topic Re: AP 2602 - AP cycling through dot11_set_rm_scan and dot11_return_serving_channel in Wireless

AP 2602 - AP cycling through dot11_set_rm_scan and dot11_return_serving_channel

gary_the_network_guy — Mon, 05 Jul 2021 19:53:01 GMT

So basically I got complaints regarding bad wireless connectivity and I found an AP not showing any signal in the heatmap.

Looked in on the eventlogs and found:

%EVT-5-NTC_PROC: dot11_set_rm_scan:DFS Disable
Process: Dot11 Offchannel PROCESS
%EVT-5-NTC_PROC: : d0 Channel 6 width 0
Process: Dot11 Offchannel PROCESS
%EVT-5-NTC_PROC: mh_driver_off_chnl_complete: to Channel 6 for d0
Process: Dot11 driver
%EVT-5-NTC_PROC: dot11_return_serving_channel: d0 Channel 1
Process: Dot11 driver

%EVT-5-NTC_PROC: dot11_set_rm_scan:DFS Disable
Process: Dot11 Offchannel PROCESS
%EVT-5-NTC_PROC: dot11_set_rm_scan: d1 Channel 52 width 0
Process: Dot11 Offchannel PROCESS
%EVT-5-NTC_PROC: mh_driver_off_chnl_complete: to Channel 52 for d1
Process: Dot11 driver
%EVT-5-NTC_PROC: dot11_return_serving_channel: d1 Channel 48
Process: Dot11 driver
%EVT-5-NTC_PROC: dot11_set_rm_scan:DFS Disable

My first thought was about some sort of Interference causing that cycling and complaints from costumers and the missing signal in the heatmap? How do I find the interferring device(s)?

Re: AP 2602 - AP cycling through dot11_set_rm_scan and dot11_return_serving_channel

Mark Elsen — Tue, 08 Dec 2020 15:49:14 GMT

- Cleanair capable ap's might offer a solution , here is a sample document :

https://content.cisco.com/chapter.sjs?uri=/searchable/chapter/content/en/us/td/docs/wireless/controller/7-5/configuration-guide/b_cg75/b_cg75_chapter_010000101.html.xml#:~:text=Choose%20Monitor%20%3E%20Cisco%20CleanAir%20%3E%20802.11,the%20interference%20device%20is%20detected.

Re: AP 2602 - AP cycling through dot11_set_rm_scan and dot11_return_serving_channel

Scott Fella — Tue, 08 Dec 2020 15:52:02 GMT

Swap the ap around with another one that is functioning and see if the problem follows the ap or not. Can help determine if the issue is with the ap or an issue in the area which you would need tools to find the source.

Re: AP 2602 - AP cycling through dot11_set_rm_scan and dot11_return_serving_channel

gary_the_network_guy — Fri, 22 Jan 2021 13:59:08 GMT

what tools would I need?

Re: AP 2602 - AP cycling through dot11_set_rm_scan and dot11_return_serving_channel

gary_the_network_guy — Fri, 22 Jan 2021 14:11:39 GMT

I also looked into the stats with:

show ap stats 802.11b <broken_ap>

Stats Information
Number of Users................................ 0
TxFragmentCount................................ 10084553
MulticastTxFrameCnt............................ 2160656
FailedCount.................................... 250381
RetryCount..................................... 1054785
MultipleRetryCount............................. 480771
FrameDuplicateCount............................ 0
RtsSuccessCount................................ 1895390
RtsFailureCount................................ 228626
AckFailureCount................................ 2770749
RxIncompleteFragment........................... 0
MulticastRxFrameCnt............................ 0
FcsErrorCount.................................. 92191931
TxFrameCount................................... 10214739
WepUndecryptableCount.......................... 5
TxFramesDropped................................ 21548

this is what I found