NTPsec

ntp2.wiktel.com

Report generated: Thu Apr 25 22:53:02 2024 UTC
Start Time: Wed Apr 24 22:53:01 2024 UTC
End Time: Thu Apr 25 22:53:01 2024 UTC
Report Period: 1.0 days

Top   Daily Stats   Weekly Stats  

Local Clock Time/Frequency Offsets

local offset plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Time Offset -21.932 -9.033 -5.703 0.572 2.906 4.071 8.798 8.609 13.104 2.596 -0.000 µs -5.858 22.38
Local Clock Frequency Offset -13.866 -13.811 -13.729 -13.569 -13.291 -13.248 -13.204 0.438 0.562 0.136 -13.542 ppm -1.02e+06 1.028e+08

The time and frequency offsets between the ntpd calculated time and the local system clock. Showing frequency offset (red, in parts per million, scale on right) and the time offset (blue, in μs, scale on left). Quick changes in time offset will lead to larger frequency offsets.

These are fields 3 (time) and 4 (frequency) from the loopstats log file.



Local RMS Time Jitter

local jitter plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local RMS Time Jitter 0.550 1.056 1.449 3.187 5.582 6.929 11.040 4.133 5.873 1.286 3.306 µs 9.263 28.84

The RMS Jitter of the local clock offset. In other words, how fast the local clock offset is changing.

Lower is better. An ideal system would be a horizontal line at 0μs.

RMS jitter is field 5 in the loopstats log file.



Local RMS Frequency Jitter

local stability plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local RMS Frequency Jitter 0.839 1.536 2.108 4.610 7.875 9.840 15.538 5.767 8.304 1.797 4.743 ppb 9.946 31.14

The RMS Frequency Jitter (aka wander) of the local clock's frequency. In other words, how fast the local clock changes frequency.

Lower is better. An ideal clock would be a horizontal line at 0ppm.

RMS Frequency Jitter is field 6 in the loopstats log file.



Local Clock Time Offset Histogram

local offset histogram plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Offset -21.932 -9.033 -5.703 0.572 2.906 4.071 8.798 8.609 13.104 2.596 -0.000 µs -5.858 22.38

The clock offsets of the local clock as a histogram.

The Local Clock Offset is field 3 from the loopstats log file.



Local GPS

local gps plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
nSats 6.000 6.000 7.000 9.000 11.000 11.000 12.000 4.000 5.000 1.198 8.860 nSat 280.8 1919
TDOP 0.540 0.580 0.620 0.830 1.430 3.440 4.920 0.810 2.860 0.408 0.928 11.64 90.45

Local GPS. The Time Dilution of Precision (TDOP) is plotted in blue. The number of visible satellites (nSat) is plotted in red.

TDOP is field 3, and nSats is field 4, from the gpsd log file. The gpsd log file is created by the ntploggps program.

TDOP is a dimensionless error factor. Smaller numbers are better. TDOP ranges from 1 (ideal), 2 to 5 (good), to greater than 20 (poor). Some GNSS receivers report TDOP less than one which is theoretically impossible.



Server Offsets

peer offsets plot

The offset of all refclocks and servers. This can be useful to see if offset changes are happening in a single clock or all clocks together.

Clock Offset is field 5 in the peerstats log file.



Server Offset 132.163.97.5

peer offset 132.163.97.5 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 132.163.97.5 1.243 1.249 1.259 1.300 1.336 1.357 1.373 0.077 0.108 0.024 1.299 ms 1.58e+05 8.545e+06

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 132.246.11.229

peer offset 132.246.11.229 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 132.246.11.229 0.292 0.294 0.298 1.430 1.442 1.453 1.504 1.144 1.159 0.460 1.196 ms 7.452 15.77

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 204.9.54.119

peer offset 204.9.54.119 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 204.9.54.119 -684.217 -681.532 -679.082 -673.170 -668.897 -666.325 -664.004 10.185 15.207 3.060 -673.386 µs -1.08e+07 2.387e+09

