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

[Carsten Bormann <[e-mail]>]

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 <[e-mail]> 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
> 
>