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Configuration of ISDN hunt groups

How can I configure ISDN hunt groups.If I have two BRIs( in the main site) how can I configure these BRIs.

In my situation I have few remote locations .These remote locations have ISDN as the backup for T1.

How can I configure these remote sites to dial to BRI hunt group in the main site.Means should I give two IP addresses to the two BRI interface in the hunt group.If this is the case how do I canfigure the dialer -map on the remote location as I can have only one dialer map to a location.

If I configure dialer group for these two BRIs on the remote site then there will be a problem as a dialer group has only one IP address and if a remote location has used that IP address then no other remote location can dial in to that BRI even thought the channels are free.

If any one can answer this it will be really helpful.


Cisco Employee

Re: Configuration of ISDN hunt groups

Dialer Profiles can solve this problem. Given that the main site's BRI's have been provisioned as a hunt group by the telco, the remote sites' calls could potentially land on either of main site's BRIs, which presents you with this problem. Dialer Profiles (as well as the less flexible Dialer Rotary feature) permit you to decouple the DDR logic from the physical BRI interface configuration. Dialer Profiles permit you to configure a unique Dialer interface for each remote site (i.e., Dialer Profiles). Each Dialer Profile can have it's own local IP address...each profile will also contain the remote site's hostname. The Dialer Profiles are bound to the physical BRI interaces by way of dialer-pool logic + authentication. A call can arrive on either BRI (now members of a common "dialer-pool"), as the user gets authenticated (you must have ppp authentication on both the physical and the Dialer interfaces), IOS will know which Dialer Profile to bind the incoming call to. The remote sites, can continue using the Legacy DDR dialer map (or dialer string) logic. The URLs below does a good job of describing the details and offer sample configs...


Re: Configuration of ISDN hunt groups

Thanks a lot it was very much helpful.

One more thing that I wanted to ask is -

If I have a remote site with T1 as the main link and BRI as the Backup ,how can I configure this to dial a BRI first ( which is in the main site ) and then

then a PRI if the dial to the BRI fails ( as there are other remote sites dialed in the main site).

The router with the PRI is having a T1 connection with the main site.

Can secondary ip address to the remote site and floating statics slove this problem.or will there be any problem with this.


New Member

Re: Configuration of ISDN hunt groups

I couldn't get clear picture so I am assuming two things

1. Central site has both PRI and BRI.

2. Remote sites have primary T1 connection and Backup BRI.

You can have multiple strings in your configuration. To dial out router will use these strings in order you put it in.



Re: Configuration of ISDN hunt groups

Central site has only BRIs.

There is one more site that has PRI which connects to the main site thorugh T1.

Remote sites have BRI as the back up to T1.

Cisco Employee

Re: Configuration of ISDN hunt groups

You should use dialer string logic, instead of dialer map logic on the remote site. Dialer Profiles (discussed in my previous post) and Legacy DDR both support the use of dialer string command. If the call to the first dialer string is busy, the second dialer string will get called. Note: if you currently are using dialer maps at the remote sites and you migrate to using dialer string logic, you'll need to modify your static route(s) to use the interface (BRI, if using Legacy DDR; or Dialer, if using Dialer Profiles) as your next hop, rather than an IP address. If you decide not to use the dialer Profile Logic at the remote site, here's a link which covers Legacy DDR w/ Dialer String...