[ntp:questions] clock selection

Harlan Stenn stenn at ntp.org
Sat Feb 4 22:57:30 UTC 2012


Mark wrote:

> For the clock selection to work properly, do I need at least 2 other
> time sources?

Strictly speaking, no, not if the 2 sources are in close enough
agreement.

> I have noticed that if I have one ref clock and one server configured
> they both get marked as false ticklers.

Yes, because they differ by "too much" - which one should ntpd believe?

> Add a third server and it all works. Just want to check if this is the
> expected behaviour.

Yes, ntpd builds "cliques" of server and looks for overlap and stuff.
If it cannot identify something resembling a "majority" it doesn't know
who to listen to.

H


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