Re: [dtn] I-D Action: draft-ietf-dtn-bpbis-15.txt

Dear Scott,

I agree with your proposed update to the text. This reflects how we
understood it previously and have implemented it in uPCN. Works quite
well for us.

Felix

On 22.10.19 00:03, Burleigh, Scott C (US 312B) wrote:
>
> Thanks, Brian.  How about byte strings?  Could we say that the CRC
> SHALL be represented as a CBOR byte string of length either 2 or 4,
> and that the content of each such byte string is to be processed as an
> integer in network byte order?
>
>  
>
> Scott
>
>  
>
> *From:* Brian Sipos <BSipos@rkf-eng.com>
> *Sent:* Monday, October 21, 2019 2:42 PM
> *To:* dtn@ietf.org; Burleigh, Scott C (US 312B)
> <scott.c.burleigh@jpl.nasa.gov>
> *Subject:* [EXTERNAL] Re: [dtn] I-D Action: draft-ietf-dtn-bpbis-15.txt
>
>  
>
> Scott,
>
> The new text leaves me confused about the correct encoding and
> interpretation of the CRC values themselves. The earlier text said
> that the values are a "sequence of bytes" representing an integer. The
> new -15 text says that the values are CBOR integer type but still
> talks about sequences of bytes.
>
>  
>
> For some background on my desire for specific requirements here: there
> are many COTS CBOR encoders today (mostly for higher-level languages,
> e.g. Python and ECMAScript) which do not allow a fine-grained level of
> control about how numbers are CBOR-encoded. These COTS encoders don't
> have an API to tell the encoder to make a non-shortest-length output;
> so it's not possible to implement the BPv7-CRC-required behavior of:
>
>    ...including the CRC field itself, which for this purpose SHALL be
>    temporarily populated with the value zero.
>
> When these encoders see a native integer/number value of zero the
> output is always the encoded bytestring 0x00. My opinion is that
> unnecessarily limits environments which BPv7 can be used in (at least
> when CRC handling is intended). I understand that these may not be
> expected use environments for BP, so take all of this with a grain of
> salt.
>
> Thanks,
>
> Brian S..
>
>  
>
> ------------------------------------------------------------------------
>
> *From:*dtn <dtn-bounces@ietf.org <mailto:dtn-bounces@ietf.org>> on
> behalf of internet-drafts@ietf.org <mailto:internet-drafts@ietf.org>
> <internet-drafts@ietf.org <mailto:internet-drafts@ietf.org>>
> *Sent:* Friday, October 18, 2019 17:02
> *To:* i-d-announce@ietf.org <mailto:i-d-announce@ietf.org>
> <i-d-announce@ietf.org <mailto:i-d-announce@ietf.org>>
> *Cc:* dtn@ietf.org <mailto:dtn@ietf.org> <dtn@ietf.org
> <mailto:dtn@ietf.org>>
> *Subject:* [dtn] I-D Action: draft-ietf-dtn-bpbis-15.txt
>
>  
>
>
> A New Internet-Draft is available from the on-line Internet-Drafts
> directories.
> This draft is a work item of the Delay/Disruption Tolerant Networking
> WG of the IETF.
>
>         Title           : Bundle Protocol Version 7
>         Authors         : Scott Burleigh
>                           Kevin Fall
>                           Edward J. Birrane
>         Filename        : draft-ietf-dtn-bpbis-15.txt
>         Pages           : 61
>         Date            : 2019-10-18
>
> Abstract:
>    This Internet Draft presents a specification for Bundle Protocol,
>    adapted from the experimental Bundle Protocol specification
>    developed by the Delay-Tolerant Networking Research group of the
>    Internet Research Task Force and documented in RFC 5050.
>
>
> The IETF datatracker status page for this draft is:
> https://datatracker.ietf.org/doc/draft-ietf-dtn-bpbis/
>
> There are also htmlized versions available at:
> https://tools.ietf.org/html/draft-ietf-dtn-bpbis-15
> https://datatracker.ietf.org/doc/html/draft-ietf-dtn-bpbis-15
>
> A diff from the previous version is available at:
> https://www.ietf.org/rfcdiff?url2=draft-ietf-dtn-bpbis-15
>
>
> Please note that it may take a couple of minutes from the time of
> submission
> until the htmlized version and diff are available at tools.ietf.org.
>
> Internet-Drafts are also available by anonymous FTP at:
> ftp://ftp.ietf.org/internet-drafts/
>
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