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LAN Protocols

Valli ChandrasekaranAugust,2009

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Common LAN Technologies

• Ethernet

• Token Ring

• FDDIFDDI

Dual Ring

TokenRing

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Ethernet

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Ethernet and IEEE 802.3

Benefits and background Ethernet is the most popular physical layer LAN technology because it strikes

a good balance between speed, cost, and ease of installation

Supports virtually all network protocols

Xerox initiated, then joined by DEC & Intel in 1980

Revisions of Ethernet specification Fast Ethernet (IEEE 802.3u) raises speed from 10 Mbps to 100 Mbps

Gigabit Ethernet is an extension of IEEE 802.3 which increases speeds to 1000 Mbps, or 1 Gbps

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LANspeed (bps)

100BaseFX

“Base” = baseband“Broad” = broadband

Indicates type of cableand maximum length. If a number,max. length = # x 100 m

Ethernet Protocol Names

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Ethernet and Fast Ethernet

ProtocolMax. Segment

Length (m)Transmission

Medium Application

10Base2 185 50-ohm coaxial A: Link user stations

10Base5 500 50-ohm coaxial A: Link user stations

10BaseF Refers to 10BaseFB, 10BaseFL, and 10Base FP

10BaseFB 2000 Fiber-optic A: Add segments

10BaseFL 1000–2000 Fiber-optic A: Operate w/ FOIRL

10BaseFP 500 Fiber-optic Star topo w/out repeaters

10BaseT 100 2-pairs TP Sends link signals

10Broad36 3600 Broadband coax A: Broadband

100BaseFX 400 2 strands of multimode fiber-optic cable

100BaseT 100 UTP 10BaseT function + more

100BaseT4 100 4 prs Cat 3-5 UTP -

100BaseTX 100 2 prs UTP or STP -

100BaseX Refers to 2 strand/pair 100BaseFX and 100BaseTX

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Ethernet Operation

AA BB CC DD

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Ethernet Operation

AA BB CC DD

D

Data LinkNetworkTransportSessionPresentationApplication

Physical

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Ethernet Operation

AA BB CC DD

D

Data LinkNetworkTransportSessionPresentationApplication

Physical

B and C

Data LinkNetworkTransportSessionPresentationApplication

Physical

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Ethernet Broadcast

D

Data LinkNetworkTransportSessionPresentationApplication

Physical

C

Data LinkNetworkTransportSessionPresentationApplication

Physical

B

Data LinkNetworkTransportSessionPresentationApplication

Physical

A

Data LinkNetworkTransportSessionPresentationApplication

Physical

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Ethernet Reliability

B C DDAA

B C DAFigure 1

Figure 2

Collision

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Ethernet Reliability

Collision

CC

B C DDAA

BA D

JAMJAMJAMJAMJAM JAM

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Ethernet Reliability

B C DA

Collision

B C DA

JAMJAMJAMJAMJAM JAM

Carrier sense multiple access with collision detection (CSMA/CD)

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High-Speed Ethernet Options

Fast Ethernet

Fast EtherChannel®

Gigabit Ethernet

Gigabit EtherChannel

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What Is Fast EtherChannel?

Grouping of multiple Fast Ethernet interfaces Grouping of multiple Fast Ethernet interfaces into one logical transmission pathinto one logical transmission path

Grouping of multiple Fast Ethernet interfaces Grouping of multiple Fast Ethernet interfaces into one logical transmission pathinto one logical transmission path

• Scalable bandwidth up to 800+ Mbps

• Using industry-standard Fast Ethernet

• Load balancing across parallel links

• Extendable to Gigabit Ethernet400 Mb400 Mb400 Mb400 Mb

600 Mb600 Mb600 Mb600 Mb

800 Mb800 Mb800 Mb800 Mb

800 Mb800 Mb800 Mb800 Mb

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• 1000-Mbps data rate

• 802.3/Ethernet frames

• Full duplex or half duplex

• Fiber or copper media

• 100% compatible with existing:– Network protocols

– Network operating systems

– Network applications

– Network management

What Is Gigabit Ethernet?

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Q and A

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