NTPsec

ntp-sdr

Report generated: Tue Nov 20 23:00:04 2018 UTC
Start Time: Mon Nov 19 23:00:02 2018 UTC
End Time: Tue Nov 20 23:00:02 2018 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-1,632.000-578.000-325.0005.000294.000 412.000673.000619.000990.000200.367-5.311ns-4.948 17.03
Local Clock Frequency Offset-5.542-5.531-5.528-5.513-5.506 -5.504-5.5030.0220.0270.0065-5.514ppm-6.027e+085.091e+11

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 Jitter97.000128.000147.000216.000300.000 342.000428.000153.000214.00046.549218.760ns 62.14 278.7

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 Jitter40.00051.00060.00085.000130.000 257.000606.00070.000206.00037.16491.20110e-12 13.14 102.4

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-1,632.000-578.000-325.0005.000294.000 412.000673.000619.000990.000200.367-5.311ns-4.948 17.03

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 192.36.143.1509.38211.64715.14521.86929.253 32.90634.44414.10821.2594.54122.126µs 69.71 318.1

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 192.36.143.151-6.4852.8446.15713.00219.913 23.60924.19313.75620.7654.28413.117µs 14.86 46.97

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 192.36.143.234

peer offset 192.36.143.234 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Offset 192.36.143.234-4.309-1.392-0.2100.0750.299 1.3262.4290.5102.7170.4290.037ms-7.948 72.11

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 194.58.202.14854.57661.12763.26867.91173.254 75.34379.2859.98614.2163.04367.838µs 97152.082e+05

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 194.58.202.200.3521.1054.2599.25915.916 19.82422.96011.65718.7193.7389.477µs 8.795 26.97

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 194.58.205.148-8.615-5.573-3.8481.9218.296 12.22217.79312.14417.7953.7842.189µs-0.8897 4.443

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 SHM(0)

peer offset SHM(0) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Offset SHM(0)-704.051-527.655-450.677-363.708-302.079 10.77628.701148.599538.43168.959-361.691ms-259.7 1708

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 SHM(2)

peer offset SHM(2) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Offset SHM(2)-1,633.000-579.000-326.0006.000295.000 413.000674.000621.000992.000201.101-5.288ns -4.94 16.95

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 192.36.143.1503.2354.6875.28811.84029.546 156.452161.75324.258151.76519.54715.827µs 5.199 35.79

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 192.36.143.1512.6663.4474.48110.24230.855 607.530656.63826.374604.08372.69322.077µs 5.456 47.2

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 192.36.143.234

peer jitter 192.36.143.234 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Jitter 192.36.143.23411.99516.18724.94353.943239.439 995.7312,668.870214.496979.544230.75096.707µs 6.968 73.81

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 194.58.202.1482.0202.0833.9728.90425.519 184.680203.98221.547182.59728.73915.365µs 3.718 21.55

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 194.58.202.202.0192.3303.77411.31732.189 126.102231.56128.415123.77220.15615.317µs 5.852 51.64

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 194.58.205.1482.5103.2604.94010.82941.032 195.415219.00036.092192.15528.87117.841µs 4.096 25.54

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 SHM(0)

peer jitter SHM(0) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Jitter SHM(0)3.3095.5328.08924.059204.876 384.874582.331196.787379.34270.87849.503ms 2.317 11.57

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 SHM(2)

peer jitter SHM(2) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Peer Jitter SHM(2)34.00084.000109.000196.000368.000 473.0001,218.000259.000389.00083.119212.402ns 9.826 36.71

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-5.542-5.531-5.528-5.513-5.506 -5.504-5.5030.0220.0270.0065-5.514ppm-6.027e+085.091e+11
Local Clock Time Offset-1,632.000-578.000-325.0005.000294.000 412.000673.000619.000990.000200.367-5.311ns-4.948 17.03
Local RMS Frequency Jitter40.00051.00060.00085.000130.000 257.000606.00070.000206.00037.16491.20110e-12 13.14 102.4
Local RMS Time Jitter97.000128.000147.000216.000300.000 342.000428.000153.000214.00046.549218.760ns 62.14 278.7
Peer Jitter 192.36.143.1503.2354.6875.28811.84029.546 156.452161.75324.258151.76519.54715.827µs 5.199 35.79
Peer Jitter 192.36.143.1512.6663.4474.48110.24230.855 607.530656.63826.374604.08372.69322.077µs 5.456 47.2
Peer Jitter 192.36.143.23411.99516.18724.94353.943239.439 995.7312,668.870214.496979.544230.75096.707µs 6.968 73.81
Peer Jitter 194.58.202.1482.0202.0833.9728.90425.519 184.680203.98221.547182.59728.73915.365µs 3.718 21.55
Peer Jitter 194.58.202.202.0192.3303.77411.31732.189 126.102231.56128.415123.77220.15615.317µs 5.852 51.64
Peer Jitter 194.58.205.1482.5103.2604.94010.82941.032 195.415219.00036.092192.15528.87117.841µs 4.096 25.54
Peer Jitter SHM(0)3.3095.5328.08924.059204.876 384.874582.331196.787379.34270.87849.503ms 2.317 11.57
Peer Jitter SHM(2)34.00084.000109.000196.000368.000 473.0001,218.000259.000389.00083.119212.402ns 9.826 36.71
Peer Offset 192.36.143.1509.38211.64715.14521.86929.253 32.90634.44414.10821.2594.54122.126µs 69.71 318.1
Peer Offset 192.36.143.151-6.4852.8446.15713.00219.913 23.60924.19313.75620.7654.28413.117µs 14.86 46.97
Peer Offset 192.36.143.234-4.309-1.392-0.2100.0750.299 1.3262.4290.5102.7170.4290.037ms-7.948 72.11
Peer Offset 194.58.202.14854.57661.12763.26867.91173.254 75.34379.2859.98614.2163.04367.838µs 97152.082e+05
Peer Offset 194.58.202.200.3521.1054.2599.25915.916 19.82422.96011.65718.7193.7389.477µs 8.795 26.97
Peer Offset 194.58.205.148-8.615-5.573-3.8481.9218.296 12.22217.79312.14417.7953.7842.189µs-0.8897 4.443
Peer Offset SHM(0)-704.051-527.655-450.677-363.708-302.079 10.77628.701148.599538.43168.959-361.691ms-259.7 1708
Peer Offset SHM(2)-1,633.000-579.000-326.0006.000295.000 413.000674.000621.000992.000201.101-5.288ns -4.94 16.95
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.



This page autogenerated by ntpviz, part of the NTPsec project
html 5    Valid CSS!