Re: [rtcweb] JSEP/WebRTC API Datachannel question

Agree it would be good to make it clear that there is only ever one m=data
section; the text you suggest is a good start.

I don't think we want to add a=recvonly on the data line; it's not clear
that that attribute is well-defined for non-RTP media sections.

On Sat, May 17, 2014 at 2:08 PM, Cullen Jennings (fluffy)
<fluffy@cisco.com>wrote:

>
> On Apr 15, 2014, at 12:13 AM, Christian Groves <
> Christian.Groves@nteczone.com> wrote:
>
> > I'll take a punt that people were thinking about 2 below when data
> channel was added. In order to clarify that I propose to add the following
> text to the JSEP draft to clarify this.
> >
> > http://tools.ietf.org/html/draft-ietf-rtcweb-jsep-06#section-5.2.1
> > Replace:
> > "Lastly, if a data channel has been created, a m= section MUST be
> >   generated for data. The <media> field MUST be set to "application" and
> the <proto> field MUST be set to "DTLS/SCTP", as specified in
> [I-D.ietf-mmusic-sctp-sdp], Section 3; the "fmt" value MUST be set to the
> SCTP port number, as specified in Section 4.1."
> >
> > With:
> > /  "Lastly, if createDataChannel has been called a m= section MUST be
> generated for data. In the case of multiple createDataChannel calls only
> one m= section is generated. The <media> field MUST be set to "application"
> and the <proto> field MUST be set to "DTLS/SCTP", as specified in
> [I-D.ietf-mmusic-sctp-sdp], Section 3; the "fmt" value MUST be set to the
> SCTP port number, as specified in Section 4.1."/
> >
> > New text in
> http://tools.ietf.org/html/draft-ietf-rtcweb-jsep-06#section-5.2.2:
> > (above last paragraph)
> > / "If createDataChannel has been called and a m= section has not
> previously been generated, a m= section MUST be generated for data. In the
> case of multiple createDataChannel calls only one m= section is generated.
> The <media> field MUST be set to "application" and the <proto> field MUST
> be set to "DTLS/SCTP", as specified in [I-D.ietf-mmusic-sctp-sdp], Section
> 3; the "fmt" value MUST be set to the SCTP port number, as specified in
> Section 4.1.//
> > //
> > //If all data channels have been closed, the m= section related to the
> data channels MUST be marked as recvonly by changing the value of the
> [RFC3264] directional attribute to "a=recvonly".//"/
> >
> > It would also be good to add some text regarding the relationship
> between a createDataChannel and DCEP DATA_CHANNEL_OPEN I'm not sure if the
> JSEP draft is the place?
> >
> > Also the W3C draft could be updated to indicate the interaction of a
> createDataChannel with the negotiationneeded event in section 5.2 something
> along the lines of:
> > /7. For the first creation of a RTCDataChannel object fire a
> negotiationneeded event at connection./
> >
> >
> > Regards,
> > Christian
>
> I probably need to think about this more but I think that sounds like a
> pretty reasonable change. One way or another, JSEP needs to be clear about
> what needs to happen here.
>
>
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