I am adding on two subscribers at a remote campus to an existing CUCM cluster that resides at a main campus site. I am also adding on (2) Cisco 3925 routers at the remote campus for inbound/outbound call routing to the PSTN. Using Route List and Route Groups in the CUCM cluster, I have defined one of the gateways at the remote campus site as primary for outbound calls and one of the gateways at the main campus as a backup gateway to the PSTN. I have configured SIP trunks between the gateways and the CUCM cluster. (I have attached a very simple logical diagram).
I understand the configuration to all failover scenerios with the exception of one. If I lose all T1/PRI to the voice gateway at the remote campus, but still have network connectivity via SIP keepalives between the call manager and the voice gateway, how could I let call manager know to use the backup gateway at the main campus?
