The coverage hole alarm is sent by Lightweight Access Point Protocol (LWAPP) to the Cisco Wireless LAN Controller (WLC) or Access Control Server (ACS) if the clients on the access point (AP) are detected at low received-signal-strength-indication (RSSI) levels.
If clients on an AP are detected at low RSSI levels, Cisco lightweight access points send a coverage hole alarm to the Cisco WLC or the Wireless Control System (WCS). This indicates the existence of an area where clients continually get poor signal coverage, without a viable location to which they can roam. Look up the historical record of access points in order to see if these alarms are chronic, which indicates the existence of a persistent coverage hole as opposed to an isolated problem. If the historical record information of access point is valid or correct then the Cisco Wireless LAN Controller adjusts the access point power levels in order to correct the detected hole. If not, accurate location information can be used in order to help rectify the problem.
Refer to Using Radio Resource Management to Deliver Secure and Reliable WLAN Services for more information on Radio resource management.
The signal is weak or fluctuating
Wireless LAN Controllers
Lightweight Access Points
Wireless Devices Errors, Warnings, Statistics and Log Messages
Wireless LAN Controller Errors, Warnings and Log Messages
Lightwieght Access Point Protocol (LWAPP)