Bug 33039

Summary:	Call: Support SDP Capability Negotiation (RFC 5939)
Product:	Telepathy	Reporter:	Olivier Crête <olivier.crete>
Component:	tp-spec	Assignee:	Telepathy bugs list <telepathy-bugs>
Status:	RESOLVED MOVED	QA Contact:	Telepathy bugs list <telepathy-bugs>
Severity:	normal
Priority:	medium	CC:	david.laban
Version:	git master
Hardware:	Other
OS:	All
Whiteboard:	Call-later
i915 platform:		i915 features:

Description Olivier Crête 2011-01-12 13:03:57 UTC

Look at how to support SDEP Cap Neg..

It is required by TS 126.114 section 6.2.1a (LTE SIP/RTP requirements) to use a profile other than RTP/AVP, so we must make sure that our API supports it.

The big thing about SDPCapNeg is that you can offer more than one possible configuration at the same time.

There are three ways we can support this:
1. Modify the MediaDescriptionOffer to include multiple offers at the same time
2. Have the CM do each offer in order until one is accepted by the client
3. Completely move the negotation inside the CM and make the API more simple by only having the client declare all of its capabilities and then have the CM just tell the client about the chosen offer.

Comment 1 David Laban 2011-03-22 14:19:52 UTC

The fallback behaviour is well defined by the rfc (ignore the other offers), so we can implement the fallback behaviour for the undrafted Call spec without any extra effort. I'm marking this as later.

To do full cap-neg support, the CM could add an optional interface for cap neg which contains the other possible configurations as lists of MediaDescriptionMaps (possibly with some compression with numbered descriptions like how the RFC does it). If the client supports it, then everything is peachy. Otherwise it gets ignored, and we're also good.

I'm assuming here that clients are allowed to ignore MD interfaces they don't understand in MDOffers. We should probably specify that.

Comment 2 Guillaume Desmottes 2012-02-16 09:18:50 UTC

Is this considered as a blocker for Call1?

Comment 3 Olivier Crête 2012-02-16 09:41:06 UTC

No, that's why the whiteboard says "Call-later"

Comment 4 GitLab Migration User 2019-12-03 20:23:38 UTC

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