[SR-Users] RTPengine with rejected RE-INVITE when port is changing

[Daniel Tryba]

On Thu, Dec 05, 2019 at 09:37:51AM +0000, Laurent Schweizer wrote:
> Hello,
> 
> I already see old post about this :
> https://opensips.org/pipermail/users/2014-November/030451.html
> 
> but I???m interested to know if now they is a solution ????
> 
> so the issue is a RE-INVITE rejected (415 Unsupported Media or 488 ) and the RTP port is changing.
> Is that case the old RTP relay (I???m using RTPengine) is destroyed after 30sec.
> Any way to restore them ?

I'm confused:
- opensips != kamailio
- rtpproxy != rtpengine

But RFC 3261 states (page 16):

   During the session, either Alice or Bob may decide to change the
   characteristics of the media session.  This is accomplished by
   sending a re-INVITE containing a new media description.  This re-
   INVITE references the existing dialog so that the other party knows
   that it is to modify an existing session instead of establishing a
   new session.  The other party sends a 200 (OK) to accept the change.
   The requestor responds to the 200 (OK) with an ACK.  If the other
   party does not accept the change, he sends an error response such as
   488 (Not Acceptable Here), which also receives an ACK.  However, the
   failure of the re-INVITE does not cause the existing call to fail -
   the session continues using the previously negotiated
   characteristics.  Full details on session modification are in Section
   14.

So if this happens with kamailio/rtpengine that is a bug in (I  presume) rtpengine.