There are not any real time messages that we are depending on besides the control channel between the AP and vWLAN. The AP checks for the control channel every 20 seconds and after 12 failed attempts, the AP will deem the control channel was been lost. At this point the backup SSID would begin to be broadcasted if configured. If there is not a broadcast SSID configured, the AP would then fail over if there was a High Availability vWLAN. If neither of these are true, the AP would reboot if the AP Control Channel Timeout (Configuration > System > Settings > Domain) is left at the default of 0 seconds. The AP Control Channel Timeout is the time in seconds before APs reboot if control channel is confirmed to be lost to the vWLAN (defaults to 0, meaning APs reboot immediately after confirming the control channel is lost).