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 2600:2600::99 (ntp1.wiktel.com)

peer offset 2600:2600::99 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 2600:2600::99 (ntp1.wiktel.com) -14.533 -11.419 -7.603 6.188 21.463 26.744 29.850 29.066 38.163 8.472 6.418 µs -0.5902 3.021

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 2602:fd53:11e:123::1 (time1.mbix.ca)

peer offset 2602:fd53:11e:123::1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 2602:fd53:11e:123::1 (time1.mbix.ca) -722.223 -654.913 -499.852 24.811 253.777 294.797 298.164 753.629 949.710 189.574 4.959 µs -5.487 19.44

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 2606:4700:f1::123 (time.cloudflare.com)

peer offset 2606:4700:f1::123 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 2606:4700:f1::123 (time.cloudflare.com) -896.911 -860.070 -810.003 -332.402 -194.877 -112.851 -101.136 615.126 747.219 212.257 -428.270 µs -37.36 149.8

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 2607:f128::50

peer offset 2607:f128::50 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 2607:f128::50 503.320 520.049 533.234 563.438 601.583 626.225 633.822 68.349 106.176 21.393 564.779 µs 1.646e+04 4.202e+05

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset 2607:f388::123:2 (ntp2.doit.wisc.edu)

peer offset 2607:f388::123:2 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 2607:f388::123:2 (ntp2.doit.wisc.edu) -76.278 -71.625 -65.094 -47.630 -29.401 -23.166 -18.519 35.693 48.459 10.441 -47.767 µs -190 1155

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Offset SHM(1)

peer offset SHM(1) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset SHM(1) -21.933 -9.034 -5.704 0.573 2.907 4.072 8.799 8.611 13.106 2.597 0.000 µs -5.857 22.38

The offset of a server in seconds. This is useful to see how the measured offset is behaving.

The chart also plots offset±rtt, where rtt is the round trip time to the server. NTP can not really know the offset of a remote chimer, NTP computes it by subtracting rtt/2 from the offset. Plotting the offset±rtt reverses this calculation to more easily see the effects of rtt changes.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local LAN server 80µs; 90% ranges for WAN server may be 4ms and much larger.

Clock Offset is field 5 in the peerstats log file. The Round Trip Time (rtt) is field 6 in the peerstats log file.



Server Jitters

peer jitters plot

The RMS Jitter of all refclocks and servers. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 132.163.97.5

peer jitter 132.163.97.5 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 132.163.97.5 13.813 14.915 19.001 34.754 64.622 86.038 122.431 45.621 71.123 14.498 37.131 µs 9.95 36.96

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 132.246.11.229

peer jitter 132.246.11.229 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 132.246.11.229 0.002 0.004 0.006 0.015 2.719 3.634 3.769 2.713 3.630 0.816 0.303 ms 0.8302 5.496

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 204.9.54.119

peer jitter 204.9.54.119 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 204.9.54.119 2.187 2.226 3.702 7.383 14.014 18.733 20.252 10.312 16.507 3.177 8.051 µs 9.14 29.5

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 2600:2600::99 (ntp1.wiktel.com)

peer jitter 2600:2600::99 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 2600:2600::99 (ntp1.wiktel.com) 4.917 6.688 9.476 16.746 31.100 39.706 134.618 21.624 33.018 11.709 18.555 µs 8.671 83.83

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 2602:fd53:11e:123::1 (time1.mbix.ca)

peer jitter 2602:fd53:11e:123::1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 2602:fd53:11e:123::1 (time1.mbix.ca) 3.683 5.058 7.053 13.193 43.308 58.898 64.309 36.255 53.840 10.968 16.522 µs 3.801 13.79

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 2606:4700:f1::123 (time.cloudflare.com)

peer jitter 2606:4700:f1::123 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 2606:4700:f1::123 (time.cloudflare.com) 0.006 0.006 0.008 0.024 0.135 2.182 5.414 0.127 2.176 0.379 0.079 ms 8.247 112.9

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 2607:f128::50

peer jitter 2607:f128::50 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 2607:f128::50 8.808 12.615 17.009 31.561 65.728 113.155 798.633 48.719 100.540 48.338 37.991 µs 13.14 204.5

