NTPsec

chronos

Report generated: Tue Aug 3 00:05:01 2021 UTC
Start Time: Mon Aug 2 00:05:01 2021 UTC
End Time: Tue Aug 3 00:05:01 2021 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 -8.477 -2.635 -1.973 -0.328 2.292 7.045 21.288 4.265 9.680 1.829 -0.046 µs -0.5753 22.31
Local Clock Frequency Offset -5.327 -5.324 -5.316 -5.107 -4.896 -4.885 -4.876 0.419 0.439 0.133 -5.106 ppm -6.164e+04 2.438e+06

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 0.230 0.310 0.358 0.572 2.337 3.942 5.957 1.979 3.632 0.697 0.814 µs 3.594 16.23

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 0.067 0.082 0.102 0.314 0.804 1.682 2.483 0.702 1.600 0.276 0.366 ppb 4.234 22.39

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 -8.477 -2.635 -1.973 -0.328 2.292 7.045 21.288 4.265 9.680 1.829 -0.046 µs -0.5753 22.31

The clock offsets of the local clock as a histogram.

The Local Clock Offset is field 3 from the loopstats 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 162.159.200.1

peer offset 162.159.200.1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 162.159.200.1 -2.487 -2.251 -2.185 -2.053 -1.927 -1.858 -1.789 0.258 0.393 0.085 -2.054 ms -1.62e+04 4.113e+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 185.57.191.229

peer offset 185.57.191.229 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 185.57.191.229 -359.210 -197.448 -138.653 -3.015 70.574 91.387 121.512 209.227 288.835 62.958 -12.280 µs -6.471 22.13

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 194.0.5.123

peer offset 194.0.5.123 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 194.0.5.123 -1.078 -1.015 -0.937 -0.826 -0.749 -0.727 -0.715 0.188 0.288 0.057 -0.830 ms -3837 6.06e+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 85.199.214.100

peer offset 85.199.214.100 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 85.199.214.100 -410.501 -307.151 -237.152 -103.194 -37.510 -15.559 8.879 199.642 291.592 62.615 -112.206 µs -31.55 129.1

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 85.199.214.101

peer offset 85.199.214.101 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 85.199.214.101 -444.265 -256.026 -169.688 -91.382 -23.172 -9.842 17.197 146.516 246.184 50.502 -94.750 µs -34.01 147.2

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 -296.519 -203.264 -151.380 -84.102 -8.200 3.172 16.327 143.180 206.436 45.273 -85.560 µs -33.22 128.6

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 85.199.214.99

peer offset 85.199.214.99 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 85.199.214.99 -351.311 -258.967 -216.087 -89.411 -17.556 8.832 21.505 198.531 267.799 58.280 -97.489 µs -28.02 107.9

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 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) -565.840 -554.378 -541.238 -429.900 -26.004 -24.740 -22.620 515.235 529.638 244.024 -274.215 ms -15.95 48.42

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) -8.478 -2.636 -1.974 -0.329 2.293 7.046 21.289 4.267 9.682 1.829 -0.046 µs -0.5785 22.29

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 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 162.159.200.1

peer jitter 162.159.200.1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 162.159.200.1 0.012 0.017 0.023 0.088 1.410 44.845 54.481 1.387 44.828 6.547 1.039 ms 4.293 36.45

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 185.57.191.229

peer jitter 185.57.191.229 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 185.57.191.229 0.011 0.017 0.020 0.091 1.692 37.723 66.657 1.671 37.706 7.665 1.320 ms 4.026 35.8

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 194.0.5.123

peer jitter 194.0.5.123 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 194.0.5.123 0.007 0.011 0.020 0.078 0.303 1.835 50.549 0.284 1.824 2.922 0.277 ms 13.63 237.7

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 85.199.214.100

peer jitter 85.199.214.100 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 85.199.214.100 0.024 0.036 0.045 0.107 1.338 60.879 64.937 1.293 60.844 7.337 1.105 ms 4.891 44.53

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 85.199.214.101

peer jitter 85.199.214.101 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 85.199.214.101 0.021 0.025 0.045 0.109 1.545 54.109 56.074 1.500 54.084 7.115 1.187 ms 4.225 35.48

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 0.027 0.032 0.043 0.102 0.866 54.424 57.837 0.823 54.392 6.736 1.035 ms 4.513 39.25

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 85.199.214.99

peer jitter 85.199.214.99 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 85.199.214.99 0.023 0.037 0.045 0.111 0.415 24.523 64.786 0.371 24.486 4.374 0.600 ms 8.583 123

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) 265.608 282.093 303.699 350.295 387.704 398.579 407.142 84.004 116.486 27.697 346.992 ms 1566 1.845e+04

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) 0.094 0.186 0.243 0.487 2.730 8.149 19.572 2.487 7.963 1.460 0.871 µs 4.471 36.88

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.



