Incoming PSTN voice call over ISDN to CCM

Unanswered Question

My problem is that an incoming call to an ISDN line deivered through a Cisco2851 VIC2-BRI card does not get passed onto CCM to complete the call to a VOIP ext number. From the following debug ISDN q931 I get the following:

Cause i = 0x8081 - Unallocated/unassigned number

The following is the full transcript.

ISDN BR0/2/0 Q931: RX <- SETUP pd = 8 callref = 0x64

Sending Complete

Bearer Capability i = 0x9090A3

Standard = CCITT

Transfer Capability = 3.1kHz Audio

Transfer Mode = Circuit

Transfer Rate = 64 kbit/s

Channel ID i = 0x89

Progress Ind i = 0x8483 - Origination address is non-ISDN

ISDN BR0/2/0 Q931: TX -> RELEASE_COMP pd = 8 callref

Cause i = 0x8081 - Unallocated/unassigned number

I have this problem too.
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Paolo Bevilacqua Fri, 02/16/2007 - 09:16

Interesting, there are no numbers in the call setup. Ask telco to make that they send calling and called number as in any normal circuit of the world.

icabrera Mon, 02/19/2007 - 00:51

Hi, are you using h323 or mgcp with ccm?, if using h323 can you post the config?. Can you post the output of "debug voip ccapi inout" to try to see if the telco is sending you any number?


Paolo Bevilacqua Mon, 02/19/2007 - 04:22

As I said above, the definitive way to see what number are sent on ISDN circuits, is "debug isdn q931". Voip ccapi debugs are way too verbose to permit easy diagnostics and clear proof to be given to the simple minds of telco providers.

icabrera Mon, 02/19/2007 - 08:57

Hi, Cause i = 0x8081 means that the router is saying it's receiving the ISDN number in the correct format, however, the number does not belong to destination equipment.

But I can't see the called number at the full transcript in your post this is why I suggest you to use the other debug "debug voip ccapi inout", it's a very useful command and if you haven't used it before you can see at the CCO the next useful link:


If you see the number with this command then you'll know the problem, it can be the number the telco is sending you it isn't the number you expected for or it can be the number it's correct but the setup at the ccm it's not the correct (for instance, you could need add a prefix or something like that).

Finally, I asked you if you're using h323 or mgcp because it can be an incorrect configuration at the router if you're using h323.

You can ask to your telco to do some test too, but normally this is a very slow way so it's better try to find by yourself the problem.


Paolo Bevilacqua Mon, 02/19/2007 - 09:54

Once again, "debug voip ccapi inout" is useless in this case, precisely because "debug isdn q931" is already telling us that both calling and called number are not present in call setup.

Altough it is technically legal to place a call this way, it puts the router in trouble because it doesn't know how to further route the call.

The cause code returned is perfectly appriated, it means no number == no such number.

It does not indicate an incorrect format, but simply what the error text says "unexistent/unallocated number".

icabrera Tue, 02/20/2007 - 00:18

I'm not going to start a discussion about this subject because I'm only trying to helping someone to solve a problem, only that I want to say it's that cisco offers a lot of tools you can use for troubleshooting and it's good to know and use them, everyone decides what and how to use at every moment, and for me always it has been very useful trying to see all the points I mentioned previously.


Paolo Bevilacqua Tue, 02/20/2007 - 03:50

No discussion and no polemics. All help is appreciated and your point of view is welcome.

I was simply pointing out that because the ccapi is feed with parameters from the Q931 call setup, in this case the relevant is that one, that's it.

Best regards.

kumar.vijayarajan_2 Fri, 02/23/2007 - 06:43


If Service Provider is Not sending digits, you can use the "Connection plar" in serial interface to reach the specific extension.



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