NTPsec

ntp2.wiktel.com

Report generated: Sat Jul 27 06:53:00 2024 UTC
Start Time: Fri Jul 26 06:53:00 2024 UTC
End Time: Sat Jul 27 06:53:00 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 -23.700 -10.580 -6.894 0.672 3.401 4.800 9.247 10.295 15.380 3.068 -0.002 µs -5.851 22.02
Local Clock Frequency Offset -14.359 -14.241 -14.181 -13.927 -13.736 -13.700 -13.659 0.445 0.541 0.137 -13.943 ppm -1.096e+06 1.13e+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 0.712 1.276 1.809 3.759 6.511 8.076 12.362 4.702 6.800 1.455 3.897 µs 10.43 33.04

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 1.156 1.949 2.705 5.484 9.185 11.296 18.519 6.480 9.347 2.014 5.645 ppb 11.87 38.04

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 -23.700 -10.580 -6.894 0.672 3.401 4.800 9.247 10.295 15.380 3.068 -0.002 µs -5.851 22.02

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 5.000 5.000 7.000 9.000 10.000 11.000 11.000 3.000 6.000 1.179 8.510 nSat 259 1727
TDOP 0.540 0.590 0.630 0.870 1.560 2.280 11.550 0.930 1.690 0.707 1.001 13.24 195.6

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 1.093 1.095 1.108 1.138 1.182 1.208 1.229 0.073 0.113 0.024 1.142 ms 1.061e+05 5.026e+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 132.246.11.229 229.440 232.821 242.891 251.398 257.995 263.182 267.304 15.104 30.361 4.921 251.020 µs 1.253e+05 6.272e+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 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 -865.201 -862.575 -859.880 -855.442 -851.309 -849.587 -847.039 8.571 12.988 2.663 -855.575 µs -3.346e+07 1.078e+10

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) 317.689 322.693 329.767 344.605 362.020 366.332 367.771 32.253 43.639 9.546 344.354 µs 4.325e+04 1.521e+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 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) -410.608 -400.339 -392.333 -377.287 -367.429 -362.998 -359.632 24.904 37.341 7.553 -378.353 µs -1.336e+05 6.832e+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 2606:4700:f1::1 (time.cloudflare.com)

peer offset 2606:4700:f1::1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 2606:4700:f1::1 (time.cloudflare.com) -803.974 -801.191 -775.969 -662.172 -562.049 -533.150 -519.691 213.920 268.041 62.444 -666.096 µs -1623 1.935e+04

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 -148.323 -140.642 -120.286 -85.635 -48.148 -31.664 -26.947 72.138 108.978 21.860 -84.761 µs -130.6 711.3

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) -92.140 -87.778 -74.643 -47.697 -19.902 -4.594 10.994 54.741 83.184 16.243 -48.478 µs -75 347.4

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) -23.701 -10.581 -6.895 0.673 3.402 4.801 9.248 10.297 15.382 3.068 -0.002 µs -5.85 22.01

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 12.014 15.038 18.144 35.734 67.782 80.734 95.924 49.638 65.696 14.705 37.936 µs 9.51 29.93

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 0.001 0.004 0.005 0.014 0.304 1.688 18.029 0.299 1.683 1.067 0.145 ms 12.67 215.9

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 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 1.824 2.644 3.957 7.467 13.028 15.055 18.731 9.071 12.411 2.744 7.824 µs 12.57 40.9

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 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) 3.097 6.314 8.676 19.634 36.978 302.567 304.790 28.302 296.253 39.798 25.976 µs 5.274 35.43

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) 3.759 4.873 6.479 12.265 21.305 30.626 827.964 14.826 25.753 48.185 15.563 µs 14.3 238.5

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 2606:4700:f1::1 (time.cloudflare.com)

peer jitter 2606:4700:f1::1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 2606:4700:f1::1 (time.cloudflare.com) 2.355 3.751 6.626 18.879 52.066 92.958 156.443 45.440 89.207 16.392 22.454 µs 4.288 25.88

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 8.754 9.561 13.979 30.181 66.122 263.708 723.054 52.143 254.147 48.722 37.655 µs 9.899 130.6

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) 0.009 0.010 0.013 0.027 0.436 5.212 6.381 0.424 5.202 0.748 0.181 ms 4.029 33.38

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) 0.148 0.458 0.757 3.275 8.344 11.490 23.906 7.587 11.032 2.451 3.706 µs 3.014 10.43

