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
Chapter 6 High-Speed LANs3
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
Chapter 6 High-Speed LANs7
Frame Transmission on a Frame Transmission on a BusBus
Chapter 6 High-Speed LANs9
CSMA/CD OperationCSMA/CD Operation
Chapter 6 High-Speed LANs10
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.
Chapter 6 High-Speed LANs11
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
Chapter 6 High-Speed LANs12
IP & IEEE 802.3 FramingIP & IEEE 802.3 Framing
Frame Relay Frame Format
ATM Cell Format
Chapter 6 High-Speed LANs15
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
Chapter 6 High-Speed LANs16
Hubs and SwitchesHubs and Switches
High-Speed Backplane or Interconnection fabric
Chapter 6 High-Speed LANs21
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)
Chapter 6 High-Speed LANs22
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’
Chapter 6 High-Speed LANs24
Gigabit Ethernet Gigabit Ethernet Example (IEEE 802.3z)Example (IEEE 802.3z)
Chapter 6 High-Speed LANs25
Gigabit Ethernet Media Gigabit Ethernet Media OptionsOptions
Chapter 6 High-Speed LANs26
Ethernet Data Rate - Ethernet Data Rate - DistanceDistance
Chapter 6 High-Speed LANs27
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
Chapter 6 High-Speed LANs28
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
Chapter 6 High-Speed LANs31
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
Chapter 6 High-Speed LANs33
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
Chapter 6 High-Speed LANs34
Fibre Channel Protocol Fibre Channel Protocol ArchitectureArchitecture
Chapter 6 High-Speed LANs35
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
Chapter 6 High-Speed LANs36
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
Chapter 6 High-Speed LANs38
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)
Chapter 6 High-Speed LANs43
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?