VoIP, problem transferring calls after upgrade of Router/IOS

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Aug 1st, 2007
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Dear all,

we have a Voice over IP connection to some offices abroad which are on both sides connected with a Cisco router via an E1 connection to an Ericsson MD110. It used to be a 3725 with IOS 12.2(13)T16 on both sides. Since we upgraded to a 2811 with 12.4(13r)T on the remote side, when ever a call is transferred on the remote side or an automatic diversion is set, we get a disconnect. ISDN debugging showed the error message: "Mandatory information element missing", see the attachment for full output.

Any ideas on what might be missing and what might be a workaround?

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paolo bevilacqua Wed, 08/01/2007 - 05:35
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the cause seems to be:

remote PBX sends to router:

*Aug 1 12:35:32 CST: ISDN Se0/2/0:15 Q931: RX <- USER_INFO pd = 8 callref

= 0x8226

User-User i = 0x00FEB07F030F82000D05098112, '4',

0xF0901101800F0D818585, 'LucieMAFFO', 0x0E10818687, 'HachimKoumare',

0x0C070081, '21410'

local router sends instead to PBX:

*Apr 21 22:51:07.802: ISDN Se1/0:15 Q931: TX -> USER_INFO pd = 8 callref

= 0x8E27

Note the information is lost. Consequently, local PBX clears with:

*Apr 21 22:51:07.830: ISDN Se1/0:15 Q931: RX <- STATUS pd = 8 callref =


Cause i = 0x81E07E - Mandatory information element missing

Call State i = 0x04

I'm not sure if there is a workaround. Can you try to upgrade to 12.4(11)XJ4 that has many bug fixes for ISDN and more ?

thesmiler Wed, 08/01/2007 - 05:45
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I could try. But upgrading from 12.2(13)T16 (on 3725) created the problem in the first place.

paolo bevilacqua Wed, 08/01/2007 - 06:05
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What happens it that bugs are created then fixed; supposedly they should not stay forever.

Else you can raise a case with th TAC, but the may ask you to upgrade anyway before filing a new bug.

You can investigate if the message is sent in H.323 and "local router" drops it, but I think it is more likely is that the message is never sent over H.323. That would isolate the defect on one or the other router.

pranabgaya Thu, 08/23/2007 - 23:46
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can u pls change the signalling type in d-channel config on router and on pbx aswell and retest.

can u upload the running config of both routers .


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