[Ntp] Antw: [EXT] Re: [Last-Call] Last Call: <draft-ietf-ntp-yang-data-model-10.txt> (A YANG Data Model for NTP) to Proposed Standard

Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de> Mon, 15 February 2021 08:50 UTC

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Date: Mon, 15 Feb 2021 09:50:28 +0100
From: Ulrich Windl <Ulrich.Windl@rz.uni-regensburg.de>
To: daedulus@btconnect.com, dhruv.ietf@gmail.com, stenn@nwtime.org
Cc: ankit.ietf@gmail.com, Dieter Sibold <dsibold.ietf@gmail.com>, ek.ietf@gmail.com, draft-ietf-ntp-yang-data-model@ietf.org, last-call@ietf.org, "ntp@ietf.org" <ntp@ietf.org>, "ntp-chairs@ietf.org" <ntp-chairs@ietf.org>
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Subject: [Ntp] Antw: [EXT] Re: [Last-Call] Last Call: <draft-ietf-ntp-yang-data-model-10.txt> (A YANG Data Model for NTP) to Proposed Standard
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>>> Harlan Stenn <stenn@nwtime.org> schrieb am 12.02.2021 um 21:48 in Nachricht
> On 2/12/2021 4:01 AM, tom petch wrote:
>> On 11/02/2021 09:39, Dhruv Dhody wrote:
>>> ...
>>       leaf poll {
>>         type uint8;
>> This seems wrong to me.  Looking at s.7.3
>>    Poll: 8-bit signed integer representing the maximum interval between
>>    successive messages, in log2 seconds.  Suggested default limits for
>>    minimum and maximum poll intervals are 6 and 10, respectively.
>> ie signed integer and not uint
> Why are 6 and 10 useful as suggested limits for minimum and maximum poll
> values?

Maybe because of this (man ntp.conf):
"The maximum poll interval  defaults  to 10 (1,024 s), but can be increased by the
maxpoll option to an upper limit of 17 (36.4 h).  The minimum  poll interval
defaults to 6 (64 s), but can be decreased by the minpoll option to a lower limit
of 4 (16 s)."

Also (RFC): "Typical secondary servers and clients on fast LANs are within a few
hundred microseconds with poll intervals up to 1024 seconds, which was the maximum
with NTPv3.  With NTPv4, servers and clients are precise within a few tens of
milliseconds with poll intervals up to 36 hours."
"A client sends messages to each server with a poll interval of 2^tau seconds,
as determined by the poll exponent tau.  In NTPv4, tau ranges from 4 (16 s) to
17 (36 h)."

"Suggested default limits for minimum and maximum poll intervals are 6 and 10, respectively."


> -- 
> Harlan Stenn <stenn@nwtime.org>
> http://networktimefoundation.org - be a member!
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