Chapter 6. Reducing Congestion and Driving Faster on
the Local (Network) Roadway
What You Will Learn
After reading this chapter, you should be able to
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Explain the basic operation of a LAN switch
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Describe how LAN switches can eliminate collisions
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Explain why LAN switches allow for more throughput in a LAN, as
compared to a hub
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Describe the conditions under which full duplex operations can
be allowed, and describe the advantages of full duplex operation
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List the different speeds that Ethernet supports
So far in this book, I've explained how you can build a small
Ethernet with two computers by using a single cable, or build a larger Ethernet
by cabling lots of devices to a single Ethernet hub. From what you've read so
far, if you have more than two devices, using a hub is the way to go. However,
there are some performance issues when using hubs, particularly when you need to
send a lot of traffic over the LAN. This chapter explains more about how LANs
are created today, using devices called switches. LAN
switches overcome the performance problems with hubs, allowing much
more traffic to pass across the LAN in the same time period.
Another more obvious way to make a LAN support more traffic is
to send the traffic more quickly. This chapter ends with some coverage of the
versions of Ethernet that simply run faster than the original 10 Mbps Ethernet
specifications.