Way to get DFS notices in the WLC log

[derek.small]

If you are using UNII-2 Ext channels, is there a way to get DFS notices in the WLC log?  I thought they showed up there by default, but I just found DFS pauses in the logs on several APs, and there was nothing in the WLC log about it.  I've logged into about 20 APs to check and only found DFS issues on 2.  I really don't want to have to log into the other 200 to check them, but if only two APs are seeing DFS traffic, I hate to abandon all the UNI-2 Ext channels, when I can just set those two APs manually to UNII-1 or UNII-3 channels.

[rrudling]

You don't mention WLC model, AP model or software versions - but on 8540 currently running 8.10.130.0 we see logs like these on the WLC all the time - no special config required:

Radar signals have been detected on channel 104 by 802.11a radio with MAC: aa:bb:cc:dd:ee:ff and slot 1

Radar signals have been cleared on channel 104 by 802.11a radio with MAC: aa:bb:cc:dd:ee:ff and slot 1

Note that some AP models are more prone to false radar detection, especially if you use 80MHz channel width.  Reducing channel width (40 better, 20 best) and updating WLC code can help reduce these substantially.  There were a number of fixes to reduce false radar detections but it's fundamentally a problem with the chipset in certain models of AP.