A couple interesting items I learned about Cisco Unified Communications Manager’s (UCM) Automated Alternate Routing (AAR) feature today.

1. In UCM 8.6, even with 1kb of bandwidth allocated for audio it still lets one call through. The second gets stopped or uses AAR. This one might be a bug… more research on that.
2. If a DN has a Remote Destination or Dual Mode phone associated to it, AAR will not kick in. The call will be placed to the RD only and the AAR path will not be used. I’m still trying to decide if this is desirable and I’m leaning towards no and a TAC case.
3. When exceeding Video Bandwidth for a location a call between two video phones will still traverse the WAN as usual if there is audio bandwidth available, but just set itself up as an audio-only call. Then if video bandwidth opens up and the call is held/resumed video will be added back into the call (unfortunately, looks like a hold/resume is required to get UCM to renegotiate the media. It’d be cool if UCM would keep track of the call and add video when the bandwidth opened up.).