Small and midsized businesses frequently encounter a situation where their PCs are separated into two groups a small distance apart. For example, a company might have several PCs in an office area, and then several PCs out in a warehouse or plant. Or often an organization has outgrown its office and leased a bit of space down the hall or next door. In any event, the IT department has a dilemma in terms of how to connect these PCs together.
One option is to put a switch in one group and run wires out to the other group. This may not be possible if the other group is more than 100 meters away. It can also be expensive. If the company wants to add PCs in the future, there can often be a delay to run more cables.
Another option is to put a small switch in each group and connect the switches. If the distance is less than 100 meters, you can use a regular Cat 5 cable. If it is greater, assuming you don't want to spend the money for fiber, your best option is a wireless bridge. Wireless bridges are most commonly small appliances that resemble wireless access points but are much more expensive.
Most administrators are familiar with Windows "Connection Sharing" feature and are understandably wary of using it in a corporate network. But many don't realize that Windows XP also has a bridging feature that is quite different from Connection Sharing. There are, frankly, few instances where I would recommend using a PC in place of dedicated network hardware, but in a small, peer-to-peer type network, the bridging feature can be a useful solution when combined with a couple of wireless network interface cards (NICs).
If you put a wireless card in one PC from each group (or more if you have more groups) and turn on bridging between the Ethernet and wireless NICs, you have effectively extended one subnet across both groups, so that you don't need to route. That is, all your devices can be in the 192.168.1.x subnet.
This takes just a few quick keystrokes to set up. NICs are a lot less expensive than access points or bridges, and the wireless signal can extend (depending on your antenna) well over a mile. Of course, the downside, like Connection Sharing, is that if anyone turns off either of those two PCs, the whole group loses its connection. By the same token, everyone's performance will depend on how busy those two PCs are. As usual, you get what you pay for.
Tom Lancaster, CCIE# 8829 CNX# 1105, is a consultant with 15 years experience in the networking industry, and co-author of several books on networking, most recently, CCSP: Secure PIX and Secure VPN Study Guide , published by Sybex.