[ntp:questions] Keeping NTP Honest Redux

Richard B. Gilbert rgilbert88 at comcast.net
Sat Nov 7 01:12:12 UTC 2009


Unruh wrote:
> "Richard B. Gilbert" <rgilbert88 at comcast.net> writes:
> 
>> Terje Mathisen wrote:
>>> Evandro Menezes wrote:
>>>> I've come to the conclusion that since NTP doesn't correct for
>>>> temperature variations, it's long-term compensation is counter-
>>>> productive.  Therefore, instead of letting the poll period increase to
>>>> the default 1024s, perhaps it'd be best to limit it to 64s.  However,
>>>> this requires that each server has the option maxpoll attached to it.
>>>> It'd be more convenient to have set this parameter for all servers
>>>> from a single place, such as the old tinker maxpoll option.
>>>>
>>>> So, why was tinker maxpoll removed?  Any chance to get it back in?
>>> Maybe because the algorithms have been optimized to get the best 
>>> possible time with minimum load on the servers?
>>>
>>> Making it more convenient to lock polling at 64s isn't a good idea, imho.
> 
>> Locking the polling interval at ANY value probably isn't a good idea. 
>> If not tampered with, NTPD will adjust the polling interval to the 
>> optimum value for the conditions then obtaining.  The conditions do change.
> 
> Well, not really. ntp is designed to quite rapidly go to maxpoll of 10
> and to stay there. The routine is very loath to decrease the poll and
> quick to increase it, so that it rarely decreases the poll interval. Ie,

My observations do not support that.  The polling interval changes 
throughout the day in both directions.

<snip>




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