of using the hardware address of devices on a LAN to segment a network.
Since you've got the basic ideas down, I'm now going to focus on the partic-
ulars of layer-2 switching and nail down how it works.
or more devices sharing the same bandwidth. A hub network is a typical
example of this type of technology. But since each port on a switch is actually
its own collision domain, you can make a much better Ethernet LAN net-
work just by replacing your hubs with switches!
result in a clean, cost-effective, and resilient internetwork. In this chapter,
we'll survey and compare network design before and after switching tech-
nologies were introduced.
layer. However, if you have redundant physical links between your switches,
routing protocols won't do a thing to stop loops from occurring at the Data
Link layer. That's exactly the reason Spanning Tree Protocol was developed--
to put a stop to loops in a layer-2 switched internetwork. The essentials of
this vital protocol, as well as how it works within a switched network, are
also important subjects this chapter will cover thoroughly.
switch. There are three different types of LAN switch methods, and each one
handles frames differently as they are forwarded through a switch. This
chapter will close with a discussion on the three methods used by Cisco
switches.