Re: [apps-discuss] Fwd: New Version Notification for draft-shelby-exi-registration-01.txt

ht@inf.ed.ac.uk (Henry S. Thompson) Wed, 11 April 2012 15:15 UTC

Return-Path: <ht@inf.ed.ac.uk>
X-Original-To: apps-discuss@ietfa.amsl.com
Delivered-To: apps-discuss@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 1944111E8170 for <apps-discuss@ietfa.amsl.com>; Wed, 11 Apr 2012 08:15:24 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -6.299
X-Spam-Level:
X-Spam-Status: No, score=-6.299 tagged_above=-999 required=5 tests=[AWL=0.300, BAYES_00=-2.599, RCVD_IN_DNSWL_MED=-4]
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 uUlQH8gFIBoT for <apps-discuss@ietfa.amsl.com>; Wed, 11 Apr 2012 08:15:23 -0700 (PDT)
Received: from nougat.ucs.ed.ac.uk (nougat.ucs.ed.ac.uk [129.215.13.205]) by ietfa.amsl.com (Postfix) with ESMTP id BDD2711E8164 for <apps-discuss@ietf.org>; Wed, 11 Apr 2012 08:15:22 -0700 (PDT)
Received: from nutty.inf.ed.ac.uk (nutty.inf.ed.ac.uk [129.215.33.33]) by nougat.ucs.ed.ac.uk (8.13.8/8.13.4) with ESMTP id q3BFFCmQ023161; Wed, 11 Apr 2012 16:15:12 +0100 (BST)
Received: from calexico.inf.ed.ac.uk (calexico.inf.ed.ac.uk [129.215.24.15]) by nutty.inf.ed.ac.uk (8.13.8/8.13.8) with ESMTP id q3BFFD5s003155; Wed, 11 Apr 2012 16:15:13 +0100
Received: from calexico.inf.ed.ac.uk (localhost [127.0.0.1]) by calexico.inf.ed.ac.uk (8.14.4/8.14.4) with ESMTP id q3BFFDj3009860; Wed, 11 Apr 2012 16:15:13 +0100
Received: (from ht@localhost) by calexico.inf.ed.ac.uk (8.14.4/8.14.4/Submit) id q3BFFCEl009856; Wed, 11 Apr 2012 16:15:12 +0100
X-Authentication-Warning: calexico.inf.ed.ac.uk: ht set sender to ht@inf.ed.ac.uk using -f
To: Carsten Bormann <cabo@tzi.org>
References: <20120329204732.13711.266.idtracker@ietfa.amsl.com> <5580A282-E191-4962-9410-6CF9FB14EDFC@sensinode.com> <20120402124522.GX16698@jay.w3.org> <8B84EAAD-CD22-4461-9BC6-AB78974A94A2@sensinode.com> <20120411075024.GN18899@jay.w3.org> <4F85410D.20802@toshiba.co.jp> <20120411085920.GP18899@jay.w3.org> <FBCADBF9-D6FB-4E0D-9668-F5B3EF744037@tzi.org>
From: ht@inf.ed.ac.uk (Henry S. Thompson)
Date: Wed, 11 Apr 2012 16:15:12 +0100
In-Reply-To: <FBCADBF9-D6FB-4E0D-9668-F5B3EF744037@tzi.org> (Carsten Bormann's message of "Wed, 11 Apr 2012 14:04:05 +0200")
Message-ID: <f5bobqye1vj.fsf@calexico.inf.ed.ac.uk>
User-Agent: Gnus/5.1008 (Gnus v5.10.8) XEmacs/21.4.21 (linux)
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
X-Edinburgh-Scanned: at nougat.ucs.ed.ac.uk with MIMEDefang 2.60, Sophie, Sophos Anti-Virus, Clam AntiVirus
X-Scanned-By: MIMEDefang 2.60 on 129.215.13.205
Cc: apps-discuss@ietf.org
Subject: Re: [apps-discuss] Fwd: New Version Notification for draft-shelby-exi-registration-01.txt
X-BeenThere: apps-discuss@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: General discussion of application-layer protocols <apps-discuss.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/apps-discuss>, <mailto:apps-discuss-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/apps-discuss>
List-Post: <mailto:apps-discuss@ietf.org>
List-Help: <mailto:apps-discuss-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/apps-discuss>, <mailto:apps-discuss-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 11 Apr 2012 15:15:24 -0000

Carsten Bormann writes:

> EXI requires out of band information to use the "Schema-Informed"
> mode.  In the Internet, This would normally be provided in an
> Internet media-type definition.  The media-type definition may also
> want to constrain the allowable values for the numerous options EXI
> provides, allowing for constrained implementations of EXI.

Your conclusion (use media type) doesn't follow.  Consider the analogy
of Content-Encoding: gzip -- suppose gzip provided improved
performance based on the decade in which the encoded document was
written, since natural language priors slowly shift over time.  Now
decoding requires OOB information about document creation date.  How shall
we provide it.  I know -- we'll define media types
application/...+gzip for every decade of interest!  I hope it's
obvious that would be a mistake. . .

If decoding requires some parameters, surely the right thing to do is
to transmit them in the obvious place, i.e. in the response message
header.

Either use the Content-Encoding (and Accept-Encoding) header itself,
by registering a new Content-Coding value [1] (foo+exi), or (better)
ask the W3C EXI WG to publish a Note defining an extension-header for
specifying or requesting a schemaID (and more generally, perhaps,
other properties specifiable in the EXI Options docuemtns).

Not only would the second option fit the architecture better, it would
remove the necessity for publishing a new RFC every time you update
the relevant schema!

ht

[1] http://www.iana.org/assignments/http-parameters/http-parameters.xml
-- 
       Henry S. Thompson, School of Informatics, University of Edinburgh
      10 Crichton Street, Edinburgh EH8 9AB, SCOTLAND -- (44) 131 650-4440
                Fax: (44) 131 650-4587, e-mail: ht@inf.ed.ac.uk
                       URL: http://www.ltg.ed.ac.uk/~ht/
 [mail from me _always_ has a .sig like this -- mail without it is forged spam]