Workshop

to connect geograph-ically disperse areas. A switch can be used as a hub replacement, allowing users to
enjoy an unshared line to communicate to other devices on the network.
The documentation that comes with your switch or router should become bathroom reading material if
you really want to be able to handle problems. Of course, the theory is really important, but router and
switch theory by itself won’t do you a lot of good; you’ll also need to know specific informational and
configuration commands for your devices.
Routers are much more complex than switches, and they communicate back and forth quite a lot via
routing protocols. Switches, on the other hand, are pretty dumb, and they only talk to each other to avoid
a duplicate path to a workstation. Both switches and routers, however, are more often than not hybrid
devices that can route packets at a protocol level or switch packets at a data link level, all depending on
how you configure them.
Workshop
Q&A
Q My boss has been saying that we should chuck all our routing and switching gear and get in
some layer-three switches. What the heck is she talking about?
A Let’s first define what a layer-three switch does. To do so, we need to review that icky OSI sevenlayer
cake I talked about earlier. Here are the OSI layers in order:
• Physical
• Data link
• Network
• Transport
• Session
• Presentation
• Application
Without getting heavy into it, layer-three switching refers to the network layer, meaning the network
protocol (TCP/IP or IPX/SPX, for example). And a device for taking in stuff and deciding what to do
with it based on the network protocol is what? Yep, a router. Layer-three switch is just a new marketing
term for a very fast router. So, the question for you is this: Do you need a new router?
Q I tried to connect to my router/switch with a serial cable. I’m pretty sure that I’m using a null
modem cable, but every time I use my communications program, all I see is a bunch of ç
characters. Why is my device speaking French to me? Does it think I’m cute or something?
A Don’t worry, your device isn’t making a pass at you; it’s not even speaking French! Any time you see