I have a problem with our remote branch 7970 phones re-registering intermittently. I appreciate this is question that could be be any number of things and I am speaking with our WAN providers at present.
However, I have a hunch that it might be firmware related.
We recently upgraded our CUCM cluster from 6.1(4) to 7.1(3)SU2. I left the firmware on 8-5-3 and plan on upgrading it soon. However, this week we had our branch phones re-register more frequently than normal.
On our previous CUCM version we were running the 7970 firmware 9-0-2 and our phones seemed pretty stable for at least 3 weeks. However, when I was running 8-5-3 and 8-5-4 we seemed to experience the problem more often.
Has anyone else experienced this problem? Our local phones in London are completely stable. I even had a test phone setup in London pointing to the branch subscriber and that remained stable also.
We are running G7.11 across our whole cluster and bandwidth utilisation isn't a problem either. Some branches are not even on active call when the phones drop out.
Any ideas would be appreciated.