NTPsec

wells

Report generated: Mon Mar 25 10:00:27 2019 UTC
Start Time: Sun Mar 24 10:00:01 2019 UTC
End Time: Mon Mar 25 10:00:01 2019 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%95%StdDev  MeanUnits nessosis
Local Clock Time Offset-62.325-2.001-0.9180.0360.775 2.71811.9041.6934.7191.0220.001µs-20.14 858.5
Local Clock Frequency Offset0.9801.0691.1271.5641.904 1.9882.0360.7770.9190.2531.551ppm 149.7 844.8

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%95%StdDev  MeanUnits nessosis
Local RMS Time Jitter0.2000.2990.3560.5541.431 3.61117.2741.0753.3120.6370.692µs 8.059 110.3

This shows 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%95%StdDev  MeanUnits nessosis
Local RMS Frequency Jitter0.3160.4740.5510.8473.440 7.23259.4322.8896.7581.6031.190ppb 12.92 340.7

This shows 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%95%StdDev  MeanUnits nessosis
Local Clock Offset-62.325-2.001-0.9180.0360.775 2.71811.9041.6934.7191.0220.001µs-20.14 858.5

This shows the clock offsets of the local clock as a histogram.

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



Peer Offsets

peer offsets plot

This shows the offset of all refclocks, peers 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.



Peer Offset 155.94.164.121

peer offset 155.94.164.121 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Offset 155.94.164.1210.3341.3191.9812.5133.726 4.88218.3001.7453.5620.9592.680ms 21.01 254.9

This shows the offset of a peer or 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 remote. 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 peer 80µs; 90% ranges for WAN servers 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 file.



Peer Offset 172.98.77.203

peer offset 172.98.77.203 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Offset 172.98.77.2030.6540.6541.7142.9635.771 17.07817.0784.05716.4242.6863.572ms 4.693 23.41

This shows the offset of a peer or 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 remote. 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 peer 80µs; 90% ranges for WAN servers 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 file.



Peer Offset 184.105.182.16

peer offset 184.105.182.16 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Offset 184.105.182.165.3606.8047.1108.0959.276 10.21117.8512.1663.4070.8258.186ms 742.8 7050

This shows the offset of a peer or 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 remote. 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 peer 80µs; 90% ranges for WAN servers 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 file.



Peer Offset 204.9.54.119

peer offset 204.9.54.119 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Offset 204.9.54.1190.8061.3042.1852.6353.740 4.38314.7361.5553.0780.8452.778ms 27.24 244.7

This shows the offset of a peer or 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 remote. 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 peer 80µs; 90% ranges for WAN servers 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 file.



Peer Offset 216.6.2.70

peer offset 216.6.2.70 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Offset 216.6.2.70-1.378-1.378-0.0450.8672.051 10.74210.7422.09612.1201.3050.987ms 4.005 32.39

This shows the offset of a peer or 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 remote. 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 peer 80µs; 90% ranges for WAN servers 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 file.



Peer Offset 72.30.35.89

peer offset 72.30.35.89 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Offset 72.30.35.890.3080.8852.2142.5874.381 5.19820.1182.1674.3131.0722.818ms 18.74 233.1

This shows the offset of a peer or 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 remote. 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 peer 80µs; 90% ranges for WAN servers 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 file.



Peer Offset 98.152.165.38

peer offset 98.152.165.38 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Offset 98.152.165.383.6814.7195.2265.6456.728 7.67617.6831.5022.9570.7965.779ms 273.5 2122

This shows the offset of a peer or 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 remote. 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 peer 80µs; 90% ranges for WAN servers 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 file.



Peer Offset SHM(0)

peer offset SHM(0) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Offset SHM(0)-131.529-126.797-125.062-118.183-113.677 -112.194-108.34111.38514.6023.340-118.597ms-4.877e+041.785e+06

This shows the offset of a peer or 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 remote. 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 peer 80µs; 90% ranges for WAN servers 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 file.



Peer Offset SHM(1)

peer offset SHM(1) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Offset SHM(1)-62.326-2.002-0.9190.0370.776 2.71911.9051.6954.7211.0220.001µs-20.12 857.2

This shows the offset of a peer or 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 remote. 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 peer 80µs; 90% ranges for WAN servers 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 file.



Peer Jitters

peer jitters plot

This shows the RMS Jitter of all refclocks, peers and servers. Jitter is the current estimated dispersion; 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.



Peer Jitter 155.94.164.121

peer jitter 155.94.164.121 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Jitter 155.94.164.1210.2690.7971.1273.01711.341 16.54998.24310.21415.7524.4794.191ms 10.47 208.3

This shows the RMS Jitter of a remote peer or server. Jitter is the current estimated dispersion; 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.



Peer Jitter 172.98.77.203

peer jitter 172.98.77.203 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Jitter 172.98.77.2030.6780.6780.8062.10714.552 20.88520.88513.74620.2074.5454.564ms 1.417 4.216

This shows the RMS Jitter of a remote peer or server. Jitter is the current estimated dispersion; 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.



Peer Jitter 184.105.182.16

peer jitter 184.105.182.16 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Jitter 184.105.182.160.3890.6110.9222.54813.769 16.89030.15312.84716.2793.8954.049ms 2.208 8.169

This shows the RMS Jitter of a remote peer or server. Jitter is the current estimated dispersion; 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.



