[ntp:questions] jumpy offset/drift
brad at stop.mail-abuse.org
Thu Aug 11 14:07:36 UTC 2005
At 11:15 AM +0200 2005-08-11, Folkert van Heusden wrote:
> I did some investigating and found that ntpd constantly switches between
> servers and my local DCF receiver:
Yup. If you've got four falsetickers that are all in reasonably
close agreement, they can result in the truechimer being kicked off
If you don't want this to happen, you've got to take extra steps
to try to guarantee that you only ever sync to your DCF receiver.
> What I now don't understand is why it sometimes marks the dcf receiver
> as a bad clock. The delay is constantly 0 and the offset as well as the
> jitter are always low.
See above. You've got too many other clocks that are all
reasonably close to each other, so they're pulling the overall
average away from your DCF receiver. As a result, instead of the
three or four falsetickers being kicked off the island, your one
truechimer is being kicked off.
Of course, that's assuming that your DCF receiver really is the
one truechimer -- maybe it's the falseticker and the others are
truechimers instead. That's a hard question to answer without a lot
Brad Knowles, <brad at stop.mail-abuse.org>
"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."
-- Benjamin Franklin (1706-1790), reply of the Pennsylvania
Assembly to the Governor, November 11, 1755
SAGE member since 1995. See <http://www.sage.org/> for more info.
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