CUCM - unknown SIP header transformation

[mcgeehonjp]

I am running CUCM/CUC 10.5.2 with mgcp controlled voice gateways and SIP trunking between CUCM and CUC.

The problem is that the SIP Invite from CUCM to CUC has the 'From:' and 'Contact:' header modified from the original DN.  This causes CUC not to recognize the inbound caller and thus not answer with the mailbox login greeting.

We have checked the transformation patterns, translation patterns, route patterns and  device pool and trunk for where the calling DN could have been modified.  Everything was working perfectly until recently.

My question is two part:

1.Is there a way to do a trace on CUCM other than DNA that would show you transformations/translations or similar digit manipulation?  We have checked all the obvious places and cannot find out why CUCM is modying the DN.

2.Are there any other places that may be the cause of a calling DN/extension being changed.

When I ran the analysis on DNA for the DN in question, it showed no modifications to the outbound calling extension.

[Manish Gogna · Accepted solution]

Hi,

This can be tracked by enabling detailed callmanager service traces on cucm and collecting the traces for a test call using RTMT. The traces can show the value of these fields for each hop, like when it reaches cucm from gateway and when cucm contacts Unity Connection, any intermediate call legs will also show up.

https://supportforums.cisco.com/document/126666/collecting-cucm-traces-cucm-862-tac-sr

Manish

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[mcgeehonjp]

Thanks.  Tracing didn't help, but it is very useful to look at and learn and can be used as an ellimination option.  The cause turned out to be a field on the enterprise parameters field that was inserting digits to the outbound SIP headers.  We removed this and the problem went away.