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RE: HTTP 2.0 "Upgrade" flow

From: Gabriel Montenegro <Gabriel.Montenegro@microsoft.com>
Date: Wed, 17 Apr 2013 17:02:01 +0000
To: Mark Nottingham <mnot@mnot.net>
CC: Ilari Liusvaara <ilari.liusvaara@elisanet.fi>, Ilya Grigorik <ilya@igvita.com>, "ietf-http-wg@w3.org Group" <ietf-http-wg@w3.org>
Message-ID: <90099830fdb44516902b45476a184b92@BN1PR03MB072.namprd03.prod.outlook.com>
> Personally, I'm not thrilled with how the server session header is conflated
> with a SETTINGS frame... if we're going to require that the server send a
> SETTINGS frame first (which is fine), let's just come out and say that, rather
> than making it a side effect of requiring a (largely fictional) server session
> header.

The spec already says that in section 3.8.4 that a SETTINGS frame MUST be the first frame sent by either party in a new session.

So that part is fine. If we wish to say that a server has no session header, that would be fine. 

As for " As proposed by Gabriel, SETTINGS (or equivalent) would/could be carried in the headers in the UPGRADE request."

For the record, I did not say that in the Upgrade scenario the client session header is sent in HTTP/1.1 along with the Upgrade request. My understanding is that the Upgrade request goes without the client session header. As we have discussed in Orlando, we could add some HTTP/1.1 headers to address the known state by conveying *some* of the settings (only those absolutely necessary to achieve known initial state). But that's a separate proposal/discussion from this thread.

At any rate, the server sends back the 101, and begins its HTTP/2.0 traffic by  sending its SETTINGS frame and its response frames, and the client upon receiving the 101, and only then, begins sending HTTP/2.0 traffic starting with its client session header (which includes the magic sequence and the client SETTINGS frame).
Received on Wednesday, 17 April 2013 17:04:24 UTC

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