NTPsec

STR1clock

Report generated: Sat Sep 26 03:30:41 2020 UTC
Start Time: Fri Sep 25 03:30:39 2020 UTC
End Time: Sat Sep 26 03:30:39 2020 UTC
Report Period: 1.0 days

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 -1,033.608 -45.862 -21.002 2.217 42.097 175.318 811.476 63.099 221.180 72.641 7.215 µs -1.892 106.5
Local Clock Frequency Offset -39.523 -28.707 -6.214 -4.915 -4.818 3.203 6.796 1.396 31.909 3.824 -5.505 ppm -27.29 164.8

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 9.191 9.867 11.061 16.681 110.504 324.718 383.709 99.443 314.851 55.426 30.767 µs 2.993 15.62

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 0.0077 0.0088 0.0100 0.0156 0.704 5.414 11.493 0.693 5.406 0.953 0.192 ppm 4.868 51.32

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 -1,033.608 -45.862 -21.002 2.217 42.097 175.318 811.476 63.099 221.180 72.641 7.215 µs -1.892 106.5

The clock offsets of the local clock as a histogram.

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



Local Temperatures

local temps plot

Local temperatures. These will be site-specific depending upon what temperature sensors you collect data from. Temperature changes affect the local clock crystal frequency and stability. The math of how temperature changes frequency is complex, and also depends on crystal aging. So there is no easy way to correct for it in software. This is the single most important component of frequency drift.

The Local Temperatures are from field 3 from the tempstats log file.



Local Frequency/Temp

local freq temps plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset -39.523 -28.707 -6.214 -4.915 -4.818 3.203 6.796 1.396 31.909 3.824 -5.505 ppm -27.29 164.8
Temp ZONE0 51.540 52.078 52.616 56.920 59.610 60.148 60.686 6.994 8.070 2.376 56.521 °C

The frequency offsets and temperatures. Showing frequency offset (red, in parts per million, scale on right) and the temperatures.

These are field 4 (frequency) from the loopstats log file, and field 3 from the tempstats log file.



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 130.133.1.10

peer offset 130.133.1.10 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 130.133.1.10 -5.504 -4.907 -4.171 -3.060 -1.883 -1.434 -0.813 2.288 3.473 0.700 -3.105 ms -176.8 1052

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 140.203.204.77

peer offset 140.203.204.77 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 140.203.204.77 -3.016 -2.212 -1.722 -0.695 0.536 1.062 1.282 2.258 3.273 0.709 -0.664 ms -13 39.03

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 150.214.94.10

peer offset 150.214.94.10 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 150.214.94.10 -0.874 -0.115 0.531 1.563 2.646 3.265 3.525 2.115 3.380 0.662 1.544 ms 6.392 17.29

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 150.214.94.5

peer offset 150.214.94.5 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 150.214.94.5 -0.894 0.068 0.489 1.392 2.751 3.398 3.445 2.262 3.330 0.717 1.482 ms 4.758 12.63

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 192.168.5.9

peer offset 192.168.5.9 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 192.168.5.9 -290.115 -33.622 -20.358 1.580 27.130 66.778 811.477 47.488 100.400 59.348 5.830 µs 6.826 94.46

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 85.199.214.98

peer offset 85.199.214.98 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 85.199.214.98 -1.295 -0.395 -0.045 1.126 2.645 3.141 3.631 2.690 3.536 0.820 1.189 ms 1.658 4.492

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(0)

peer offset SHM(0) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset SHM(0) -5.076 -3.964 -2.610 2.627 6.877 7.909 9.282 9.487 11.872 2.875 2.425 ms -0.7 2.713

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) -1,093.837 228.742 239.755 265.074 294.070 411.085 888.527 54.315 182.343 53.190 267.210 µs 70.48 465.9

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 130.133.1.10

peer jitter 130.133.1.10 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 130.133.1.10 0.369 0.847 1.398 3.717 20.987 46.615 48.070 19.589 45.768 7.238 5.865 ms 2.995 15.09

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 140.203.204.77

peer jitter 140.203.204.77 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 140.203.204.77 0.991 1.084 1.733 3.799 31.589 82.971 101.430 29.857 81.887 13.648 7.352 ms 3.14 18.33

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 150.214.94.10

peer jitter 150.214.94.10 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 150.214.94.10 0.814 0.898 1.595 4.199 23.149 43.846 170.437 21.553 42.948 11.535 7.163 ms 8.828 122.4

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 150.214.94.5

peer jitter 150.214.94.5 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 150.214.94.5 0.338 0.750 1.333 3.630 18.458 55.474 203.691 17.125 54.724 15.684 6.843 ms 7.217 83.77

