NTPsec

ntp.as397444.net

Report generated: Wed Feb 24 17:47:10 2021 UTC
Start Time: Wed Feb 17 17:46:52 2021 UTC
End Time: Wed Feb 24 17:46:52 2021 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 -1,216.000 -6.724 -4.130 0.100 3.584 5.844 1,235.000 7.714 12.568 11.747 0.008 µs -3.262 6191
Local Clock Frequency Offset 15.068 15.206 15.320 17.453 21.670 22.716 23.512 6.350 7.510 1.976 17.820 ppm 540.6 4548

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 0.000 0.314 0.651 14.260 20.930 24.140 1,413.000 20.279 23.826 7.324 13.752 µs 98.97 1.867e+04

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 3.000 7.000 12.000 44.000 134.000 202.000 619.000 122.000 195.000 41.852 54.483 ppb 3.175 15.99

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 -1,216.000 -6.724 -4.130 0.100 3.584 5.844 1,235.000 7.714 12.568 11.747 0.008 µs -3.262 6191

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 15.068 15.206 15.320 17.453 21.670 22.716 23.512 6.350 7.510 1.976 17.820 ppm 540.6 4548
Temp LM0 54.100 55.000 55.700 57.500 61.000 62.300 63.700 5.300 7.300 1.652 57.833 °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 13.000 16.000 17.000 21.000 24.000 26.000 28.000 7.000 10.000 2.200 20.915 nSat 641.3 5675
TDOP 0.400 0.470 0.510 0.640 0.930 1.160 2.660 0.420 0.690 0.138 0.670 70.75 346.7

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 127.127.20.0 NMEA(0)

peer offset 127.127.20.0 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock Offset 127.127.20.0 NMEA(0) -83.230 -38.400 -20.270 25.190 63.490 77.150 113.400 83.760 115.550 25.520 23.970 ms -0.4415 2.993

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 127.127.20.1 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) -26.700 -14.390 -12.980 -7.236 19.280 20.540 25.920 32.260 34.930 14.078 3.055 ms -2.81 5.051

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) -7.918 -2.996 -1.267 3.212 7.435 9.242 12.880 8.702 12.238 2.643 3.168 ms 0.572 3.186

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 127.127.22.3 PPS(3)

peer offset 127.127.22.3 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock Offset 127.127.22.3 PPS(3) -1.704 -1.472 -1.121 0.088 1.250 1.597 1.797 2.371 3.069 0.725 0.030 ms -3.711 8.523

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) -1,236.000 -32.790 -29.420 -20.790 -10.220 -4.748 863.000 19.200 28.042 51.224 -17.306 µs 8.241 188.4

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 127.127.46.2 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) -1,208.000 -0.776 0.187 7.582 16.110 22.470 894.500 15.923 23.246 51.080 11.062 µs 11.73 215.2

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 128.59.0.245

peer offset 128.59.0.245 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 128.59.0.245 -12.560 -6.933 -3.238 0.964 6.476 9.552 12.840 9.714 16.485 2.946 1.149 ms -2.018 7.537

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 17.253.14.125

peer offset 17.253.14.125 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 17.253.14.125 -9.537 -5.467 -2.364 1.134 5.827 12.640 18.560 8.191 18.107 2.723 1.407 ms -0.4789 9.091

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 17.253.20.125

peer offset 17.253.20.125 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 17.253.20.125 -3.451 -0.492 0.535 3.128 6.498 10.010 15.600 5.963 10.502 1.917 3.260 ms 3.726 14.63

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 2001:470:0:2c8::2 (clock.nyc.he.net)

peer offset 2001:470:0:2c8::2 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 2001:470:0:2c8::2 (clock.nyc.he.net) -2.248 -1.144 0.269 2.311 4.586 5.547 14.050 4.317 6.691 1.381 2.310 ms 3.073 14.18

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 209.87.233.53

peer offset 209.87.233.53 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 209.87.233.53 -23.820 -20.190 -14.640 -1.222 9.080 14.550 16.380 23.720 34.740 6.599 -1.540 ms -5.985 17.38

