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Re: [Ntp] NTS4UPTP Rev 03 - Formal request for WG adoption

Daniel Franke <dfoxfranke@gmail.com> Tue, 01 June 2021 18:03 UTC

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From: Daniel Franke <dfoxfranke@gmail.com>
Date: Tue, 01 Jun 2021 14:03:06 -0400
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To: Danny Mayer <mayer@pdmconsulting.net>
Cc: Heiko Gerstung <heiko.gerstung=40meinberg.de@dmarc.ietf.org>, Miroslav Lichvar <mlichvar@redhat.com>, NTP WG <ntp@ietf.org>
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Subject: Re: [Ntp] NTS4UPTP Rev 03 - Formal request for WG adoption
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Depends on your clock discipline algorithm. Yes, if you feed an excessive
number of samples into a underdamped PLL then your clock is just going to
bounce around a lot without ever getting more accurate. But e.g. a Kalman
filter should happily slurp up as many samples as you throw at it. Having
more information can't be bad unless you use it badly.

On Tue, Jun 1, 2021, 13:54 Danny Mayer <mayer@pdmconsulting.net> wrote:

> Noone should be using a polling interval that small. Oversampling is as
> bad as undersampling.
>
> Danny
> On 6/1/21 1:28 PM, Daniel Franke wrote:
>
> It's in units of log2(seconds) so a negative value makes fine sense. E.g.
> -1 means half a second.
>
> On Tue, Jun 1, 2021, 13:24 Danny Mayer <mayer@pdmconsulting.net> wrote:
>
>>
>> On 6/1/21 11:42 AM, Miroslav Lichvar wrote:
>> >
>> > I'm not sure I follow here. You can send NTP requests at any rate you
>> > like. That doesn't require a new protocol. The poll field is a signed
>> > 8-bit integer if you had a server that actually looked in the content
>> > of the field.
>>
>> I hope not. How would you implement a negative poll interval? :)
>>
>> It really should be unsigned. If not, then that's really an error.
>>
>> Danny
>>
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