Chapter6.Reducing Congestion and Driving Faster on the Local (Network) Roadway

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

• Explain the basic operation of a LAN switch

• Describe how LAN switches can eliminate collisions

• Explain why LAN switches allow for more throughput in a LAN, as compared to a hub

• Describe the conditions under which full duplex operations can be allowed, and describe the advantages of full duplex operation

• 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.