NTPsec

ntp-sdr

Report generated: Thu Aug 8 00:00:03 2024 UTC
Start Time: Wed Aug 7 00:00:03 2024 UTC
End Time: Thu Aug 8 00:00:03 2024 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-0.000-0.000-0.0000.0000.000 0.0002,904.0000.0000.00056.3061.092s 47.65 2462
Local Clock Frequency Offset-4.612-4.516-4.328-4.129-4.078 -3.996-3.9630.2500.5200.093-4.160ppm-9.483e+044.329e+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 Jitter0.0000.0330.0410.0900.535 83.690164.8000.49483.65713.1472.209µs 3.637 32.72

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 Jitter0.0000.0001.0005.00059.000 162.000462.00058.000162.00030.01814.278ppb 3.912 39.72

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-0.000-0.000-0.0000.0000.000 0.0002,904.0000.0000.00056.3061.092s 47.65 2462

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

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 192.36.143.150

peer offset 192.36.143.150 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Offset 192.36.143.150-0.000-0.000-0.000-0.000-0.000 0.0002,904.0000.0000.000228.86318.150s 8.988 117.7

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 log file.



Peer Offset 192.36.143.151

peer offset 192.36.143.151 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Offset 192.36.143.151-0.000-0.000-0.000-0.000-0.000 0.0002,904.0000.0000.000238.70219.755s 8.477 106.7

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 log file.



Peer Offset 194.58.202.148

peer offset 194.58.202.148 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Offset 194.58.202.148-0.000-0.000-0.0000.0000.000 0.0002,904.0000.0000.001254.69022.512s 7.733 91.75

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 log file.



Peer Offset 194.58.202.20

peer offset 194.58.202.20 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Offset 194.58.202.20-0.000-0.000-0.000-0.0000.000 0.0002,904.0000.0000.000250.86021.835s 7.902 95.06

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 log file.



Peer Offset 194.58.205.148

peer offset 194.58.205.148 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Offset 194.58.205.148-0.000-0.000-0.0000.0000.000 0.0002,904.0000.0000.000263.99124.200s 7.343 84.34

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 log file.



Peer Offset GPS

peer offset GPS plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Offset GPS-310.900-244.100-147.400-11.55036.020 333.000661.700183.420577.10079.726-19.322ms-3.961 20.84

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 log file.



Peer Offset PPS

peer offset PPS plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Offset PPS-5.428-0.972-0.2560.0030.245 0.583223.4000.5011.5554.4020.079µs 46.62 2371

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 log file.



Peer Jitters

peer jitters plot

The RMS Jitter of all refclocks, peers 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.



Peer Jitter 192.36.143.150

peer jitter 192.36.143.150 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Jitter 192.36.143.1500.5812.3439.80019.84035.990 55.09064.38026.19052.7479.14222.075µs 7.959 26.41

The RMS Jitter of a remote peer or 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.



Peer Jitter 192.36.143.151

peer jitter 192.36.143.151 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Jitter 192.36.143.1510.4081.4578.36723.03036.630 65.65073.56028.26364.19310.05423.563µs 7.606 28.5

The RMS Jitter of a remote peer or 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.



Peer Jitter 194.58.202.148

peer jitter 194.58.202.148 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Jitter 194.58.202.14818.29019.07022.40056.19083.900 139.500162.30061.500120.43022.59752.929µs 7.789 28.77

The RMS Jitter of a remote peer or 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.



Peer Jitter 194.58.202.20

peer jitter 194.58.202.20 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Jitter 194.58.202.200.8132.79212.03021.63046.920 102.900137.30034.890100.10816.37425.321µs 5.625 32.91

The RMS Jitter of a remote peer or 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.



Peer Jitter 194.58.205.148

peer jitter 194.58.205.148 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Jitter 194.58.205.1480.4533.23612.06033.46065.610 94.660146.90053.55091.42418.53134.206µs 5.662 27.77

The RMS Jitter of a remote peer or 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.



Peer Jitter GPS

peer jitter GPS plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Jitter GPS0.0814.3736.50711.04096.100 202.500335.00089.593198.12734.21322.196ms 3.109 17.99

The RMS Jitter of a remote peer or 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.



Peer Jitter PPS

peer jitter PPS plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Jitter PPS0.0230.0680.1050.1850.494 1.0011.9310.3890.9330.1720.229µs 5.699 40.29

The RMS Jitter of a remote peer or 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-4.612-4.516-4.328-4.129-4.078 -3.996-3.9630.2500.5200.093-4.160ppm-9.483e+044.329e+06
Local Clock Time Offset-0.000-0.000-0.0000.0000.000 0.0002,904.0000.0000.00056.3061.092s 47.65 2462
Local RMS Frequency Jitter0.0000.0001.0005.00059.000 162.000462.00058.000162.00030.01814.278ppb 3.912 39.72
Local RMS Time Jitter0.0000.0330.0410.0900.535 83.690164.8000.49483.65713.1472.209µs 3.637 32.72
Peer Jitter 192.36.143.1500.5812.3439.80019.84035.990 55.09064.38026.19052.7479.14222.075µs 7.959 26.41
Peer Jitter 192.36.143.1510.4081.4578.36723.03036.630 65.65073.56028.26364.19310.05423.563µs 7.606 28.5
Peer Jitter 194.58.202.14818.29019.07022.40056.19083.900 139.500162.30061.500120.43022.59752.929µs 7.789 28.77
Peer Jitter 194.58.202.200.8132.79212.03021.63046.920 102.900137.30034.890100.10816.37425.321µs 5.625 32.91
Peer Jitter 194.58.205.1480.4533.23612.06033.46065.610 94.660146.90053.55091.42418.53134.206µs 5.662 27.77
Peer Jitter GPS0.0814.3736.50711.04096.100 202.500335.00089.593198.12734.21322.196ms 3.109 17.99
Peer Jitter PPS0.0230.0680.1050.1850.494 1.0011.9310.3890.9330.1720.229µs 5.699 40.29
Peer Offset 192.36.143.150-0.000-0.000-0.000-0.000-0.000 0.0002,904.0000.0000.000228.86318.150s 8.988 117.7
Peer Offset 192.36.143.151-0.000-0.000-0.000-0.000-0.000 0.0002,904.0000.0000.000238.70219.755s 8.477 106.7
Peer Offset 194.58.202.148-0.000-0.000-0.0000.0000.000 0.0002,904.0000.0000.001254.69022.512s 7.733 91.75
Peer Offset 194.58.202.20-0.000-0.000-0.000-0.0000.000 0.0002,904.0000.0000.000250.86021.835s 7.902 95.06
Peer Offset 194.58.205.148-0.000-0.000-0.0000.0000.000 0.0002,904.0000.0000.000263.99124.200s 7.343 84.34
Peer Offset GPS-310.900-244.100-147.400-11.55036.020 333.000661.700183.420577.10079.726-19.322ms-3.961 20.84
Peer Offset PPS-5.428-0.972-0.2560.0030.245 0.583223.4000.5011.5554.4020.079µs 46.62 2371
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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