There was a time, not so very long ago, that people only had one computer and it wasn't connected to any network. This wasn't back when I was in high school and had to outrun dinosaurs to get home for lunch. This was post-Star Wars. How times have changes in just two decades.

Now most households have high speed network access. Most have more than one computer. Some have wireless and wired networks in their house. And in at least one of them, right now, someone is wondering, what all those boxes between them and the wall do. If that's you, this column is for you.

Starting at the wall. Regardless of whether you have internet access via the telephone company or the cable company, the first box that gets plugged in is a modem. Modem is a portmanteau of MOdulate and DEModulate. It's responsibility is to convert the information on the wire into something that digital devices can understand – that's coming in – and convert digital information in the network into something that can be carried on a wire – that's going out. The modem is essentially a language translator in a box.

If you have only one computer the modem may be your only device and your computer is plugged directly into it. But if you have more than one device you're probably going to need a router. The next item on the network.

A router (also known as a residential gateway) does exactly what it sounds like, it routes traffic to and from the internet back to each computer on your network. The address that you use in an internal network doesn't work well out in the internet so, the router makes it appear that all the traffic to and from your network looks like it's coming to and from one computer. The router typically does one other job and that is the task of assigning addresses within the network. Each computer needs a unique identifier. You've probably heard this called an IP (internet protocol) address.

You can think of the router as a post office. It takes all the outgoing mail and bags it. And takes the new incoming bags of mail and sorts them to the respective boxes.

If you use wireless in your house there's a good chance that your router is what provides the wireless service. Sometimes the wireless router is a separate router, but that's less common these days.

If you have a number of devices to network, more than the number of plugins on the back of your router for example, then you need a hub or a switch.

Hubs and switches do the same job, that is they connect devices (usually computers, but also gaming consoles, internet aware media players, etc. ) to the router. Hubs will usually only have four ports and be quite small. They're essentially just like a 'Y' in a garden hose. They split the traffic.

A switch does the same job as a hub, but it's smarter. Especially useful in business environments, switches know when traffic is destined for the internet and when it's destined for another computer on the network. And they can use that knowledge to fast track data moving internally on the network.

It used to be that switches were much more expensive than hubs, but not anymore. You can think of switches as being just like the telephone operators of old, plugging cables into boards to connect telephone calls.

Just a couple setup tips if you're dealing with this kind of network complexity. The WAN port on the device always goes upstream. Upstream being towards the internet. The LAN ports go downstream or into your network in other words. If you have a hub or switch that does not have a WAN port, then use port one to go upstream. This is much less important than it used to be, but it's still good practice. Use the shortest cable you can get away with at each connection. Also, if you have to restart equipment, always restart from the upstream device and work downstream. So, modem first, than router, than switch, then computer.

That's it for this month. Happy computing.