How to Avoid Most Wrecks

How to Avoid Most Wrecks

Ethernet standards define a basic algorithm that helps reduce collisions, as well as defining what to do when collisions occur. The algorithm is called the carrier sense multiple access collision detect (CSMA/CD) algorithm. Boy, there's a fun trivia question for your next party, huh?

The concept is pretty simple. Imagine that you are connected to a hub, and you are currently receiving a frame. What would happen if you sent a frame at that time? Well, you would cause a collision. So why not just wait a moment? Well, that's exactly what the algorithm calls for. Figure 5-3 shows the basic logic, with Bob waiting on Larry to finish sending his frame before sending his own frame.