I have two main sites, every with router with ISDN PRI link. Other branch offices have ISDN BRI link for backup and they will connect to both sites.
I'll use watch groups on branch side and two dialer string command. If first main PRI link doesn't work, it tries to dial the second one.
But, I have doubt how to configure main sites, how to configure dialer interfaces (can I use only one dialer interface) and what is with IP address, should I use unnumbered interfaces or put static IP addresses for every branch office? How will this work.
Does anyone have suggestions how to configure these routers?
I don't have radius or tacacs server and all configuration shoul be on routers.