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Unity and G.729

I am working through a large IPT rollout over MPLS (Sprint). Its been a long process but we have finally got to the point where QOS is working properly end_to_end and we have done extensive VOIP stress testing with NetIQ.

The one outstanding issue is that we are still experiencing random voice quality issues as it relates to Unity. It is garbled messages and prompts. The Unity servers were deployed using G.711 for the prompts and the site where Unity is located access Unity via G.711. They are not experiencing any quality issues. The issues are over the WAN where G.729 is used as the codec.

As I said earlier, we have a rock solid QOS (LAN and WAN) configuration so I am just not sure if its a transcoding issue or what is going on. We are using software transcoding within Unity and have also tried hardware transcoding using CMM's and 6608's.

Anyway, before this issue gets moved further up the chain, I wanted to make sure there isn't anything I am doing not in conformance with "best practices".

Unity is version 4.0(5).

New Member

Re: Unity and G.729

No answers, but thought I'd chime in..

I have seen similar issues to Unity using G.729 RTP when using G.711 prompts on Unity. The only resolution we ever came to on these was the use of native G.711 RTP streams to Unity instead, as an exception to the rest of the codec plan. Not exactly optimal of course.

At the time there was some discussion with Cisco TAC about using the G.729 prompt set instead and connecting *all* users to Unity via G.729 streams and using G.729 recording formats. But I never tried it and not sure how good that advice is either frankly.


Re: Unity and G.729

Yeah, I thats what kind of prompted me to ask this question. I saw a post by someone from Cisco that the largest Unity implementation out there actually used G.729 for all calls to Unity but I don't know the validity of that. I can see how it would help though, if you didn't have to transcode each prompt it would decrease the delay a little (and I stress little).

Currently, we have the Voicemail ports in a G.711 region like you said, but there are certain sites where there is high volume and G.711 isn't an optimal option.

Thanks for the response, I was just curions as to what info was out there and if Cisco could comment on that large Unity install and using G.729 for all prompts.



New Member

Re: Unity and G.729

Hi, I'm suffering from the same problem. Unity set for 711 recording and remote users using 729 are having problems. I'm also using a few call-handlers to control calls and they have issues with the prompts. All native 729 RTP streams work fine, only issue is through Unity.

Did you resolve your issue, or did you set the system to use 729 as the default?

Many thanks

Chris Habberjam


New Member

Re: Unity and G.729

I know this post has become ancient history; but i am having the same problems over our MCI MPLS network. End to end QoS is in play and i have priority classes written around the Unity traffic that are showing no drops whatsoever, but we still experience the problems with 729 sites on an occasional basis.

I am still recording in 711, but prompts are 729 as well.

Sorry to unearth the past, but have any of you expereinced success with different configuration options? The client is getting close to asking for a Unity in each of the 7 sites.

Thanks in advance,

Jan Pattishall

New Member

Re: Unity and G.729

I'm having the same issue. Was there any resolution to fix this kind of issue?

Appreciate any inputs.


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