The ORIGIN HTTP/2 Frame
RFC 8336
Internet Engineering Task Force (IETF) M. Nottingham
Request for Comments: 8336
Category: Standards Track E. Nygren
ISSN: 2070-1721 Akamai Technologies
March 2018
The ORIGIN HTTP/2 Frame
Abstract
This document specifies the ORIGIN frame for HTTP/2, to indicate what
origins are available on a given 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/rfc8336.
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
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Nottingham & Nygren Standards Track [Page 1]
RFC 8336 ORIGIN Frames March 2018
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Notational Conventions . . . . . . . . . . . . . . . . . 2
2. The ORIGIN HTTP/2 Frame . . . . . . . . . . . . . . . . . . . 3
2.1. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Processing ORIGIN Frames . . . . . . . . . . . . . . . . 3
2.3. The Origin Set . . . . . . . . . . . . . . . . . . . . . 4
2.4. Authority, Push, and Coalescing with ORIGIN . . . . . . . 6
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
4. Security Considerations . . . . . . . . . . . . . . . . . . . 7
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1. Normative References . . . . . . . . . . . . . . . . . . 8
5.2. Informative References . . . . . . . . . . . . . . . . . 8
Appendix A. Non-Normative Processing Algorithm . . . . . . . . . 10
Appendix B. Operational Considerations for Servers . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
HTTP/2 [RFC7540] allows clients to coalesce different origins
[RFC6454] onto the same connection when certain conditions are met.
However, in some cases, a connection is not usable for a coalesced
origin, so the 421 (Misdirected Request) status code ([RFC7540],
Section 9.1.2) was defined.
Using a status code in this manner allows clients to recover from
misdirected requests, but at the penalty of adding latency. To
address that, this specification defines a new HTTP/2 frame type,
"ORIGIN", to allow servers to indicate for which origins a connection
is usable.
Additionally, experience has shown that HTTP/2's requirement to
establish server authority using both DNS and the server's
certificate is onerous. This specification relaxes the requirement
to check DNS when the ORIGIN frame is in use. Doing so has
additional benefits, such as removing the latency associated with
some DNS lookups.
1.1. Notational Conventions
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.
Nottingham & Nygren Standards Track [Page 2]
RFC 8336 ORIGIN Frames March 2018
2. The ORIGIN HTTP/2 Frame
This document defines a new HTTP/2 frame type ([RFC7540], Section 4)
called ORIGIN, that allows a server to indicate what origin(s)
[RFC6454] the server would like the client to consider as members of
the Origin Set (Section 2.3) for the connection within which it
occurs.
2.1. Syntax
The ORIGIN frame type is 0xc (decimal 12) and contains zero or more
instances of the Origin-Entry field.
+-------------------------------+-------------------------------+
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