ISDN Config

Unanswered Question
Aug 16th, 2009

can anybody provide me ISDN Config for backup serial interface.(complete config)


This is basic question but help is apreciable....

I have this problem too.
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Giuseppe Larosa Sun, 08/16/2009 - 10:47

Hello Ariujn,

you can use the file in attachment that shows the usage of dialer pools and dialer interfaces.


you need to verify the ISDN switch type on each side with the provider.

it is very important to define what is the interesting traffic that can trigger a call and can keep the link up.

Failing to do this leads to high bills to be payed

BRI requires a slightly different configuration but it can use the dialer profiles.

Hope to help


arjunsawant Tue, 08/18/2009 - 02:40

Hi Giuseppe...

Thanx for reply.

Pls find the attachment and help me to figure out this config.I want to configure autobackup, when my Rel link goes down my isdn will fire automatically.

Which steps require for avoiding unnecessary auto isdn Firing.

Thanx in advance....

Giuseppe Larosa Tue, 08/18/2009 - 08:05

Hello Arjun,

the key point is this:

dialer-list 1 protocol ip permit

you should use an extended ACL

dialer-list 1 protocol ip list 111

to define exactly what traffic is considered interesting

Hope to help


arjunsawant Tue, 08/18/2009 - 23:10


Thanx once again..

Is config correct?

dialer-list 1 protocol ip list 111

ip access-list extended 111

permit ip

deny udp any any eq ntp

Also on serial interface:

backup interface bri 0



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