[ntp:questions] Polling time backoff

shane-dated-2009 at csy.ca shane-dated-2009 at csy.ca
Sun Nov 29 19:49:28 UTC 2009


>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

Hmm, I think Richard Gilbert's post was pretty well spot on, watching the
poll last night, it did go as high as 512 at around 2 AM for some of the
servers. I just unconfig'd the refclock to see if that's making a difference
but so far, polling is still at 64s. A bit odd, my connection to the net
isn't terrible, res. cable connection but delays are decent. It's asymmetric
though which I understand can give ntpd some grief.

I have my net speed throttled slightly below upstream max so I can do packet
prioritization and have ntp packets pretty high up in the queues so it's not
like they're being held up in the modem buffers either.

Shane




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