[asterisk-dev] SDP negotation problem

[Kristian Kielhofner]

On Tue, Feb 9, 2010 at 3:46 AM, Salvatore Frandina
<salvatore.frandina at gmail.com> wrote:
> I'm using SIPp not with pcapplay only with modified uac scenario. I have
> adapted the uac.xml scenario for my purposes.
> VLC can't choose the payload type but it selects the first dynamic payload
> type 96. The strange thing is that my application works with Asterisk 1.6
> family but not with Asterisk 1.4. Hence I think that there is a bug in one
> on these version.
> I can't understand why response of Asterisk is different from request by
> SIPp+VLC...
> PS I have attached the scenarios sipp.xml and SIP message between SIPp and
> Asterisk.
>

Salvatore,

  Kevin and Olle have already explained that Asterisk 1.6 has a
different codec negotiation scheme that will (even though it doesn't
need to) attempt to use the same payload type as the far end.  Just
because it is different does not mean that 1.4 is broken or invalid.
They've already quoted the relevant RFCs that back up Asterisk in this
case.

  Changing the payload type in your sipp scenario is simple.  VLC
starting at 96 is not a problem but if it expects Asterisk to use the
same dynamic payload type it is broken.  Have you asked the VLC
developers about this?

-- 
Kristian Kielhofner
http://www.astlinux.org
http://blog.krisk.org
http://www.star2star.com
http://www.submityoursip.com
http://www.voalte.com