NTPsec

ntp.as397444.net

Report generated: Fri Jul 4 00:01:21 2025 UTC
Start Time: Fri Jun 27 00:01:06 2025 UTC
End Time: Fri Jul 4 00:01:06 2025 UTC
Report Period: 7.0 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 -6.000 -2.000 -1.000 0.000 1.000 2.000 12.000 2.000 4.000 0.727 -0.007 ns -3.03 20.14
Local Clock Frequency Offset 22.276 22.326 22.352 22.531 23.390 23.516 23.535 1.038 1.190 0.331 22.684 ppm 3.077e+05 2.078e+07

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 1.000 8.000 14.000 31.000 48.000 56.000 76.000 34.000 48.000 10.166 31.233 ns 15.21 48.02

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 0.000 0.000 0.000 0.000 0.000 0.000 1,000.000 0.000 0.000 66.398 4.428 10e-12 11.31 174.1

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 -6.000 -2.000 -1.000 0.000 1.000 2.000 12.000 2.000 4.000 0.727 -0.007 ns -3.03 20.14

The clock offsets of the local clock as a histogram.

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



Local Temperatures

local temps plot

Local temperatures. These will be site-specific depending upon what temperature sensors you collect data from. Temperature changes affect the local clock crystal frequency and stability. The math of how temperature changes frequency is complex, and also depends on crystal aging. So there is no easy way to correct for it in software. This is the single most important component of frequency drift.

The Local Temperatures are from field 3 from the tempstats log file.



Local Frequency/Temp

local freq temps plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset 22.276 22.326 22.352 22.531 23.390 23.516 23.535 1.038 1.190 0.331 22.684 ppm 3.077e+05 2.078e+07
Temp LM0 57.800 58.300 58.600 59.800 67.800 71.200 72.700 9.200 12.900 2.896 61.115 °C

The frequency offsets and temperatures. Showing frequency offset (red, in parts per million, scale on right) and the temperatures.

These are field 4 (frequency) from the loopstats log file, and field 3 from the tempstats log file.



Local GPS

local gps plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
nSats 14.000 18.000 19.000 24.000 28.000 29.000 31.000 9.000 11.000 2.660 23.620 nSat 512.9 4228
TDOP 0.180 0.180 0.180 0.190 0.200 0.210 0.240 0.020 0.030 0.008 0.191 1.139e+04 2.574e+05

Local GPS. The Time Dilution of Precision (TDOP) is plotted in blue. The number of visible satellites (nSat) is plotted in red.

TDOP is field 3, and nSats is field 4, from the gpsd log file. The gpsd log file is created by the ntploggps program.

TDOP is a dimensionless error factor. Smaller numbers are better. TDOP ranges from 1 (ideal), 2 to 5 (good), to greater than 20 (poor). Some GNSS receivers report TDOP less than one which is theoretically impossible.



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.



Refclock Offset 127.127.20.1 NMEA(1)

peer offset 127.127.20.1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock Offset 127.127.20.1 NMEA(1) -14.310 -7.187 -4.796 4.103 10.510 12.040 16.440 15.306 19.227 5.092 3.481 ms -1.211 2.82

The offset of a local refclock in seconds. This is useful to see how the measured offset is behaving.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local serial GPS 200 ms; local PPS 20µs.

Clock Offset is field 5 in the peerstats log file.



Refclock Offset 127.127.20.2 NMEA(2)

peer offset 127.127.20.2 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock Offset 127.127.20.2 NMEA(2) -37.980 -8.943 -6.868 -1.664 4.488 7.023 12.730 11.356 15.966 3.432 -1.506 ms -7.095 18.72

The offset of a local refclock in seconds. This is useful to see how the measured offset is behaving.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local serial GPS 200 ms; local PPS 20µs.

Clock Offset is field 5 in the peerstats log file.



Refclock Offset 127.127.20.3 NMEA(3)

peer offset 127.127.20.3 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock Offset 127.127.20.3 NMEA(3) -76.950 -52.330 -44.120 -22.160 -3.027 3.355 19.630 41.093 55.685 12.411 -22.661 ms -31.25 116.9

The offset of a local refclock in seconds. This is useful to see how the measured offset is behaving.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local serial GPS 200 ms; local PPS 20µs.

Clock Offset is field 5 in the peerstats log file.



Refclock Offset 127.127.46.1 GPS(1)

peer offset 127.127.46.1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock Offset 127.127.46.1 GPS(1) -32.000 -13.000 -7.000 6.000 20.000 27.000 41.000 27.000 40.000 8.449 6.510 ns -0.6976 3.61

The offset of a local refclock in seconds. This is useful to see how the measured offset is behaving.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local serial GPS 200 ms; local PPS 20µs.

