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Tips for Setting Up Wireless Networks

This week we outline some of the more common problems you might run into when attempting to set up a wireless network. We'll also introduce a low cost alternative to 802.11b, HomePlug.

By Ron Pacchiano

Q. I recently installed a USB wireless network adapter into my desktop PC. The adapter is configured to obtain its IP address automatically, but for some reason can't. No matter what I try, the card's configuration utility always reports an IP address beginning with a 169, when my router's DHCP scope is supposed to be assigning IP addresses of 192.168.0.x. This leads me to believe that the USB adapter and the wireless router are not communicating with each other. Windows Device Manager indicates that the adapter is functioning properly and I've doubled-checked all of my settings, but I still can't get it to work. Do you have any suggestions that might explain why this is happening and what I can do to fix it?

A. I believe you are correct in your assumption that your USB wireless adapter isn't communicating with your router. If your network adapter is reporting an IP address of 169.254.x.x, it typically means that your Windows client is unable to connect to a DHCP server. There are a variety of variables that could be causing this to happen. Here are some of the things you should check to help resolve this situation.

First, you should verify that both devices are using the same SSID. The SSID, or Service Set Identifier, is a unique 32-character identifier which differentiates one wireless LAN (WLAN) from another. All devices attempting to connect to a specific WLAN must use the same SSID.

Next, you need to confirm that both devices are set to broadcast on the same channel. There are 11 channels available, and I believe 6 is the default channel for most 802.11b products. Wireless networks also operate in one of two modes -- Infrastructure or AdHoc; your USB wireless adapter should be running in Infrastructure mode. In AdHoc mode, a wireless client can communicate directly with other wireless clients without the need for an access point or router. In Infrastructure mode, however, an access point or router is needed for a wireless client to gain access to the WLAN network.

To make things easier on yourself, I would highly recommend you disable WEP encryption while building your wireless network. Get the network up and running before worrying about securing it. This will make troubleshooting much easier.

When you are ready to enable encryption, there are a few things you should be aware of. For starters, you should make sure that the encryption type you are trying to use is available on both products. With products made by the same vendor, this shouldn't be a problem. However, if your router was made by D-Link and your USB adapter came from Zoom, for example, you might run into some difficulties.

Encryption comes in many flavors, with the most common being 64- and 128-bit, and some products, like those from D-Link, can even support 256-bit encryption. In order for encrypted devices to communicate with each other, they need to share a common key. Key types are typically made up of either HEX (Hexadecimal) or ASCII (American Standard Code for Information Interchange) characters. Both the USB wireless adapter and the router must be using the same encryption level and key type. While this may sound simple enough, some vendors will implement encryption differently, requiring you to experiment with various WEP configurations.

For example, we recently tested an SMC Wireless Bridge with a D-Link Wireless router. Both devices were configured to use a 128-bit encryption key. Yet even with what we thought was an identical key, the two devices were not able to communicate with each other. After a bit of trial and error, we discovered that SMC's version of the key defaulted to ASCII, while the D-Link version defaulted to HEX. The SMC didn't offer a HEX option or even give an indication of which key type it was running. Fortunately, the D-Link did. Once that change was implemented, they worked fine. So you can see how WEP implementation can be somewhat tricky.

Once your USB wireless adapter and the wireless router are configured correctly, the DHCP service will automatically start assigning suitable IP addresses. Best of Luck!

Q. I have two computers in different rooms of my house and would like to share a cable modem between them. The primary PC is located on the 3rd floor of our house along with the cable modem. My second PC, used primarily for gaming, is located in my basement. I'd like to share the upstairs Internet connection with the PC in the basement, but between the distance and the concrete, I don't think a wireless connection is going to be feasible. I'd like to avoid installing a second cable modem, if possible. What do you think is the best way for me to go about doing this?

A. I don't think you'll have to resort to a second cable modem. Most 802.11b products have pretty good range, so even in your basement you should be able to get a decent wireless signal. And while it's true that concrete and distance can be problematic, they don't preclude you from using 802.11b products. The signal strength on these products can be increased to help compensate for the environment using tools like directional antennas or Repeaters. However, instead of spending a ton of money on all of these 802.11b products and accessories, you might want to consider a less expensive alternative.

HomePlug or Powerline networks use the electrical cabling already running throughout your house to carry data between your systems. They have a throughput rating of 14Mbps and support 56-bit DES encryption for security and privacy. They also don't use any device drivers, which makes them easy to install, and many of them can be purchased for about $100.

One of the best I've seen is the Siemens SpeedStream SS2502 Powerline Ethernet adapter. It's roughly the size of a pack of cigarettes and plugs directly into one of your home's standard power outlets. It connects to your PC's Ethernet adapter via an RJ-45 cable.

To setup a HomePlug network that would solve your problem, you would need two SpeedStream adapters, a cable modem router, and three RJ-45 cables. In the office upstairs, you'll need to connect the cable modem to the router's WAN port. Then use one of the RJ-45 cables to connect the PC's Ethernet adapter to one of the Router's LAN ports. Now plug the SpeedStream adapter into a nearby AC outlet and connect the second RJ-45 cable to another of the Router's LAN ports. Next, take the other SpeedStream adapter and plug it into an AC outlet next to the downstairs PC. Connect the SpeedStream adapter to the PC's Ethernet adapter with the remaining RJ-45 cable. After assigning an IP address to each of your network adapters, you should be good to go.

For more information about SpeedStream products you can check out their web site at http://www.speedstream.com/products_powerline.html. A complete review of the SpeedStream SS2502 Powerline Ethernet adapter can be found at http://www.practicallynetworked.com/review.asp?pid=508. Good Luck!

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