G711alaw and G711ulaw conversion in CUBE

Unanswered Question
Apr 15th, 2012


We got CUBE/SIP trunking deployment in Europe, the incoming leg from provider is G711alaw,  however we do have SIP based IVR application  that only support G711ulaw.  I know DSP/trancoder in CUBE can make such conversion, but I wonder if such conversion can be done without DSP?   if so,  is it a good configuration example?



I have this problem too.
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anchoudh Sun, 04/15/2012 - 20:03

Hi Wei,

The Cisco Unified Border Element (CUBE)  supports transcoding for calls that pass through and that require  different codecs on the two call legs. Transcoding between various  codecs is supported, and CUBE inserts a transcoder based on  configuration as well as a mismatch between the codecs negotiated on the  two call legs of the calls.

Transcoding requires DSPs to terminate the RTP stream and to decode  and encode the voice payload with the appropriate codec. The DSPs used  by CUBE for transcoding may be either co-resident on the same router as  CUBE or may be located on a separate router platform.



Hope it helps.


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tapk5@hotmail.com Mon, 04/16/2012 - 19:40

Hi,  Anand,

If the call goes through CUCM,  CUCM can use software MTP (no DSP) for conversion between G711alaw and ulaw.    CUBE definitely can't do the same thing?   



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