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 192.168.5.9

peer jitter 192.168.5.9 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 192.168.5.9 0.000 2.356 4.518 21.651 51.179 91.335 675.817 46.661 88.979 42.464 26.294 µs 9.395 120.6

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 85.199.214.98

peer jitter 85.199.214.98 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 85.199.214.98 1.284 1.350 1.641 3.708 29.803 48.034 49.500 28.162 46.684 8.775 6.740 ms 2.441 10.32

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(0)

peer jitter SHM(0) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter SHM(0) 0.122 0.283 0.420 1.106 2.422 3.310 4.766 2.002 3.027 0.645 1.228 ms 4.699 15.39

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) 0.038 0.164 0.248 0.807 2.864 15.097 1,022.418 2.616 14.933 11.645 1.684 µs 55.99 4218

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 -39.523 -28.707 -6.214 -4.915 -4.818 3.203 6.796 1.396 31.909 3.824 -5.505 ppm -27.29 164.8
Local Clock Time Offset -1,033.608 -45.862 -21.002 2.217 42.097 175.318 811.476 63.099 221.180 72.641 7.215 µs -1.892 106.5
Local RMS Frequency Jitter 0.0077 0.0088 0.0100 0.0156 0.704 5.414 11.493 0.693 5.406 0.953 0.192 ppm 4.868 51.32
Local RMS Time Jitter 9.191 9.867 11.061 16.681 110.504 324.718 383.709 99.443 314.851 55.426 30.767 µs 2.993 15.62
Server Jitter 130.133.1.10 0.369 0.847 1.398 3.717 20.987 46.615 48.070 19.589 45.768 7.238 5.865 ms 2.995 15.09
Server Jitter 140.203.204.77 0.991 1.084 1.733 3.799 31.589 82.971 101.430 29.857 81.887 13.648 7.352 ms 3.14 18.33
Server Jitter 150.214.94.10 0.814 0.898 1.595 4.199 23.149 43.846 170.437 21.553 42.948 11.535 7.163 ms 8.828 122.4
Server Jitter 150.214.94.5 0.338 0.750 1.333 3.630 18.458 55.474 203.691 17.125 54.724 15.684 6.843 ms 7.217 83.77
Server Jitter 192.168.5.9 0.000 2.356 4.518 21.651 51.179 91.335 675.817 46.661 88.979 42.464 26.294 µs 9.395 120.6
Server Jitter 85.199.214.98 1.284 1.350 1.641 3.708 29.803 48.034 49.500 28.162 46.684 8.775 6.740 ms 2.441 10.32
Server Jitter SHM(0) 0.122 0.283 0.420 1.106 2.422 3.310 4.766 2.002 3.027 0.645 1.228 ms 4.699 15.39
Server Jitter SHM(1) 0.038 0.164 0.248 0.807 2.864 15.097 1,022.418 2.616 14.933 11.645 1.684 µs 55.99 4218
Server Offset 130.133.1.10 -5.504 -4.907 -4.171 -3.060 -1.883 -1.434 -0.813 2.288 3.473 0.700 -3.105 ms -176.8 1052
Server Offset 140.203.204.77 -3.016 -2.212 -1.722 -0.695 0.536 1.062 1.282 2.258 3.273 0.709 -0.664 ms -13 39.03
Server Offset 150.214.94.10 -0.874 -0.115 0.531 1.563 2.646 3.265 3.525 2.115 3.380 0.662 1.544 ms 6.392 17.29
Server Offset 150.214.94.5 -0.894 0.068 0.489 1.392 2.751 3.398 3.445 2.262 3.330 0.717 1.482 ms 4.758 12.63
Server Offset 192.168.5.9 -290.115 -33.622 -20.358 1.580 27.130 66.778 811.477 47.488 100.400 59.348 5.830 µs 6.826 94.46
Server Offset 85.199.214.98 -1.295 -0.395 -0.045 1.126 2.645 3.141 3.631 2.690 3.536 0.820 1.189 ms 1.658 4.492
Server Offset SHM(0) -5.076 -3.964 -2.610 2.627 6.877 7.909 9.282 9.487 11.872 2.875 2.425 ms -0.7 2.713
Server Offset SHM(1) -1,093.837 228.742 239.755 265.074 294.070 411.085 888.527 54.315 182.343 53.190 267.210 µs 70.48 465.9
Temp ZONE0 51.540 52.078 52.616 56.920 59.610 60.148 60.686 6.994 8.070 2.376 56.521 °C
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!