Clock Offset is field 5 in the peerstats log file.



Refclock Offset 127.127.46.2 GPS(2)

peer offset 127.127.46.2 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock Offset 127.127.46.2 GPS(2) -79.000 -53.000 -46.000 -29.000 -11.000 -3.000 20.000 35.000 50.000 10.775 -28.525 ns -59.45 259.8

The offset of a local refclock in seconds. This is useful to see how the measured offset is behaving.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local serial GPS 200 ms; local PPS 20µs.

Clock Offset is field 5 in the peerstats log file.



Refclock Offset 127.127.46.3 GPS(3)

peer offset 127.127.46.3 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock Offset 127.127.46.3 GPS(3) -6.000 3.000 8.000 22.000 35.000 42.000 61.000 27.000 39.000 8.250 21.895 ns 9.547 27.44

The offset of a local refclock in seconds. This is useful to see how the measured offset is behaving.

Closer to 0s is better. An ideal system would be a horizontal line at 0s. Typical 90% ranges may be: local serial GPS 200 ms; local PPS 20µs.

Clock Offset is field 5 in the peerstats log file.



Server Offset 162.159.200.123

peer offset 162.159.200.123 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 162.159.200.123 -2.772 -1.140 -0.637 0.664 2.296 3.775 4.938 2.933 4.915 0.933 0.726 ms 0.0145 5.19

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 169.229.128.134

peer offset 169.229.128.134 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 169.229.128.134 -3.945 -2.349 -1.113 1.162 3.537 4.351 6.290 4.650 6.700 1.384 1.211 ms -0.4056 4.153

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 2001:470:0:50::2 (clock.fmt.he.net)

peer offset 2001:470:0:50::2 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 2001:470:0:50::2 (clock.fmt.he.net) -3.731 -2.649 -1.405 1.310 4.205 6.747 7.434 5.610 9.396 1.647 1.398 ms -0.07747 4.836

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 2607:f140:ffff:8000:0:8006:0:a (ntp1.net.berkeley.edu)

peer offset 2607:f140:ffff:8000:0:8006:0:a plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 2607:f140:ffff:8000:0:8006:0:a (ntp1.net.berkeley.edu) -3.108 -2.461 -1.486 0.855 2.944 4.658 5.203 4.430 7.119 1.440 0.906 ms -1.128 3.699

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 2610:20:6f96:96::4 (time-d-b.nist.gov)

peer offset 2610:20:6f96:96::4 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 2610:20:6f96:96::4 (time-d-b.nist.gov) -17.730 -16.470 -15.240 -12.450 -8.375 -4.410 -0.407 6.865 12.060 2.186 -12.206 ms -303.7 2107

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 2610:20:6f97:97::6 (time-e-wwv.nist.gov)

peer offset 2610:20:6f97:97::6 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 2610:20:6f97:97::6 (time-e-wwv.nist.gov) -16.020 -15.740 -14.480 -12.290 -9.417 -3.708 5.010 5.063 12.032 2.048 -12.058 ms -344.1 2469

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 PPS1

peer offset PPS1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset PPS1 -64.470 -19.150 -9.108 15.990 64.850 77.590 115.700 73.958 96.740 22.722 21.099 µs 0.4368 2.731

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.



Refclock RMS Jitter 127.127.20.1 NMEA(1)

peer jitter 127.127.20.1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock RMS Jitter 127.127.20.1 NMEA(1) 0.021 0.335 0.567 1.576 2.970 3.643 9.993 2.403 3.308 0.746 1.649 ms 6.109 18.52

The RMS Jitter of a local refclock. 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.



Refclock RMS Jitter 127.127.20.2 NMEA(2)

peer jitter 127.127.20.2 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock RMS Jitter 127.127.20.2 NMEA(2) 0.071 0.698 1.000 1.585 2.299 2.866 11.380 1.299 2.168 0.425 1.614 ms 31.58 135.5

The RMS Jitter of a local refclock. 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.



Refclock RMS Jitter 127.127.20.3 NMEA(3)

peer jitter 127.127.20.3 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock RMS Jitter 127.127.20.3 NMEA(3) 0.013 0.277 0.474 1.362 2.694 3.548 8.656 2.220 3.271 0.692 1.450 ms 5.584 18.08

The RMS Jitter of a local refclock. 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.



Refclock RMS Jitter 127.127.46.1 GPS(1)

peer jitter 127.127.46.1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock RMS Jitter 127.127.46.1 GPS(1) 1.000 2.000 2.000 4.000 7.000 9.000 31.000 5.000 7.000 1.568 4.477 ns 15.8 102.6

The RMS Jitter of a local refclock. 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.



