Moving forward with HTTP/2.0: proposed charter

In the second Vancouver session, we discussed the proposals, expressions of interest in them, and the proposed charter text sent to the list earlier. 

The result of those discussions has been captured in the charter proposal below.

Please have a look and discuss, express your support or concern, and of course make proposals for any changes that you believe will be able to gain consensus. Barring serious problems, I'd like to get it to the ADs in the next week.


This Working Group is charged with maintaining and developing the "core"
specifications for HTTP.

The Working Group's specification deliverables are:
* A document (or set of documents) that is suitable to supersede RFC 2616 as
 the definition of HTTP/1.1 and move RFC 2817 to Historic status
* A document cataloguing the security properties of HTTP/1.1
* A document (or set of documents) that specifies HTTP/2.0, an improved
 binding of HTTP's semantics to an underlying transport.


HTTP/1.1 is one of the most successful and widely-used protocols on the
Internet today. However, its specification has several editorial issues.
Additionally, after years of implementation and extension, several ambiguities
have become evident, impairing interoperability and the ability to easily
implement and use HTTP.

The working group will refine RFC2616 to:
* Incorporate errata and updates (e.g., references, IANA registries, ABNF)
* Fix editorial problems which have led to misunderstandings of the
* Clarify conformance requirements
* Remove known ambiguities where they affect interoperability
* Clarify existing methods of extensibility
* Remove or deprecate those features that are not widely implemented and
 also unduly affect interoperability
* Where necessary, add implementation advice
* Document the security properties of HTTP and its associated mechanisms
 (e.g., Basic and Digest authentication, cookies, TLS) for common

It will also incorporate the generic authentication framework from RFC
2617, without obsoleting or updating that specification's definition of
the Basic and Digest schemes.

Finally, it will incorporate relevant portions of RFC 2817 (in
particular, the CONNECT method and advice on the use of Upgrade), so
that that specification can be moved to Historic status.

In doing so, it should consider:
* Implementer experience
* Demonstrated use of HTTP
* Impact on existing implementations and deployments


There is emerging implementation experience and interest in a protocol that
retains the semantics of HTTP without the legacy of HTTP/1.x message
framing and syntax, which have been identified as hampering performance and
encouraging misuse of the underlying transport.

The Working Group will produce a specification of a new expression of HTTP's
current semantics in ordered, bi-directional streams. As with HTTP/1.x, 
the primary target transport is TCP, but it should be possible to use
other transports.

Work will begin using draft-mbelshe-httpbis-spdy-00 as a starting point;
proposals are to be expressed in terms of changes to that document. Note that
consensus is required both for changes to the document and anything that
remains in the document.

As part of that work, the following issues are explicitly called out for
* A negotiation mechanism that is capable of not only choosing between
 HTTP/1.x and HTTP/2.x, but also for bindings of HTTP URLs to other
 transports (for example).
* Header compression (which may encompass header encoding or tokenisation)
* Server push (which may encompass pull or other techniques)

It is expected that HTTP/2.0 will:
* Substantially and measurably improve end-user perceived latency in most
 cases, over HTTP/1.1 using TCP.
* Address the "head of line blocking" problem in HTTP.
* Not require multiple connections to a server to enable parallelism, thus
 improving its use of TCP, especially regarding congestion control.
* Retain the semantics of HTTP/1.1, leveraging existing documentation (see
 above), including (but not limited to) HTTP methods, status codes, URIs, and
 where appropriate, header fields.
* Clearly define how HTTP/2.0 interacts with HTTP/1.x, especially in
 intermediaries (both 2->1 and 1->2).
* Clearly identify any new extensibility points and policy for their 
 appropriate use.

The resulting specification(s) are expected to be meet these goals for common
existing deployments of HTTP; in particular, Web browsing (desktop and
mobile), non-browsers ("HTTP APIs"), Web serving (at a variety of scales), and
intermediation (by proxies, corporate firewalls, "reverse" proxies and Content
Delivery Networks). Likewise, current and future semantic extensions to
HTTP/1.x (e.g., headers, methods, status codes, cache directives) should be
supported in the new protocol.

Note that this does not include uses of HTTP where non-specified behaviours
are relied upon (e.g., connection state such as timeouts or client affinity,
and "interception" proxies); these uses may or may not be enabled by the final

Explicitly out-of-scope items include:
* Specifying the use of alternate transport-layer protocols. Note that it
 is expected that the Working Group will define how the protocol is used
 with the TLS Protocol.
* Specifying how the HTTP protocol is to be used or presented in a specific
 use case (e.g., in Web browsers).

The Working Group will coordinate this item with:
* The TLS Working Group, regarding use of TLS.
* The Transport Area, regarding impact on and interaction with transport
* The HYBI Working Group, regarding the possible future extension of HTTP/2.0
 to carry WebSockets semantics.

The Working Group will prioritize HTTP/1.1 work until it is complete.

Other HTTP-Related Work

The Working Group may define additional extensions to HTTP as work items,
provided that:
* There is clear consensus to do so, and
* It does not, in the judgement of the Chair(s), interfere with the work 
 described above, and
* The Area Director(s) give consent, and add corresponding milestones.

Additionally, the Working Group will not start work on any extensions that 
are specific to HTTP/2.0 until that work is completed.

Goals and Milestones

Done	First HTTP/1.1 Revision Internet Draft
Done	First HTTP Security Properties Internet Draft
Done	Call for Proposals for HTTP/2.0
Aug 2012	Working Group Last Call for HTTP/1.1 Revision
Sep 2012	Working Group Last Call for HTTP Security Properties
Sep 2012	First WG draft of HTTP/2.0, based upon draft-mbelshe-httpbis-spdy-00
Oct 2012	Submit HTTP/1.1 Revision to IESG for consideration as a Proposed Standard
Oct 2012	Submit HTTP Security Properties to IESG for consideration as Informational RFC
Apr 2014	Working Group Last call for HTTP/2.0
Nov 2014	Submit HTTP/2.0 to IESG for consideration as a Proposed Standard


Mark Nottingham   Systems Architect, Cloud Standards and APIs

Mark Nottingham

Received on Friday, 3 August 2012 20:06:29 UTC