Re: [rtcweb] RTCWEB Data Channel: message interleaving

[Michael Tuexen <[e-mail]>]

On Feb 6, 2014, at 9:38 AM, Christer Holmberg <[e-mail]> wrote:

> Hi,
> 
>> If NDATA is not supported, the message size is limited to avoid the monopolization. This limit will be signalled through SDP.
> 
> What do you mean by "signaled through SDP"?
> 
> Will the browser inform the JS app, using SDP, if the local and/or remote peer doesn't support NDATA?
What will be signalled in SDP is the maximum message size the end-point can handle. This is needed
anyway... If you don't support NDATA, you can signal a smaller value of, let's say 16KB or so.

NDATA is negotiated via the SCTP setup and there is no need for another signalling channel.

After the association is up, both sides know if NDATA is supported and, if I remember correctly,
there is a JS way of making message size limits available to the application. So you can
limit the message size if NDATA is not supported by both peers. So that is the plan:
* If NDATA is supported by both peers, message size are only limited by reassembly
  memory and any limit is signalled via SDP. The corresponding support will be in the
  next revision of the SDP ID.
* If NDATA is not supported by both peers, a message size limit applies to avoid monopolisation.

Best regards
Michael
> 
> Regards,
> 
> Christer
> 
>