Summary


Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset -5.327 -5.324 -5.316 -5.107 -4.896 -4.885 -4.876 0.419 0.439 0.133 -5.106 ppm -6.164e+04 2.438e+06
Local Clock Time Offset -8.477 -2.635 -1.973 -0.328 2.292 7.045 21.288 4.265 9.680 1.829 -0.046 µs -0.5753 22.31
Local RMS Frequency Jitter 0.067 0.082 0.102 0.314 0.804 1.682 2.483 0.702 1.600 0.276 0.366 ppb 4.234 22.39
Local RMS Time Jitter 0.230 0.310 0.358 0.572 2.337 3.942 5.957 1.979 3.632 0.697 0.814 µs 3.594 16.23
Server Jitter 162.159.200.1 0.012 0.017 0.023 0.088 1.410 44.845 54.481 1.387 44.828 6.547 1.039 ms 4.293 36.45
Server Jitter 185.57.191.229 0.011 0.017 0.020 0.091 1.692 37.723 66.657 1.671 37.706 7.665 1.320 ms 4.026 35.8
Server Jitter 194.0.5.123 0.007 0.011 0.020 0.078 0.303 1.835 50.549 0.284 1.824 2.922 0.277 ms 13.63 237.7
Server Jitter 85.199.214.100 0.024 0.036 0.045 0.107 1.338 60.879 64.937 1.293 60.844 7.337 1.105 ms 4.891 44.53
Server Jitter 85.199.214.101 0.021 0.025 0.045 0.109 1.545 54.109 56.074 1.500 54.084 7.115 1.187 ms 4.225 35.48
Server Jitter 85.199.214.98 0.027 0.032 0.043 0.102 0.866 54.424 57.837 0.823 54.392 6.736 1.035 ms 4.513 39.25
Server Jitter 85.199.214.99 0.023 0.037 0.045 0.111 0.415 24.523 64.786 0.371 24.486 4.374 0.600 ms 8.583 123
Server Jitter SHM(0) 265.608 282.093 303.699 350.295 387.704 398.579 407.142 84.004 116.486 27.697 346.992 ms 1566 1.845e+04
Server Jitter SHM(1) 0.094 0.186 0.243 0.487 2.730 8.149 19.572 2.487 7.963 1.460 0.871 µs 4.471 36.88
Server Offset 162.159.200.1 -2.487 -2.251 -2.185 -2.053 -1.927 -1.858 -1.789 0.258 0.393 0.085 -2.054 ms -1.62e+04 4.113e+05
Server Offset 185.57.191.229 -359.210 -197.448 -138.653 -3.015 70.574 91.387 121.512 209.227 288.835 62.958 -12.280 µs -6.471 22.13
Server Offset 194.0.5.123 -1.078 -1.015 -0.937 -0.826 -0.749 -0.727 -0.715 0.188 0.288 0.057 -0.830 ms -3837 6.06e+04
Server Offset 85.199.214.100 -410.501 -307.151 -237.152 -103.194 -37.510 -15.559 8.879 199.642 291.592 62.615 -112.206 µs -31.55 129.1
Server Offset 85.199.214.101 -444.265 -256.026 -169.688 -91.382 -23.172 -9.842 17.197 146.516 246.184 50.502 -94.750 µs -34.01 147.2
Server Offset 85.199.214.98 -296.519 -203.264 -151.380 -84.102 -8.200 3.172 16.327 143.180 206.436 45.273 -85.560 µs -33.22 128.6
Server Offset 85.199.214.99 -351.311 -258.967 -216.087 -89.411 -17.556 8.832 21.505 198.531 267.799 58.280 -97.489 µs -28.02 107.9
Server Offset SHM(0) -565.840 -554.378 -541.238 -429.900 -26.004 -24.740 -22.620 515.235 529.638 244.024 -274.215 ms -15.95 48.42
Server Offset SHM(1) -8.478 -2.636 -1.974 -0.329 2.293 7.046 21.289 4.267 9.682 1.829 -0.046 µs -0.5785 22.29
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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