CUCM CDR Cause Codes

Lately I've been doing a fair amount of work with CUCM call detail records. The cause codes are always a pain, since they're listed as numeric codes that correspond to meanings listed only in otherwise obscure documents.

To help with this, I created a big list of all the different cause codes used in Cisco Unified Communication Manager call detail records, put them into Python dictionary format, and posted them on Github:

https://github.com/jayswan/cdr/blob/master/causecodes.py

They should be human readable as-is, and easy enough to convert into hash tables for use in other scripting languages. Hopefully this will save someone from having to pore through the Cisco PDFs that otherwise are the only source for this information. I used the CUCM 6.x documentation when creating it, but it should be quite similar for other versions.

One of these days I'll clean up my CDR analysis scripts enough for public consumption.

IP phones show bogus "unknown" status in UCM

If you end up with a bunch of normally functioning, non-problematic IP phones showing up as "unknown" instead of "registered" in CallManager administration, you can restart the RIS Data Collector service on the publisher to solve the problem. This doesn't affect call processing, but it does seem to restart some media resources like the annunciator, etc.

Weird application interactions

Recently we made some changes to our media resource configuration in CallManager 6.x. Specifically, we stopped using DSPs on a 6608 blade in a Catalyst 6500 and started using DSPs in a couple of 2811 routers. Immediately after this change, a couple of users reported that they could no longer make outbound PSTN calls that transit a particular H.323 gateway. The weirdest part was that if they rebooted their 7940 phone, they could make a single call, but all subsequent calls would fail with a fast busy until they rebooted again. Calls through other gateways worked fine.

A ISDN Q.931 debug showed that the second outbound call was setting up as "unrestricted digital" instead of "speech".

I went 'round with TAC about this for a few emails and they were getting ready to blame the telco (?!) when I realized that the thing these two users have in common is VT Advantage (a Cisco desktop video-conferencing application). I asked them to turn off VT Advantage, and presto, all calls now worked.

Upgrading to the latest VT Advantage version solved the problem completely.

Why a change in media resources would affect outbound calling through a single H.323 gateway on users with an old version of VT Advantage is beyond me, but that's my story and I'm sticking to it.

Changes don't take effect in UCM 6

If you make a change to a Cisco Unified Communications Manager 6.x system and it doesn't seem to take effect, try restarting the Database Layer Monitor service and the TFTP service. This can be done during production hours.

In my case, the change in question was a change to the CallManager Group setting in a device pool.

CallManager Trace Decoding Tools

Triple Combo looks to be a nice tool for decoding CCM/UCM trace files:


http://www.employees.org/~tiryaki/tc/

In the past I've also used TranslatorX, which is good but has some missing pieces:

http://www.employees.org/~pgiralt/TranslatorX/