ISDN errors

Unanswered Question
Aug 30th, 2007

I have PRI ISDN connection between Cisco 2801 VoIP gateway and PBX (Bosch) also I have another PRI ISDN to PSTN. From some phones on PBX I have outgoing i incoming calls but from others I cannot make outgoing calls. In the attach I put debug isdn q931 for phones that cannot make a call.

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Overall Rating: 4.5 (2 ratings)
Avner Izhar Fri, 08/31/2007 - 07:32


Try to verify the B channel selection order, make sure that the PBX is using descending and the gateway is using ascending (to eliminate collisions).

Also, you can add the 'isdn bchan negotiate' under the serial interface, that might help.

IMHO your problem is not in the 'Channel_ID IE invalid 96' message, but in the channel negotiation process.

HTH, Avner.

Paolo Bevilacqua Sun, 09/02/2007 - 11:54

I agree with aizhar, thing is that PBX is not indicating a channel at all in the setuo message hence the router complains.

Which IOS on the router ?

Paolo Bevilacqua Mon, 09/03/2007 - 15:01

For a stable release please upgrade to latest 12.4 mainline or even better to 12.4(11)XJ4 that has many bug fixes.

After that please take the trace again and we can see what can be done in the case the PBX insist not indicating a channel at setup time.

Paolo Bevilacqua Tue, 09/04/2007 - 07:53

Should be OK, however it is an higher risk compared to XJ4 that is the fourth maintenance release and very stable in all my installations.

mljevakovic Wed, 09/05/2007 - 01:10

At first I will describe current situation. I have router 2801 with IOS c2801-spservicesk9-mz.124-3g (in last message I made a mistake I've put c2800nm-spservicesk9-mz.124-3g) and two E1 card.

Also there is Bosch PBX with E1 card to PSTN. I did next: took PRI ISDN from PBX(for PSTN) and put to one E1 card on router, another E1 card from router I've connect to PBX E1. In the attach is my configuration (I think it's correct.)

I've tried what you suggested me (aizhar "isdn negotiate-bchan" also "isdn bchan-number-order ascending" and "isdn bchan-number-order descending" but every time I got the same message "ISDN Se0/2/0:15 **ERROR**: CCPMSG_InCall: Channel_ID IE invalid 96 (0x60)"

(see the attach)

I didn't replace IOS with suggested version because I didn't have with me last nigh (2801-spservicesk9-mz.124-11.XJ4 is this one correct?)I will do it tomorrow night :(

As I said from digital extension on PBX it works but from analog is the problem).PLS any kind of HELP or advice. :(

Avner Izhar Wed, 09/05/2007 - 07:58

Looks like the calls coming from the pbx, does not have called party sent with them. and since your router has direct-inward-dial, it can't do anything with them.

Just to be sure, try to remove the direct-inward-dial from dial-peer 20 and see if you get a secondary dial tone and can dtmf the destination 4 digits.

R U sure about the primary-net5 and the network side you have configured on the pri interface? what can you see from the other pbx? It should send the called party hence my suspicions that the parameters might be wrong.

Let me know, Avner.

mljevakovic Thu, 09/06/2007 - 07:40

I'm sure that is PRI ISDN switch net5.Also E1 towards PSTN is "user" PRI and towards PBX is "network" PRI. In both cases PRI switch is "primary-net5".

In the first attach I put debug isdn q931 for successful call where user from local number 145 call outside number (mobile phone). In the second attach I put debug isdn q931 for unsuccessful call.

Also when I don't have DID in dial-peer 20 I have next situation: when I call numbers 286145 from outside I get sounds from router and after that I have to press local number 145 (in this case) and have successful call (phone rings).

Paolo Bevilacqua Thu, 09/06/2007 - 08:04


what your PBX is trying to do, is in-band dialing, as you can see it does not indicate a called number neither a B-channel. For this latter problem, it seems the router is providing a channel so it's OK. But the destination number is still missing.

Please try configuring "isdn overlap-receiving" under the interface and let's see if the router does recognizes the digits this way. If it does not, I can think of some trick using "connection plar", but the best would be if you can configure the PBX to send digits via D-channel, either enbloc, or overlap.

Avner Izhar Thu, 09/06/2007 - 08:12

If all the PRI is set correctlly with regards to the bosch side, then perhaps it is (the bosch) configured to not send the called number on this pri link.

Has this port ever worked (the bosch side)?

Looks like we need someone to check from the bosch side.

regards, Avner.

Paolo Bevilacqua Thu, 09/06/2007 - 08:16

As I was saying before, lack of called number means overlap dialing. The PBX will communicate the number to be called via tones or ISDN INFO messages, one for each digit dialed by the user.

