Bootstrapping WebSockets with HTTP/2
RFC 8441

Document Type RFC - Proposed Standard (September 2018; Errata)
Updates RFC 6455
Last updated 2018-09-21
Replaces draft-mcmanus-httpbis-h2-websockets
Stream IETF
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Reviews
Stream WG state Submitted to IESG for Publication
Document shepherd Mark Nottingham
Shepherd write-up Show (last changed 2018-05-07)
IESG IESG state RFC 8441 (Proposed Standard)
Consensus Boilerplate Yes
Telechat date
Responsible AD Alexey Melnikov
Send notices to Mark Nottingham <mnot@mnot.net>
IANA IANA review state IANA OK - Actions Needed
IANA action state RFC-Ed-Ack
Internet Engineering Task Force (IETF)                        P. McManus
Request for Comments: 8441                                       Mozilla
Updates: 6455                                             September 2018
Category: Standards Track
ISSN: 2070-1721

                  Bootstrapping WebSockets with HTTP/2

Abstract

   This document defines a mechanism for running the WebSocket Protocol
   (RFC 6455) over a single stream of an HTTP/2 connection.

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
   https://www.rfc-editor.org/info/rfc8441.

Copyright Notice

   Copyright (c) 2018 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
   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 and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

McManus                      Standards Track                    [Page 1]
RFC 8441                      H2 WebSockets               September 2018

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  The SETTINGS_ENABLE_CONNECT_PROTOCOL SETTINGS Parameter . . .   3
   4.  The Extended CONNECT Method . . . . . . . . . . . . . . . . .   4
   5.  Using Extended CONNECT to Bootstrap the WebSocket Protocol  .   4
     5.1.  Example . . . . . . . . . . . . . . . . . . . . . . . . .   6
   6.  Design Considerations . . . . . . . . . . . . . . . . . . . .   6
   7.  About Intermediaries  . . . . . . . . . . . . . . . . . . . .   6
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
     9.1.  A New HTTP/2 Setting  . . . . . . . . . . . . . . . . . .   7
     9.2.  A New HTTP Upgrade Token  . . . . . . . . . . . . . . . .   7
   10. Normative References  . . . . . . . . . . . . . . . . . . . .   8
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   8
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   The Hypertext Transfer Protocol (HTTP) [RFC7230] provides compatible
   resource-level semantics across different versions, but it does not
   offer compatibility at the connection-management level.  Other
   protocols that rely on connection-management details of HTTP, such as
   WebSockets, must be updated for new versions of HTTP.

   The WebSocket Protocol [RFC6455] uses the HTTP/1.1 Upgrade mechanism
   (Section 6.7 of [RFC7230]) to transition a TCP connection from HTTP
   into a WebSocket connection.  A different approach must be taken with
   HTTP/2 [RFC7540].  Due to its multiplexing nature, HTTP/2 does not
   allow connection-wide header fields or status codes, such as the
   Upgrade and Connection request-header fields or the 101 (Switching
   Protocols) response code.  These are all required by the [RFC6455]
   opening handshake.

   Being able to bootstrap WebSockets from HTTP/2 allows one TCP
   connection to be shared by both protocols and extends HTTP/2's more
   efficient use of the network to WebSockets.

   This document extends the HTTP CONNECT method, as specified for
   HTTP/2 in Section 8.3 of [RFC7540].  The extension allows the
   substitution of a new protocol name to connect to rather than the
   external host normally used by CONNECT.  The result is a tunnel on a
   single HTTP/2 stream that can carry data for WebSockets (or any other
   protocol).  The other streams on the connection may carry more
   extended CONNECT tunnels, traditional HTTP/2 data, or a mixture of
   both.

McManus                      Standards Track                    [Page 2]
RFC 8441                      H2 WebSockets               September 2018

   This tunneled stream will be multiplexed with other regular streams
   on the connection and enjoys the normal priority, cancellation, and
   flow-control features of HTTP/2.

   Streams that successfully establish a WebSocket connection using a
   tunneled stream and the modifications to the opening handshake
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