I have two different versions of CUCM at two different offices. Let’s call them Office A and Office B.
Office A - (USA, Version 8.6, MGCP Gateway, 2 x PRIs)
Office B - (UK, Version 8.0, H323 Gateway, 2 x PRIs)
Inter-cluster trunk is configured on both CUCM meaning we can call local extensions at both offices. The long term goal is to upgrade CUCM at Office B to match Office A version then add Office B to CUCM group at Office A. The issue we currently have is that when the 2 PRIs at office B are down, external calls are not possible until the provider rectifies the ISDN issue.
The question is during the PRI outage - how do we route calls originating from Office B out of the CUCM/MGCP gateway in office A (tail end hop off)? What would be ideal is to apply CSS to each line which then routes the calls out of Office A.
At the moment, users are having to dial a different prefix i.e. 8 + number i.e. 8 + 001 646 xxx xxxx for tail end hop off which works. 9 + 001 646 xxx xxxx would be best utilizing a CSS which points to the CUCM/MGCP at office A.
Any help/ideals would be helpful.