Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 
Community Member

Conferencing and Transcoding

is the following correct

1) you need to configure HW transcoder if you are using multiple codecs within CM (reigions)

2) you need to add a HW conference bridge when you require more conference resources.

does any one have details on HW conferences and transcoders.

Super Bronze

Re: Conferencing and Transcoding


1) Maybe - it depends what devices/software you are using. For example - if you have Cisco IP Phones on all sites, or Cisco Gateways, they will all support G729 or G711 (assuming you have sufficient DSPs on your gateways). So if you are calling between two phones or a phone and a gateway no transcoder would be required.

If you called from a phone into an IPCC port and IPCC could only support G711, and the phone and IPCC port were in regions that were limited to G729... Then a trancoder in the site that IPCC is in would be required.

2) CallManager supports quite a lot of conference participants in software - you can even have a dedicated node in the cluster providing conference services. The Callmanager software conference bridge is another service that only supports G711 however - so you would either need a transcoder to support G729 conferencing or a hardware conference bridge as you suggest.

HW conference/transcoders can be the same device - the most common types are standard Cisco gateways (e.g. a 2800) with lots of PVDM2 DSP cards.

This SRND section goes into some detail on this subject:



Please rate helpful posts....

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!
Community Member

Re: Conferencing and Transcoding


My question is which media resource group list should you apply the transcoding resources to for conferencing with the software conference bridge in CallManager? Does it get assigned to the CFB software, the IP phone that initiates the conference or the IP phone that gets added to the stream that is a G.729 phone and needs to transcode?

I notice with MeetingPlace Express (which is H.323) it requires that you specify the requirement of a MTP in order to force calls to that device to use the transcoder. Do you do something similar with the software CFB? If so, how do you? Thanks.

-Jeremy Combs


Re: Conferencing and Transcoding

If using software conf bridge, and you want to do conferencing with a g729 participant in the conf call, then we need to use transcoder and the transcoder resource should be in the MRGL that is assigned to the software conference bridge as the bridge will request the transcoding resource.

CreatePlease to create content