Re: Design Issue: Max Concurrent Streams Limit and Unidirectional Streams

Martin Thomson <martin.thomson@gmail.com> Thu, 25 April 2013 23:19 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 72A7221F972B for <ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com>; Thu, 25 Apr 2013 16:19:44 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -6.88
X-Spam-Level:
X-Spam-Status: No, score=-6.88 tagged_above=-999 required=5 tests=[AWL=3.719, BAYES_00=-2.599, 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 AE+5CgHPyChh for <ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com>; Thu, 25 Apr 2013 16:19:43 -0700 (PDT)
Received: from frink.w3.org (frink.w3.org [128.30.52.56]) by ietfa.amsl.com (Postfix) with ESMTP id C982221F9708 for <httpbisa-archive-bis2Juki@lists.ietf.org>; Thu, 25 Apr 2013 16:19:43 -0700 (PDT)
Received: from lists by frink.w3.org with local (Exim 4.72) (envelope-from <ietf-http-wg-request@listhub.w3.org>) id 1UVVRP-0007c7-1E for ietf-http-wg-dist@listhub.w3.org; Thu, 25 Apr 2013 23:19:03 +0000
Resent-Date: Thu, 25 Apr 2013 23:19:03 +0000
Resent-Message-Id: <E1UVVRP-0007c7-1E@frink.w3.org>
Received: from maggie.w3.org ([128.30.52.39]) by frink.w3.org with esmtp (Exim 4.72) (envelope-from <martin.thomson@gmail.com>) id 1UVVRK-0007bI-Np for ietf-http-wg@listhub.w3.org; Thu, 25 Apr 2013 23:18:58 +0000
Received: from mail-wg0-f47.google.com ([74.125.82.47]) by maggie.w3.org with esmtps (TLS1.0:RSA_ARCFOUR_SHA1:16) (Exim 4.72) (envelope-from <martin.thomson@gmail.com>) id 1UVVRK-0006j0-6q for ietf-http-wg@w3.org; Thu, 25 Apr 2013 23:18:58 +0000
Received: by mail-wg0-f47.google.com with SMTP id j13so1769973wgh.2 for <ietf-http-wg@w3.org>; Thu, 25 Apr 2013 16:18:32 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:x-received:in-reply-to:references:date:message-id :subject:from:to:cc:content-type; bh=kZ81xp90uwwbR62mRkw7y2vOz3fWGMZsD+J6SbXeCG4=; b=Awoo2ErSzfmi5rJeyUToPJE/zwhn233p73px67J5efrF2LLl8KUg21qCJuIvAB4QYh TubsYqKHD6G4pCwyIJ0P4lTOiVVp6xW4MctpLUrHmP1sf/fVjaGoHdktRU/hbAno4ebn rAao7bhnsmRD0Oq1wjnEcwyu4ZB1K02mAxrP0jwHDbUoPQ4V+vR1aJqEec1AwlFkKfxB HIkZyAzPXhnwAVXDNV9+hLuWQTCtXzNHY2x/Dud4azYIPeHK3SOiBjRJtG/PJ68VmsPm KKyFctAZDOWgQCfRSgEktE7Gl5OSNaSje8mOqw1fFji5hY9Yd/3Ft1xTd4pOJvH4jTqk FcMQ==
MIME-Version: 1.0
X-Received: by 10.180.183.133 with SMTP id em5mr569951wic.26.1366931912116; Thu, 25 Apr 2013 16:18:32 -0700 (PDT)
Received: by 10.194.33.102 with HTTP; Thu, 25 Apr 2013 16:18:32 -0700 (PDT)
In-Reply-To: <CABP7RbdH+YnH2V8HX=1YzrT-m06ggdXNGqvEMwng2nDv5AeXXg@mail.gmail.com>
References: <CABP7RbdBe-Xkx+CMvpN=_oNAqm6SyLyL+XNHRUKSqn8mjSDw1Q@mail.gmail.com> <CABkgnnW=Ve=9p2do5PncTVswTYCZqt-LMK50SYCKV1r8zEg=SQ@mail.gmail.com> <CABP7Rbc=hYTxuGm7jn=eDipbA23UW3MUc_jx2ALHfqHQt94OJg@mail.gmail.com> <CABkgnnVoHv+Wf=oYN=RSq2GHod-KrZ5gPq-gYmNvcRpMWFjNEQ@mail.gmail.com> <CABP7RbdH+YnH2V8HX=1YzrT-m06ggdXNGqvEMwng2nDv5AeXXg@mail.gmail.com>
Date: Thu, 25 Apr 2013 16:18:32 -0700
Message-ID: <CABkgnnXrku1B8ehWWeCCaWBeTfhsWGTagHTKbA3F_HYe0Fux0Q@mail.gmail.com>
From: Martin Thomson <martin.thomson@gmail.com>
To: James M Snell <jasnell@gmail.com>
Cc: "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>
Content-Type: text/plain; charset="UTF-8"
Received-SPF: pass client-ip=74.125.82.47; envelope-from=martin.thomson@gmail.com; helo=mail-wg0-f47.google.com
X-W3C-Hub-Spam-Status: No, score=-4.4
X-W3C-Hub-Spam-Report: AWL=-1.713, BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_LOW=-0.7, SPF_PASS=-0.001
X-W3C-Scan-Sig: maggie.w3.org 1UVVRK-0006j0-6q 482af6512d4a758aeba6908d28bfab5a
X-Original-To: ietf-http-wg@w3.org
Subject: Re: Design Issue: Max Concurrent Streams Limit and Unidirectional Streams
Archived-At: <http://www.w3.org/mid/CABkgnnXrku1B8ehWWeCCaWBeTfhsWGTagHTKbA3F_HYe0Fux0Q@mail.gmail.com>
Resent-From: ietf-http-wg@w3.org
X-Mailing-List: <ietf-http-wg@w3.org> archive/latest/17582
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>

> On Thu, Apr 25, 2013 at 4:11 PM, Martin Thomson
> <martin.thomson@gmail.com> wrote:
>> Do you mean that only outward bound streams count toward the
>> concurrency limit.  That could be workable; it's certainly easier to
>> explain.

On 25 April 2013 16:13, James M Snell <jasnell@gmail.com> wrote:
> Yes, Outward bound only.

This has the biggest impact on servers and intermediaries.  How do
they feel about having clients initiating more requests while the
server is sending responses.

Thinking on this more, it does add an interesting pipelining-like
problem.  If all I'm doing is sending GET requests, then I can
probably open up thousands of streams, but the server can only respond
to a limited subset of those requests, holding requests (or responses)
in waiting until the response logjam frees up.  I think that this is
an undesirable property of the solution.  (MAX_CONCURRENT_STREAMS
could then look very much like HTTP/1.1 with pipelining.)