This technique allows to avoid any inter-digit timeout associate with enbloc dialing, hence minimize post-dial delay.

So the interface has to be configured with "isdn overlap-receiving".

mljevakovic Thu, 09/06/2007 - 12:50

A current situation is that PBX use E1(PRI) to PSTN and serves loc numbers (this works now). We'd like to put another E1 in PBX and connect to router who should provide telephony services to remote location. But this doesn't work because the PBX cannot provide transition from PSTN's E1 to router's E1 (a guy who configure PBX said this).Because of this we put two e1s one to PSTN the second to PBX. We took PSTN's PRI from PBX and connect to one E1 on the router. The second E1 we use to connect to PBX.(Every time when we try this we work in the midnight not to interrupt services :()In my opinion (am I wrong?) PBX doesn't know now it's connected to router. So everything should be work.

Tomorrow I will try what you suggest but the first I will ungraded the IOS. I hope this will work.

Paolo Bevilacqua Thu, 09/06/2007 - 12:58


What you are doing is quite common and should work.

To avoid receiving dialtone on incoming calls you need to configure a DP that matches incoming-called number with direct-inward-dialing, eg:

dial-peer voice 1 pots

incoming called-number 603905..

direct-inward dial

Do not forget that most likely you will need isdn overlap-receiving on the PRI connected to PSTN as well.

mljevakovic Tue, 09/11/2007 - 05:46


at first thank you for all support what you gave me. But I still have the problem. I've changed the IOS also tried the command but the same errors I'm getting "Channel_ID IE invalid 96 (0x60)". Pls if you have time look th router log from the last attempt as also the schema of my network. If find any mistake which I made it pls show me or suggest some steps in configuration dial-peer or something else.

The behavior of the system is very strange because from some inside telephone I can always make a call (see the router log) but from some I cannot make a call. If you need more information or if you need specific detail pls tell to pick it up from the router.

Paolo Bevilacqua Tue, 09/11/2007 - 05:58


see that you are getting the INFORMATIONAl messages that will make the called number. But I see that all the numbers you tried were invalid. Call a valid number and should be fine.

mljevakovic Tue, 09/11/2007 - 06:37

Let you help me to understand:

For example I'm user on PBX when I want to call outside I press "0" and after that press the rest of number (061.., 033...,etc.)PBX removes "0" and send the rest of numbers to PBX.

Now I've just put PRI from PBX to router and router took PRI to PSTN. The User from PBX again press the "0" and dial the rest numbers. Which dial peer I have to have on router? The first:

"dial-peer voice 20 pots

answer-address 0T

port 0/2/0:15"

to reach the router and the second

"dial-peer voice 10 pots

description to PSTN

destination-pattern .T

port 0/3/0:15"

to reach PSTN. Is this correct? Or I have to have the first dial-peer

"dial-peer voice 20 pots

answer-address 33286...

port 0/2/0:15"

And this is for outgoing calls I mean from local phone to outside world.

In the case for incoming call I have to have next:

"dial-peer voice 30 pots


port 0/3/0:15"

"dial-peer voice 40 pots

destination-pattern ...


port 0/2/0:15


Are these correct?

Paolo Bevilacqua Tue, 09/11/2007 - 14:44


suppose you know that the shortest number that can be called to PSTN is three digits, a valid dial-peer would be

dial-peer voice 10 pots

description to PSTN

destination-pattern ...T

forward-digits all <--- important to prevent DP to consume matched digits

port 0/3/0:15

now for the other questions:

- you don't need answer-address unless you are trying to match calling number and do something special with it.

- you don't need port x/y/z for incoming DP with direct-inward-dial. You need instead correct "incoming called-number", eg:

incoming called-number .+

will catch everything, while

incoming called-number 33286... will catch that pattern only, the rest would receive dial-tone.

also remember that when collecting overlap on one side to send enbloc, you are looking for interdigit timeout to terminate collect and dial, so make sure the corresponding timer under voice-port is set low enough, like 4 or 5.

finally remember that having correct DP for outgoing will aslso help shortening and controlling calling from users. Suppose you know that all cellphones numbers in your contry start with 48 followed by seven digits, then:

destination-pattern 48.......

forward-digits all

will produce no wait for interdigit timeout for calls to cellphones.

Hope this helps, please rate post if it does!

mljevakovic Wed, 09/12/2007 - 00:16

I'll do it tonight. Also I'll hope it will help us.

I want to vote for you with maximum points for all your effort until now. But also I 'll hope will be in touch till end of this issue.


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