Connectivity Troubleshooting

Properly configured wireless clients should automatically and quickly connect to the desired SSID. If this isn't taking place, it's time for some troubleshooting. Most wireless connectivity problems come down to either an incorrect configuration (like an incorrect password) or low signal strength. Without a strong signal, even a properly configured wireless client isn't going to work. Wireless clients use a multi-bar graph (usually five bars) to give an idea of signal strength: zero bars indicates no signal and five bars indicates maximum signal.

Whether configuration or signal strength, the process to diagnose and repair uses the same methods you use for a wired network. First, check the wireless NIC's link light to see whether it's passing data packets to and from the network. Second, check the wireless NIC's configuration utility. Typically, the utility has an icon in your System Tray that shows the strength of your wireless signal. Windows XP Professional's built-in wireless configuration utility-called Wireless Zero Configuration (or just Zeroconf)-displaying the link state and signal strength.

NOTE If you're lucky enough to have a laptop with an internally installed NIC (instead of a PC Card), your device may not have a link light.

The link state defines the wireless NIC's connection status to a wireless network: connected or disconnected. If your link state indicates that your computer is currently disconnected, you may have a problem with your WAP. If your signal is too weak to receive a signal, you may be out of range of your access point, or there may be a device causing interference.

You can fix these problems in a number of ways. Because Wi-Fi signals bounce off objects, you can try small adjustments to your antennae to see if the signal improves. You can swap out the standard antenna for one or more higher-gain antennae. You can relocate the PC or access point, or locate and move the device causing interference.

NOTE One trick that works for wireless networks that seem a bit flaky with a Windows XP client is to disable the Wireless Zero Configuration service on the client. To do this, simply open the Services applet in Administrative Tools and change the Startup Type option from Automatic to Disabled. Document your change, of course, so you'll remember to turn Zeroconf back on in case it doesn't provide the fix you want.

Other wireless devices that operate in the same frequency range as your wireless nodes can cause interference as well. Look for wireless telephones, intercoms, and so on as possible culprits. One fix for interference caused by other wireless devices is to change the channel your network uses. Another is to change the channel the offending device uses, if possible. If you can't change channels, try moving the interfering device to another area or replacing it with a different device.