NTPsec

ntp.as397444.net

Report generated: Tue Sep 2 00:01:21 2025 UTC
Start Time: Tue Aug 26 00:01:06 2025 UTC
End Time: Tue Sep 2 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 -31.000 -2.000 -1.000 0.000 1.000 2.000 13.000 2.000 4.000 0.724 0.011 ns -2.702 24.17
Local Clock Frequency Offset 22.323 22.338 22.368 22.505 23.202 23.376 23.410 0.834 1.038 0.249 22.604 ppm 7.268e+05 6.536e+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 7.000 13.000 30.000 47.000 55.000 71.000 34.000 48.000 10.243 29.807 ns 12.8 38.98

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 69.888 4.908 10e-12 10.58 155

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 -31.000 -2.000 -1.000 0.000 1.000 2.000 13.000 2.000 4.000 0.724 0.011 ns -2.702 24.17

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 22.323 22.338 22.368 22.505 23.202 23.376 23.410 0.834 1.038 0.249 22.604 ppm 7.268e+05 6.536e+07
Temp LM0 57.600 58.200 58.500 59.200 64.200 66.700 67.700 5.700 8.500 1.807 59.947 °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 2.686 23.580 nSat 494.2 4027
TDOP 0.180 0.180 0.180 0.190 0.210 0.210 0.240 0.030 0.030 0.008 0.192 1.057e+04 2.329e+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) -150.800 -7.367 -4.747 3.639 10.400 11.850 34.250 15.147 19.217 5.083 3.375 ms -1.31 4.54

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) -26.220 -8.611 -6.669 -1.449 4.836 7.450 13.700 11.505 16.061 3.486 -1.248 ms -6.335 16.21

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) -70.780 -54.180 -44.450 -20.510 -2.186 4.134 18.030 42.264 58.314 12.738 -21.432 ms -27.72 101.8

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 127.127.46.1 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) -195.100 -0.013 -0.007 0.006 0.020 0.025 2,096.000 0.027 0.038 2.742 0.010 µs 753.1 5.762e+05

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) -78.000 -53.000 -44.000 -27.000 -10.000 -2.000 18.000 34.000 51.000 10.496 -27.156 ns -56.94 246.4

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) -11.000 -0.000 6.000 21.000 35.000 41.000 54.000 29.000 41.000 8.695 20.754 ns 6.713 17.65

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 -0.820 -0.559 -0.236 0.735 1.771 2.688 2.837 2.007 3.247 0.648 0.740 ms 0.667 3.211

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 -3.818 -1.991 -0.824 1.063 2.921 3.978 4.230 3.745 5.969 1.075 1.066 ms -0.3297 5.046

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) -5.273 -4.350 -1.875 0.514 3.006 3.794 4.269 4.881 8.144 1.504 0.355 ms -3.122 9.202

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) -4.533 -3.756 -1.171 0.863 3.359 4.488 4.828 4.530 8.244 1.392 0.893 ms -1.291 5.875

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) -15.930 -14.900 -13.770 -10.700 5.213 5.720 5.920 18.983 20.620 6.617 -6.786 ms -13.8 38.46

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) -19.360 -16.270 -13.860 -11.320 2.893 3.873 7.073 16.753 20.143 5.781 -8.672 ms -22 67.96

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 -71.880 -19.470 -9.415 14.930 63.400 76.980 113.300 72.815 96.450 21.907 19.419 µs 0.4158 2.975

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) 0.035 0.322 0.532 1.408 2.734 3.441 81.920 2.201 3.119 0.722 1.494 ms 14.31 993.4

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) 0.054 0.682 0.988 1.585 2.319 2.930 9.595 1.331 2.248 0.433 1.617 ms 29.71 121.6

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 127.127.20.3 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) 0.023 0.273 0.457 1.303 2.576 3.341 8.363 2.119 3.068 0.659 1.388 ms 5.585 17.62