Refclock RMS Jitter 127.127.46.2 GPS(2)

peer jitter 127.127.46.2 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock RMS Jitter 127.127.46.2 GPS(2) 1.000 2.000 3.000 4.000 6.000 8.000 32.000 3.000 6.000 1.527 4.282 ns 16.1 118.1

The RMS Jitter of a local refclock. 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.



Refclock RMS Jitter 127.127.46.3 GPS(3)

peer jitter 127.127.46.3 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock RMS Jitter 127.127.46.3 GPS(3) 1.000 1.000 1.000 2.000 5.000 8.000 31.000 4.000 7.000 1.681 2.676 ns 6.72 61.91

The RMS Jitter of a local refclock. 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 162.159.200.123

peer jitter 162.159.200.123 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 162.159.200.123 0.021 0.062 0.105 0.255 2.156 2.640 3.588 2.051 2.578 0.746 0.630 ms 0.9562 2.918

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 169.229.128.134

peer jitter 169.229.128.134 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 169.229.128.134 0.268 0.830 1.081 1.645 2.489 2.817 3.338 1.408 1.987 0.428 1.681 ms 34.28 133.7

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 2001:470:0:50::2 (clock.fmt.he.net)

peer jitter 2001:470:0:50::2 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 2001:470:0:50::2 (clock.fmt.he.net) 0.678 0.781 1.229 2.009 3.012 3.818 4.646 1.783 3.037 0.579 2.066 ms 25.12 91.89

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 2607:f140:ffff:8000:0:8006:0:a (ntp1.net.berkeley.edu)

peer jitter 2607:f140:ffff:8000:0:8006:0:a plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 2607:f140:ffff:8000:0:8006:0:a (ntp1.net.berkeley.edu) 0.049 0.146 0.729 2.043 2.760 3.065 3.232 2.031 2.919 0.653 1.940 ms 12.87 35.82

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 2610:20:6f96:96::4 (time-d-b.nist.gov)

peer jitter 2610:20:6f96:96::4 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 2610:20:6f96:96::4 (time-d-b.nist.gov) 0.326 0.403 0.862 1.739 3.369 6.809 11.300 2.507 6.407 1.086 1.971 ms 7.006 44.96

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 2610:20:6f97:97::6 (time-e-wwv.nist.gov)

peer jitter 2610:20:6f97:97::6 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 2610:20:6f97:97::6 (time-e-wwv.nist.gov) 0.999 1.084 1.339 1.962 2.910 6.231 10.080 1.571 5.147 0.934 2.105 ms 10.86 76.81

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 PPS1

peer jitter PPS1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter PPS1 0.065 0.501 16.820 34.920 42.120 46.710 72.590 25.300 46.209 8.412 32.935 µs 31.73 109.8

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.



