Q931 Translation for Dropped Call on PSTN

Answered Question
Feb 27th, 2007

Hello,

We had 3 dropped calls when making and receiving calls over an ISDN30 Circuit.

I searched in the Q931 Translator and dicovered one of the calls. I have attached the Q931 TRanslation output which may indicate (to the trained eye) why the call dropped.

Any help would be greatly appreciated.

Thanks.

I have this problem too.
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Correct Answer by Paolo Bevilacqua about 9 years 7 months ago

You can leave debug q931 on all the time as it is very little overhead. Debug output can be sent / saved in a variety of means, too many to mention here, but the easier way often is to configure "logging buffer" ad debug level, and buffer large enough to hold some days of data locally on the router. To see it, just do show log. You will see the router is saving all the significant events for you to see.

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Paolo Bevilacqua Tue, 02/27/2007 - 13:30

The "transient failure' code doesn't say much. How the trace as been taken ? Is a router, CCM, or what ?

paulblohm Wed, 02/28/2007 - 00:55

Hello,

The trace is from the Q931 Translation Tool on Cisco Call Manager 4.1 (3).

The Voice Gateway involved is a Cisco 2651XM with 1 Channelized E1/PRI port and 1 ATM AIM.

Hope this helps

Paolo Bevilacqua Wed, 02/28/2007 - 06:33

Ok. I can't even tell if the failure comes from network or router, and can't be correlated to any particular event. This CCM decode is too limited.

Why don't you retake it on the router itself with "debug isdn q931" and "terminal monitor". And since you're there, check that interface and controller counters are free of errors, slips, etc.

paulblohm Thu, 03/01/2007 - 05:16

OK.

The dropped call event hasn't happened since so I won't gain much in running a q931 debug at this moment to capture live debug data. Unless you know of a way of sending debug data to a log file? I could then consult this in the event of another call drop.

I did check the interface and controller stats at the time and all was OK apart from 3 Interface Resets. I have now cleared the counters and will check them periodically.

Correct Answer
Paolo Bevilacqua Thu, 03/01/2007 - 10:53

You can leave debug q931 on all the time as it is very little overhead. Debug output can be sent / saved in a variety of means, too many to mention here, but the easier way often is to configure "logging buffer" ad debug level, and buffer large enough to hold some days of data locally on the router. To see it, just do show log. You will see the router is saving all the significant events for you to see.

Please remember to rate useful posts!

paulblohm Fri, 03/02/2007 - 05:02

Thanks very much for your help.

It remains to be seen if the debugs offer more helpful information than Q931 Translator but at lest now we have two options...

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