2821 Router Config

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Mar 19th, 2009
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We use a Cisco 2821 Router as our voice gateway. When I run the config file there is:

mgcp rtp payload-type g726r 16 static

If we change the codec to g711ulaw from g726r will that cause any problems?

Thank You

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Paolo Bevilacqua Thu, 03/19/2009 - 13:41
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Do you have a WAN bottleneck? If not, changing to g711 would be recommended.

Mojo1 Thu, 03/19/2009 - 13:45
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We use Berbee Informacast and that works best over g.711 codec. There is an issue of the audio portion of a live message not coming thru on a recipient device. They said it was due to the gateway not having a g.711 codec.

I just want to know what effects if any will there be if we change the gateway from g726r to g711 ?


Paolo Bevilacqua Thu, 03/19/2009 - 13:54
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I'm not 100% sure, but with MGCP you control the codecs from CM, so you've to look into it as well.

Beside, the phones do not support g726 at all, so that setting you've is a bit strange.

Nicholas Matthews Thu, 03/19/2009 - 14:27
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Hi Mojo,

This is a default configuration that CUCM puts in the router with 'ccm-manager config'.

What this is saying is that the payload type 16 is assigned to g726.

The actual codec is negotiated on call by call basis in the CRCX and MDCX messages from CUCM.

Check the device pool your gateway is in, and see what region it is in. Then check the regions to see what codec is in use for that region to other devices.




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