Re: [AVT] Fwd: I-D Action:draft-perkins-avt-rapid-rtp-sync-03.txt

["Ali C. Begen (abegen)" <abegen at cisco.com>]

Hi Colin,

I read the draft and I found it informative. The funny thing it shares a
similar title with our draft :)
I wonder whether we can come up with a better, non-colliding name for
any of the drafts. Furthermore, we are also defining control messages (3
for now), one of which is rapid (multicast) synch request (RMS-R).
Similar names can be confusing, IMO.

Others comments:
- FYI: Section 3.1: reg. "next available FMT is 5?" We used 5, 6 and 7
in the our draft. Of course, it is not reserved yet.
- Could the draft also mention about the other useful properties of
having a sender report earlier? I also think a more appropriate name
could be found for this message.
- Section 4.2 says "The frequency of intersing ntp header exs is up to
the sender." Any guidance/constraints on this?
- There are a few inconsistent intra-document references.

Chairs:
I support this draft to become a WG item as it has two good solution for
(timestamp) synchronization for RTP flows.

-acbegen

> -----Original Message-----
> From: avt-bounces at ietf.org [mailto:avt-bounces at ietf.org] On 
> Behalf Of Colin Perkins
> Sent: Monday, March 09, 2009 12:43 PM
> To: avt at ietf.org WG
> Subject: [AVT] Fwd: I-D Action:draft-perkins-avt-rapid-rtp-sync-03.txt
> 
> The changes in this version are primarily editorial; we're 
> aware that  
> not all the open issues have been addressed yet. Any further 
> comments  
> are welcomed.
> 
> Chairs: we'd like this to be considered as an AVT working group  
> draft, as indicated privately.
> 
> Cheers,
> Colin
> 
> 
> 
> 
> Begin forwarded message:
> > From: Internet-Drafts at ietf.org
> > Date: 9 March 2009 17:15:02 GMT
> > To: i-d-announce at ietf.org
> > Subject: I-D Action:draft-perkins-avt-rapid-rtp-sync-03.txt
> > Reply-To: internet-drafts at ietf.org
> >
> > A New Internet-Draft is available from the on-line Internet-Drafts  
> > directories.
> >
> > 	Title           : Rapid Synchronisation of RTP Flows
> > 	Author(s)       : C. Perkins, T. Schierl
> > 	Filename        : draft-perkins-avt-rapid-rtp-sync-03.txt
> > 	Pages           : 17
> > 	Date            : 2009-03-09
> >
> > This memo outlines how RTP multimedia sessions are synchronised, and
> > discusses how rapidly such synchronisation can occur.  We show that
> > most RTP sessions can be synchronised immediately, but that the use
> > of video switching multipoint conference units (MCUs) or 
> large source
> > specific multicast (SSM) groups can greatly increase the initial
> > synchronisation delay.  This increase in delay can be 
> unacceptable to
> > some applications that use layered and/or multi-description codecs.
> >
> > This memo updates the RTP Control Protocol (RTCP) timing rules to
> > reduce the initial synchronisation delay for SSM sessions.  A new
> > feedback packet is defined for use with the Extended RTP Profile for
> > RTCP-based Feedback (RTP/AVPF), allowing video switching MCUs to
> > rapidly request resynchronisation.  Two new RTP header 
> extensions are
> > defined to allow rapid synchronisation of late joiners, and 
> guarantee
> > correct timestamp based decoding order recovery for layered 
> codecs in
> > the presence of clock skew.
> >
> > A URL for this Internet-Draft is:
> > http://www.ietf.org/internet-drafts/draft-perkins-avt-rapid-rtp- 
> > sync-03.txt
> >
> > Internet-Drafts are also available by anonymous FTP at:
> > ftp://ftp.ietf.org/internet-drafts/
> >
> > Below is the data which will enable a MIME compliant mail reader
> > implementation to automatically retrieve the ASCII version of the
> > Internet-Draft.
> > Content-Type: text/plain
> > Content-ID: <2009-03-09100610.I-D at ietf.org>
> >
> > _______________________________________________
> > I-D-Announce mailing list
> > I-D-Announce at ietf.org
> > https://www.ietf.org/mailman/listinfo/i-d-announce
> > Internet-Draft directories: http://www.ietf.org/shadow.html
> > or ftp://ftp.ietf.org/ietf/1shadow-sites.txt
> 
> _______________________________________________
> Audio/Video Transport Working Group
> avt at ietf.org
> https://www.ietf.org/mailman/listinfo/avt
>