Subject: [Megaco] [Megaco]Listning on RTP port based on payload_type

From: [email-masked]
Date: Thu, 21 Mar 2002 20:59:25 +0530

Hello,
     Consider that MGC sends Add for ehermeral to MG (MG1), asking MG to choose
the codec. Consider that MG is capable of reserving two codecs and sends this
info back in Add Resp. MGC then sends this info in remote descriptor to other MG
(MG2). Consider that the modes were thus sent that it is backward path switched.
MG2 is also capable of sending and receiving on the same set of codecs and
returns these back in the Add resp.

     Now after getting back Add Resp from MG2, if MGC instructs MG2 to play tone
on ephermeral termination, MG2 plays tone on ehermeral, using one of the two
reserved codecs.

Can MG1 use the payload_type in RTP header and use the corresponding codec to
decode the media packet or does MGC have to specify which of the codec is the
final one?

Regards,
- R. Ezhirpavai

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---

From: "Balasubramanian Pitchandi" <[email-masked]>
Date: Thu, 21 Mar 2002 13:33:25 -0500

Its basically an implementation (more particularly a DSP Hardware)
question. The DSP can look into the "payload_type" field in the RTP
header of the very first packet and start decoding the rest of the
packets using that codec. Eventually it would have to inform the MG of
the codec type it is decoding (just for statistics purposes).

If the DSP hardware/software can do it, you can implement it that way.
The protocol does not prevent you from doing that, infact it encourages
doing that.

Thanks
Bala

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of
[email-masked]
Sent: Thursday, March 21, 2002 10:29 AM
To: [email-masked]
Subject: [Megaco] [Megaco]Listning on RTP port based on payload_type

Hello,
     Consider that MGC sends Add for ehermeral to MG (MG1), asking MG to
choose the codec. Consider that MG is capable of reserving two codecs
and sends this info back in Add Resp. MGC then sends this info in remote
descriptor to other MG (MG2). Consider that the modes were thus sent
that it is backward path switched. MG2 is also capable of sending and
receiving on the same set of codecs and returns these back in the Add
resp.

     Now after getting back Add Resp from MG2, if MGC instructs MG2 to
play tone on ephermeral termination, MG2 plays tone on ehermeral, using
one of the two reserved codecs.

Can MG1 use the payload_type in RTP header and use the corresponding
codec to decode the media packet or does MGC have to specify which of
the codec is the final one?

Regards,
- R. Ezhirpavai

"DISCLAIMER: This message is proprietary to Hughes Software Systems
Limited
(HSS) and is intended solely for the use of the individual  to whom it
is addressed. It may contain  privileged or confidential information
and should not be circulated or used for any purpose other than for what
it is intended. If you have received this message in error, please
notify the originator immediately. If you are not the intended
recipient, you are notified that you are strictly prohibited from using,
copying, altering, or disclosing the contents of this message. HSS
accepts no responsibility for loss or damage arising from the use of the
information transmitted by this email including damage from virus."

---

From: "Balasubramanian Pitchandi" <[email-masked]>
Date: Thu, 21 Mar 2002 13:33:25 -0500

Thanks
Bala

-----Original Message-----

Hello,

Regards,
- R. Ezhirpavai

---

From: SHRI KUMAR <[email-masked]>
Date: Fri, 22 Mar 2002 08:37:37 +0000 (GMT)

Hello Bala

That means the Call control between MGC and MG is
dependent on the DSP hardware support.
In a public network scenario, how does the MGC know
that the MG hardware supports this feature or not. 
Well the protocol should just not encourage, it should
dictate that this is the intent. And, then it is the
MGs responsibility to figure out how it handles the
command.
If the protocol allows the MGC to send MODIFY with
multiple codec(ResvValue=TRUE or ResvGroup=TRUE)...it
must dictate what it means. MG should be prepared to
listen to RTP packets for any of the codecs or MGC
will identify the codec to be used for RTP packets in
a subsequent command.
This is certainly not an implementation issue, but a
protocol definition issue which should be resolved
within the RFC.

Cheerio
ShriKumar

 --- Balasubramanian Pitchandi <[email-masked]> wrote:
> From: [email-masked]
> [mailto:[email-masked]] On Behalf Of
> [email-masked]

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---

From: SHRI KUMAR <[email-masked]>
Date: Fri, 22 Mar 2002 08:37:37 +0000 (GMT)

Hello Bala

Cheerio
ShriKumar

---

From: "Balasubramanian Pitchandi" <[email-masked]>
Date: Fri, 22 Mar 2002 09:29:20 -0500

Hello,

The protocol does not depend on the DSP hardware support.

On receiving the Modify (with ResvValue=TRUE or ResvGroup=TRUE), if the
MG does not have the capability to support the "Group Reservation", it
can very well send an error back to MGC.

IF and ONLY IF it has the capability and the resources at that moment to
support that, it should allocate the resources and send an ACK back to
MGC.

So, the choice is left to MG and its an implementor's decision.

Hope this helps.

Thanks
Bala

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of
SHRI KUMAR
Sent: Friday, March 22, 2002 3:38 AM
To: Balasubramanian Pitchandi; [email-masked]; [email-masked]
Subject: RE: [Megaco] [Megaco]Listning on RTP port based on payload_type

Hello Bala

Cheerio
ShriKumar

 --- Balasubramanian Pitchandi <[email-masked]> wrote:
> [mailto:[email-masked]] On Behalf Of [email-masked]

---

From: "Balasubramanian Pitchandi" <[email-masked]>
Date: Fri, 22 Mar 2002 09:29:20 -0500

Hello,

Hope this helps.

Thanks
Bala

-----Original Message-----

Hello Bala

Cheerio
ShriKumar