RFC 9220

Internet Engineering Task Force (IETF)                       R. Hamilton
Request for Comments: 9220                                        Google
Category: Standards Track                                      June 2022
ISSN: 2070-1721

                  Bootstrapping WebSockets with HTTP/3


   The mechanism for running the WebSocket Protocol over a single stream
   of an HTTP/2 connection is equally applicable to HTTP/3, but the
   HTTP-version-specific details need to be specified.  This document
   describes how the mechanism is adapted for HTTP/3.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at

Copyright Notice

   Copyright (c) 2022 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   include Revised BSD License text as described in Section 4.e of the
   Trust Legal Provisions and are provided without warranty as described
   in the Revised BSD License.

Table of Contents

   1.  Introduction
   2.  Conventions and Definitions
   3.  WebSockets Upgrade over HTTP/3
   4.  Security Considerations
   5.  IANA Considerations
   6.  Normative References

   Author's Address

1.  Introduction

   "Bootstrapping WebSockets with HTTP/2" [RFC8441] defines an extension
   to HTTP/2 [HTTP/2] that is also useful in HTTP/3 [HTTP/3].  This
   extension makes use of an HTTP/2 setting.  Appendix A.3 of [HTTP/3]
   gives some guidance on what changes (if any) are appropriate when
   porting settings from HTTP/2 to HTTP/3.

2.  Conventions and Definitions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "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.  WebSockets Upgrade over HTTP/3

   [RFC8441] defines a mechanism for running the WebSocket Protocol
   [RFC6455] over a single stream of an HTTP/2 connection.  It defines
   an Extended CONNECT method that specifies a new ":protocol" pseudo-
   header field and new semantics for the ":path" and ":authority"
   pseudo-header fields.  It also defines a new HTTP/2 setting sent by a
   server to allow the client to use Extended CONNECT.

   The semantics of the pseudo-header fields and setting are identical
   to those in HTTP/2 as defined in [RFC8441].  Appendix A.3 of [HTTP/3]
   requires that HTTP/3 settings be registered separately for HTTP/3.
   The SETTINGS_ENABLE_CONNECT_PROTOCOL value is 0x08 (decimal 8), as in

   If a server advertises support for Extended CONNECT but receives an
   Extended CONNECT request with a ":protocol" value that is unknown or
   is not supported, the server SHOULD respond to the request with a 501
   (Not Implemented) status code (Section 15.6.2 of [HTTP]).  A server
   MAY provide more information via a "problem details" response

   The HTTP/3 stream closure is also analogous to the TCP connection
   closure of [RFC6455].  Orderly TCP-level closures are represented as
   a FIN bit on the stream (Section 4.4 of [HTTP/3]).  RST exceptions
   are represented with a stream error (Section 8 of [HTTP/3]) of type
   H3_REQUEST_CANCELLED (Section 8.1 of [HTTP/3]).

4.  Security Considerations

   This document introduces no new security considerations beyond those
   discussed in [RFC8441].

5.  IANA Considerations

   This document registers a new setting in the "HTTP/3 Settings"
   registry (Section 11.2.2 of [HTTP/3]).

   Value:  0x08
   Default:  0
   Status:  permanent
   Specification:  This document
   Change Controller:  IETF
   Contact:  HTTP Working Group (ietf-http-wg@w3.org)

6.  Normative References

   [HTTP]     Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
              Ed., "HTTP Semantics", STD 97, RFC 9110,
              DOI 10.17487/RFC9110, June 2022,

   [HTTP/2]   Thomson, M., Ed. and C. Benfield, Ed., "HTTP/2", RFC 9113,
              DOI 10.17487/RFC9113, June 2022,

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

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,

   [RFC6455]  Fette, I. and A. Melnikov, "The WebSocket Protocol",
              RFC 6455, DOI 10.17487/RFC6455, December 2011,

   [RFC7807]  Nottingham, M. and E. Wilde, "Problem Details for HTTP
              APIs", RFC 7807, DOI 10.17487/RFC7807, March 2016,

   [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/info/rfc8174>.

   [RFC8441]  McManus, P., "Bootstrapping WebSockets with HTTP/2",
              RFC 8441, DOI 10.17487/RFC8441, September 2018,


   This document had reviews and input from many contributors in the
   IETF HTTP and QUIC Working Groups, with substantive input from David
   Schinazi, Martin Thomson, Lucas Pardue, Mike Bishop, Dragana
   Damjanovic, Mark Nottingham, and Julian Reschke.

Author's Address

   Ryan Hamilton
   Email: rch@google.com