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Dial Backup Solution


We are trying to implement a new dial backup solution for our WAN. We have ~900 remote 2610 routers dialing into a AS5300 when they lose their frame relay circuit. I have been able to authenicate the remote routers using tacacs, but I would like to assign a ip address also.

I'm having trouble configuring the ACS (on NT) server to do this? Also, where can I assign the ip address? On the remote router Async/Bri interface or on a virtual access interface on the host? Plus, how do I configure the router interfaces?



Re: Dial Backup Solution

Common problem with a wide range of possible solutions. My preferred solution is to use unnumbered interfaces assigned on the calling router and dial on demand routing. There are examples in the hub and spokes chapter of my book High Availability Networking with Cisco. See my web site ( for more info and example configurations from the book, including tricks for using multiple hub access servers.

Note that the book examples use local authentication. There is nothing magic about that (other than not requiring a TACACS server :-). Also, if you use my trick of defining identical IP target addresses on each hub router, make sure you have unique loopback addresses defined with higher numeric values so routing protocols like EIGRP and OSPF use unique IP addresses for the router ID.

Good luck and have fun!

VIncent C Jones

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