Peer Jitter 204.9.54.119

peer jitter 204.9.54.119 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Jitter 204.9.54.1190.3690.6931.0682.49711.218 14.02420.76710.14913.3313.2613.865ms 2.388 7.985

This shows the RMS Jitter of a remote peer or server. Jitter is the current estimated dispersion; 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.



Peer Jitter 216.6.2.70

peer jitter 216.6.2.70 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Jitter 216.6.2.700.6520.6520.8412.65410.999 11.51011.51010.15810.8572.9313.526ms 1.972 5.289

This shows the RMS Jitter of a remote peer or server. Jitter is the current estimated dispersion; 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.



Peer Jitter 72.30.35.89

peer jitter 72.30.35.89 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Jitter 72.30.35.890.2930.8031.0302.45710.261 16.69321.7139.23215.8903.2483.719ms 2.677 10.58

This shows the RMS Jitter of a remote peer or server. Jitter is the current estimated dispersion; 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.



Peer Jitter 98.152.165.38

peer jitter 98.152.165.38 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Jitter 98.152.165.380.4140.6350.8512.38612.330 17.66818.41411.47917.0333.5263.725ms 2.263 7.727

This shows the RMS Jitter of a remote peer or server. Jitter is the current estimated dispersion; 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.



Peer Jitter SHM(0)

peer jitter SHM(0) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Jitter SHM(0)0.1160.2710.3870.9953.055 5.35411.8282.6685.0831.0291.284ms 4.158 25.69

This shows the RMS Jitter of a remote peer or server. Jitter is the current estimated dispersion; 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.



Peer Jitter SHM(1)

peer jitter SHM(1) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%95%StdDev  MeanUnits nessosis
Peer Jitter SHM(1)0.0810.1810.2470.5211.568 5.07660.3971.3214.8951.0530.716µs 15.9 579.6

This shows the RMS Jitter of a remote peer or server. Jitter is the current estimated dispersion; 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%95%StdDev  MeanUnits nessosis
Local Clock Frequency Offset0.9801.0691.1271.5641.904 1.9882.0360.7770.9190.2531.551ppm 149.7 844.8
Local Clock Time Offset-62.325-2.001-0.9180.0360.775 2.71811.9041.6934.7191.0220.001µs-20.14 858.5
Local RMS Frequency Jitter0.3160.4740.5510.8473.440 7.23259.4322.8896.7581.6031.190ppb 12.92 340.7
Local RMS Time Jitter0.2000.2990.3560.5541.431 3.61117.2741.0753.3120.6370.692µs 8.059 110.3
Peer Jitter 155.94.164.1210.2690.7971.1273.01711.341 16.54998.24310.21415.7524.4794.191ms 10.47 208.3
Peer Jitter 172.98.77.2030.6780.6780.8062.10714.552 20.88520.88513.74620.2074.5454.564ms 1.417 4.216
Peer Jitter 184.105.182.160.3890.6110.9222.54813.769 16.89030.15312.84716.2793.8954.049ms 2.208 8.169
Peer Jitter 204.9.54.1190.3690.6931.0682.49711.218 14.02420.76710.14913.3313.2613.865ms 2.388 7.985
Peer Jitter 216.6.2.700.6520.6520.8412.65410.999 11.51011.51010.15810.8572.9313.526ms 1.972 5.289
Peer Jitter 72.30.35.890.2930.8031.0302.45710.261 16.69321.7139.23215.8903.2483.719ms 2.677 10.58
Peer Jitter 98.152.165.380.4140.6350.8512.38612.330 17.66818.41411.47917.0333.5263.725ms 2.263 7.727
Peer Jitter SHM(0)0.1160.2710.3870.9953.055 5.35411.8282.6685.0831.0291.284ms 4.158 25.69
Peer Jitter SHM(1)0.0810.1810.2470.5211.568 5.07660.3971.3214.8951.0530.716µs 15.9 579.6
Peer Offset 155.94.164.1210.3341.3191.9812.5133.726 4.88218.3001.7453.5620.9592.680ms 21.01 254.9
Peer Offset 172.98.77.2030.6540.6541.7142.9635.771 17.07817.0784.05716.4242.6863.572ms 4.693 23.41
Peer Offset 184.105.182.165.3606.8047.1108.0959.276 10.21117.8512.1663.4070.8258.186ms 742.8 7050
Peer Offset 204.9.54.1190.8061.3042.1852.6353.740 4.38314.7361.5553.0780.8452.778ms 27.24 244.7
Peer Offset 216.6.2.70-1.378-1.378-0.0450.8672.051 10.74210.7422.09612.1201.3050.987ms 4.005 32.39
Peer Offset 72.30.35.890.3080.8852.2142.5874.381 5.19820.1182.1674.3131.0722.818ms 18.74 233.1
Peer Offset 98.152.165.383.6814.7195.2265.6456.728 7.67617.6831.5022.9570.7965.779ms 273.5 2122
Peer Offset SHM(0)-131.529-126.797-125.062-118.183-113.677 -112.194-108.34111.38514.6023.340-118.597ms-4.877e+041.785e+06
Peer Offset SHM(1)-62.326-2.002-0.9190.0370.776 2.71911.9051.6954.7211.0220.001µs-20.12 857.2
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 Peer 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 remote clock 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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