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New Member


--moderator edit --

I have a 3640 router and 17 remote site on a 2520 router. Each branch has a

frame-relay connection. I now want to setup a backup connection using ISDN bri at the remote site. I need help on setting up the ISDN PRI on a 3640 router. I have already setup the interface. I need a sample config or some guidance on how to make all work.

Thanks if you can provide some additional guidance.

Cisco Employee

Re: ISDN PRI 3640

First you need to decide which backup scheme will be the best for your network..Here is the link which will help you for that.

After that above link has a sample configs for all the schemes (all the way down on that doc) that you can refer to..

New Member

Re: ISDN PRI 3640

I have read through Evaluating Backup Interfaces, Floating,Static Routes, and Dialer Watch for DDR Backup. I would like find out how to test the Pri on 3640 to make sure it works. I do have spare equipment and and a working ISDN line that I can simulate the branch connection. The choice that suite my network scheme is dialer watch for ddr.

New Member

Re: ISDN PRI 3640

We use ISDN as backup for Frame-Relay. That is we created on the central side dialer interfaces (each location ist own dialer interface with its own ip-address and dialer-string) and floating static routes, on the remote side only one dialer interface with ist dialer string to the central side and of course a floating static route to the central side. So when the Frame-Relay-link goes down ISDN will be used as backup. In this case the ISDN-link can be opened from the central side as well as from the remote side, depending which side sents its first interesting ip-packet.

Works fine, no problem !!

Edwin van Wijk

New Member

Re: ISDN PRI 3640

Dear Sir

I have 2 cisco 1750 routers on which i have terminated 2 diff bri lines , i have 1 pri line terminated on 2610 router, i want to dial into pri from both of my bri lines at the same time but want to set up same over frame relay, . Can you pl help me in configuring this, I have configured my 1750 for simple dialing out and on pri i have cretaed a dialer interface with two ip addresses. I tried to configure pri router with dialer rotary group command and with dialer pool member comamnd too. bnut in both the case i am able to use 1 channel of pri at a time. if one my bri is already connected then i call never get connected from 2nd bri to pri. Though technically i should be able to use all 30 channels of pri but i am able to use one at a time. How can i resolve this issue.

thanx in advance


Re: ISDN PRI 3640

You really should post this as a new question; it has nothing to do with helping the original poster with thier issue.

For the DDR issues, have a look here for some guidance.

New Member

Re: ISDN PRI 3640

try the following config

int controller 1

encap ppp

framing no crc

clock line

no shut

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