I have 2 4402 controllers with ~20 APs on each. For some reason, all the APs will go down on one controller and migrate to the other, like the controller has gone offline. This only happens to one controller. I've checked the network switches and no errors. This happens every 6 hours or sometimes completely random. I have the latest version on the controllers. Any ideas on where to start to look?
Have you tried to compare the settings on Controller1 with the second controller? I suspect the interface settings on the controller. In your case the APs are trying to stay on the controller but they can't because the AP interface manager settings are wrong. To prove it, what happens if you completely turn-off the good controller - will all APs stay up continuously on the other one?
I turned the 'bad' controller off, but I am getting many of these errors:
An Alert of Category Security is generated with severity 1
by Switch controller_1/192.168.1.50 .
The message of the alert is IDS 'Disassoc flood' Signature attack detected on AP 'AP34' protocol '802.11a' on Controller '192.168.1.50'. The Signature description is 'Disassociation flood', with precedence '7'. The attacker's mac address is '00:12:7f:47:d5:7d', channel number is '36', and the number of detections is '30'..