Re: Design Issue: Frame Size Items

James M Snell <jasnell@gmail.com> Tue, 07 May 2013 19:08 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 762A521F8EAF for <ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com>; Tue, 7 May 2013 12:08:54 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -10.599
X-Spam-Level:
X-Spam-Status: No, score=-10.599 tagged_above=-999 required=5 tests=[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 nMjT22KTeywi for <ietfarch-httpbisa-archive-bis2Juki@ietfa.amsl.com>; Tue, 7 May 2013 12:08:48 -0700 (PDT)
Received: from frink.w3.org (frink.w3.org [128.30.52.56]) by ietfa.amsl.com (Postfix) with ESMTP id 31E6121F8972 for <httpbisa-archive-bis2Juki@lists.ietf.org>; Tue, 7 May 2013 12:08:48 -0700 (PDT)
Received: from lists by frink.w3.org with local (Exim 4.72) (envelope-from <ietf-http-wg-request@listhub.w3.org>) id 1UZnFS-0001it-AC for ietf-http-wg-dist@listhub.w3.org; Tue, 07 May 2013 19:08:26 +0000
Resent-Date: Tue, 07 May 2013 19:08:26 +0000
Resent-Message-Id: <E1UZnFS-0001it-AC@frink.w3.org>
Received: from maggie.w3.org ([128.30.52.39]) by frink.w3.org with esmtp (Exim 4.72) (envelope-from <jasnell@gmail.com>) id 1UZnFH-0001hr-4v for ietf-http-wg@listhub.w3.org; Tue, 07 May 2013 19:08:15 +0000
Received: from mail-oa0-f41.google.com ([209.85.219.41]) by maggie.w3.org with esmtps (TLS1.0:RSA_ARCFOUR_SHA1:16) (Exim 4.72) (envelope-from <jasnell@gmail.com>) id 1UZnFF-0006RM-6v for ietf-http-wg@w3.org; Tue, 07 May 2013 19:08:15 +0000
Received: by mail-oa0-f41.google.com with SMTP id k1so1110478oag.0 for <ietf-http-wg@w3.org>; Tue, 07 May 2013 12:07:47 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:mime-version:in-reply-to:references:from:date:message-id :subject:to:cc:content-type; bh=lOQVs/k8yZ3BMUR3BOZj3EPx9pS4I/201LxQqZACQGc=; b=qIPCDQQkYQytZzrxPEml9r31yTh60ikH5FkM3csuNaskDgJzyK1+wcy/7O4MFln47g yEIP6+q8SuTEfXRs1Xih2fxkfWjuKs/CHGAw/1rjY2fgb80oYVQz4UZSoSH1Dadc7Ts2 ZkFH1UwTatCFbSs8yVcG3B1gbZqjA1YI6Tldo2uM9icSQpsIAepPSWuzXBMQKExr4BtN MB/AjcgwBBVmtzgQoijTLD7+CTpIMKIUobr65spVBb+S85/avH3cB5L+eobm/lOZk0AS f77bF2O57B9cGuVWjnlXZ9EUlxQiDXv0b87qCMYyYmb3dn4pTjcEzyfzJ0hOknZ3pk4O DsKQ==
X-Received: by 10.60.55.231 with SMTP id v7mr924584oep.135.1367953667364; Tue, 07 May 2013 12:07:47 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.60.3.137 with HTTP; Tue, 7 May 2013 12:07:27 -0700 (PDT)
In-Reply-To: <CABkgnnWDvyUajrhYLvGzqeenUsyq9h720LYZNUzqzHNR8r0LxQ@mail.gmail.com>
References: <CABP7RbcUDvmYjUjE703UTgOcYTSLBohR7EFw2Rb9u-EDkB7htg@mail.gmail.com> <CABkgnnWDvyUajrhYLvGzqeenUsyq9h720LYZNUzqzHNR8r0LxQ@mail.gmail.com>
From: James M Snell <jasnell@gmail.com>
Date: Tue, 07 May 2013 12:07:27 -0700
Message-ID: <CABP7Rbc37nJ20txdYLQrRFquEbk9uUJeHu+mnb+tAKDo1A7zUg@mail.gmail.com>
To: Martin Thomson <martin.thomson@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=209.85.219.41; envelope-from=jasnell@gmail.com; helo=mail-oa0-f41.google.com
X-W3C-Hub-Spam-Status: No, score=-3.5
X-W3C-Hub-Spam-Report: AWL=-2.678, 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 1UZnFF-0006RM-6v 168a908eb545f8003d2ae257baf83079
X-Original-To: ietf-http-wg@w3.org
Subject: Re: Design Issue: Frame Size Items
Archived-At: <http://www.w3.org/mid/CABP7Rbc37nJ20txdYLQrRFquEbk9uUJeHu+mnb+tAKDo1A7zUg@mail.gmail.com>
Resent-From: ietf-http-wg@w3.org
X-Mailing-List: <ietf-http-wg@w3.org> archive/latest/17874
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 Tue, May 7, 2013 at 11:07 AM, Martin Thomson
<martin.thomson@gmail.com> wrote:
> On 7 May 2013 08:19, James M Snell <jasnell@gmail.com> wrote:
>> 1. There is an existing ed note in the draft indicating that we
>> currently do not have any way of specifying the maximum frame size.
>> There are several possibilities:
>>
>>   a. We decide we don't need to report a maximum frame size.
>
> This has been discussed.  The problem is that you have to then FIX the
> maximum frame size and require that all implementations support that
> size.  No one can decide on a goldilocks number: 4096, 8192, 16384,
> 32768 or 65536 have all been variously proposed.  Others want to add
> extra bits to the length field to open up other options (i.e.,
> petabytes).
>
>>   b. We introduce a MAX_FRAME_SIZE setting for the SETTINGS frame.
>
> This introduces another "known state" issue (see Gabriel's issues).
> You have to have a default (see above), and then a robust way to
> change.
>

Option (b) certainly isn't perfect but it works. Since our frame size
field is expressed as an unsigned 16-bit integer, we already have a
fixed maximum size (2^16-1 + 8) which ought to be the default
MAX_FRAME_SIZE. If an implementation needs it to be smaller, they can
specify so using the SETTINGS.

>>   c. We add a headers block to the RST_FRAME and GOAWAY frames ;-) ..
>
> I'm not following you.
>

I was being silly.. never mind ;-)

>>   I think I prefer option (a) but (b) works too.
>>
>> 2. In the current draft we say that all implementations MUST be
>> capable of supporting frames up to 8192 octets in length. We don't
>> say, however, whether that size includes the 8-byte header or is that
>> just payload octets?
>
> That's a simple fix.  Toss a coin.  ;)

Ok, coin toss says the 8-byte header is not included. That work for everyone?

- James