Subject: RE: [MMUSIC] Accept wew workitem:draft-hautakorpi-mmusic-sdp-media-content-01.txt?

From: "Eric Burger" <[email-masked]>
Date: Wed, 24 Aug 2005 02:26:26 -0400

On the one hand, the concept of adding semantics to a stream is
sensible.  See RFC3458.

However, at the SDP level, is the "content" anything other than an
opaque string?  It is the application (two layers over SDP) that applies
semantics to the "content."

Why is this important?  For one thing, if there is an IANA registry at
all, it belongs to the Applications, not to MMUSIC. 

Once it is recognized this is an application-layer construct, do we
really need anything other than "label" from
draft-ietf-mmusic-sdp-media-label?

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf
Of Joerg Ott
Sent: Tuesday, August 23, 2005 10:02 PM
To: [email-masked]
Cc: Colin Perkins; Jon Peterson; [email-masked]
Subject: Re: [MMUSIC] Accept wew
workitem:draft-hautakorpi-mmusic-sdp-media-content-01.txt?

Folks,

from the comments that were made to the list, the chairs conclude
that there is interest and justification in pursuing this individual
draft as an MMUSIC work item.

The discussion has also shown that a delineation of this work
from what is done in e.g. XCON is needed.  The authors are encouraged
to ensure a well-defined scope and define the relationship to and
difference from the work pursued in XCON.

The chairs will take up the necessary actions with the ADs.

Cheers,
Joerg

> From: [email-masked] [mailto:[email-masked]] On
Behalf
> Of Joerg Ott
> Sent: Monday, August 15, 2005 3:34 PM
> To: [email-masked]
> Cc: Colin Perkins; [email-masked]
> Subject: [MMUSIC] Accept wew work
> item:draft-hautakorpi-mmusic-sdp-media-content-01.txt?
> 
> Folks,
> 
> at the last IETF, we had some discussion of
> draft-hautakorpi-mmusic-sdp-media-content-01.txt entitled "The SDP
> (Session Description Protocol) Content Attribute"
> and it appeared to be considered generally useful.
> 
> It definitely poses a couple of questions on where to draw the line in
> "semantic" descriptions of media streams in SDP.
> 
> An interesting aspect to bear in mind is that we are already capable
of
> labeling media streams and thus can, in principle, assign semantics by
> means of a conference control protocol developed in XCON or some other
> external means.
> 
> However, the scope of semantic identification of the purposes of
> individual m= lines is valuable beyond conferencing scenarios (e.g.,
in
> the case of media streaming with several streams of the same media
type,
> among others).  So, there appears value in a conferencing-independent
> approach.
> 
> This is a poll to whether or not the MMUSIC WG should consider this
> problem as "its own" and create a working group document for this
> purpose -- which includes a commitment from the group to put effort
into
> this.  The WG draft may be based upon the input received so far from
the
> authors of the above individual submission but further contributors
are
> encouraged if we decide to take this up.
> 
> Please comment to the list.
> 
> Thanks,
> Joerg

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---

From: Gonzalo Camarillo <[email-masked]>
Date: Wed, 24 Aug 2005 11:04:41 +0300

Hi Eric,

I already addressed in a previous mail the difference between "label" 
and "content". We cannot use the exisiting labels because we would have 
a backwards compatibility problem. The issue has to do with reserving 
entries within a name space at any time in the future... it does not 
work because you may have collisions. We better define a different 
namespace for well-known semantics (i.e., a new SDP attribute different 
from label).

Regarding the registry, it was discussed in the meeting, and it is clear 
that, as you point out, we want a common registry. Note that the 
registry does not belong to any WG... it belongs to IANA. The only thing 
we have to come up with is the rules to populate that registry (e.g., an 
RFC is needed, or fist come first serve...)

Thanks,

Gonzalo