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 -14.359 -14.241 -14.181 -13.927 -13.736 -13.700 -13.659 0.445 0.541 0.137 -13.943 ppm -1.096e+06 1.13e+08
Local Clock Time Offset -23.700 -10.580 -6.894 0.672 3.401 4.800 9.247 10.295 15.380 3.068 -0.002 µs -5.851 22.02
Local RMS Frequency Jitter 1.156 1.949 2.705 5.484 9.185 11.296 18.519 6.480 9.347 2.014 5.645 ppb 11.87 38.04
Local RMS Time Jitter 0.712 1.276 1.809 3.759 6.511 8.076 12.362 4.702 6.800 1.455 3.897 µs 10.43 33.04
Server Jitter 132.163.97.5 12.014 15.038 18.144 35.734 67.782 80.734 95.924 49.638 65.696 14.705 37.936 µs 9.51 29.93
Server Jitter 132.246.11.229 0.001 0.004 0.005 0.014 0.304 1.688 18.029 0.299 1.683 1.067 0.145 ms 12.67 215.9
Server Jitter 204.9.54.119 1.824 2.644 3.957 7.467 13.028 15.055 18.731 9.071 12.411 2.744 7.824 µs 12.57 40.9
Server Jitter 2600:2600::99 (ntp1.wiktel.com) 3.097 6.314 8.676 19.634 36.978 302.567 304.790 28.302 296.253 39.798 25.976 µs 5.274 35.43
Server Jitter 2602:fd53:11e:123::1 (time1.mbix.ca) 3.759 4.873 6.479 12.265 21.305 30.626 827.964 14.826 25.753 48.185 15.563 µs 14.3 238.5
Server Jitter 2606:4700:f1::1 (time.cloudflare.com) 2.355 3.751 6.626 18.879 52.066 92.958 156.443 45.440 89.207 16.392 22.454 µs 4.288 25.88
Server Jitter 2607:f128::50 8.754 9.561 13.979 30.181 66.122 263.708 723.054 52.143 254.147 48.722 37.655 µs 9.899 130.6
Server Jitter 2607:f388::123:2 (ntp2.doit.wisc.edu) 0.009 0.010 0.013 0.027 0.436 5.212 6.381 0.424 5.202 0.748 0.181 ms 4.029 33.38
Server Jitter SHM(1) 0.148 0.458 0.757 3.275 8.344 11.490 23.906 7.587 11.032 2.451 3.706 µs 3.014 10.43
Server Offset 132.163.97.5 1.093 1.095 1.108 1.138 1.182 1.208 1.229 0.073 0.113 0.024 1.142 ms 1.061e+05 5.026e+06
Server Offset 132.246.11.229 229.440 232.821 242.891 251.398 257.995 263.182 267.304 15.104 30.361 4.921 251.020 µs 1.253e+05 6.272e+06
Server Offset 204.9.54.119 -865.201 -862.575 -859.880 -855.442 -851.309 -849.587 -847.039 8.571 12.988 2.663 -855.575 µs -3.346e+07 1.078e+10
Server Offset 2600:2600::99 (ntp1.wiktel.com) 317.689 322.693 329.767 344.605 362.020 366.332 367.771 32.253 43.639 9.546 344.354 µs 4.325e+04 1.521e+06
Server Offset 2602:fd53:11e:123::1 (time1.mbix.ca) -410.608 -400.339 -392.333 -377.287 -367.429 -362.998 -359.632 24.904 37.341 7.553 -378.353 µs -1.336e+05 6.832e+06
Server Offset 2606:4700:f1::1 (time.cloudflare.com) -803.974 -801.191 -775.969 -662.172 -562.049 -533.150 -519.691 213.920 268.041 62.444 -666.096 µs -1623 1.935e+04
Server Offset 2607:f128::50 -148.323 -140.642 -120.286 -85.635 -48.148 -31.664 -26.947 72.138 108.978 21.860 -84.761 µs -130.6 711.3
Server Offset 2607:f388::123:2 (ntp2.doit.wisc.edu) -92.140 -87.778 -74.643 -47.697 -19.902 -4.594 10.994 54.741 83.184 16.243 -48.478 µs -75 347.4
Server Offset SHM(1) -23.701 -10.581 -6.895 0.673 3.402 4.801 9.248 10.297 15.382 3.068 -0.002 µs -5.85 22.01
TDOP 0.540 0.590 0.630 0.870 1.560 2.280 11.550 0.930 1.690 0.707 1.001 13.24 195.6
nSats 5.000 5.000 7.000 9.000 10.000 11.000 11.000 3.000 6.000 1.179 8.510 nSat 259 1727
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.



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