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

From: Gonzalo Camarillo <[email-masked]>
Date: Tue, 28 Feb 2012 13:20:01 +0200

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

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From: "Ravindran, Parthasarathi" <[email-masked]>
Date: Tue, 28 Feb 2012 11:49:10 +0000

Hi all,

Just adding more information about SIPREC protocol, "SIPREC Metadata is transported in the body of INVITE or UPDATE or RE-INVITE or any SIP message with SDP from Session recording client (SRC) to Session Recording Server(SRS). Metadata request from SRS is a separate UPDATE transaction and SRC replies metadata in the subsequent transaction using RE-INVITE or UPDATE."

Thanks
Partha

>-----Original Message-----
>From: [email-masked] [mailto:[email-masked]] On Behalf Of
>Gonzalo Camarillo
>Sent: Tuesday, February 28, 2012 4:50 PM
>To: [email-masked]
>Subject: [RAI] How to exchange metadata about the media streams
>established with a SIP session
>
>Folks,
>
>_______________________________________________
>RAI mailing list
>[email-masked]
>https://www.ietf.org/mailman/listinfo/rai

---

From: Mary Barnes <[email-masked]>
Date: Tue, 28 Feb 2012 09:36:17 -0600

There is additional detail (and drafts) on the signaling options for CLUE
being discussed in these email threads:
http://www.ietf.org/mail-archive/web/clue/current/msg01076.html
http://www.ietf.org/mail-archive/web/clue/current/msg01089.html
So, if anyone chooses to contribute to the discussion in CLUE, this email
discussion is a good place to start.

I also think the problem spaces are different enough that having a common
mechanism should not be required (or expected).

Mary.
CLUE WG co-chair