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 127.127.20.0 NMEA(0)

peer jitter 127.127.20.0 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock RMS Jitter 127.127.20.0 NMEA(0) 0.008 1.466 2.374 5.301 9.338 11.810 24.620 6.964 10.344 2.169 5.512 ms 9.142 30.23

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 127.127.20.1 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) 0.050 0.260 0.407 0.843 1.216 1.419 11.300 0.809 1.159 0.422 0.849 ms 15.41 257.6

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 127.127.20.2 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) 0.016 0.240 0.381 0.840 1.503 2.077 7.401 1.122 1.837 0.379 0.883 ms 8.633 46.75

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 127.127.22.3 PPS(3)

peer jitter 127.127.22.3 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Refclock RMS Jitter 127.127.22.3 PPS(3) 0.590 10.720 13.010 27.120 89.940 115.500 186.600 76.930 104.780 24.667 36.201 µs 3.036 9.326

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) 0.123 1.126 1.728 3.462 5.763 7.093 11.630 4.035 5.967 1.252 3.578 µs 12.66 42.04

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) 0.157 0.434 0.591 1.399 4.353 6.317 12.680 3.762 5.883 1.278 1.823 µs 3.252 12.49

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 128.59.0.245

peer jitter 128.59.0.245 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 128.59.0.245 0.298 0.759 1.090 2.590 4.969 5.814 6.907 3.879 5.055 1.205 2.831 ms 7.016 19.78

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 17.253.14.125

peer jitter 17.253.14.125 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 17.253.14.125 0.347 0.793 1.165 2.109 3.661 5.084 6.695 2.496 4.291 0.814 2.195 ms 11.42 43.07

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 17.253.20.125

peer jitter 17.253.20.125 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 17.253.20.125 0.085 0.124 0.198 0.614 2.426 3.580 3.972 2.228 3.456 0.703 0.833 ms 2.833 10.38

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 2001:470:0:2c8::2 (clock.nyc.he.net)

peer jitter 2001:470:0:2c8::2 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 2001:470:0:2c8::2 (clock.nyc.he.net) 0.031 0.072 0.129 0.414 1.111 1.857 3.194 0.983 1.785 0.360 0.500 ms 3.628 18.05

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 209.87.233.53

peer jitter 209.87.233.53 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 209.87.233.53 1.840 2.882 4.422 7.244 11.300 12.380 17.560 6.878 9.498 2.126 7.520 ms 24.29 87.31

