We are running Expressway MRA X12.5.6. The other day, the external servers had trouble syncing with NTP.
Right after a reboot, NTP would sync up, but within a few minutes the jitter would climb to around 60000, the status would be REJECT, and time would be unsynchronized. When in this state, Jabber users would not work properly.
We also had a pair of Expressways in the same subnet for video conferencing that kept working properly with the same NTP servers.
There had been zero configuration changes between the successful operation of the MRA Expressways until they started to have this NTP problem. Various troubleshooting attempts did not yield success.
Eventually, the fix was to restore the two external MRA Expressways from backups. Everything started to work.
My question is what went wrong? I would appreciate any reasoned speculation so we can come up with some sort of explanation what may have happened so we can monitor for such in the future.