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) 0.000 0.000 0.000 0.000 0.000 0.000 10.570 0.000 0.000 0.014 0.000 ms 763.6 5.861e+05

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 31.000 3.000 6.000 1.541 4.286 ns 15.92 117

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 30.000 4.000 7.000 1.696 2.636 ns 6.679 60.89

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 26.930 52.720 111.700 201.000 643.200 960.500 1,137.000 531.500 907.780 175.887 262.541 µs 3.786 14.3

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 0.578 0.688 1.024 1.612 2.412 2.728 2.984 1.388 2.040 0.441 1.700 ms 31.97 119.6

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) 0.522 0.929 1.204 1.903 2.595 2.989 3.865 1.391 2.060 0.394 1.934 ms 71.6 332.2

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) 0.378 0.519 1.037 1.748 2.845 3.467 4.022 1.808 2.948 0.533 1.842 ms 22.85 84.16

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) 0.372 0.427 0.490 1.527 2.810 7.781 9.040 2.320 7.354 1.145 1.673 ms 4.936 27.28

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) 0.552 0.742 1.061 1.670 3.027 7.877 9.061 1.966 7.135 1.172 1.916 ms 6.148 33.36

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 0.075 0.503 17.020 35.090 42.170 46.810 75.780 25.150 46.307 8.395 33.139 µs 32.55 113.1

