Monday, October 25, 2010

CUCM conferencing remote sites without transcoders

Scenario: Two main sites with CUCMs clustered over WAN, remote sites are 28XX gateways. All calls are G.711 intra-site and G.729 inter-site to conserve bandwidth. Remote sites use IOS / DSP conferencing, main sites use CUCMs as software conference resources.

Q. How to conference users in main site using G.711 with remote G.729 users without transcoders, or just converting all inter-site calls to G.711? There are no transcoder resources available and bandwidth issues prevent conversion to G.711.

A. Create a new CUCM region using G.711 to all other regions. Create a new device pool with that region. Change CUCM conference resource to use new device pool (no resets necessary except for conference resource). Repeat for other CUCM server to allow registration on conferencing server to local CUCM server.

Now, calls between main and remote sites negotiate G.729 normally, but when main site conferences other local or remote sites, the calls renegotiate to G.711.