incoming frame buffered and then

switched to one outgoing lineswitched to one outgoing line Many transmissions at same timeMany transmissions at same time


Hubs and SwitchesHubs and Switches

High-Speed Backplane or Interconnection fabric


IEEE 802.3 100Base-T IEEE 802.3 100Base-T Option TaxonomyOption Taxonomy

High-qualityHigh-qualitycablingcabling

Lower-qualityLower-qualitycablingcabling

Note: 100Base-T specification also allows full-duplex operation.Note: 100Base-T specification also allows full-duplex operation.

IEEE 802.3u (100 Mbps)


802.3 Ethernet CSMA/CD 802.3 Ethernet CSMA/CD EfficiencyEfficiency

Efficiency = Efficiency =

11

1 + 6.44( 1 + 6.44(

) )ttpropprop

tttranstrans

the parameter ‘a’


Gigabit Ethernet Gigabit Ethernet Example (IEEE 802.3z)Example (IEEE 802.3z)


Gigabit Ethernet Media Gigabit Ethernet Media OptionsOptions


Ethernet Data Rate - Ethernet Data Rate - DistanceDistance


Benefits of 10 Gbps Ethernet Benefits of 10 Gbps Ethernet over ATMover ATMNo expensive, bandwidth consuming No expensive, bandwidth consuming

conversionconversion between Ethernet between Ethernet packets and ATM cellspackets and ATM cells

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

traffic policingtraffic policing capabilities capabilities approaching that of ATMapproaching that of ATM

Wide Wide varietyvariety of standard optical of standard optical interfaces for 10 Gbps Ethernetinterfaces for 10 Gbps Ethernet


Fibre ChannelFibre Channel In data communications, there are 2 In data communications, there are 2

common methods to deliver data to the common methods to deliver data to the processor:processor:– via and via and I/O channelI/O channel– via the via the NetworkNetwork

Fibre channel combines best of both to Fibre channel combines best of both to provideprovide– the simplicity and speed of I/O channel the simplicity and speed of I/O channel

communicationscommunications– the flexibility and interconnectivity of network the flexibility and interconnectivity of network

communicationscommunications NotNot a shared-medium like 802.3 a shared-medium like 802.3

– switching fabric is point-to-point/multipointswitching fabric is point-to-point/multipoint– no medium access issuesno medium access issues


Switched Fibre Channel Switched Fibre Channel Network Network

F_PortsF_Ports

N_PortsN_Ports

E_PortsE_Ports

Also:Also:L_Ports &L_Ports &G_PortsG_Ports


Fibre Channel Protocol Fibre Channel Protocol ArchitectureArchitecture

FC-4 Mapping:FC-4 Mapping: mappings to IEEE mappings to IEEE 802, ATM, 802, ATM, IPIP, , SCSISCSI, etc., etc.

FC-3 Common Services:FC-3 Common Services: multicasting (multiple ports on multicasting (multiple ports on one node), etc.one node), etc.

FC-2 Framing Protocol:FC-2 Framing Protocol: framing, framing, grouping, flow and error controlgrouping, flow and error control

FC-1 Transmission Protocol:FC-1 Transmission Protocol: signal signal encoding/decoding schemeencoding/decoding scheme

FC-0 Physical Media:FC-0 Physical Media: signaling for signaling for optical fiber, coax, STPoptical fiber, coax, STP

MappingMapping

Common Common

ServicesServices

FramingFraming

TransmissionTransmission

PhysicalPhysical


Fibre Channel Protocol Fibre Channel Protocol ArchitectureArchitecture


Fibre Channel TopologiesFibre Channel Topologies Point-to-pointPoint-to-point

– no intervening fabric no intervening fabric switchesswitches

– no routingno routing Arbitrated loopArbitrated loop

– conceptually similar to conceptually similar to token ringtoken ring

– up to 126 nodesup to 126 nodes– SCSISCSI

Fabric, or switchedFabric, or switched– switched connectionswitched connection– simple for nodes to managesimple for nodes to manage– IPIP


Fibre Channel Application Fibre Channel Application ExampleExample

133 Mbps 133 Mbps – 1 Gbps– 1 Gbps

33 m – 10 33 m – 10 kmkm

point-to-point-to-pointpoint

Fiber, Fiber, video video coax,coax,STPSTP


IEEE 802.11 Protocol IEEE 802.11 Protocol ArchitectureArchitecture

(PCF)

(DCF)

(1997)(1997) (1999)(1999)

2.4 Ghzorthogonal

FDM6, 12, 24,

36, 48,54 Mbps

(2003)(2003)

IEEE 802.11g)IEEE 802.11g)


Performance Issues in Performance Issues in Wireless NetworksWireless NetworksBandwidth limitationBandwidth limitationHigh relative bit error rate (BER)High relative bit error rate (BER)Higher latencyHigher latencyUser mobility (handoff)User mobility (handoff)

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

1 chapter 6 high-speed lans. chapter 6 high-speed lans 2 introduction fast ethernet and gigabit...

Documents

emergence of highspeed

bus slide

frame length

gigabit ethernet fast

frame transmission

csmacd operation slide

length of data segment

problem data