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 22.323 22.338 22.368 22.505 23.202 23.376 23.410 0.834 1.038 0.249 22.604 ppm 7.268e+05 6.536e+07
Local Clock Time Offset -31.000 -2.000 -1.000 0.000 1.000 2.000 13.000 2.000 4.000 0.724 0.011 ns -2.702 24.17
Local RMS Frequency Jitter 0.000 0.000 0.000 0.000 0.000 0.000 1,000.000 0.000 0.000 69.888 4.908 10e-12 10.58 155
Local RMS Time Jitter 1.000 7.000 13.000 30.000 47.000 55.000 71.000 34.000 48.000 10.243 29.807 ns 12.8 38.98
Refclock Offset 127.127.20.1 NMEA(1) -150.800 -7.367 -4.747 3.639 10.400 11.850 34.250 15.147 19.217 5.083 3.375 ms -1.31 4.54
Refclock Offset 127.127.20.2 NMEA(2) -26.220 -8.611 -6.669 -1.449 4.836 7.450 13.700 11.505 16.061 3.486 -1.248 ms -6.335 16.21
Refclock Offset 127.127.20.3 NMEA(3) -70.780 -54.180 -44.450 -20.510 -2.186 4.134 18.030 42.264 58.314 12.738 -21.432 ms -27.72 101.8
Refclock Offset 127.127.46.1 GPS(1) -195.100 -0.013 -0.007 0.006 0.020 0.025 2,096.000 0.027 0.038 2.742 0.010 µs 753.1 5.762e+05
Refclock Offset 127.127.46.2 GPS(2) -78.000 -53.000 -44.000 -27.000 -10.000 -2.000 18.000 34.000 51.000 10.496 -27.156 ns -56.94 246.4
Refclock Offset 127.127.46.3 GPS(3) -11.000 -0.000 6.000 21.000 35.000 41.000 54.000 29.000 41.000 8.695 20.754 ns 6.713 17.65
Refclock RMS Jitter 127.127.20.1 NMEA(1) 0.035 0.322 0.532 1.408 2.734 3.441 81.920 2.201 3.119 0.722 1.494 ms 14.31 993.4
Refclock RMS Jitter 127.127.20.2 NMEA(2) 0.054 0.682 0.988 1.585 2.319 2.930 9.595 1.331 2.248 0.433 1.617 ms 29.71 121.6
Refclock RMS Jitter 127.127.20.3 NMEA(3) 0.023 0.273 0.457 1.303 2.576 3.341 8.363 2.119 3.068 0.659 1.388 ms 5.585 17.62
Refclock RMS Jitter 127.127.46.1 GPS(1) 0.000 0.000 0.000 0.000 0.000 0.000 10.570 0.000 0.000 0.014 0.000 ms 763.6 5.861e+05
Refclock RMS Jitter 127.127.46.2 GPS(2) 1.000 2.000 3.000 4.000 6.000 8.000 31.000 3.000 6.000 1.541 4.286 ns 15.92 117
Refclock RMS Jitter 127.127.46.3 GPS(3) 1.000 1.000 1.000 2.000 5.000 8.000 30.000 4.000 7.000 1.696 2.636 ns 6.679 60.89
Server Jitter 162.159.200.123 26.930 52.720 111.700 201.000 643.200 960.500 1,137.000 531.500 907.780 175.887 262.541 µs 3.786 14.3
Server Jitter 169.229.128.134 0.578 0.688 1.024 1.612 2.412 2.728 2.984 1.388 2.040 0.441 1.700 ms 31.97 119.6
Server Jitter 2001:470:0:50::2 (clock.fmt.he.net) 0.522 0.929 1.204 1.903 2.595 2.989 3.865 1.391 2.060 0.394 1.934 ms 71.6 332.2
Server Jitter 2607:f140:ffff:8000:0:8006:0:a (ntp1.net.berkeley.edu) 0.378 0.519 1.037 1.748 2.845 3.467 4.022 1.808 2.948 0.533 1.842 ms 22.85 84.16
Server Jitter 2610:20:6f96:96::4 (time-d-b.nist.gov) 0.372 0.427 0.490 1.527 2.810 7.781 9.040 2.320 7.354 1.145 1.673 ms 4.936 27.28
Server Jitter 2610:20:6f97:97::6 (time-e-wwv.nist.gov) 0.552 0.742 1.061 1.670 3.027 7.877 9.061 1.966 7.135 1.172 1.916 ms 6.148 33.36
Server Jitter PPS1 0.075 0.503 17.020 35.090 42.170 46.810 75.780 25.150 46.307 8.395 33.139 µs 32.55 113.1
Server Offset 162.159.200.123 -0.820 -0.559 -0.236 0.735 1.771 2.688 2.837 2.007 3.247 0.648 0.740 ms 0.667 3.211
Server Offset 169.229.128.134 -3.818 -1.991 -0.824 1.063 2.921 3.978 4.230 3.745 5.969 1.075 1.066 ms -0.3297 5.046
Server Offset 2001:470:0:50::2 (clock.fmt.he.net) -5.273 -4.350 -1.875 0.514 3.006 3.794 4.269 4.881 8.144 1.504 0.355 ms -3.122 9.202
Server Offset 2607:f140:ffff:8000:0:8006:0:a (ntp1.net.berkeley.edu) -4.533 -3.756 -1.171 0.863 3.359 4.488 4.828 4.530 8.244 1.392 0.893 ms -1.291 5.875
Server Offset 2610:20:6f96:96::4 (time-d-b.nist.gov) -15.930 -14.900 -13.770 -10.700 5.213 5.720 5.920 18.983 20.620 6.617 -6.786 ms -13.8 38.46
Server Offset 2610:20:6f97:97::6 (time-e-wwv.nist.gov) -19.360 -16.270 -13.860 -11.320 2.893 3.873 7.073 16.753 20.143 5.781 -8.672 ms -22 67.96
Server Offset PPS1 -71.880 -19.470 -9.415 14.930 63.400 76.980 113.300 72.815 96.450 21.907 19.419 µs 0.4158 2.975
TDOP 0.180 0.180 0.180 0.190 0.210 0.210 0.240 0.030 0.030 0.008 0.192 1.057e+04 2.329e+05
Temp LM0 57.600 58.200 58.500 59.200 64.200 66.700 67.700 5.700 8.500 1.807 59.947 °C
nSats 14.000 18.000 19.000 24.000 28.000 29.000 31.000 9.000 11.000 2.686 23.580 nSat 494.2 4027
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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