Codec and transcoding configuration when integrating CCM and CCME

Unanswered Question
Nov 7th, 2008

Hi Gurus,

After one-day reading, I am still not clear about how to configure codec and transcoding when integrating CCM and CCME.

Customer Environment

Central site:

CCM 4.2

Unity 4.x

Router and DSP resource are unknown

Remote sites:

one 2821 router with CCME 4.1, CUE 3.1, DSP-PVDM2-32, and a T1 PRI to PSTN. This CCME router register as H.323 gateway in CCM.

one 2821 router for site-site IPSec VPN and Internet access. Inter-site VoIP calls go through this router.

Only G.711 is currently used in the whole environment. The reserved bandwith can support four G.711 inter-site calls. No gatekeeper and CAC are configured. Inter-site VoIP calls have dropped sometime. There is no problem with PSTN calls.

I am thinking to change the codec of inter-site calls to G.729 so that more calls can be supported.

Here are my questions:

1. How can I configure g.729 codec in both sites? In each device, gateways, CallManager?

2. Obviously, transcoding is needed, should transcoding resource be available in both of centeral and remote site? How is it be configured?


I have this problem too.
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btmulgrew Fri, 11/07/2008 - 15:04

Hi - micahelzhq, I'm not entirely clear on your design, but if all phones register with CCM4.2 at main site and remote CCME is being used for (WAN failure) failover, you just need to use the CCM regions feature. This will allow G729 calls between sites and G711 within. No transcoding should be required on CCM or gateway as long as all Cisco UC Phones are set to accept call on G711 and G729.


michaelzhq Fri, 11/07/2008 - 15:15

Thanks for your reply.

Maybe I need to make the questions clear.

1. Phones in central site register with CCM4.2

2. Phones in remote site register with CCME 4.1. The remote site is a completed, independant system. Its gateway registers as a H.323 gateway in CCM 4.2, a VOIP dial-peer is the only configuration related to CCM.

3. The reason I ask transcoding is that CUE only support g.711.



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