Hi,
I'm setting up a system: 3 CUCM servers (2 on Site A, 1 on Site B). On both sites A & B I have a 2921 Voice Gateway, connected to ISDN with 1 PRI. The Voice Gateways are controlled via SIP Trunks.
I want to set up failover to PSTN: if Voice Gateway on site A goes down, site B should be handling all voice calls. And vice versa: site B goes down, site A will be used for ISDN access.
If I create a Route Group with both Voice Gateways in it and the first one in line (using Top Down algorithm) goes down, then the calls to PSTN fail. If I force the other Voice Gateway as first one in the Route Group, then calls go to PSTN!
I tried also to create a Route Group with only 1 Voice Gateway in it and configured a Route List with 2 Route Groups in it (so Route Group for site A and Route Group for site B), but the same result: if the first one in line is not reachable, then calls fail.
Any idea why? SIP timers?
In normal conditions all PSTN calls are working.
Greets,
David
