Chapter 6. How a Switch Works

What You Will Learn

On completing this chapter, you will be able to:

  • Differentiate among unicast, multicast, and broadcast transmission methods

  • Describe store-and-forward, cut-through, and fragment-free switching mechanisms

  • Describe Layer 2 and Layer 3 switching operation

Up to this point, frames going in and out of the LAN switch have been discussed, but not what those frames are doing while in the switch and what the switch is doing with the frames. As you might have surmised by now, this chapter discusses these very points, and a few more. To understand how a switch processes the frames that it receives and forwards, you will first learn about the three types of transmission methods found in a local-area network (LAN): unicast, multicast, and broadcast.