[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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