The Medium Access ControlSublayer

Chapter 4_2

IEEE 802.x

• IEEE 802.1

• IEEE 802.2

• IEEE 802.3

• Ethernet is a family of computer networking technologies for LAN.

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Definitions

• Segment

• Repeater• Bridge

• Hub

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Switch

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Repeaters, Hubs, Bridges, Switches, Routers and Gateways

(a) Which device is in which layer.

(b) Frames, packets, and headers.5

Repeaters, Hubs, Bridges, Switches, Routers and Gateways (2)

(a) A hub. (b) A bridge. (c) a switch.6

Ethernet Cabling

The most common kinds of Ethernet cabling. 7

Ethernet Cabling (2)

Three kinds of Ethernet cabling.

(a) 10Base5, (b) 10Base2, (c) 10Base-T. 8

Ethernet Cabling (4)

(a) Binary encoding, (b) Manchester encoding, (c) Differential Manchester encoding. 9

Ethernet MAC Sublayer Protocol

Frame formats. IEEE 802.3.10

Ethernet MAC Sublayer Protocol (2)

Collision detection can take as long as 2 .τ11

Binary Exponential Backoff

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Ethernet Performance

Efficiency of Ethernet at 10 Mbps with 512-bit slot times.13

Fast Ethernet

The original fast Ethernet cabling.14

Gigabit Ethernet

(a) A two-station Ethernet. (b) A multistation Ethernet.

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IEEE 802.4

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IEEE 802.5

• It uses a special three-byte frame called a token that travels around the ring.

• Initially used only in IBM computers.

• It was eventually standardized with protocol IEEE 802.5.

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