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Chapter 1

Planning a Network Topology

2. What phenomenon never occurs on a properly functioning Token Ring network

but is a normal occurrence on an Ethernet network?

3. List two advantages and two disadvantages of using fiber-optic cable to build a

network.

Lesson Summary

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The OSI reference model splits the network communications process into seven

layers—physical, data-link, network, transport, session, presentation, and applica-

tion—which isolate the various functions performed by the networking protocols.

■

Selecting a data-link layer protocol is primarily a matter of choosing an appropri-

ate network medium. Unshielded twisted pair, fiber-optic, and wireless media all

have benefits and drawbacks making them suitable for some installations and

unsuitable for others.

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Transmission speed is an important criterion in selecting the data-link layer proto-

col. There are various types of Ethernet that run at 10, 100, and 1,000 Mbps.