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

From: Justin Uberti <juberti@google.com>
Date: Fri, 22 Nov 2013 14:51:59 -0800
Message-ID: <CAOJ7v-228p+Tt=9+RmaD=cghLHp0u-w2zALedXbZ4XwjT=dBhw@mail.gmail.com>
To: Peter Thatcher <pthatcher@google.com>
Cc: "public-webrtc@w3.org" <public-webrtc@w3.org>
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 22:52:47 UTC

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