Re: [AVT] draft-schierl-avt-rtp-multi-session-transmission-00.txt

[Colin Perkins <csp at csperkins.org>]

Ye-Kui,

On 15 Nov 2008, at 07:57, <Ye-Kui.Wang at nokia.com> wrote:
> > > > My question is ..how serious is the identified problem ?.
> > > > My gut feeling is that a receiver that implements e.g decoding
> > > > of G.718 content will likely update the RTP stack to recognize
> > > > header extensions if header extensions are used to carry e.g
> > > > the NTP timestamp related to the RTP timetstamp in the RTP header.
> >
> > What if an intermediary deletes the header extension?  (SBC, B2BUA,
> > raw message store, etc).
>
> What are the (good) reasons for an intermediary to delete header
> extensions? Isn't so that if there is something an intermediary  
> does not
> understand, it'd better not to touch the something?

Perhaps, but RTP doesn't give you that guarantee.  An RTP header  
extension is designed to be optional and ignorable, and middleboxes  
are within their right to strip it out.  You can't rely on a header  
extension.

--
Colin Perkins
http://csperkins.org/



_______________________________________________
Audio/Video Transport Working Group
avt at ietf.org
https://www.ietf.org/mailman/listinfo/avt