CUBE and transcoding and dsp

[whanson]

                   CAn someone explain to me when I need dsp if I am running cube and the relationship to transcoding?  I have seen examples that show a telephony-service defintion in the cube  router to define local transcoding resources but if that' the case then can I assume that you could not run srst in a cube environment? Confused?  so am I...thx as always,.

[Leonardo Santana]

Take a look on CUBE FAQ:

https://supportforums.cisco.com/docs/DOC-17964

Regards

Leonardo Santana

[Ayodeji Okanlawon]

DSPs are used for multiple purposes. Conferencing, Xcoding, MTP etc. If you are going to host any of these media resources on your CUBE, then you are going to need dsp on the CUBE.

Yes you can configure transcoding resources locally on the cube or you can host it externally. When you configure it locally on the CUBE, it is done similary to how it is on CCME. You use the telephony-service command.

This does not affect SRST on the CUBE. You can run transcoding and SRST on your CUBE

Please rate all useful posts

"'Nature is too thin a screen, the glory of the omnipresent God bursts through it everywhere"-Ralph Waldo Emerson

[whanson]

Let;s make it simpler. Suppose the carrier terminates the call to me as G729. I assume like with h323 if I have a codec class defined I don't need dsps in this case or do I?  Secondly, I have to disagree with you on the SRST. If I define telephony service to allow transcoding then I can't also define telephony service for fallback which means to me that I would have to define specific dns and ephones and butttons and whatnot just like CME to provide SRST.

[chrysostomos1980]

Hi whanson

Just to clarify

do you have a cme or the users are registered to the cucm

yes with voice class into dial peers you should be fine.You have  to test it also

Regards

cc

[Ayodeji Okanlawon]

Whether you need transcoding or not depends on a few things.

1. Outbound direction.

With outbound calls when you have voice class codec on dial-peer and you use early offer, the list of codecs you can support is sent to your provider, they will then pick a codec based on your preferred codec (usually the first one)

The next thing is that the region setting between CUCM and the CUBE will then determine if a xocdder is used or not. If the region is the same as the prefered codec, no xcoder will be invoked, otherwise you will need a xcoder...

eg

CUCM-------------G711------CUBE-------------g729,g711------>ITSP

CUCM ------CUBE (region=g711)

CUBE------ITSP (g729 was selected)

In this scenario CUBE will invoke a xcoder.

2. In the inbound direction, the codec that will be used will be determined a number of factors

1. Inbound dial-peer to CUCM

2. Region setting between CUBE and IP Phone

Eg, If your Provider offers only G729, and you have configured dial-peer to cucm to use G729, but the region between ip phone and CUBE set to G711, well a xcoder will be invoked....

Please have a look at this detailed documentation I did on this subject...

https://supportforums.cisco.com/docs/DOC-26098

Lastly for SRST,

Yes and Yes, you can use CUBE for SRST even if it is configured for transcoding. The same command can be used for transcoding and SRST, If this is not possible then Transcoding on CME wont work

Please rate all useful posts

"'Nature is too thin a screen, the glory of the omnipresent God bursts through it everywhere"-Ralph Waldo Emerson