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter 2607:f388::123:2 (ntp2.doit.wisc.edu)

peer jitter 2607:f388::123:2 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 2607:f388::123:2 (ntp2.doit.wisc.edu) 4.513 5.229 7.732 22.993 206.107 388.586 752.174 198.375 383.357 86.072 50.904 µs 3.485 26.72

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Server Jitter SHM(1)

peer jitter SHM(1) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter SHM(1) 0.154 0.452 0.698 2.756 7.137 9.838 22.620 6.439 9.386 2.085 3.149 µs 3.109 11.3

The RMS Jitter of a server. Jitter is the current estimated dispersion, in other words the variation in offset between samples.

Closer to 0s is better. An ideal system would be a horizontal line at 0s.

RMS Jitter is field 8 in the peerstats log file.



Summary


Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset -13.866 -13.811 -13.729 -13.569 -13.291 -13.248 -13.204 0.438 0.562 0.136 -13.542 ppm -1.02e+06 1.028e+08
Local Clock Time Offset -21.932 -9.033 -5.703 0.572 2.906 4.071 8.798 8.609 13.104 2.596 -0.000 µs -5.858 22.38
Local RMS Frequency Jitter 0.839 1.536 2.108 4.610 7.875 9.840 15.538 5.767 8.304 1.797 4.743 ppb 9.946 31.14
Local RMS Time Jitter 0.550 1.056 1.449 3.187 5.582 6.929 11.040 4.133 5.873 1.286 3.306 µs 9.263 28.84
Server Jitter 132.163.97.5 13.813 14.915 19.001 34.754 64.622 86.038 122.431 45.621 71.123 14.498 37.131 µs 9.95 36.96
Server Jitter 132.246.11.229 0.002 0.004 0.006 0.015 2.719 3.634 3.769 2.713 3.630 0.816 0.303 ms 0.8302 5.496
Server Jitter 204.9.54.119 2.187 2.226 3.702 7.383 14.014 18.733 20.252 10.312 16.507 3.177 8.051 µs 9.14 29.5
Server Jitter 2600:2600::99 (ntp1.wiktel.com) 4.917 6.688 9.476 16.746 31.100 39.706 134.618 21.624 33.018 11.709 18.555 µs 8.671 83.83
Server Jitter 2602:fd53:11e:123::1 (time1.mbix.ca) 3.683 5.058 7.053 13.193 43.308 58.898 64.309 36.255 53.840 10.968 16.522 µs 3.801 13.79
Server Jitter 2606:4700:f1::123 (time.cloudflare.com) 0.006 0.006 0.008 0.024 0.135 2.182 5.414 0.127 2.176 0.379 0.079 ms 8.247 112.9
Server Jitter 2607:f128::50 8.808 12.615 17.009 31.561 65.728 113.155 798.633 48.719 100.540 48.338 37.991 µs 13.14 204.5
Server Jitter 2607:f388::123:2 (ntp2.doit.wisc.edu) 4.513 5.229 7.732 22.993 206.107 388.586 752.174 198.375 383.357 86.072 50.904 µs 3.485 26.72
Server Jitter SHM(1) 0.154 0.452 0.698 2.756 7.137 9.838 22.620 6.439 9.386 2.085 3.149 µs 3.109 11.3
Server Offset 132.163.97.5 1.243 1.249 1.259 1.300 1.336 1.357 1.373 0.077 0.108 0.024 1.299 ms 1.58e+05 8.545e+06
Server Offset 132.246.11.229 0.292 0.294 0.298 1.430 1.442 1.453 1.504 1.144 1.159 0.460 1.196 ms 7.452 15.77
Server Offset 204.9.54.119 -684.217 -681.532 -679.082 -673.170 -668.897 -666.325 -664.004 10.185 15.207 3.060 -673.386 µs -1.08e+07 2.387e+09
Server Offset 2600:2600::99 (ntp1.wiktel.com) -14.533 -11.419 -7.603 6.188 21.463 26.744 29.850 29.066 38.163 8.472 6.418 µs -0.5902 3.021
Server Offset 2602:fd53:11e:123::1 (time1.mbix.ca) -722.223 -654.913 -499.852 24.811 253.777 294.797 298.164 753.629 949.710 189.574 4.959 µs -5.487 19.44
Server Offset 2606:4700:f1::123 (time.cloudflare.com) -896.911 -860.070 -810.003 -332.402 -194.877 -112.851 -101.136 615.126 747.219 212.257 -428.270 µs -37.36 149.8
Server Offset 2607:f128::50 503.320 520.049 533.234 563.438 601.583 626.225 633.822 68.349 106.176 21.393 564.779 µs 1.646e+04 4.202e+05
Server Offset 2607:f388::123:2 (ntp2.doit.wisc.edu) -76.278 -71.625 -65.094 -47.630 -29.401 -23.166 -18.519 35.693 48.459 10.441 -47.767 µs -190 1155
Server Offset SHM(1) -21.933 -9.034 -5.704 0.573 2.907 4.072 8.799 8.611 13.106 2.597 0.000 µs -5.857 22.38
TDOP 0.540 0.580 0.620 0.830 1.430 3.440 4.920 0.810 2.860 0.408 0.928 11.64 90.45
nSats 6.000 6.000 7.000 9.000 11.000 11.000 12.000 4.000 5.000 1.198 8.860 nSat 280.8 1919
Summary as CSV file


