FYI this morning we cut to UC as planned and were forced to back out shortly after.
A few weeks ago we upgraded from 7.1(2) to 7.1(3) to resolve some issues. Right after this upgrade we started getting some issues between Call Manager gateways and PBX's (Qsig) with 8 second delays before calls would ring through. (Call setup issues). We have a case opened on this now and have always been pointing fingers at the Call Manager upgrade to 7.1(2) and the PBX's (that haven't changed in years). The problem was pretty isolated and didn't occur often.... we only had 80 pilot users on UC -- little did we know UC was causing the problems.
So when we cut 6000 users over, the problem started happening with the 8second delays very frequently and took us out of business.
After backing out the problems have subsided.
Case with all the traces: 612605877
Problem is the call manager forwards a call without some required info to the PBX.