Multiplexing Requirements

[aboba]

One of the assumptions of WebRTC is that DTLS, STUN/TURN and RTP and/or RTCP can be multiplexed over the same port. The description of how the multiplexing works is contained in draft-petithuguenin-avtcore-rfc5764-mux-fixes yet this document is not referenced in any RTCWEB WG work item.

To make it clear that this draft needs to be implemented, I'd propose to add the following text to Section 2.2:

"In order to enable multiplexing of DTLS and STUN/TURN with RTP and/or RTCP, implementations must support [MUX-FIXES]."

[MUX-FIXES]
M. Petit-Huguenin; G. Salgueiro. Multiplexing Scheme Updates for Secure Real-time Transport Protocol (SRTP) Extension for Datagram Transport Layer Security (DTLS). 2 July 2014. Internet Draft (work in progress). URL: http://tools.ietf.org/html/draft-petithuguenin-avtcore-rfc5764-mux-fixes

[aboba]

Since [MUX-FIXES] is not yet a WG work item, a normative reference is probably pre-mature, so how about the following revised-text:

"Since the DTLS negotiation occurs between transport endpoints determined via Interactive Connectivity Establishment (ICE), implementations of this specification MUST support multiplexing of STUN, TURN, DTLS and RTP and/or RTCP. This multiplexing, originally described in [RFC5764] Section 5.1.2, is being revised in [MUX-FIXES]."

[ibc]

It is perfect IMHO.

[aboba]

Also recommend adding the following text to Section 16.1:
16.1 BUNDLE

Via the use of [BUNDLE] it is possible for WebRTC 1.0 implementations to multiplex audio and video on the same RTP session. Within ORTC API, equialent behavior can be obtained by constructing multiple RTCRtpReceiver and RTCRtpSender objects from the same RTCDtlsTranport object. As noted in [RTP-USAGE] Section 4.4, support for audio/video multiplexing is required, as described in [RTP-MULTI-STREAM].