chapter 6 high-speed lans 1 chapter 6 high-speed lans
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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
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Solution to First ProblemSolution to First Problem
Data transmitted in blocks called frames:– User data– Frame header containing unique address of
destination station
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Figure 6.1Figure 6.1
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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)
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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
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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
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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
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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
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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
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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
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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
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Wireless LAN RequirementsWireless LAN RequirementsThroughputNumber of nodesConnection to backboneService areaBattery power consumptionTransmission robustness and securityCollocated network operationLicense-free operationHandoff/roamingDynamic configuration
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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