Re: [DNSOP] Benjamin Kaduk's Discuss on draft-ietf-dnsop-dns-capture-format-08: (with DISCUSS and COMMENT)

Tony Finch <dot@dotat.at> Mon, 26 November 2018 14:54 UTC

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Date: Mon, 26 Nov 2018 14:54:38 +0000
From: Tony Finch <dot@dotat.at>
To: Richard Gibson <richard.j.gibson@oracle.com>
cc: Sara Dickinson <sara@sinodun.com>, Benjamin Kaduk <kaduk@mit.edu>, Tim Wicinski <tjw.ietf@gmail.com>, dnsop@ietf.org, dnsop-chairs@ietf.org, The IESG <iesg@ietf.org>, draft-ietf-dnsop-dns-capture-format@ietf.org
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Subject: Re: [DNSOP] Benjamin Kaduk's Discuss on draft-ietf-dnsop-dns-capture-format-08: (with DISCUSS and COMMENT)
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Richard Gibson <richard.j.gibson@oracle.com>; wrote:
>
> I am currently going through a similar exercise in another context, and the
> best current text there explicitly characterizes the non-obvious day-based
> accounting of POSIX time.

In general I think it's best to just refer to POSIX on this matter, and
not try to restate the definition. POSIX is very clear and explicit about
the day-based accounting of seconds.

http://pubs.opengroup.org/onlinepubs/9699919799.2016edition/basedefs/V1_chap04.html#tag_04_16

> However, there may be C-DNS purposes that cannot tolerate such
> discontinuities, and they would presumably want to use a continuous monotonic
> timescale with a fixed offset from TAI (as is the case for e.g. GPS time).

That's practically unobtanium on most systems :-) Even if you have PTP
there isn't a fixed PTP epoch, though the SMPTE profile defines it to be
equivalent to POSIX time plus the TAI-UTC value from the IERS / NIST
leapsecond tables.

Tony.
-- 
f.anthony.n.finch  <dot@dotat.at>;  http://dotat.at/
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