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 15.068 15.206 15.320 17.453 21.670 22.716 23.512 6.350 7.510 1.976 17.820 ppm 540.6 4548
Local Clock Time Offset -1,216.000 -6.724 -4.130 0.100 3.584 5.844 1,235.000 7.714 12.568 11.747 0.008 µs -3.262 6191
Local RMS Frequency Jitter 3.000 7.000 12.000 44.000 134.000 202.000 619.000 122.000 195.000 41.852 54.483 ppb 3.175 15.99
Local RMS Time Jitter 0.000 0.314 0.651 14.260 20.930 24.140 1,413.000 20.279 23.826 7.324 13.752 µs 98.97 1.867e+04
Refclock Offset 127.127.20.0 NMEA(0) -83.230 -38.400 -20.270 25.190 63.490 77.150 113.400 83.760 115.550 25.520 23.970 ms -0.4415 2.993
Refclock Offset 127.127.20.1 NMEA(1) -26.700 -14.390 -12.980 -7.236 19.280 20.540 25.920 32.260 34.930 14.078 3.055 ms -2.81 5.051
Refclock Offset 127.127.20.2 NMEA(2) -7.918 -2.996 -1.267 3.212 7.435 9.242 12.880 8.702 12.238 2.643 3.168 ms 0.572 3.186
Refclock Offset 127.127.22.3 PPS(3) -1.704 -1.472 -1.121 0.088 1.250 1.597 1.797 2.371 3.069 0.725 0.030 ms -3.711 8.523
Refclock Offset 127.127.46.1 GPS(1) -1,236.000 -32.790 -29.420 -20.790 -10.220 -4.748 863.000 19.200 28.042 51.224 -17.306 µs 8.241 188.4
Refclock Offset 127.127.46.2 GPS(2) -1,208.000 -0.776 0.187 7.582 16.110 22.470 894.500 15.923 23.246 51.080 11.062 µs 11.73 215.2
Refclock RMS Jitter 127.127.20.0 NMEA(0) 0.008 1.466 2.374 5.301 9.338 11.810 24.620 6.964 10.344 2.169 5.512 ms 9.142 30.23
Refclock RMS Jitter 127.127.20.1 NMEA(1) 0.050 0.260 0.407 0.843 1.216 1.419 11.300 0.809 1.159 0.422 0.849 ms 15.41 257.6
Refclock RMS Jitter 127.127.20.2 NMEA(2) 0.016 0.240 0.381 0.840 1.503 2.077 7.401 1.122 1.837 0.379 0.883 ms 8.633 46.75
Refclock RMS Jitter 127.127.22.3 PPS(3) 0.590 10.720 13.010 27.120 89.940 115.500 186.600 76.930 104.780 24.667 36.201 µs 3.036 9.326
Refclock RMS Jitter 127.127.46.1 GPS(1) 0.123 1.126 1.728 3.462 5.763 7.093 11.630 4.035 5.967 1.252 3.578 µs 12.66 42.04
Refclock RMS Jitter 127.127.46.2 GPS(2) 0.157 0.434 0.591 1.399 4.353 6.317 12.680 3.762 5.883 1.278 1.823 µs 3.252 12.49
Server Jitter 128.59.0.245 0.298 0.759 1.090 2.590 4.969 5.814 6.907 3.879 5.055 1.205 2.831 ms 7.016 19.78
Server Jitter 17.253.14.125 0.347 0.793 1.165 2.109 3.661 5.084 6.695 2.496 4.291 0.814 2.195 ms 11.42 43.07
Server Jitter 17.253.20.125 0.085 0.124 0.198 0.614 2.426 3.580 3.972 2.228 3.456 0.703 0.833 ms 2.833 10.38
Server Jitter 2001:470:0:2c8::2 (clock.nyc.he.net) 0.031 0.072 0.129 0.414 1.111 1.857 3.194 0.983 1.785 0.360 0.500 ms 3.628 18.05
Server Jitter 209.87.233.53 1.840 2.882 4.422 7.244 11.300 12.380 17.560 6.878 9.498 2.126 7.520 ms 24.29 87.31
Server Offset 128.59.0.245 -12.560 -6.933 -3.238 0.964 6.476 9.552 12.840 9.714 16.485 2.946 1.149 ms -2.018 7.537
Server Offset 17.253.14.125 -9.537 -5.467 -2.364 1.134 5.827 12.640 18.560 8.191 18.107 2.723 1.407 ms -0.4789 9.091
Server Offset 17.253.20.125 -3.451 -0.492 0.535 3.128 6.498 10.010 15.600 5.963 10.502 1.917 3.260 ms 3.726 14.63
Server Offset 2001:470:0:2c8::2 (clock.nyc.he.net) -2.248 -1.144 0.269 2.311 4.586 5.547 14.050 4.317 6.691 1.381 2.310 ms 3.073 14.18
Server Offset 209.87.233.53 -23.820 -20.190 -14.640 -1.222 9.080 14.550 16.380 23.720 34.740 6.599 -1.540 ms -5.985 17.38
TDOP 0.400 0.470 0.510 0.640 0.930 1.160 2.660 0.420 0.690 0.138 0.670 70.75 346.7
Temp LM0 54.100 55.000 55.700 57.500 61.000 62.300 63.700 5.300 7.300 1.652 57.833 °C
nSats 13.000 16.000 17.000 21.000 24.000 26.000 28.000 7.000 10.000 2.200 20.915 nSat 641.3 5675
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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