Internet DRAFT - draft-engelbart-multiplex-roq-qdc
draft-engelbart-multiplex-roq-qdc
Network Working Group M. Engelbart
Internet-Draft J. Ott
Intended status: Standards Track Technical University Munich
Expires: 25 April 2024 23 October 2023
Multiplexing RTP and Data Channels over QUIC
draft-engelbart-multiplex-roq-qdc-00
Abstract
This document defines a multiplexing scheme for using RTP over QUIC
and QUIC Data Channels in a single QUIC connection.
Discussion Venues
This note is to be removed before publishing as an RFC.
Source for this draft and an issue tracker can be found at
https://github.com/mengelbart/draft-engelbart-multiplex-roq-qdc.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 25 April 2024.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Connection Establishment . . . . . . . . . . . . . . . . . . 2
2.1. Draft version identification . . . . . . . . . . . . . . 2
3. Multiplexing . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Multiplexing using External Signaling . . . . . . . . . . 3
3.2. Multiplexing without Signaling . . . . . . . . . . . . . 4
4. Error Handling . . . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6.1. Registration of an ALPN Identification String . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
7.1. Normative References . . . . . . . . . . . . . . . . . . 4
7.2. Informative References . . . . . . . . . . . . . . . . . 5
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
One of the requirements in the development of RTP over QUIC (RoQ)
([I-D.draft-ietf-avtcore-rtp-over-quic]) was the ability to share a
QUIC connection for RTP, RTCP, and other protocols. RoQ uses a flow
identifier to multiplex different RTP streams, RTCP, and possibly
other protocols. However, RoQ does not describe which protocol can
be multiplexed with RoQ on the same QUIC connection.
[I-D.draft-engelbart-quic-data-channels] describes a simple protocol
similar to WebRTC data channels ([RFC8831]) called QUIC Data Channels
(QDC). QDC uses QUIC instead of SCTP over DTLS and also uses an
identifier similar to the one used by RoQ. This document describes
how the two protocols can be multiplexed in one QUIC connection.
2. Connection Establishment
QUIC requires the use of ALPN [RFC7301] during connection setup.
Connections multiplexing RoQ and QDC use the "roq-qdc-mux" token
during the TLS handshake.
2.1. Draft version identification
*RFC Editor's note:* Please remove this section prior to
publication of a final version of this document.
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Only implementations of the final, published RFC can identify
themselves as "roq-qdc-mux". Until such an RFC exists,
implementations MUST NOT identify themselves using this string.
Implementations of draft versions of the protocol MUST add the string
"-" and the corresponding draft number to the identifier. For
example, draft-engelbart-multiplex-roq-qdc-04 is identified using the
string "roq-qdc-mux-04".
Non-compatible experiments based on these draft versions MUST append
the string "-" and an experiment name to the identifier.
3. Multiplexing
The two protocols for which this document describes a multiplexing
scheme use a variable length integer as the first element on every
QUIC stream and datagram. In RoQ, this integer is called a flow
identifier, and it is used to multiplex different RTP streams and
RTCP. In QDC, the integer is called a channel identifier and is used
to multiplex multiple data channels.
This document describes two options for multiplexing RoQ and QDC.
The first option builds upon the external signaling that is required
by RoQ (Section 3.1). The second one works without any external
signaling but places some restrictions on the chosen flow and channel
identifiers (Section 3.2).
*TODO:* If we define two methods, we also need to say how to
choose between them. This could involve more external signaling,
e.g., SDP, or we could use two different ALPNs. It might be
easier to just settle on one single way to do it.
3.1. Multiplexing using External Signaling
RoQ requires using an external signaling protocol like the one
described in [I-D.draft-dawkins-avtcore-sdp-rtp-quic]. The signaling
includes the negotiation of flow identifiers for RoQ. In this
scheme, applications MUST agree on all identifiers used by RoQ using
the external signaling. Any identifier not assigned to a RoQ flow
using external signaling MUST be treated as a QDC channel ID.
