If you have a large home (or even a smaller one with outbuildings that you want to cover with your wireless network), building a wireless network that covers the whole thing is not impossible.
Large houses can be a problem for wireless networks. Apart from the issue of trying to remember which bedroom is yours, most consumer-grade wireless access points aren't powerful enough to provide wireless access over a home that's bigger than your typical split-level house. And you don't have to be a dot-com millionaire to have problems: if you have outbuildings or a large garden that you want covered by your wireless network, a single router probably won't cut it. Fortunately, it isn't difficult to extend the range of a wireless network to cover the entire house and garden.
There are three approaches to dealing with this problem: use hi-gain antennas that increase or direct the signal from your access point range [Hack #52], use Wireless Distribution System (WDS) to extend your wireless range [Hack #69], or use multiple access points. This hack shows how to use the third approach, providing multiple access points in different locations.
7.3.1. Two Antennas Are Better Than One
Let's take a typical example. Say you live in a large house or apartment that's spread over several floors, as shown in Figure 7-4. You've bought a wireless router or access point and tried it in several locations, surveying the signal strength around the house. The signal won't go between floors, because it can't penetrate the floor. If you put the router on one floor, you get no signal (or a signal too weak to use) on the next.
So, we are going to put the wireless router on one floor, and then run an Ethernet cable from the router up to the next floor and add an access point that provides wireless signal upstairs. Similarly, you might find that there is a dead spot in one room of a smaller house that you want to add wireless coverage to, and adding an access point can easily do this.
An access point is different from a wireless router in that it doesn't contain any of the code or equipment that connects your wireless network to your broadband Internet connection. Instead, it acts as an interface or bridge between a wired network and the wireless one. Most wireless equipment manufacturers sell them, and they are typically a bit cheaper than the wireless routers. It's a good idea to go with the same manufacturer as your wireless router: although these devices are designed to be compatible between manufacturers, using one manufacturer makes finding problems and tech support calls easier. You should also go with the same wireless standard as your router.
Figure 7-4. Wireless coverage that does not span the whole house Router
Next, you'll need to run an Ethernet cable from the wireless router to the access point. You can either buy a pre-made cable or make your own. There's a good guide to rolling your own at http://www.groundcontrol.com/galileo/ch5-ethernet.htm. For this hack, you'll need a standard cable, not the crossover type. Either way, use a Category-5 cable that can support gigabit networking speeds. (Even if your network isn't that fast, it is easier to use a cable that supports it than running a new cable when you upgrade.)
You'll also need to find a way to run the cable between the floors. If you have air conditioning or other pipes that run between floors, they provide a handy prebuilt route, and there's usually enough room to run a cable or two alongside them.
7.3.2. Plugging Into Wireless
Once you've run the cable, plug one end into one of the Ethernet ports of the wireless router and the other into the access point. To avoid interference, follow the manufacturer's instructions to configure the access point to run on a different channel than the wireless router. Select channels that are at least four numbers apart (say, channel 1 and channel 6). You should now have wireless coverage on both floors, as shown in Figure 7-5. Computers on the floor with the wireless router should connect to that, while those on the floor with the access point should connect to that instead.
Figure 7-5. Wireless coverage for the whole house
You can use the same SSID for both networks if you want, but I generally recommend that you use a variation to avoid confusion. If, for instance, your network is called HomeNet, set the router to use the SSID of HomeNet-first and the access point to use HomeNet-second.
7.3.3. Hacking the Hack
You can also adapt this to provide coverage to outbuildings and outdoor areas. Instead of running the Ethernet cable between floors, run the cable to the outbuilding or a location that provides coverage to the area. If you need to run the cable outdoors, either bury it in conduit at least eight inches underground or use special hardened outdoor Ethernet cable running along a fence or between poles. Gel-filled direct burial Ethernet cable is also available, budget permitting. In any case, the maximum length you can run is around 100 meters. Any longer than that and you will need to add a switch or hub to the run, or look at using a wireless link [Hack #69].
Bluetooth, Mobile Phones, and GPS
Network Discovery and Monitoring
Wireless Network Design
Appendix A. Wireless Standards
Appendix B. Wireless Hardware Guide