Network CommunicationsChapter 10

Fast Ethernet (100Mb/s) Networking Technology

Fast Ethernet Protocol Stack

Figure 10.1

MII

100BaseT4

• 100 – Speed

• Base – baseband

• T – twisted pair

• 4 – pairs

Figure 10.2

Pair 3 data

Pair 4 data

One wire from pair 2

One wire from pair 1

PMD

CSMA/CDCSMA/CD

100BaseTX

• X - 2 pair (or 1- rare)

• UDP CAT5

• MLT-3

• 4B/5BFigure 10.3: example MLT-3 Signal

(0 0 0 0 1 1 1 0)

(1 1 1 1 0 1 1 1 0 0)

-V

0

+V1 1 1 1 0 1 1 1 0 0

100BaseFX

• F - Fiber

• Separate send & receive fibers

Figure 10.4: Repeater (Hub) Connection

Tx Rx

100Base-FxNIC

Class II OpticalRepeaterTx Rx Tx Rx Tx Rx

Repeater (or Hub)

• Class 1– Larger internal delay– One per Fast Ethernet Segment– Interfaces 100BaseFX 100BaseTX

• Class 2– Two allowed per segment– All nodes of the same type

Network Diameter

• Maximum distance (UDP) between repeaters – 5 meters

• No cable exceeds 100 meters (check Hub specifications)

• Maximum distance between switches – 2000 meters (using fiber)

Expanding Network Diameter:Using An Ethernet Switch

Figure 10.9

Class I Repeater

100BaseTX 100BaseFX

LAN Sw itch100m UTP

Class II Repeater

100BaseTX 100BaseTX

Class II Repeater

100BaseTX 100BaseTX

5metersUTP

Fiber or100 meters UTP