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New Member

what would happen if site to site conference call using G.729

conference bridge I am currently using is software conference , I am aware that Cisco software conference bridge only support G.711. and my project is a multisite project and site to site calls are via wan not PSTN. so my question is what would happen if a site to site add hoc or meet me conference call is made based on G.729. it doesnt work at all or there are some alternatives. I appreciate any input, thank you in advance

3 REPLIES
Green

Re: what would happen if site to site conference call using G.72

It wont work. You need a HW Conference Bridge or a Transcoder.

Obviously you will need to configure all to G711 but we dont want that BW oversubcribe your WAN link right?

Silver

Re: what would happen if site to site conference call using G.72

The main problem is that you will need some xcodes or MTPs in order to use the Software conf bridge, but be aware that using G.711 conf through a WAN link will decrease the available bandwidth and it might fail, for instance, G.711 uses 80 kbps, rather than G.729 that uses 24 (3 G7.29 calls per 1 G.711).

Here is the codecs' bandwidth utilization:

- G.711 call uses 80 kbps

- G.723 call uses 24 kbps

- G.729 call uses 24 kbps

- GSM call uses 29 kbps

- Wideband call uses 272 kbps

At this point the only option that you have is to get an HDV module and some DSPs and configure a HW xcode and conf bridge.

New Member

Re: what would happen if site to site conference call using G.72

There's a fairly simple alternative if you don't mind that conferences use G711. Just create a new region that uses G711 to all sites and place the S/W conf bridge in that region. Your normal IP calls will still use G729, but for the odd occassion when you need a conf, the S/W can still be used. Just make sure you take this into account with B/W and Qos calculations.

If B/W is an issue then go the H/W DSP path.

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