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Community Member

DDR/Dialer profile

Having tried and failed to get the following scenario to work can anyone offer some advise please?

Central router with one ISDN WIC dials another router to reach a particular network. That works fine. The snag is , that when the number it is dialing either fails or is unavailable, it should dial a different number to a different router, to reach the same network.

Sounds easy I thought - not so to date!

I've tried floating statics, different methods of defining the default route, two profiles etc. Tried EIGRP but I cannot have the customers ISDN line up just for the sake of EIGRP, due to cost issues.

So, using the same physical interface, I need to have a backup method to dial a different router

Any ideas/alternatives please?



Cisco Employee

Re: DDR/Dialer profile

All you need to configure is two dialer strings under the lagacy dialer interface one after the other in the order of which you want the router to dial. So with that router will always try to dial the first dialer string number and if it rings busy or the router do not get CONNECT at isdn layer, it will dial the next dialer string to get connection.

So all you need to have is a good backup scheme which triggers isdn dialing and two dialer strings under a physical or a dialer interface one after the other the way you want router to attempt the call.

Community Member

Re: DDR/Dialer profile


I thought I'd covered that already ... I'll give it a go though as I may well have missed it.

So, assuming that the second number is dialed, is there any way that the router will know if the first number is available again apart from when the connection has dropped out and is re-established?

Also, if MLP is used for the first dialer string, can you define only one channel for the second?


Cisco Employee

Re: DDR/Dialer profile

Router will always dial the first number. So lets say 2nd number is working fine but now the router need to dialout again because of load increased, it will still follow the top down approach for number dialing. So it will dial the first number again and if it fails again, it will dial the 2nd number. So the first number will be dialed all the time.

So everytime the call is triggred, router will dial the first one and then go onwards if it fails.

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