[ntp:questions] large dispersion
Richard B. Gilbert
rgilbert88 at comcast.net
Wed May 23 17:16:28 UTC 2007
Dave wrote:
> I'm experiencing large values of dispersion when I use 'ntpq -p':
>
> 3:22pm:ntp>ntpq -p
> remote refid st t when poll reach delay
> offset disp
> ==============================================================================
> *10.2.100.10 .GPS. 1 u 25 64 377 0.46
> 943.557 439.36
> 3:22pm:ntp>
>
>
> but when I look at the peerstats log file, my dispersion is low:
>
> 3:22pm:ntp>tail /var/ntp/ntpstats/peerstats.log
> 54243 54804.018 10.2.100.10 9634 0.617563 0.00046 0.31154
> 54243 54868.013 10.2.100.10 9634 0.813226 0.00043 0.32210
> 54243 54932.018 10.2.100.10 9634 0.099169 0.00046 0.55225
> 54243 54996.010 10.2.100.10 9634 0.300057 0.00047 0.28690
> 54243 55060.014 10.2.100.10 9634 0.584358 0.00044 0.31111
> 54243 55124.009 10.2.100.10 9634 0.781632 0.00047 0.32353
> 54243 55188.014 10.2.100.10 9634 0.065932 0.00043 0.55287
> 54243 55252.013 10.2.100.10 9634 0.657674 0.00044 0.37859
> 54243 55316.018 10.2.100.10 9634 0.943557 0.00046 0.43936
> 54243 55380.013 10.2.100.10 9634 0.139388 0.00044 0.59772
> 3:23pm:ntp>
>
>
> I'm also concerned with the large amount of maximum/estimated error
> when I use the xntpdc command 'kerninfo':
>
> xntpdc> kerninfo
> pll offset: 0 us
> pll frequency: -391.137 ppm
> maximum error: 524704 us
> estimated error: 408368 us
> status: 0089
> pll time constant: 2
> precision: 1 us
> frequency tolerance: 512 ppm
> pps frequency: 0.000 ppm
> pps stability: 512.000 ppm
> pps jitter: 200 us
> calibration interval: 4 s
> calibration cycles: 0
> jitter exceeded: 0
> stability exceeded: 0
> calibration errors: 0
> xntpdc>
>
> Here is the output of the pstats command:
>
> xntpdc> pstats 10.2.100.10
> remote host: 10.2.100.10
> local interface: 10.2.100.5
> time last received: 3s
> time until next send: 61s
> reachability change: 2947s
> packets sent: 59
> packets received: 59
> bad authentication: 0
> bogus origin: 0
> duplicate: 0
> bad dispersion: 15
> bad reference time: 0
> candidate order: 1
> xntpdc>
>
> And lastly, my ntp.conf file:
>
> 3:25pm:inet>more ntp.conf
> server 10.2.100.10 # NTP server
>
> driftfile /etc/ntp.drift # Drift available for next restart
> logfile /var/ntp/ntp.log # NTP logging
>
> statsdir /var/ntp/ntpstats/
> statistics loopstats peerstats clockstats
> filegen loopstats file loopstats.log type day link enable
> filegen peerstats file peerstats.log type day link enable
> filegen clockstats file clockstats.log type day link enable
> 3:25pm:inet>
>
>
>
> Anyone have any ideas? I have a GPS signal coming in to a Brandywine
> NTA-100, which is configured at 10.2.100.10. Thanks in advance!
>
If you are using "X"ntpdc you would appear to be using a version that
may be as much as ten years old! Just what are you using and what are
you running it on?
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