Glossary:

frequency offset:
The difference between the ntpd calculated frequency and the local system clock frequency (usually in parts per million, ppm)
jitter, dispersion:
The short term change in a value. NTP measures Local Time Jitter, Refclock Jitter, and Server Jitter in seconds. Local Frequency Jitter is in ppm or ppb.
kurtosis, Kurt:
The kurtosis of a random variable X is the fourth standardized moment and is a dimension-less ratio. ntpviz uses the Pearson's moment coefficient of kurtosis. A normal distribution has a kurtosis of three. NIST describes a kurtosis over three as "heavy tailed" and one under three as "light tailed".
ms, millisecond:
One thousandth of a second = 0.001 seconds, 1e-3 seconds
mu, mean:
The arithmetic mean: the sum of all the values divided by the number of values. The formula for mu is: "mu = (∑xi) / N". Where xi denotes the data points and N is the number of data points.
ns, nanosecond:
One billionth of a second, also one thousandth of a microsecond, 0.000000001 seconds and 1e-9 seconds.
percentile:
The value below which a given percentage of values fall.
ppb, parts per billion:
Ratio between two values. These following are all the same: 1 ppb, one in one billion, 1/1,000,000,000, 0.000,000,001, 1e-9 and 0.000,000,1%
ppm, parts per million:
Ratio between two values. These following are all the same: 1 ppm, one in one million, 1/1,000,000, 0.000,001, and 0.000,1%
‰, parts per thousand:
Ratio between two values. These following are all the same: 1 ‰. one in one thousand, 1/1,000, 0.001, and 0.1%
refclock:
Reference clock, a local GPS module or other local source of time.
remote clock:
Any clock reached over the network, LAN or WAN. Also called a peer or server.
time offset:
The difference between the ntpd calculated time and the local system clock's time. Also called phase offset.
σ, sigma:
Sigma denotes the standard deviation (SD) and is centered on the arithmetic mean of the data set. The SD is simply the square root of the variance of the data set. Two sigma is simply twice the standard deviation. Three sigma is three times sigma. Smaller is better.
The formula for sigma is: "σ = √[ ∑(xi-mu)^2 / N ]". Where xi denotes the data points and N is the number of data points.
skewness, Skew:
The skewness of a random variable X is the third standardized moment and is a dimension-less ratio. ntpviz uses the Pearson's moment coefficient of skewness. Wikipedia describes it best: "The qualitative interpretation of the skew is complicated and unintuitive."
A normal distribution has a skewness of zero.
upstream clock:
Any server or reference clock used as a source of time.
µs, us, microsecond:
One millionth of a second, also one thousandth of a millisecond, 0.000,001 seconds, and 1e-6 seconds.



This page autogenerated by ntpviz, part of the NTPsec project
html 5    Valid CSS!