[webrtc-pc] data channel ids are set before SCTP init is exchanged (#3071)

fippo has just created a new issue for https://github.com/w3c/webrtc-pc:

== data channel ids are set before SCTP init is exchanged ==
https://github.com/w3c/webrtc-stats/issues/805#issuecomment-3162026930

I am a bit surprised that no actual DTLS negotiation is required but that seems consistent across browsers?
https://w3c.github.io/webrtc-pc/#sctp-transport-connected might need to be updated as it currently says 

> Once an SCTP transport is connected, meaning the SCTP association of an [RTCSctpTransport](https://w3c.github.io/webrtc-pc/#dom-rtcsctptransport) has been established

but as https://jsfiddle.net/fippo/gLs015hm/6 shows the SCTP transport exists without packets being exchanged.
The specification is safer as it since it avoids my potential (theoretical?) concern about role conflicts but browsers behave differently and seem to determine the [odd/even](https://www.rfc-editor.org/rfc/rfc8832.html#section-4) based on the DTLS role negotiated in the SDP (which seems ok)

I can volunteer a WPT but [from ](https://github.com/w3c/webrtc-stats/issues/805#issuecomment-3161616138) looks like implementations agree.

Please view or discuss this issue at https://github.com/w3c/webrtc-pc/issues/3071 using your GitHub account


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Received on Thursday, 7 August 2025 00:55:39 UTC