The lay of the LAN
Because physical structures can eat up wireless signals, the layout of your home or office-- the placement of walls, hallways, and doors--counts for everything. If you ignore the floor plan, you may end up with a network that fails to reach every nook and cranny.
Break out the blueprints
First, size up your location. We know Wi-Fi works best for large spaces and 802.11a for high-throughput applications, while Bluetooth simply requires devices to be in close proximity. Our sample office floor plan shows how you could use just one Wi-Fi access point, centrally located, to cover a 20,000-square-foot workspace. It could also cover a typical one- or two-story home and the outdoor property around it. A single 802.11a access point could cover a modest house or apartment. Remember, wireless networks range vertically as well as horizontally; depending on the building's construction, you may be able to cover as much as a floor above and below the access point or router. Still, various physical and technical obstacles may require you to place networking devices strategically or add extras to compensate for problems.
Every wall and ceiling is a potential barrier to radio signals of any kind. Plaster walls are the easiest to go through, although older construction (which includes wood, lathe, metal screens, and plaster) can eat up signals. Steel or stone is the worst wall material; the signal barely trickles through. Glass acts like a reflector, bouncing back the signal. The only solution is to place the access points to avoid walls and dead ends. Sometimes the best technique is trial and error--testing a device in a variety of locations for the best receptivity.
Choosing the right gear
In most environments, you'll need three different types of equipment. Check out our side-by- side comparison of the different types of equipment.
| Pros | Cons | Approximate cost: Wi-Fi 802.11a |
|
| Router/gateway | Combines Ethernet router and access point in one small box | Can't mix and match devices to get best of breed | US$150 N/A |
| Access point | Powerful central radio for setting up wireless LAN | Expensive Involved setup Sometimes hard to get it in the best position |
US$150 US$250 |
| PC Card | Small, power-efficient radio for notebooks | Puts extra power drain on battery-operated equipment and takes up a PC Card slot | US$75 US$125 |
| CompactFlash card | Very small For use in PDAs and cell phones |
Range is limited Devices are expensive Battery drain cuts into runtime |
US$100 N/A |
| USB radio | Desktop or notebook radio that connects via USB port With a boom antenna, it can be directed to get best signal |
Bandwidth is often too low for high-speed LANs | US$80 N/A |
| Bluetooth | Radio connects to desktop computer via internal card slot, but antenna is stuck behind PC | Have to open computer to install Some products require a PC Card to operate |
US$75 US$150 |
Every device you want to network will need a radio for exchanging communications wirelessly. If you have an older notebook, you can easily add a wireless PC Card adapter (such as the Orinoco or a USB radio), while newer notebooks such as the Dell Inspiron 8200 offer these features as standard equipment. (There are currently no integrated 802.11a radios available for notebooks.) Smaller CompactFlash cards such as the D-Link DCF-650W work well for handheld computers, but they're expensive and have limited range. For desktops, think USB or PCI adapters. The WECA logo assures Wi-Fi compatibility, but the organization's process for testing 802.11a devices is just getting started.
Once all your devices are wireless ready, they need a basic access-point (AP) radio to communicate. An AP can act as the wireless network's hub, letting multiple computers share a broadband connection, or it can be hooked up to a wired network to add wireless devices. If your network needs to span larger spaces, you can always add extra access points and place them in an overlapping pattern to minimize dead spots. You can connect the extra access points to your wired network or use them as bridges to relay the signal to other APs.
If you want to create a network combining both wired and wireless connections, a wireless gateway, which adds an Ethernet router, would be a good choice. Wi-Fi devices can be an inexpensive, one-stop distribution center for your wireless LAN.
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