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Re: [Ntp] Antw: Re: Antw: [EXT] comments on draft‑mlichvar‑ntp‑ntpv5‑03

Miroslav Lichvar <mlichvar@redhat.com> Wed, 24 November 2021 12:09 UTC

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Date: Wed, 24 Nov 2021 13:09:06 +0100
From: Miroslav Lichvar <mlichvar@redhat.com>
To: Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>
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Subject: Re: [Ntp] Antw: Re: Antw: [EXT] comments on draft‑mlichvar‑ntp‑ntpv5‑03
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On Wed, Nov 24, 2021 at 12:37:00PM +0100, Ulrich Windl wrote:
> I had always wondered whether MAXDISP wasn't just some arbitrary larger
> number; Couldn't it be 1 second as well?
> Is there any specific reasoning behind?

MAXDISP is the threshold when the server is considered unsynchronized
after it stops updating its clock. It should be larger than any
normally expected dispersion to not block synchronization.

With the default PHI of 15 ppm, it takes 16/15e-6 seconds (about
12.3 days) for the dispersion to accumulate 16 seconds. In the worst
case it should cover up to 15 strata updating clocks at a maximum
polling interval.

I think 1 second would be too small.

-- 
Miroslav Lichvar

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