[ntp:questions] Improving ACTS performance

Joshua Coombs jcoombs at gwi.net
Thu Apr 6 15:37:03 UTC 2006

I finally have my stratum 2 servers working as good as I think they 
can given their environments.  Now I'm working on my stratum 1 clock 
which pulls it's time via ACTS.

I'm currently dialing NIST so I can take advantage of the automatic 
latency compensation.  Problem is, the time I get back seems to vary 
by up to 20ms.  I may get 3 or 4 calls where the reported time stays 
within a couple ms of what I believe true time to be, and then a call 
will come back close to 20ms off.  When ntpd has decided to stretch 
out to it's max call interval, that glitch induces drift in the clock, 
resulting in an eventual 40ms offset before it corrects.

I've tried the following:
 - switched to manual latency adjustment using time1
 - only configured 1 number to avoid different latencies for different 
 - dialing USNO instead of NIST

I can't seem to shake the random wild offsets.

I'm running the 4.2.1RC on FreeBSD 4.11, soekris 4501, and a Microcom 
28.8 external modem.

I'm open to any suggestions on how to improve things.

Joshua Coombs 

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