intermittend E1 ISDN PRI outcalling issue

Unanswered Question
Oct 19th, 2007

Hi All,

I'm having an issue with about 10% of my ougoing calls with Q931 issuing a release_complete message right after I send a SETUP message. Cause code is 0x80A2: no circuit/channel available. Checking with show idsn status I can see that there are plenty of available circuits (also DSPs are available). The fact that we can see a 0x80 in the cause code tells me that it's the router who is unable to get a circuit. The gateway is a 2821 running 12.4(6)T software.

As most calls go through, I suspect that it isn't a configuration issue. The call will succeed after a second attempt.

I have the feeling it might be linked to the fact that we are spoofing the interface. Could it be that layer 2 of the signaling channel doesn't get enough time to come up in order to deal with the request?

Any help or directions would be greatly appreciated.



I have this problem too.
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Paolo Bevilacqua Fri, 10/19/2007 - 09:06


should work fine. Two things:

- use 12.4(11)XJ that has many many bugs fixed.

- configure "isdn tei-negotiation preserve" to accelerate L2 on L1 re-activation.

Hope this helps, please rate post if it does!

Paolo Bevilacqua Fri, 10/19/2007 - 12:29

Woops, misread the title. This is PRI not BRI, interface is not actually spoofed.

TEI does not apply. Please upgrade IOS and get complete trace if it happens again. debug isdq931, various show dsp, etc.


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