Sharing proposals for negotiation and flow control for HTTP/2.0 at IETF 85


Gabriel Montenegro
Principal Software Development Engineer, Microsoft Corporation

Brian Raymor
Senior Program Manager, Microsoft Open Technologies, Inc.

Rob Trace
Senior Program Manager Lead, Microsoft Corporation


We just returned from the IETF 85 meeting in Atlanta, where the HTTPbis working group held face to face meetings to begin work on HTTP/2.0. As outlined in our previous IETF 84 report, there are seven key technical areas where consensus has not yet emerged or the initial draft did not specify clear behavior for an interoperable implementation. The IETF 85 meeting focused on three of these areas:

Discussion on server push was deferred until more data is available.


As noted in the HTTPbis charter, the working group needs to explicitly consider:

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).

To move the discussion forward, Microsoft presented Upgrade-based Negotiation for HTTP/2.0 at the HTTPbis meeting. This presentation is based on our draft proposal which allows HTTP/2.0 to be negotiated either in the clear or over TLS. Further details on its design and MS Open Tech related HTML5 Labs prototype are available in More HTTP/2.0 Prototyping: a Suggested Approach to the Protocol Upgrade.

The working group consensus was “to pursue this path” and gather more data on its success in real world deployments when the connection is not secure. Drafts for alternatives that enhance or bypass the Upgrade approach were also solicited.

Flow Control

There has been limited discussion in the HTTPbis working group on flow control. Microsoft presented Flow Control Principles for HTTP 2.0 to build consensus around the rules and guidelines for future Flow Control prototypes and experimentation. Based on the response to the presentation, Mark Nottingham, the HTTPbis chair, requested a draft proposal to be submitted which incorporated suggestions from other participants. Microsoft submitted the first version of HTTP 2.0 Principles for Flow Control with contributions from Ericsson. Further versions with additional contributors are expected.


We were very pleased with the progress of the discussions as reflected in the audio and the draft meeting minutes.

As Lao Tzu wrote “A journey of a thousand miles begins with a single step”. IETF 85 was the first step towards the proposed completion date of November 2014. Next steps are a potential interim face to face meeting in January or February 2013 and then IETF 86 in March 2014. We’re looking forward to contributing and participating in these sessions.

Gabriel Montenegro, Brian Raymor, and Rob Trace

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