Re: [rtcweb] JSEP: Relaxing SDP O/A rules?
Martin Thomson <martin.thomson@gmail.com> Thu, 04 October 2012 18:43 UTC
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Date: Thu, 04 Oct 2012 11:43:55 -0700
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From: Martin Thomson <martin.thomson@gmail.com>
To: Christer Holmberg <christer.holmberg@ericsson.com>
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Subject: Re: [rtcweb] JSEP: Relaxing SDP O/A rules?
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On 4 October 2012 11:21, Christer Holmberg <christer.holmberg@ericsson.com> wrote: > I don't think the reason for PRANSWER comes from SDP O/A as such. It's more about supporting serial forking. Not my point. My point is that the desired functionality (apply the answer without invalidating the offer) cannot be easily provided using SDP O/A. Most scenarios leave the possibility that the offerer sends the (provisional) answerer stuff that the answerer doesn't want. > If you want to support parallel forking, you need to be able to simultanously perform ICE etc with all remote peers. Right. You can almost get that by pretending that it's just one remote peer with lots of candidates. You can at least get to the consent point by doing that. But you aren't going to nominate more than one pair. Similarly, this will only generate a single DTLS session. Media is a complete mess if you manage to get that far. Unless you like scenarios were A and hear B and C, but B and C can't hear each other and other such joys (there's a consent issue too, but it's a minor issue of scale). >>Both of these complicate the API significantly. I'd rather see the >>complexity pushed to the applications that need this complexity. > > I want to be able to support forking. Exactly HOW it's done can be discussed. One approach is to create as many RTCPeerConnection objects as you feel might be needed. Then it becomes YOUR problem, not our problem. And those are the sorts of problem I like ;) (I might be interested in forking too, but I'm happy to keep my problems private.) > Also, I can live without support of parallel forking, and I don't really care if serial forking support is provided using cloning or being able to update the remote descriptor (using PRANSWER, or something else). Serial forking is potentially far easier to support by doing a series of O/A exchanges: 10: setLocal(offer) 20: get next answer 30: setRemote(answer) 40: goto 10 There's the small matter of having no guarantee that the offer will set successfully, but I'd consider that an unlikely scenario in practice. >>That is, unless you are willing to consider a better API that makes >>these issues SEP. > > You have one in mind? ;) I am not at liberty to disclose that information.
- [rtcweb] JSEP: Relaxing SDP O/A rules? Christer Holmberg
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Kaiduan Xie
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Martin Thomson
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Christer Holmberg
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Kaiduan Xie
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Martin Thomson
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Harald Alvestrand
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Christer Holmberg
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Christer Holmberg
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Martin Thomson
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Christer Holmberg
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Martin Thomson
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Cullen Jennings (fluffy)
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Christer Holmberg
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Harald Alvestrand
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Martin Thomson
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Roman Shpount
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Christer Holmberg
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Christer Holmberg
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Martin Thomson
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Parthasarathi R
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Christer Holmberg
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Christer Holmberg
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Cullen Jennings (fluffy)
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Cullen Jennings (fluffy)
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Cullen Jennings (fluffy)
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Roman Shpount
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Christer Holmberg
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Christer Holmberg
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Cullen Jennings (fluffy)
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Paul Kyzivat
- Re: [rtcweb] JSEP: Relaxing SDP O/A rules? Paul Kyzivat