[cisco-voip] Strange behaviour of CME

[Cisco Voip]

Ok i get my confusion.

The codec between R1 and R2 was g729, while the default codec between R1 and 
IPC-1 is g711. How did IPC knew that it has to use g729 instead of g711 ?

Please clarify this




________________________________
From: Nick Matthews <matthnick at gmail.com>
To: Cisco Voip <cisco_newbie at yahoo.com>
Cc: ccieid1ot <ccieid1ot at gmail.com>; cisco-voip at puck.nether.net
Sent: Wed, January 26, 2011 10:32:29 AM
Subject: Re: [cisco-voip] Strange behaviour of CME

The phone supports multiple codecs.  They simply have different priorities.  The 
reason you always see g711 instead of g729 is because g711 has a higher 
priority.  The modern phones (7942/7962 and above) support something like 7+ 
codecs.

-nick


On Tue, Jan 25, 2011 at 11:37 PM, Cisco Voip <cisco_newbie at yahoo.com> wrote:

Dear Sir, 
>
>As a followup, by default SCCP phones use codec g711. So did you mean that 
>phones automatically switched to g729 ? i totally believe your point but for my 
>further studies can you also refer me any cisco config guide to strengthen my 
>concept 
>
>
>Pls verify my above point
>
>
>
>
________________________________
From: Nick Matthews <matthnick at gmail.com>
>To: ccieid1ot <ccieid1ot at gmail.com>
>Cc: Cisco Voip <cisco_newbie at yahoo.com>; cisco-voip at puck.nether.net
>Sent: Wed, January 26, 2011 5:10:12 AM
>Subject: Re: [cisco-voip] Strange behaviour of CME
>
>
>Transcoding is only required when there is a codec mismatch.  In this case it's 
>something like:
>
>Phone 1:
>g711ulaw
>g711alaw
>g729r8
>g729br8
>g722
>...
>etc
>
>GW1 to GW2:
>g729r8
>
>Phone 2:
>same as above phone 1
>
>
>Since g729r8 is available by all, there is no need for transcoding.
>
>-nick
>
>
>On Tue, Jan 25, 2011 at 2:47 PM, ccieid1ot <ccieid1ot at gmail.com> wrote:
>
>The phones has built in dsp to do the transcoding.
>>duy
>>ccie #27737 voice
>>tmobile g2
>>On Jan 25, 2011 10:03 AM, "Cisco Voip" <cisco_newbie at yahoo.com> wrote:
>>> Hi all. 
>>> 
>>> I have setup the current setup in my lab
>>> 
>>> IPcommunicator-1 
>>> ------------------R1-GW-------------------R2-GW-------------IPcommunicator-2
>>> 
>>>                                SCCP (g711)                  default (g729)
>>> 
>>> On R1 i simply created a dial-peer voice 2141 voip, and defined the session 
>>> target and destination pattern, and also codec to be g729r8. Now when i call 

>>> from IPc-1 to IPc-2, the call is successful !!
>>> 
>>> I have set this up in dynamips and 2 IPcs are infact vmware machines. What i 

>>> dont understand is, why there was no need for transcoding ? the default codec 
>
>>> between R1-GW and IPc-1 is g711, while between R1-GW and R2-GW, i set it to 
>>> g729, so isnt transcoding needed here ?
>>> 
>>> 
>>> 
>>> 
>>
>>_______________________________________________
>>cisco-voip mailing list
>>cisco-voip at puck.nether.net
>>https://puck.nether.net/mailman/listinfo/cisco-voip
>>
>>
>
>



      
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