Deploying Secure 802.11 Wireless Networks with Microsoft Windows
Wireless AP Troubleshooting Tools
Although the set of troubleshooting tools for wireless APs varies with each manufacturer and with each model, some of the more common troubleshooting tools are the following:
Panel indicators
Site survey software
SNMP support
Diagnostics
These tools are described in the following sections. Consult your wireless AP documentation for information about the set of troubleshooting tools provided with your wireless AP.
Panel Indicators
Most wireless APs have one or more indicators, status lights that are visible on the housing of the wireless AP, from which you can obtain a quick assessment of the wireless AP s hardware status. For example, you might see the following:
An indicator to show that the wireless AP has electrical power.
An indicator to show general operation status. For example, the indicator might show whether the wireless AP is associated with any wireless clients.
An indicator to show wireless network traffic. This indicator might blink for each frame received on the wireless network.
An indicator to show data collisions. If the blinking of this indicator seems excessive, evaluate the performance of the link using the methods suggested by the wireless AP vendor.
An indicator to show wired network traffic. This indicator might blink for each frame received on the wired network.
Alternately, the wireless AP might have a liquid crystal display (LCD) panel that shows icons indicating its current status. Consult your wireless AP documentation for information about panel indicators and their interpretation.
Site Survey Software
Site survey software, which you use during the deployment of wireless APs to determine their optimal placement, is typically installed on a wireless-capable laptop computer from a CD-ROM provided by the wireless AP or wireless network adapter vendor.
As described in Chapter 7, Wireless AP Placement, the site survey software is used to determine the coverage volume and where the data rate changes for each wireless AP. If wireless clients cannot connect to a specific wireless AP, use the site survey software to perform a site survey for that wireless AP. There might have been a change in the devices that create interference and objects that interfere with signal propagation since the original site survey and AP placement was done.
SNMP Support
Many wireless APs include a Simple Network Management Protocol (SNMP) agent with support for the following SNMP Management Information Bases (MIBs):
IEEE 802.11 MIB
IEEE 802.1 PAE (Port Access Entity) MIB
SNMP Management MIB (described in RFC 1157)
SNMP MIB II (described in RFC 1213)
Bridge MIB (described in RFC 1286)
Ethernet Interface MIB (described in RFC 1398)
IETF Bridge MIB (described in RFC 1493)
Remote Monitoring (RMON) MIB (described in RFC 1757)
RADIUS Client Authentication MIB (described in RFC 2618)
The SNMP agent on the wireless AP can be used in conjunction with your existing SNMP-based network management infrastructure to configure your wireless APs, set trap conditions, and monitor loads on your wireless APs.
Diagnostics
Diagnostics for wireless APs can be of the following forms:
Diagnostic facilities that are available through the main wireless AP configuration program, such as a Windows program provided on the wireless AP vendor product CD-ROM or a series of Web pages.
Diagnostic facilities that are available through a command-line tool or facility, such as terminal access to the wireless AP.
The exact diagnostic facilities of a wireless AP vary from one wireless AP to another; however, the purpose of the diagnostics is to ensure that the wireless AP is operating properly (from a hardware standpoint) and to validate its current configuration.