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Automated testing of ISDN


We have a network of more than 500 leased lines ( 64 kbps ) backed up by ISDN lines. But coincidently when leased lines fail even ISDN fails. Very few cases are where we get ISDN backup when leased line fails. It is practically impossible to test ISDN connectivity on a regular basis in production environment. It is very difficult to make any link down for testing purpose. Even if we clould test that ISDN call is getting established from source to destination , it will help us a lot because configuration wise everything is ok.

Thanx in advance

Subodh Bapat


Re: Automated testing of ISDN

Hello Subodh,

you can use the command 'isdn test call interface' to test an ISDN connection, e.g. :

isdn test call interface bri 0 123456

As for why your ISDN backup is not working properly, there could be various reasons. You say that when your leased line fails, the ISDN (backup) fails as well. There is a chance that the problem is with the provider equipment, where both the leased line and the ISDN are connected to the same (failing) device.

The problem might also be with the configuration of your backup. There are numerous ways to configure the ISDN backup, can you, if possible, post the configuration of one of your routers ?




Re: Automated testing of ISDN

one of the biggest problems i've seen with very large ISDN backup environments. (100+ sites) has been the telco.

not seeing any traffic on the BRIs for months and months on end, their switches would bring down the ISDN. when our sites would fail due to a frame relay failure or the likes, the BRIs would not come up.

(they would try as the router is configured but the layer1 would be down so it just couldn't happen)

verify with your telco the status of all your ISDN connections and see if they impose any type of 'ISDN down' state if they do not see traffic over those links for some period of time.