[cisco-voip] Strange behaviour of CME

[Cisco Voip]

Dear Sir Nick, 

Thanks alot for prompt reply but pls bear with my dumb question. 

See, my assumption was, Phone-1 to R1 call was g711. Then b/w R1 and R2 it was 
g729. Pls clarify below points i will be really grateful

1) Isnt R1 converting from g711 to g729 and vice versa ? if yes then doesnt it 
needs dsp for that ?
2) Or if i recall correctly, transcoding is required when there is mismatch of 
codec on a call leg, so here on every call leg the codec is consistent, is that 
the reason transcoding is not required ?
3) Or is it that phone itself supports g729 so it will automatically switch to 
this codec ?

Pls my humble request to help me understand it. I know its very basic for you 
but pls





________________________________
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 ?
>> 
>> 
>> 
>> 
>
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