We have Cisco Call Manager implemented and our five remote branches are all using Cisco IP telephones.
Each remote router is configured with SRST. Each router has it's own PRI with a block of DID numbers.
The calls from branch to branch all go through the Main site CAll Manager via our MPLS data cloud and everything else
(Branch inbound/outbound calls outside our network) goes through the PRIs for the branches.
When we loose MPLS connection to the branches and they loos connectivity to Call Manager, they loose all call capability outside of their branch.
I can see in the branch router config that the phones are set up to get a DHCP address from the router and other parts of the voice config.
My understanding is that SRST is supposed to allow the router to act as a limited Call Manager to route calls when we loose data connectivity, but the branches cannot receive or place calls other than internal to the branch from IP Phone to IP Phone.
Is SRST capable of allowing calls using the PRI in these situations?
During Data network outages, the branch managers have to use Cell Phones to place calls.
It seems that if the PRI works and is part of the router config, it is a short jump from only internal calls working during data network outages to being able to place calls via the PRI.