[ntp:questions] Polling time backoff

Unruh unruh-spam at physics.ubc.ca
Tue Jan 12 02:46:27 UTC 2010


Dave Hart <davehart at gmail.com> writes:

>On Nov 28, 11:52=A0pm, shane-dated-2... at csy.ca wrote:
>> Just wondering if there is anything in particular which would keep ntpd
>> polling its servers every 64s
>>
>> server 127.127.20.0 minpoll 4 prefer
>> fudge 127.127.20.0 flag3 1 flag2 0

>The refclock is holding the poll interval down.  You have to use
>minpoll on the remote server lines to force them to a longer poll
>interval in the presence of a reflock with a smaller poll interval.

Is that really right? I thought that all of the clocks had their poll intervals
determined independently. YOu seem to be saying they do not, that the poll
intervals are "universal" the smallest poll interval for any server is used. 
On my system that is certainly not true
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
+tick.usask.ca   .GPS.            1 u  949 1024  377   44.957    0.169   0.254
+ntp.ubc.ca      142.3.100.2      2 u   70 1024  375    0.643   -0.989   4.799
*SHM(0)          .PPS.            0 l    4   16  377    0.000    0.000   0.001

The shm has a maxpoll and minpoll of 4 while the others have the default. 



>Cheers,
>Dave Hart




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