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Re: Should we put the SCTP max message size in the SDP?

From: Peter Thatcher <pthatcher@google.com>
Date: Fri, 22 Nov 2013 15:35:47 -0800
Message-ID: <CAJrXDUGVhx1TMXdQ4rHOiRxDW+iToEHCuk36mzOwFkXOvsjSGw@mail.gmail.com>
To: Michael Tuexen <Michael.Tuexen@lurchi.franken.de>
Cc: Justin Uberti <juberti@google.com>, "public-webrtc@w3.org" <public-webrtc@w3.org>
On Fri, Nov 22, 2013 at 3:31 PM, Michael Tuexen <
Michael.Tuexen@lurchi.franken.de> wrote:

> On Nov 23, 2013, at 12:16 AM, Peter Thatcher <pthatcher@google.com> wrote:
>
> > Yes, we agreed to forego putting streams in the SDP.  I'm sure I got the
> syntax of the SDP wrong.  Yours looks better.
> and the semantic is: I'm willing to accept SCTP user messages of at least
> 1000000 bytes, right?
>
>
​Correct.​



> It makes sense to put it into the SDP...
>
> Best regards
> Michael
> >
> >
> > On Fri, Nov 22, 2013 at 2:51 PM, Justin Uberti <juberti@google.com>
> wrote:
> > I like the idea, but I'm not sure the syntax in
> http://tools.ietf.org/html/draft-ietf-mmusic-sctp-sdp-04 can express this.
> >
> > The current a=sctpmap is
> >
> > a=sctpmap:5000 webrtc-datachannel [streams]
> >
> > although IIRC we agreed to forego the whole streams negotiation thing.
> >
> > So we would need something like a=fmtp:5000 max-message-size=1000000.
> >
> >
> > On Fri, Nov 22, 2013 at 2:28 PM, Peter Thatcher <pthatcher@google.com>
> wrote:
> > This is probably going to sound strange coming from me, but I think it
> might be a better idea to put the SCTP max message size in the SDP.
> >
> > I'm still OK with having an in-band message (as we discussed during
> TPAC) to swap the SCTP max message between endpoints, but I was thinking
> about it a little more and realized that it does involve some extra edge
> cases and a bit of possible latency.  It would be nice if we could do a
> handshake earlier on.... and then I realized we can because we can just put
> it in the SDP where we already do a handshake well ahead of time.
> >
> > Something like:
> >
> > a=sctpmap:5000 max-message-size 1000000
> >
> >
> > Obviously I'm not a big fan of stuffing lots of stuff into SDP, but I
> think this is very minimal and is a more simple solution.
> >
> >
> >
> >
> > What do you think?
> >
> >
>
>
Received on Friday, 22 November 2013 23:36:55 UTC

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