Unanswered Question
Jul 11th, 2007

Hi guys, we have some problem on a customer with CME 4.0 on Cisco 2851 IOS Version 12.4(9)T3; when an user make a cfa on an external line from his IP phone and if he received a call from PSTN the call fail 4 time to 5; if him recived a call from other IP phone the cfa work correctly. The router have 3 ISDN BRI Voice interface to PSTN and all other call (incoming and outgoing) work fine. I attach a part of the configuration and a log that indicate a cfa issue failed. All any suggestion is appreciate. Thx


I have this problem too.
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Paolo Bevilacqua Thu, 07/12/2007 - 00:02


Are you trying to CFA to 062222 ?

I suggest that you configure all the BRI ports active to PST in trunk-group so you can use a single dial-peer for outgoing.

Also suggestion is that you configure external call without any 0 or 9 digits as now possible with italian dialing plan. This will allow you to redial from "i received calls" and "click-to-dial" without added complications.

Telematic Thu, 07/12/2007 - 00:17

hi, I make this single dial-peer for make test in outgoing but there is the same problem if I use the 0 and i use all other port for outgoing calls. The problem append olny when I make a CFA from an IP phone and a I received a call from PSTN to that extension.

Paolo Bevilacqua Thu, 07/12/2007 - 01:56


CFA to external numbers work without problems.

Your trace was a bit hard to read because mixed with other debugs beside the fundamental "isdn q931". It appears the call is rejected because "invalid IE", however which IE is not clear. It 'could be' the calling number, but we know it works for direct calls, and TI is know to not reject the call if an arbitrary calling number is used.

Please take the trace again with debug isdn q931 only. Also take a trace of a normal call out so we can compare.

Paolo Bevilacqua Thu, 07/12/2007 - 03:00


I do not see the CFA fail debug. I go the trace you sent previously, the call is dropped because we receive a status message in connected state, that is technically illegal.

Are you connected to a TI switch ? Are the numbers made up ?

Telematic Thu, 07/12/2007 - 04:03

I don't know why i receive a status message in connected state. the BRI is cottected to PSTN of Telecom Italia. what I see is that when the call forward all place the call to outside to the numer 062222 and this is established, immediatly the first incoming call are terminated.

Paolo Bevilacqua Sun, 07/15/2007 - 23:37


it seems the TI switch is not happy with the way the incoming call is handled. On the other hand I'm not even sure the router is right in closing the call on receipt of a status message.

I haven't seen this before. Can you try "isdn send-alerting" under interface and take the CFA trace again ?

Telematic Sun, 07/15/2007 - 23:42

hi, the isdn send-alerting was already configured under the bri interfaces. I not understand why the TI would not happy; I just make a call routing. thx

Paolo Bevilacqua Mon, 07/16/2007 - 00:49

The problem is not with the call you make, but the one you received. The status message that leads to disconnect, is on the incoming call, not the outgoing one. There is only one thing that is a bit out of ordinary, thst is, on the outgoing call, we receive a "connected number" of 0x0c3.


Does it happens will all the number you CFA to?

Which IOS are you using? Can you try 12.4(11)XJ4 ?

Telematic Mon, 07/16/2007 - 00:59

yes this happen with all numbers that I make CFA. the IOS is Version 12.4(9)T3

Paolo Bevilacqua Mon, 07/16/2007 - 03:01

Ok, I have a theory, but is very thin one. The theory is that the CME is sending some IE to the switch that it doesn't like, so the switch sends the status message and router drops the call.

The weak part of my theory is that from debug nothing can be seen about the illegal IE the switch is complaining about.

I'm afraid that for further troubleshooting this should be given to the TAC, possibly a BRI analyzer should be connected for analysis. Difficult to obtain, but not impossible.

Paolo Bevilacqua Mon, 07/23/2007 - 05:21


I noticed this bugs that seems to apply to your problem:

CSCsi94745 ISDN call is dropped in due to STATUS message from PBX

Symptom Call is dropped from GW in response to STATUS message from PBX.

Conditions Then CONNECT message has Channel ID i.e., some PBX complain and send STATUS message.

Workaround There is no workaround.

Please upgrade to 12.4(11)XJ4 and try again.


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