The network is setup in a hub and spoke scenario. The primary data connections from the main branch to the 5 remote branches are point-to-point T1s. The main branch (Cisco 3745)has two BRIs (4 B channels) and each remote branch (Cisco 2621XM) has one BRI. The main branch ISDN configuration must have the ability to support up to 4 branches at one time (each on a separate B channel).
The issue I have run into is routing. I have configured the IP address on the physical BRI interface but I wonder if that is causing problems when two remote branches are connected to one BRI at the main branch. The main branch router will only hold one route through the BRI interface. I am also having trouble getting the third remote branch connected to the main branch via ISDN because if the first BRI is busy or unavailable, it is not trying the second BRI for connection.
Any suggestions on the cleanest, most effective configuration to implement ISDN backup with authentication based on the scenario described above? I am happy to include more details, just let me know. I have been searching so many documents, they are all running together for me now.