HTTP/3 over QMux
draft-kazuho-httpbis-http3-over-qmux-00

httpbis                                                           K. Oku
Internet-Draft                                                    Fastly
Intended status: Standards Track                               L. Pardue
Expires: 28 December 2026                                     Cloudflare
                                                              J. Iyengar
                                                                 Netflix
                                                            26 June 2026

                            HTTP/3 over QMux
                draft-kazuho-httpbis-http3-over-qmux-00

Abstract

   This document specifies how to use HTTP/3 over QMux.

Discussion Venues

   This note is to be removed before publishing as an RFC.

   Discussion of this document takes place on the HTTP Working Group
   mailing list (ietf-http-wg@w3.org), which is archived at
   https://lists.w3.org/Archives/Public/ietf-http-wg/.

   Source for this draft and an issue tracker can be found at
   https://github.com/kazuho/draft-kazuho-httpbis-http3-on-streams.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on 28 December 2026.

Copyright Notice

   Copyright (c) 2026 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
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   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions and Definitions . . . . . . . . . . . . . . . . .   3
   3.  The Protocol  . . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  QPACK Considerations  . . . . . . . . . . . . . . . . . .   3
   4.  Starting HTTP/3 over QMux . . . . . . . . . . . . . . . . . .   3
     4.1.  Draft Version Identification  . . . . . . . . . . . . . .   4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   As of 2026, HTTP/2 [HTTP/2] remains the most widely used version of
   HTTP across the Internet, although the adoption rate of HTTP/3
   [HTTP/3] is increasing rapidly.

   HTTP/3 has several advantages over HTTP/2, primarily due to its use
   of QUIC [QUIC] as the transport layer protocol, which provides
   features like stream multiplexing without head-of-line blocking and
   low-latency connection establishment.

   However, given that QUIC's availability and accessibility are not as
   universal as TCP's, a complete migration of all HTTP/2 traffic to
   QUIC-based HTTP/3 seems unlikely.

   This situation necessitates HTTP deployments to support both
   transport protocols and their respective HTTP versions for the
   foreseeable future.

   Maintaining dual support is costly, as the two protocols differ in
   many aspects such as wire-encoding, flow control and stream
   multiplexing machinery, and HTTP header compression.  Extensions
   operating at the HTTP wire encoding layer must be developed and

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   implemented for both HTTP/2 and HTTP/3, and both protocol stacks
   require ongoing maintenance to address bugs, performance issues, and
   vulnerabilities.

   To address this redundancy, this specification defines the method of
   running HTTP/3 over QMux version 1 [QMUX], which enables the
   operation of HTTP/3 over TCP and TLS without any modifications.

   Consequently, design, implementation, and maintenance efforts can
   concentrate on a single HTTP version: HTTP/3.

2.  Conventions and Definitions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  The Protocol

   HTTP/3 functions over QUIC version 1, employing the set of operations
   (i.e., API) defined in Section 2.4 and Section 5.3 of [QUIC].  HTTP/3
   over QMux version 1 utilizes the same set of operations that are
   available in QMux.

3.1.  QPACK Considerations

   HTTP/3 uses QPACK [QPACK] for field compression as described in
   Section 4.2.1 of [HTTP/3].  QPACK is designed to operate over QUIC
   version 1, which does not provide guarantees of global ordering
   across streams.  It provides flexibility for implementations to
   balance resilience against head-of-line blocking and optimal
   compression ratio (Section 2.1.2 of [QPACK]).

   QMux version 1 operates on top of a transport layer that guarantees
   in-order delivery and guarantees global ordering across streams.
   When HTTP/3 over QMux is used, QPACK decoders will never be blocked
   due to packet losses.  To improve compression efficiency, QPACK
   encoders can reference a dynamic table entry as soon as the entry is
   emitted to the underlying transport, regardless of the
   SETTINGS_QPACK_BLOCKED_STREAMS value advertised by the peer.

4.  Starting HTTP/3 over QMux

   HTTP/3 over QMux version 1 can be used for “https” URI schemes
   defined in Section 4.2 of [HTTP] with the same default port number as
   HTTP/1.1 [HTTP/1.1].

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   When a client uses HTTP/3 over QMux for an "https" URI scheme, it
   uses TLS [TLS] with ALPN [ALPN] as described in Section 8 of [QMUX].
   The ALPN ID for the final, published RFC is "h3qx".  Until such an
   RFC exists, implementations MUST NOT identify themselves using this
   string.

4.1.  Draft Version Identification

   [[RFC editor: please remove this section before publication.]]

   This draft describes HTTP/3 over draft version of QMux.  In order to
   support interoperability over revisions, HTTP/3 over QMux drafts
   define an ALPN ID that captures both this document revision and the
   QMux revision in use.

   The ALPN ID defined by this draft revision is "h3qx-01", which
   represents HTTP/3 over draft-ietf-quic-qmux-01.

5.  Security Considerations

   The security considerations from Section 10 of [HTTP/3] and
   Section 12 of [QMUX] apply.

6.  IANA Considerations

   If this document is adopted and published as an RFC, it will have an
   action to create a new registration for the identification of HTTP/3
   over QMux version 1 in the "TLS Application-Layer Protocol
   Negotiation (ALPN) Protocol IDs" registry established in [ALPN].

7.  References

7.1.  Normative References

   [ALPN]     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>.

   [HTTP]     Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
              Ed., "HTTP Semantics", STD 97, RFC 9110,
              DOI 10.17487/RFC9110, June 2022,
              <https://www.rfc-editor.org/rfc/rfc9110>.

   [HTTP/1.1] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
              Ed., "HTTP/1.1", STD 99, RFC 9112, DOI 10.17487/RFC9112,
              June 2022, <https://www.rfc-editor.org/rfc/rfc9112>.

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   [HTTP/3]   Bishop, M., Ed., "HTTP/3", RFC 9114, DOI 10.17487/RFC9114,
              June 2022, <https://www.rfc-editor.org/rfc/rfc9114>.

   [QMUX]     Oku, K., Pardue, L., Iyengar, J., and E. Kinnear, "QMux",
              Work in Progress, Internet-Draft, draft-ietf-quic-qmux-01,
              1 April 2026, <https://datatracker.ietf.org/doc/html/
              draft-ietf-quic-qmux-01>.

   [QPACK]    Krasic, C., Bishop, M., and A. Frindell, Ed., "QPACK:
              Field Compression for HTTP/3", RFC 9204,
              DOI 10.17487/RFC9204, June 2022,
              <https://www.rfc-editor.org/rfc/rfc9204>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/rfc/rfc2119>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.

   [TLS]      Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/rfc/rfc8446>.

7.2.  Informative References

   [HTTP/2]   Thomson, M., Ed. and C. Benfield, Ed., "HTTP/2", RFC 9113,
              DOI 10.17487/RFC9113, June 2022,
              <https://www.rfc-editor.org/rfc/rfc9113>.

   [QUIC]     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>.

Acknowledgments

   TODO acknowledge.

Authors' Addresses

   Kazuho Oku
   Fastly
   Email: kazuhooku@gmail.com

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   Lucas Pardue
   Cloudflare
   Email: lucas@lucaspardue.com

   Jana Iyengar
   Netflix
   Email: jri.ietf@gmail.com

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