[ntp:questions] why do internet servers not poll at longer intervals

Chris Albertson albertson.chris at gmail.com
Tue Feb 14 20:51:53 UTC 2012


On Tue, Feb 14, 2012 at 11:25 AM, Ron Frazier (NTP)
<timekeepingntplist at c3energy.com> wrote:
  As has been suggested by others, I know
> I can get hugely better accuracy using a different GPS and PPS, and I plan
> to experiment with that when I get time and money.  (I've been ignoring lots
> of other household things while pursuing this project.)  For the moment, I
> just want to get optimum performance out of the equipment that I have.  For
> my immediate needs, +/- 6-10 ms accuracy is perfectly adequate for what I'm
> doing.

Actually I like building stuff with "junk" (junk = ham radio term for
box of salvaged parts)  It is so easy to build anying if you can just
order whatever parts you like.   You learn more f you have to use what
you have.

Why the short polling?   NTP's real end product is a clock adjustment
rate.  NTP looks to see if this rate "moves around".    lots of
movement tel NTP that the oscillator inside your computer is not
stable and can't be trusted for "long" periods of time.      In might
be a cheap oscillator, or your PC might be right under an air
conditioning vent.  It don't matter.    The polling interval is set
baed on (1) the stabilty of the local PC internal clock and (2) jitter
on the Internet servers.     NTP finds the place two lines cross and
puts the polling interval there.

Your nest step is to stabilize the internal temp. of the PC, turn off
power management and get a thermostatically controlled fan.     A good
location for a home NTP server would be some internal closet that does
not have an external wall r a heat/AC vent inside.



Chris Albertson
Redondo Beach, California


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