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.

MBXSuite tool for troubleshooting Unity mailbox issues

I recently learned about a useful tool for troubleshooting Unity/Exchange mailbox issues. It's located in the \CommServer\TechTools folder, and it's called MBXSuite.exe.

To use it:

1) Select the user whose mailbox you want to test with.
2) Select the Unity service account you want to run as--usually UnityMsgStoreSvc.
3) Check "Verbose Diags"
4) Click "Logon Mailbox" and check the Diagnostics pane for errors.