We've had SIP trunks operating on a pair of 3300s and two Audicodes SBCs. Within an hour of each other, the trunks on each controller went down and even after a reboot failed to re-register. The SBCs are complaining the Mitel isn't accepting a connection on UDP 5060, which is the configured SIP protocol and port. SIP maintenance commands don't return any output at all. SIP licenses are still allocated.
It's as if the SIP capability has been completely removed from the two controllers, and yet the configuration wasn't altered. Has anyone experienced this before?