NTPsec

chronos

Report generated: Mon Sep 27 00:05:01 2021 UTC
Start Time: Sun Sep 26 00:05:01 2021 UTC
End Time: Mon Sep 27 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 -8.953 -3.167 -1.812 -0.192 2.111 4.620 25.100 3.923 7.787 1.676 -0.003 µs 0.1203 38.63
Local Clock Frequency Offset -5.304 -5.302 -5.296 -5.096 -5.000 -4.988 -4.986 0.296 0.315 0.103 -5.125 ppm -1.294e+05 6.549e+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 0.281 0.335 0.390 0.650 2.386 3.622 7.762 1.996 3.287 0.703 0.902 µs 3.882 20.06

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 0.058 0.080 0.106 0.251 0.757 1.505 2.951 0.651 1.425 0.276 0.325 ppb 4.607 31.4

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 -8.953 -3.167 -1.812 -0.192 2.111 4.620 25.100 3.923 7.787 1.676 -0.003 µs 0.1203 38.63

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 109.74.192.97

peer offset 109.74.192.97 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 109.74.192.97 77.386 124.220 234.275 543.971 717.759 888.530 1,118.026 483.484 764.310 145.154 530.664 µs 26.4 93.54

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 129.250.35.250

peer offset 129.250.35.250 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 129.250.35.250 0.951 1.026 1.276 1.589 1.992 2.063 2.090 0.716 1.036 0.229 1.611 ms 236.4 1535

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 0.941 1.064 1.222 1.446 1.551 1.576 1.626 0.328 0.513 0.105 1.425 ms 2001 2.549e+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 185.83.169.27

peer offset 185.83.169.27 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 185.83.169.27 0.635 0.902 1.067 1.288 1.373 1.398 1.418 0.307 0.496 0.100 1.263 ms 1596 1.886e+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 217.114.59.66

peer offset 217.114.59.66 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 217.114.59.66 174.255 207.881 340.944 633.284 821.300 885.130 916.452 480.356 677.249 139.093 616.273 µs 49.92 202.6

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 80.87.128.222

peer offset 80.87.128.222 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 80.87.128.222 -2.290 -2.189 -2.081 -1.711 -1.370 -1.316 -1.282 0.711 0.874 0.200 -1.715 ms -903.5 8923

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 65.914 217.877 323.275 553.324 680.740 719.099 754.945 357.465 501.222 107.657 534.300 µs 73.08 328.9

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) -560.157 -554.456 -541.335 -106.012 -26.286 -25.203 -23.253 515.048 529.253 241.831 -269.401 ms -15.82 48.06

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 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) -8.954 -3.168 -1.813 -0.193 2.112 4.621 25.100 3.925 7.789 1.677 -0.003 µs 0.1165 38.59

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 109.74.192.97

peer jitter 109.74.192.97 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 109.74.192.97 0.019 0.031 0.079 0.328 2.130 32.965 43.298 2.050 32.934 5.232 1.433 ms 3.303 26.03

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 129.250.35.250

peer jitter 129.250.35.250 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 129.250.35.250 0.033 0.043 0.077 0.298 8.268 40.441 52.465 8.191 40.398 7.075 1.956 ms 2.517 18.17

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 0.021 0.043 0.079 0.304 8.841 53.423 88.637 8.762 53.380 10.036 2.445 ms 3.355 28.81

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 185.83.169.27

peer jitter 185.83.169.27 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 185.83.169.27 0.025 0.047 0.085 0.319 4.528 40.360 100.563 4.444 40.313 10.759 2.280 ms 4.921 47.82

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 217.114.59.66

peer jitter 217.114.59.66 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 217.114.59.66 0.013 0.022 0.068 0.306 3.708 42.066 92.349 3.640 42.044 10.098 2.101 ms 4.463 41.99

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 80.87.128.222

peer jitter 80.87.128.222 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 80.87.128.222 0.024 0.062 0.094 0.304 6.050 32.415 40.092 5.955 32.353 5.612 1.623 ms 2.524 16.96

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 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 0.053 0.076 0.107 0.333 10.068 40.359 72.915 9.960 40.283 8.512 2.484 ms 2.992 25.15

