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Webcast-Catalyst9k
New Member

ISDN connection problem

Recently, in the middle of the night, our ISDN line stopped working. Channel one's light is on and the TXD and RXD light only flash intermittently. Channel two's lights are not on at all. It is a Cisco 800 router. Show interfaces shows that "BRI0 is up, line protocol is up (spoofing)", "BRI0:1 is up, line protocol is up", and "BRI0:2 is down, line protocol is down". The phone company swears that it is our router and not their equipment. What could be wrong (at the phone company or with our equipment)?

5 REPLIES
New Member

Re: ISDN connection problem

Do a sh isdn status to see if you have multiple frames established, deb isdn q921 and 931 also try clearing the interface.

New Member

Re: ISDN connection problem

Thanks, I have multiple frames established, and have cleared the interface with no change. In the last day I have had 4 input errors on BRI0, 152 input errors on BRI0:1, and no input at all on BRI0:2.

New Member

Re: ISDN connection problem

Another thing to do is get an externakl isdn at both ends and dial each other up without using the routes and run a bert test.A while back I used a device called bri2000 at both ends by passing the routers and was getting a ton of errors, I

presented this to telco to rule out the routers and they eventually found the problem.

New Member

Re: ISDN connection problem

It doesn't sound like a telco problem since one of your BRI channels is up and you are getting multiple frame established. Do you have IP addresses on both ends of the WAN link? If so, see if you can try to ping directly across the link to the remote peer. This will let you know whether or not traffic is able to pass over that link. If so, you may have a routing issue that needs troubleshooting.

New Member

Re: ISDN connection problem

Try using the ISDN debug commands on the dailing router to see where the call is failing.

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