Troubleshooting Wireless Configurations

You can use a number of settings and configurations when working with wireless clients and APs. Some of the more common areas to check when troubleshooting wireless configurations include the following:

• Incorrect encryption-The wireless network security features are set on the wireless router or AP. This includes the wireless encryption methods that will be used-for instance, WEP or WPA. When encryption is enabled on the AP, the client must be configured to use the encryption and know the encryption key to be authenticated to the AP. When troubleshooting a connectivity problem between an AP and a wireless client, a common problem is that the encryption security settings do not match.
• SSID/ESSID mismatch-Whether your wireless network uses infrastructure mode or ad-hoc mode, an SSID/ESSID is required. The SSID/ESSID is a configurable client identification that enables clients to communicate to a particular base station. Only client systems configured with the same SSID as the AP can communicate with it. SSIDs provide a simple password arrangement between base stations and clients. The ESSID/SSID might be broadcast from the AP and visible to all receiving devices in the area, or it might be configured not to broadcast. Not broadcasting the SSID name adds another level of security because people cannot see the SSID name when browsing for wireless networks in the area. The ESSID/SSID would need to be obtained from the network administrator.
• Overlapping channels-When troubleshooting a wireless network, be aware that overlapping channels can disrupt the wireless communications. For example, in many environments, APs are inadvertently placed close together-perhaps two access points in separate offices located next door to each other or between floors. Signal disruption will result if a channel overlap occurs between the access points. You would typically change the channel of a wireless device only if there is a channel overlap with another device. If a channel must be changed, it must be changed to another nonoverlapping channel.
• Standard mismatch-The 802.11 standards commonly used today include 802.11a/b and g, with n as the new standard. When configuring client systems, be sure they are configured to use the same or compatible wireless standard; 802.11a is not compatible with b, g, or n, but b and g are compatible.