[ntp:questions] More peering theory - refclocks in the mix

Joshua Coombs jcoombs at gwi.net
Thu Mar 16 15:22:00 UTC 2006

My test server aided with rrdtool has narrowed down my pool of 
potential remote ntp servers to 17 healthy candidates with consistent 
latency, low jitter, and similar theories on the one true tick.  That 
gives me 4 to hand to each of my peered internal servers, plus an 
extra to toss on at random.

One of these servers is dialing NIST periodically.  With the server 
set it has, it never raises the polling interval from min (12) and 
never chooses it as a time source.  The jitter seems rather high as 
well.  I was under the impression that if I used the two NIST numbers, 
the refclock driver could deduce the line latency automatically 
(always reads 0 on the scoreboard) and took multiple samples per call 
to reduce jitter.  Should I be using 'burst' on that server statement 
(is that even valid?).  I'd like to see the server stretch the poll 
interval up to the max if it can, seems like calling NIST every hour 
is a bit extreme.

Also, as that server has access to a reference clock, would I be 
better served configuring just my peers on it and no external ip 
servers, instead putting them on my 3 other internal servers?

I've also seen mention of using burst with extended intervals for 
remote time sources mentioned in a few places.  If I only have a given 
remote time source configured on one server, is using burst with a 
maxpoll of 11 considered abusive?  Should I bump my minpoll if I do?

Joshua Coombs 

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