Re: [RAI] How to exchange metadata about the media streams established with a SIP session

worth nothing the RTCweb folks also want to exchange metadata to do with labeling streams. I always find just classifying it as "metadata" sort of makes it hard to decide what to do with it. I'd prefer the groups to specifically outline what data they need to exchange and then I think it becomes clearer the best way to exchange the different types of information. Knowing if the information changes per RTP packet, or only one when the session is set up helps.

On Feb 28, 2012, at 3:20 , Gonzalo Camarillo wrote:

> Folks,
> 
> I am sending this email to the RAI list because it is about an
> architectural issue that affects more than one WG.
> 
> Both the CLUE and SIPREC WGs have identified the need to exchange
> metadata about media streams that have been established using SIP. Both
> groups need to transport such metadata between SIP UAs.
> 
> In CLUE, they are studying how to transport their metadata, as
> documented in:
> http://tools.ietf.org/html/draft-wenger-clue-transport-01
> 
> In SIPREC, they are planning to piggyback the metadata in SIP UPDATEs as
> an XML-encoded body part. When they need to send a request for full
> state (as opposed to partial state), they use an UPDATE request with a
> particular body type, as documented in:
> http://tools.ietf.org/html/draft-ietf-siprec-protocol-02
> 
> The best way to exchange metadata within a SIP session depends on the
> type of metadata and on how the UAs need to interact with each other
> (e.g., a UA simply pushing information to the other UA or a more
> complicated protocol). Given that SIPREC and CLUE have different
> metadata and interactions, it may well be that we decide to use a
> different mechanism in each group. Nevertheless, I think both groups
> would benefit from architecturally-inclined RAI people having a look at
> their work. Please, continue this discussion focusing on their specific
> requirements on either the CLUE list or the SIPREC list.
> 
> Somewhat related to this issue, the RTCWeb group discussed the use of
> SCTP over UDP as a reliable NAT-friendly way to exchange data between
> endpoints.
> 
> Cheers,
> 
> Gonzalo
> 
> _______________________________________________
> RAI mailing list
> RAI@ietf.org
> https://www.ietf.org/mailman/listinfo/rai