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Coverage hole pre alarm for client error message

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We have Cisco 4400 WLC in our network and all access point operate in lightweight mode. I have been observing these error messages in WLC logs

"Coverage hole pre alarm for client[1] 00:xx:xx:xx:xx:1c on 802.11b/g interface of AP 00:xx:xx:xx:xx:f0 (ap12). Hist: 0 0 0 0 0 6 233 205 108 0 0 0 0 0 0 0 0 0 0 7 203 71 0 0 0 0 0 0 0 0 0"


What could this error relate to? Also i have noticed that users face intermittent WIFI disconnections. I dont see any radio interference.

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Just a couple of questions regarding your WLAN; did you conduct a survey for AP placement, what version of code on the 4400, what types of STA’s are dropping off (phones, PC’s, MC’s), are you using auto-channel with TPC, have you loaded a site map into the controller?


The controller is constantly monitoring for RSSI from all AP’s and when using auto-channel with TPC has a tendency to lower the power too much. Also if you STA’s are CCX compliant and the controller is configed to use CCX then sometimes the controller will require that the clients use very low transmit power resulting in loss of data to the AP, Cisco’s valiant attempt to keep the noise floor low. Cisco came up with RRM to compete with Aruba however with the exception of very dense AP placements it has never worked. One thing to try is to config all AP’s to 20dbm and then let auto-channel figure channelization, and of course turn off CCX on the controller. And if you don’t want to see these error messages you can turn off coverage-hole detection.

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