Conference Bridge Resource, Region and Transcoder

This article will explain the relationship between CUCM Conference Bridge Resouce(CFB), Region and Transcoder.

First of all let's see the normal call within the same Region.

Then what happen when IP Phones use conference call in the same Region.

As you can see RTP stream will be mixed to CFB and passed to IP Phones(Callmanager CFB support only G.711 codec).

Next let's see the normal call between Region.

In this example call between Region Default(HQ) and Region BR_RG(BRANCH) will use G.729 codec.

So, when happen if we have conference call between Regions.

Because CUCM CFB support G.711 codec only, so conference call in this case will fail.

There are 2 solutions to make this work.

1. Using the Transcoder Resource.

This solution require DSP Resource in Router to register to Callmanager and system will automatically detect if Transcoder require or not.

2. What if I don't have Transcoder Resource(DSP quite expensive), another solution is to create Region for CFB and configure all other Regions connect to CFB Region using G.711 codec.

Note that normal call between 2 Regions still use G.729 codec but when IP Phone start to use conference call between 2 Regions it will switch to G.711 codec.