Chapter5.Rules of the Road: How to Use the Local (Network) Roadway

Chapter 5. Rules of the Road: How to Use the Local (Network) Roadway

What You Will Learn

After reading this chapter, you should be able to

• Explain the basic rules about when a computer can use an Ethernet LAN

• List the more important fields inside Ethernet headers and trailers

• Explain the format of Ethernet LAN addresses

• Explain how computers use Ethernet addresses as they send and receive data over an Ethernet LAN

• List the two major branches of Ethernet standards

When the U.S. Department of Transportation (DOT) builds a road, it concerns itself with the physical constructionmoving dirt, paving, painting the lines on the road, and so on. However, without traffic laws, too many accidents would happen, and far less traffic would be able to use the road. Everyone needs to know the rules of how to get through an intersection, when to yield to other cars, and how fast you can go. Similarly, with LANs, rules tell you when you can use the LAN, when you should yield by waiting to send data over the LAN, and how fast you can transmit the data. In this chapter, I'll explain the rules of the road for Ethernet LANs.