[ntp:questions] Slow convergence of NTP with GPS/PPS

Maarten Wiltink maarten at kittensandcats.net
Sat Oct 25 12:33:10 UTC 2008


"Unruh" <unruh-spam at physics.ubc.ca> wrote in message
news:UJyMk.3986$fF3.1213 at edtnps83...

> [...] The longer poll intervals are mainly about keeping packets off
> the servers. In principle it is always better to poll more. ...

Yes, but. One of the given reasons for polling less often is to let
the host clock accrue more error so that it becomes better measureable
amid other error sources, for example jitter from random network delays.

But you can poll every second and still correct very small frequency
errors, if only you don't _forget_ polls from very long ago. Keeping
a simple FIFO queue of poll results is too simple.

Groetjes,
Maarten Wiltink





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