I have a WCS with four WLC440's connected to it. All are on version 126.96.36.199, but one seems to keep coming up as unreachable. The strange thing is that you can still telnet and use the GUI using its management port, but the WCS cant get to it via the service port. This problem brings down our guest wireless network as the web authentication page will not load. The only way to get this working is to reboot the controller.
We have had to do this weekly but now its happening every other day :-(