Endpoints MUST NOT use an identifier for RoQ if it has not been
signaled and agreed upon by both peers using the external signaling
protocol.
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3.2. Multiplexing without Signaling
When there is no external signaling for negotiation of identifiers
available, endpoints can use the second least significant bit (0x02)
of the flow or channel identifiers for multiplexing. RoQ flows have
the bit set to 1, and QDC channels have the bit set to 0.
The second least significant bit is used instead of the least
significant bit because the least significant bit already has a
special function in QDC.
4. Error Handling
*TODO:* This looks tricky. Some error codes will be easy to
demultiplex when they are associated with a flow/channel ID. But
some might not be, e.g., in CONNECTION_CLOSE frames.
5. Security Considerations
The security considerations for the QUIC protocol and datagram
extension described in Section 21 of [RFC9000], Section 9 of
[RFC9001], Section 8 of [RFC9002] and Section 6 of [RFC9221] apply.
6. IANA Considerations
6.1. Registration of an ALPN Identification String
This document creates a new registration for the identification of
the protocol in the "TLS Application-Layer Protocol Negotiation
(ALPN) Protocol IDs" registry [RFC7301].
The "roq-qdc-mux" string identifies RoQ:
Protocol: Multiplexed RoQ and QDC
Identification Sequence: TODO
Specification: This document
7. References
7.1. Normative References
[I-D.draft-engelbart-quic-data-channels]
"*** BROKEN REFERENCE ***".
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[I-D.draft-ietf-avtcore-rtp-over-quic]
Ott, J., Engelbart, M., and S. Dawkins, "RTP over QUIC
(RoQ)", Work in Progress, Internet-Draft, draft-ietf-
avtcore-rtp-over-quic-07, 23 October 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-avtcore-
rtp-over-quic-07>.
[RFC7301] Friedl, S., Popov, A., Langley, A., and E. Stephan,
"Transport Layer Security (TLS) Application-Layer Protocol
Negotiation Extension", RFC 7301, DOI 10.17487/RFC7301,
July 2014, <https://www.rfc-editor.org/rfc/rfc7301>.
[RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", RFC 9000,
DOI 10.17487/RFC9000, May 2021,
<https://www.rfc-editor.org/rfc/rfc9000>.
[RFC9001] Thomson, M., Ed. and S. Turner, Ed., "Using TLS to Secure
QUIC", RFC 9001, DOI 10.17487/RFC9001, May 2021,
<https://www.rfc-editor.org/rfc/rfc9001>.
[RFC9002] Iyengar, J., Ed. and I. Swett, Ed., "QUIC Loss Detection
and Congestion Control", RFC 9002, DOI 10.17487/RFC9002,
May 2021, <https://www.rfc-editor.org/rfc/rfc9002>.
[RFC9221] Pauly, T., Kinnear, E., and D. Schinazi, "An Unreliable
Datagram Extension to QUIC", RFC 9221,
DOI 10.17487/RFC9221, March 2022,
<https://www.rfc-editor.org/rfc/rfc9221>.
7.2. Informative References
[I-D.draft-dawkins-avtcore-sdp-rtp-quic]
Dawkins, S., "SDP Offer/Answer for RTP using QUIC as
Transport", Work in Progress, Internet-Draft, draft-
dawkins-avtcore-sdp-rtp-quic-00, 28 January 2022,
<https://datatracker.ietf.org/doc/html/draft-dawkins-
avtcore-sdp-rtp-quic-00>.
[RFC8831] Jesup, R., Loreto, S., and M. Tüxen, "WebRTC Data
Channels", RFC 8831, DOI 10.17487/RFC8831, January 2021,
<https://www.rfc-editor.org/rfc/rfc8831>.
Acknowledgments
Authors' Addresses
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Mathis Engelbart
Technical University Munich
Email: mathis.engelbart@gmail.com
Jörg Ott
Technical University Munich
Email: ott@in.tum.de
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