IETF Logo Mail Archive

RE: Design Issue: PUSH_PROMISE and Stream Priority

RUELLAN Herve <Herve.Ruellan@crf.canon.fr> Fri, 26 April 2013 10:44 UTC

Return-Path: <ietf-http-wg-request@listhub.w3.org>
X-Original-To: ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com
Delivered-To: ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id DDE7C21F97AA for <ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com>; Fri, 26 Apr 2013 03:44:37 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -9.736
X-Spam-Level:
X-Spam-Status: No, score=-9.736 tagged_above=-999 required=5 tests=[AWL=0.513, BAYES_00=-2.599, HELO_EQ_FR=0.35, RCVD_IN_DNSWL_HI=-8]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id QbQ40FX4wQRk for <ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com>; Fri, 26 Apr 2013 03:44:37 -0700 (PDT)
Received: from frink.w3.org (frink.w3.org [128.30.52.56]) by ietfa.amsl.com (Postfix) with ESMTP id 4724B21F9799 for <httpbisa-archive-bis2Juki@lists.ietf.org>; Fri, 26 Apr 2013 03:44:37 -0700 (PDT)
Received: from lists by frink.w3.org with local (Exim 4.72) (envelope-from <ietf-http-wg-request@listhub.w3.org>) id 1UVg8T-0001YA-Bc for ietf-http-wg-dist@listhub.w3.org; Fri, 26 Apr 2013 10:44:13 +0000
Resent-Date: Fri, 26 Apr 2013 10:44:13 +0000
Resent-Message-Id: <E1UVg8T-0001YA-Bc@frink.w3.org>
Received: from maggie.w3.org ([128.30.52.39]) by frink.w3.org with esmtp (Exim 4.72) (envelope-from <Herve.Ruellan@crf.canon.fr>) id 1UVg8O-0001Ws-KE for ietf-http-wg@listhub.w3.org; Fri, 26 Apr 2013 10:44:08 +0000
Received: from inari-msr.crf.canon.fr ([194.2.158.67]) by maggie.w3.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.72) (envelope-from <Herve.Ruellan@crf.canon.fr>) id 1UVg8N-00041w-Eq for ietf-http-wg@w3.org; Fri, 26 Apr 2013 10:44:08 +0000
Received: from mir-msr.corp.crf.canon.fr (mir-msr.corp.crf.canon.fr [172.19.77.98]) by inari-msr.crf.canon.fr (8.13.8/8.13.8) with ESMTP id r3QAhe7v008671; Fri, 26 Apr 2013 12:43:40 +0200
Received: from ADELE.crf.canon.fr (adele.fesl2.crf.canon.fr [172.19.70.17]) by mir-msr.corp.crf.canon.fr (8.13.8/8.13.8) with ESMTP id r3QAheCV030852; Fri, 26 Apr 2013 12:43:40 +0200
Received: from ADELE.crf.canon.fr ([::1]) by ADELE.crf.canon.fr ([::1]) with mapi id 14.02.0342.003; Fri, 26 Apr 2013 12:43:40 +0200
From: RUELLAN Herve <Herve.Ruellan@crf.canon.fr>
To: Martin Thomson <martin.thomson@gmail.com>, James M Snell <jasnell@gmail.com>
CC: "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>
Thread-Topic: Design Issue: PUSH_PROMISE and Stream Priority
Thread-Index: AQHOQd+MJ5DQqSJZlUWaC8K1Nyj5UpjneY2AgAAEOICAAAO1gIAAzYUw
Date: Fri, 26 Apr 2013 10:43:39 +0000
Message-ID: <6C71876BDCCD01488E70A2399529D5E516416AC5@ADELE.crf.canon.fr>
References: <CABP7Rbf_hZ036vUs4LNTrGQ91kft2_97aV-9Gi2KVJnUJphbNA@mail.gmail.com> <CABkgnnUBEvDtNQM8G5vyfyqRz4tQ8su9+14gMTdaXhzY2cq+Kg@mail.gmail.com> <CABP7RbccA=Zo2NVzJJ-8-G+y2cNt_j8rLr5YVfB_7CVOXLE_JQ@mail.gmail.com> <CABkgnnV64vRPcrdYGFcJQGZW_Wud5fKT76_z5BJc0NndsAEGYg@mail.gmail.com>
In-Reply-To: <CABkgnnV64vRPcrdYGFcJQGZW_Wud5fKT76_z5BJc0NndsAEGYg@mail.gmail.com>
Accept-Language: en-US, fr-FR
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-originating-ip: [172.20.6.135]
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: base64
MIME-Version: 1.0
Received-SPF: none client-ip=194.2.158.67; envelope-from=Herve.Ruellan@crf.canon.fr; helo=inari-msr.crf.canon.fr
X-W3C-Hub-Spam-Status: No, score=-3.4
X-W3C-Hub-Spam-Report: AWL=-3.352, RP_MATCHES_RCVD=-0.001
X-W3C-Scan-Sig: maggie.w3.org 1UVg8N-00041w-Eq b93fef098b3a8c7da555bba86760aa13
X-Original-To: ietf-http-wg@w3.org
Subject: RE: Design Issue: PUSH_PROMISE and Stream Priority
Archived-At: <http://www.w3.org/mid/6C71876BDCCD01488E70A2399529D5E516416AC5@ADELE.crf.canon.fr>
Resent-From: ietf-http-wg@w3.org
X-Mailing-List: <ietf-http-wg@w3.org> archive/latest/17602
X-Loop: ietf-http-wg@w3.org
Resent-Sender: ietf-http-wg-request@w3.org
Precedence: list
List-Id: <ietf-http-wg.w3.org>
List-Help: <http://www.w3.org/Mail/>
List-Post: <mailto:ietf-http-wg@w3.org>
List-Unsubscribe: <mailto:ietf-http-wg-request@w3.org?subject=unsubscribe>


> -----Original Message-----
> From: Martin Thomson [mailto:martin.thomson@gmail.com]
> Sent: vendredi 26 avril 2013 02:17
> To: James M Snell
> Cc: ietf-http-wg@w3.org
> Subject: Re: Design Issue: PUSH_PROMISE and Stream Priority
> 
[snip]
> 
> > Another question: do pushed streams inherit the same priority as their
> > associated "parent" streams? That is, client initiates a stream #1 to
> > the server with priority 5, server responds on that stream with two
> > PUSH_PROMISES for server-initiated streams #2 and #4... do streams #2
> > and #4 inherit the same priority as stream #1. (Please say no, Please
> > say no)
> 
> I'm going to say yes and then make your day even worse by pointing out that
> RST_STREAM(CANCEL) on stream #1 is expected to terminate all related
> push streams, even if stream #1 is long gone.  (I'm assuming that one didn't
> sink in when you read it.)  At least with priority you can copy that state over
> when you copy over request headers (unless you want reprioritization of the
> "parent" to also reprioritize pushes, which seems mega-crazy to me).  The
> push cancellation thing is messy.

I'm seeing the problem in a slightly different way: in the current usage of SPDY, the client initiates the stream #1 by sending the HEADERS+PRIORITY frame with the FINAL flag set to half close it. Therefore, the client is unable to send a RST_STREAM on stream #1 to terminate the related push streams.
To take into account server push, the client will want to keep the stream #1 fully open until at least it is half closed by the server. This means that in HTTP/2.0, stream #1 will stay alive much longer.

Hervé.

v2.23.0 | Report a Bug | By Email