Summary


Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Local Clock Frequency Offset 22.276 22.326 22.352 22.531 23.390 23.516 23.535 1.038 1.190 0.331 22.684 ppm 3.077e+05 2.078e+07
Local Clock Time Offset -6.000 -2.000 -1.000 0.000 1.000 2.000 12.000 2.000 4.000 0.727 -0.007 ns -3.03 20.14
Local RMS Frequency Jitter 0.000 0.000 0.000 0.000 0.000 0.000 1,000.000 0.000 0.000 66.398 4.428 10e-12 11.31 174.1
Local RMS Time Jitter 1.000 8.000 14.000 31.000 48.000 56.000 76.000 34.000 48.000 10.166 31.233 ns 15.21 48.02
Refclock Offset 127.127.20.1 NMEA(1) -14.310 -7.187 -4.796 4.103 10.510 12.040 16.440 15.306 19.227 5.092 3.481 ms -1.211 2.82
Refclock Offset 127.127.20.2 NMEA(2) -37.980 -8.943 -6.868 -1.664 4.488 7.023 12.730 11.356 15.966 3.432 -1.506 ms -7.095 18.72
Refclock Offset 127.127.20.3 NMEA(3) -76.950 -52.330 -44.120 -22.160 -3.027 3.355 19.630 41.093 55.685 12.411 -22.661 ms -31.25 116.9
Refclock Offset 127.127.46.1 GPS(1) -32.000 -13.000 -7.000 6.000 20.000 27.000 41.000 27.000 40.000 8.449 6.510 ns -0.6976 3.61
Refclock Offset 127.127.46.2 GPS(2) -79.000 -53.000 -46.000 -29.000 -11.000 -3.000 20.000 35.000 50.000 10.775 -28.525 ns -59.45 259.8
Refclock Offset 127.127.46.3 GPS(3) -6.000 3.000 8.000 22.000 35.000 42.000 61.000 27.000 39.000 8.250 21.895 ns 9.547 27.44
Refclock RMS Jitter 127.127.20.1 NMEA(1) 0.021 0.335 0.567 1.576 2.970 3.643 9.993 2.403 3.308 0.746 1.649 ms 6.109 18.52
Refclock RMS Jitter 127.127.20.2 NMEA(2) 0.071 0.698 1.000 1.585 2.299 2.866 11.380 1.299 2.168 0.425 1.614 ms 31.58 135.5
Refclock RMS Jitter 127.127.20.3 NMEA(3) 0.013 0.277 0.474 1.362 2.694 3.548 8.656 2.220 3.271 0.692 1.450 ms 5.584 18.08
Refclock RMS Jitter 127.127.46.1 GPS(1) 1.000 2.000 2.000 4.000 7.000 9.000 31.000 5.000 7.000 1.568 4.477 ns 15.8 102.6
Refclock RMS Jitter 127.127.46.2 GPS(2) 1.000 2.000 3.000 4.000 6.000 8.000 32.000 3.000 6.000 1.527 4.282 ns 16.1 118.1
Refclock RMS Jitter 127.127.46.3 GPS(3) 1.000 1.000 1.000 2.000 5.000 8.000 31.000 4.000 7.000 1.681 2.676 ns 6.72 61.91
Server Jitter 162.159.200.123 0.021 0.062 0.105 0.255 2.156 2.640 3.588 2.051 2.578 0.746 0.630 ms 0.9562 2.918
Server Jitter 169.229.128.134 0.268 0.830 1.081 1.645 2.489 2.817 3.338 1.408 1.987 0.428 1.681 ms 34.28 133.7
Server Jitter 2001:470:0:50::2 (clock.fmt.he.net) 0.678 0.781 1.229 2.009 3.012 3.818 4.646 1.783 3.037 0.579 2.066 ms 25.12 91.89
Server Jitter 2607:f140:ffff:8000:0:8006:0:a (ntp1.net.berkeley.edu) 0.049 0.146 0.729 2.043 2.760 3.065 3.232 2.031 2.919 0.653 1.940 ms 12.87 35.82
Server Jitter 2610:20:6f96:96::4 (time-d-b.nist.gov) 0.326 0.403 0.862 1.739 3.369 6.809 11.300 2.507 6.407 1.086 1.971 ms 7.006 44.96
Server Jitter 2610:20:6f97:97::6 (time-e-wwv.nist.gov) 0.999 1.084 1.339 1.962 2.910 6.231 10.080 1.571 5.147 0.934 2.105 ms 10.86 76.81
Server Jitter PPS1 0.065 0.501 16.820 34.920 42.120 46.710 72.590 25.300 46.209 8.412 32.935 µs 31.73 109.8
Server Offset 162.159.200.123 -2.772 -1.140 -0.637 0.664 2.296 3.775 4.938 2.933 4.915 0.933 0.726 ms 0.0145 5.19
Server Offset 169.229.128.134 -3.945 -2.349 -1.113 1.162 3.537 4.351 6.290 4.650 6.700 1.384 1.211 ms -0.4056 4.153
Server Offset 2001:470:0:50::2 (clock.fmt.he.net) -3.731 -2.649 -1.405 1.310 4.205 6.747 7.434 5.610 9.396 1.647 1.398 ms -0.07747 4.836
Server Offset 2607:f140:ffff:8000:0:8006:0:a (ntp1.net.berkeley.edu) -3.108 -2.461 -1.486 0.855 2.944 4.658 5.203 4.430 7.119 1.440 0.906 ms -1.128 3.699
Server Offset 2610:20:6f96:96::4 (time-d-b.nist.gov) -17.730 -16.470 -15.240 -12.450 -8.375 -4.410 -0.407 6.865 12.060 2.186 -12.206 ms -303.7 2107
Server Offset 2610:20:6f97:97::6 (time-e-wwv.nist.gov) -16.020 -15.740 -14.480 -12.290 -9.417 -3.708 5.010 5.063 12.032 2.048 -12.058 ms -344.1 2469
Server Offset PPS1 -64.470 -19.150 -9.108 15.990 64.850 77.590 115.700 73.958 96.740 22.722 21.099 µs 0.4368 2.731
TDOP 0.180 0.180 0.180 0.190 0.200 0.210 0.240 0.020 0.030 0.008 0.191 1.139e+04 2.574e+05
Temp LM0 57.800 58.300 58.600 59.800 67.800 71.200 72.700 9.200 12.900 2.896 61.115 °C
nSats 14.000 18.000 19.000 24.000 28.000 29.000 31.000 9.000 11.000 2.660 23.620 nSat 512.9 4228
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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