Re: [Cbor] I-D Action: draft-ietf-cbor-file-magic-06.txt

Carsten Bormann <cabo@tzi.org> Wed, 03 November 2021 14:23 UTC

Return-Path: <cabo@tzi.org>
X-Original-To: cbor@ietfa.amsl.com
Delivered-To: cbor@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 269FB3A1513; Wed, 3 Nov 2021 07:23:55 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.899
X-Spam-Level:
X-Spam-Status: No, score=-1.899 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 3Gf3JRpl_GlP; Wed, 3 Nov 2021 07:23:50 -0700 (PDT)
Received: from gabriel-smtp.zfn.uni-bremen.de (gabriel-smtp.zfn.uni-bremen.de [IPv6:2001:638:708:32::15]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 215D13A1515; Wed, 3 Nov 2021 07:23:50 -0700 (PDT)
Received: from [192.168.217.118] (p5089a10c.dip0.t-ipconnect.de [80.137.161.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by gabriel-smtp.zfn.uni-bremen.de (Postfix) with ESMTPSA id 4Hkpsp2ZTJz30gm; Wed, 3 Nov 2021 15:23:42 +0100 (CET)
Content-Type: text/plain; charset=utf-8
Mime-Version: 1.0 (Mac OS X Mail 13.4 \(3608.120.23.2.7\))
From: Carsten Bormann <cabo@tzi.org>
In-Reply-To: <YYKYIzFFIGWVqNK8@hephaistos.amsuess.com>
Date: Wed, 3 Nov 2021 15:23:42 +0100
Cc: draft-ietf-cbor-file-magic@ietf.org, cbor@ietf.org
X-Mao-Original-Outgoing-Id: 657642222.007483-f200ee6e4efb285592797843ecc20fd3
Content-Transfer-Encoding: quoted-printable
Message-Id: <D67B5B60-C88D-417C-A28A-A8889306CFF6@tzi.org>
References: <163484662604.2786.6905890868276647458@ietfa.amsl.com> <YYKYIzFFIGWVqNK8@hephaistos.amsuess.com>
To: =?utf-8?Q?Christian_Ams=C3=BCss?= <christian@amsuess.com>
X-Mailer: Apple Mail (2.3608.120.23.2.7)
Archived-At: <https://mailarchive.ietf.org/arch/msg/cbor/kINtoAKHfuyl9nwFU-NSqxqpxd0>
Subject: Re: [Cbor] I-D Action: draft-ietf-cbor-file-magic-06.txt
X-BeenThere: cbor@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "Concise Binary Object Representation \(CBOR\)" <cbor.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/cbor>, <mailto:cbor-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/cbor/>
List-Post: <mailto:cbor@ietf.org>
List-Help: <mailto:cbor-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/cbor>, <mailto:cbor-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 03 Nov 2021 14:23:55 -0000

The Content-Format part has become inconsistent; we weren’t able to fix this before the I-D deadline.  We do need to have a discussion what we want to achieve here; there are two potential approaches, and we need to discuss which one we take (or possibly both, adding a 55801 or some such).

Grüße, Carsten


> On 2021-11-03, at 15:09, Christian Amsüss <christian@amsuess.com> wrote:
> 
> Signed PGP part
> Hello Carsten, hello Michael,
> 
>> A diff from the previous version is available at:
>> https://www.ietf.org/rfcdiff?url2=draft-ietf-cbor-file-magic-06
> 
> The example has now become inconsistent, mixing the CBOR Tag Wrapped and
> CBOR Tags for Content Formats parts:
> 
>> to translate the Content-Format number registered for
>> application/senml+cbor, the number 112, into the tag 1668546560+112 =
>> 1668546672.
>> 
>> 55799(1668546672([{0: "current", 6: 3, 2: 1.5}]))
> 
> puts CBOR data into the content-format generated item, whereas Appendix
> A says:
> 
>> The tag content tagged with tag number [...] is a byte string that is
>> to be interpreted as a representation of the content format
>> NNNNNNNN-1668546560.
> 
> which would look like 55799(1668546672(h'a30067...')).
> 
> My understanding so far was that with the current appendix, all data
> would be bstr-valued, and if a) the content format is CBOR based, and b)
> the transport coding is "identity", and c) the representation is
> actually well-formed in the advertised content format, only then will
> the byte string (happen to) be valid CBOR, but still encoded in a byte
> string.
> 
> I kind of like having pre-allocated tags for the CBOR protocols implied
> by a content format (where applicable) for reasons of closure, that it
> works this way and how it works (can't share the same 16bit tag range
> without creating ambiguity, can it?) needs to be spelled out -- right
> now, this is internally contradictory.
> 
> Could you clarify what your intentions are here, or whether I missed a
> discussion due to which this is being changed?
> 
> BR
> Christian
> 
> -- 
> There's always a bigger fish.
>  -- Qui-Gon Jinn
> 
>