RE: [MMUSIC] RE: alternate RTP profiles in SDP offer/answer

["Dan Wing" <dwing@xxxxxxxxx>]

> > > Sec 8.4.2 of RFC3388 suggests that the offer re-try without 
> > > "group".  That may not look good, but is not too bad either.
> > 
> > That probably works alright with RTSP, but doesn't work with 
> > SIP forking due to HERFP (Heterogeneous Error Response 
> > Forking Problem).
> 
> HERFP is a problem with SIP that anyways needs to be solved at some
> other place. 

I admit to not following it closely, but it seems HERFP hasn't yet
been solved in SIP or SIPPING.

However, let's assume, for a minute, that HERFP is solved.  If my
endpoint supports supports RTP, SRTP, feedback, and running RTP over
DCCP or over UDP, I would need to send an SDP that contains 8 m-lines
(RTP/AVP, RTP/AVPF, RTP/SAVP, RTP/SAVPF, DCCP/RTP/AVP, DCCP/RTP/SAVP,
DCCP/RTP/AVPF, DCCP/RTP/SAVPF), and each m-line would have duplicated
ICE attributes for all of the UDP transports and all of the
m-lines would have duplicated codec attributes.  This makes for a
_very_ long SDP, and requires anyone receiving it to understand
port overloading.

-d