Re: Public Release of Z-Wave G.9959 TAP Specification

[Chris Brandson via tcpdump-workers <tcpdump-workers () lists tcpdump org>]

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> From: Chris Brandson <chris.brandson () gmail com>
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> Date: Tue, 6 Dec 2022 07:55:06 -0800
>
> Hello Denis,
>
> I agree with all of your suggestions, have made the changes and pushed to the repo.
>
>
> > * Page 7: "Length is a minimum of 4 octets and must be a multiple of 4.
> >  The addition of new TLVs does not and must not require incrementing
> >  the version number." -- this definition automatically creates a
> >  problem space on the receiving/reading end of this encoding because
> >  slightly more than 75% of all possible length values are invalid by
> >  definition. The classic solution would be not to include the first 4
> >  octets into the length, and to count in multiples of 4, this way any
> >  length value would be valid, free of underflows and better consumable
> >  by simple parsers such as BPF bytecode.
>
> The length is now the number of 4 octet (32-bit) words omitting the header.
>
> > * Page 8: "Z-Wave PHY Payload" -- is this the PPDU from Figure A.7 of
> >  G.9959 2015/01, starting from "preamble sequence"?
>
> This was an unfortunate mistake on my part. The intention was to specify the MPDU (not PPDU). This has been corrected 
> and mapping to G.9959 added.
>
> > * Page 9: "length - number of octets for type in value field (not
> >  including padding)" -- this definition looks better, but in the next
> >  three TLV diagrams the length does include the T and the L.
>
> Lengths in the diagrams have been corrected.
>
> > * Page 10: If the list of region code points is a copy/subset of an
> >  external registry, it would help to give an exact reference.  Ditto
> >  bit rate code points.  Clearly there is some relation with tables A.1
> >  and A.2 from G.9959 2015/01.
>
>
> References have need added.
>
> Thank-you for your feedback.
>
> Regards,
>
> + Chris Brandson
>
> --- End Message ---
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