Subject: Re: [ppsp] re-charter issue discussion(cont'):transport mechanism

From: Arno Bakker <[email-masked]>
Date: Tue, 10 Apr 2012 11:50:20 +0200

On 30/03/2012 10:53, zhangyunfei wrote:
> Hi all,
> To continue the re-charter discussion in PPSP WG meeting, I would like
> to discuss more on the transport mechanism issue.
> I happen to know in RTCWeb, the transport protocol between two peer
> browsers seems to been decided: For media part, srtp/rtp over UDP(I am
> not quite sure of if it is accurate). For data transmit, Datagrams over
> SCTP over DTLS over UDP.
> My question is: If this related to PPSP transport mechanism? Or totally
> two different things?Any different requirements? Just to provide such
> info to incur discussion.

Hi all

to keep the re-charter discussion brief could we perhaps split the
discussion into (1) where media transport aspects should be discussed
and (2) what the transport actually is.

For (1), I'd like to keep it inside the peer protocol spec, as mentioned 
before.

For (2): The RTCWEB work is definitely relevant, so thanks for keeping 
us up-to-date, Yunfei. There are of course differences, notably PPSP is 
also about time-shifted streaming, i.e. video-on-demand. This means 
real-time is not always relevant and we also need to think about 
post-view seeding. The latter makes LEDBAT support important.
Furthermore, sender authentication and privacy may be less important for 
us than in the RTCWEB teleconferencing scenarios.
Also PPSP is more about one-to-many than RTCWEB, although they may be
looking at that too.

I think we should definitely advocate our work in RTCWEB, but in Canada 
they weren't ready for P2P scenarios yet, and I haven't followed their 
progress since.

CU,
      Arno

---

From: Wesley Eddy <[email-masked]>
Date: Tue, 10 Apr 2012 19:39:57 -0400

> they weren't ready for P2P scenarios yet, and I haven't followed their

In my view, PPSP should not be distracted by RTCWEB or
go to any effort to mimic its decisions.  The methods
of operating are very different between the RTCWEB
browser-to-browser media flows between the involved
users and the PPSP method of using a tracker to find
peers in a swarm, and then doing chunk-based retrieval
of the media from the swarm rather than direct from
a source like RTCWEB does.

I am in agreement with Arno's point 1 that media
transport within the peer protocol is highly desirable.

-- 
Wes Eddy
MTI Systems