[ntp:questions] Re: Excessive polling

Tim Shoppa shoppa at trailing-edge.com
Fri Nov 28 17:15:04 UTC 2003


"David L. Mills" <mills at udel.edu> wrote in message news:<3FBA502A.C9127E29 at udel.edu>...
> NTPv3 (xntpd) operates as you describe; the poll intervals are clamped
> to the reference clock. NTPv4 (ntpd) has no such restriction; the poll
> intervals cheerfully escalate for sources other than the reference
> clock.

That's not what I observed.  I'm running 4.2.0 on linux, and the
reference clock (I use refclock_hpgps on one of my stratum-1's and
refclock_wwv on my other) is polled every 64 seconds, and all the servers
are polled every 64 seconds too.  This is true even after weeks of
stable running.  If I remove the refclock from ntp.conf
then the poll interval to the network servers go to 1024 seconds very quickly.

In order to be a "nice" network neighbor, I explicitly pegged minpoll
and maxpoll so that they were both at 1024 seconds.

I'm not accusing the 4.2.0 maintainers of explicitly doing this, in fact
I read the source code and it looks to me like what you say is true.  But
in operation that's not how it works.

Tim.



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