Re: [rtcweb] DataChannels API and external negotiation

Randell,

What about data channel priority ?

Jerome

> -----Message d'origine-----
> De : rtcweb-bounces@ietf.org [mailto:rtcweb-bounces@ietf.org] 
> De la part de Randell Jesup
> Envoyé : lundi 1 avril 2013 04:29
> À : public-webrtc@w3.org
> Cc : rtcweb@ietf.org
> Objet : [rtcweb] DataChannels API and external negotiation
> 
> Here's a proposed API for DataChannels with external 
> negotiation, per the recent Interim and IETF meeting (most of 
> this was in my previous W3 email, but I've added info on when 
> 'stream' is valid to read, and how even/odd roles are 
> assigned for the IETF protocol). I'll note for the IETF folks 
> that 'protocol' is in a JS dictionary object in this update, 
> which avoids breaking any current experimental applications 
> (and avoids them having any incentive to UA-sniff).  Also, I 
> think it works better in the dictionary.
> 
>    channel = peerconnection.createDataChannel(label, 
> dictionary_object);
> 
> /* If either maxRetransmitTime or maxRetransmitNum are set, it's
>     unreliable, else it's a reliable channel.  If both are set it's an
>     error.  outOfOrderAllowed can be used with any type of 
> channel.  The
>     equivalent of UDP is { outOfOrderAllowed: true, 
> maxRetransmitNum: 0 }.
>     The TCP equivalent is {}.
> 
>     preset is set to true if the channel is being externally 
> negotiated, and
>     no wireline OpenRequest message should be sent.  If 
> preset is true, stream
>     can be optionally used to set a specific SCTP stream to 
> use.  If it's
>     not set but preset is true, then the application should 
> read the 'stream'
>     attribute from the returned DataChannel after onopen and 
> convey it to the
>     other end to pass in via the DataChannelInit dictionary.
>   */
> 
> dictionary DataChannelInit {
>    boolean outOfOrderAllowed;
>    unsigned short maxRetransmitTime;
>    unsigned short maxRetransmitNum;
>    DOMString protocol;
>    boolean preset;
>    unsigned short stream;
> };
> 
> And I added to the DataChannel object webidl:
> 
>    readonly attribute DOMString protocol;
>    /* the 'stream' attribute is not valid until after onopen 
> has fired */
>    readonly attribute unsigned short stream;
> 
> 
> Even/odd roles for the underlying DataChannel protocol are 
> tied to the DTLS roles on the DTLS connection.  These are 
> only available after the DTLS connection is established, and 
> so we will set the even/odd roles when the initial 
> association is established (which is when onconnection fires, 
> and then any queued DataChannels would have onopen fire).
> 
> -- 
> Randell Jesup
> randell-ietf@jesup.org
> 
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