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New Member

'Voice-class codec' ignored by Gatekeeper, is this a bug?

When our CCME router negotiates a codec with the Gatekeeper it only negotiates g711ulaw when the following 'voice-class codec' command is added to the voip dial-peer:


voice class codec 1

codec preference 1 g729r8

codec preference 2 g711ulaw


dial-peer voice 12000 voip

destination-pattern 12...

voice-class codec 1

session target ras

incoming called-number .

tech-prefix 1#

dtmf-relay h245-alphanumeric


Gatekeeper does not negotiate g729r8 unless I remove the 'voice-class codec 1' command & force g729r8.

Am I missing something or is this a bug?

I am trying to configure our CCME to be able to negotiate the best codec, but it never negotiates g729r8, even when I restrict zone bandwidth to less than 128k on the Gatekeeper. If I set the zone bandwidth to 64 on the Gatekeeper, for example, we get a fast-busy when we try to call our main site with 12xxx extensions.

Any help is greatly appreciated, I'm stumped.


Re: 'Voice-class codec' ignored by Gatekeeper, is this a bug?

What is the far end device the call is connecting to? This is where the final codec negotiation takes place. If the far end device you are connecting to is an IP Phone for example in a region configured to talk G.711 to the gatekeeper trunk, G.711 will be negotiated. When you remove the g711ulaw command from your codec class you force the far end to negotiate the codec.

So, if connecting to CallManager ensure the region the phone is in is set to talk g.729 to the gatekeeper and if you are connecting to another gateway, make sure the inbound dial-peer that the call will match has g729 as the first preference.

Also, codec negotiation and the CAC bandwidth determination do not go hand in had. If the codec negotiates g711 but not enough bandwidth is available, it won't re-negotiate to g729.

don't forget to rate posts.

andy - berbee

New Member

Re: 'Voice-class codec' ignored by Gatekeeper, is this a bug?

That was it exactly, thank you!

The far end was Call Manager. I put the GK controlled trunk in it's own region & configured it to use g729 to all other regions. However, somehow, the region the phone was in was configured to use g711 to the GK trunk region (I must have overlooked this). When I set that link to use g729 everything worked as I expected.

Thanks again for your quick, accurate response!

New Member

Re: 'Voice-class codec' ignored by Gatekeeper, is this a bug?

Decided to start new question.