Computer Networks, Fifth Edition

4THE MEDIUM ACCESS CONTROL SUBLAYER

Network links can be divided into two categories: those using point-to-point connections and those using broadcast channels. We studied point-to-point links in Chap. 2; this chapter deals with broadcast links and their protocols.

In any broadcast network, the key issue is how to determine who gets to use the channel when there is competition for it. To make this point, consider a conference call in which six people, on six different telephones, are all connected so that each one can hear and talk to all the others. It is very likely that when one of them stops speaking, two or more will start talking at once, leading to chaos. In a face-to-face meeting, chaos is avoided by external means. For example, at a ...