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) 255.450 280.267 299.718 341.794 386.159 397.192 400.657 86.441 116.925 28.285 342.196 ms 1400 1.591e+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) 0.110 0.205 0.263 0.561 2.742 7.393 25.787 2.479 7.188 1.381 0.930 µs 5.668 61.17

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 -5.304 -5.302 -5.296 -5.096 -5.000 -4.988 -4.986 0.296 0.315 0.103 -5.125 ppm -1.294e+05 6.549e+06
Local Clock Time Offset -8.953 -3.167 -1.812 -0.192 2.111 4.620 25.100 3.923 7.787 1.676 -0.003 µs 0.1203 38.63
Local RMS Frequency Jitter 0.058 0.080 0.106 0.251 0.757 1.505 2.951 0.651 1.425 0.276 0.325 ppb 4.607 31.4
Local RMS Time Jitter 0.281 0.335 0.390 0.650 2.386 3.622 7.762 1.996 3.287 0.703 0.902 µs 3.882 20.06
Server Jitter 109.74.192.97 0.019 0.031 0.079 0.328 2.130 32.965 43.298 2.050 32.934 5.232 1.433 ms 3.303 26.03
Server Jitter 129.250.35.250 0.033 0.043 0.077 0.298 8.268 40.441 52.465 8.191 40.398 7.075 1.956 ms 2.517 18.17
Server Jitter 185.57.191.229 0.021 0.043 0.079 0.304 8.841 53.423 88.637 8.762 53.380 10.036 2.445 ms 3.355 28.81
Server Jitter 185.83.169.27 0.025 0.047 0.085 0.319 4.528 40.360 100.563 4.444 40.313 10.759 2.280 ms 4.921 47.82
Server Jitter 217.114.59.66 0.013 0.022 0.068 0.306 3.708 42.066 92.349 3.640 42.044 10.098 2.101 ms 4.463 41.99
Server Jitter 80.87.128.222 0.024 0.062 0.094 0.304 6.050 32.415 40.092 5.955 32.353 5.612 1.623 ms 2.524 16.96
Server Jitter 85.199.214.101 0.053 0.076 0.107 0.333 10.068 40.359 72.915 9.960 40.283 8.512 2.484 ms 2.992 25.15
Server Jitter SHM(0) 255.450 280.267 299.718 341.794 386.159 397.192 400.657 86.441 116.925 28.285 342.196 ms 1400 1.591e+04
Server Jitter SHM(1) 0.110 0.205 0.263 0.561 2.742 7.393 25.787 2.479 7.188 1.381 0.930 µs 5.668 61.17
Server Offset 109.74.192.97 77.386 124.220 234.275 543.971 717.759 888.530 1,118.026 483.484 764.310 145.154 530.664 µs 26.4 93.54
Server Offset 129.250.35.250 0.951 1.026 1.276 1.589 1.992 2.063 2.090 0.716 1.036 0.229 1.611 ms 236.4 1535
Server Offset 185.57.191.229 0.941 1.064 1.222 1.446 1.551 1.576 1.626 0.328 0.513 0.105 1.425 ms 2001 2.549e+04
Server Offset 185.83.169.27 0.635 0.902 1.067 1.288 1.373 1.398 1.418 0.307 0.496 0.100 1.263 ms 1596 1.886e+04
Server Offset 217.114.59.66 174.255 207.881 340.944 633.284 821.300 885.130 916.452 480.356 677.249 139.093 616.273 µs 49.92 202.6
Server Offset 80.87.128.222 -2.290 -2.189 -2.081 -1.711 -1.370 -1.316 -1.282 0.711 0.874 0.200 -1.715 ms -903.5 8923
Server Offset 85.199.214.101 65.914 217.877 323.275 553.324 680.740 719.099 754.945 357.465 501.222 107.657 534.300 µs 73.08 328.9
Server Offset SHM(0) -560.157 -554.456 -541.335 -106.012 -26.286 -25.203 -23.253 515.048 529.253 241.831 -269.401 ms -15.82 48.06
Server Offset SHM(1) -8.954 -3.168 -1.813 -0.193 2.112 4.621 25.100 3.925 7.789 1.677 -0.003 µs 0.1165 38.59
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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