NTPsec

Pi4/Uputronics

Report generated: Wed Feb 8 09:03:08 2023 UTC
Start Time: Tue Feb 7 09:03:04 2023 UTC
End Time: Wed Feb 8 09:03:04 2023 UTC
Report Period: 1.0 days
Warning: plots clipped

Daily stats   Weekly stats   24 Hour Scatter Plots: ( 1   2   )

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 -93.598 -73.725 -17.629 -0.783 41.836 89.322 112.194 59.465 163.047 20.936 2.279 µs -2.243 13.52
Local Clock Frequency Offset -2.996 -2.971 -2.859 -1.936 -0.061 0.238 0.411 2.798 3.209 0.754 -1.855 ppm -50.62 203

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 0.083 0.125 0.151 0.288 5.363 7.712 11.519 5.212 7.587 1.757 1.099 µs 1.19 5.462

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 0.054 0.111 0.191 1.014 12.957 21.310 25.536 12.766 21.199 4.344 2.772 ppb 1.663 7.816

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 -93.598 -73.725 -17.629 -0.783 41.836 89.322 112.194 59.465 163.047 20.936 2.279 µs -2.243 13.52

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 -2.996 -2.971 -2.859 -1.936 -0.061 0.238 0.411 2.798 3.209 0.754 -1.855 ppm -50.62 203
Temp ZONE0 46.160 47.236 47.236 50.464 66.604 69.832 70.908 19.368 22.596 5.435 52.168 °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 7.000 8.000 9.000 12.000 16.000 17.000 18.000 7.000 9.000 1.902 12.458 nSat 187.6 1136
TDOP 0.490 0.560 0.610 0.840 1.270 1.660 3.720 0.660 1.100 0.237 0.886 30.62 134.2

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.



Server Offset 2001:470:e815::23 (pi3.rellim.com)

peer offset 2001:470:e815::23 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 2001:470:e815::23 (pi3.rellim.com) -128.156 -126.437 -77.658 -0.056 94.138 126.072 173.037 171.796 252.509 50.738 0.796 µs -3.64 9.14

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:e815::8 (spidey.rellim.com)

peer offset 2001:470:e815::8 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 2001:470:e815::8 (spidey.rellim.com) -0.970 -0.930 -0.822 0.064 0.942 1.198 1.292 1.764 2.128 0.493 0.078 ms -3.173 7.651

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 204.17.205.1

peer offset 204.17.205.1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 204.17.205.1 -1.335 -1.249 -1.104 -0.003 0.578 0.733 0.813 1.682 1.983 0.428 -0.012 ms -5.293 16.49

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 204.17.205.17

peer offset 204.17.205.17 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 204.17.205.17 -262.533 -233.897 -113.447 2.948 88.450 140.240 227.233 201.897 374.137 68.288 -2.625 µs -4.687 14.3

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 204.17.205.27

peer offset 204.17.205.27 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 204.17.205.27 -187.172 -115.510 -78.953 -8.608 70.915 117.071 138.165 149.868 232.581 45.265 -7.656 µs -5.036 13.72

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 204.17.205.30

peer offset 204.17.205.30 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 204.17.205.30 -247.807 -199.693 -114.862 -21.380 72.188 138.437 202.151 187.050 338.130 61.369 -21.959 µs -6.76 19.96

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 2606:4700:f1::123 (time.cloudflare.com)

peer offset 2606:4700:f1::123 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset 2606:4700:f1::123 (time.cloudflare.com) 0.550 0.732 0.851 1.252 1.654 1.876 2.284 0.803 1.144 0.253 1.242 ms 72.11 335.6

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 SHM(0)

peer offset SHM(0) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset SHM(0) -64.529 -32.142 -25.966 -16.380 -12.646 -11.353 -8.099 13.320 20.789 4.608 -17.541 ms -127.6 726.3

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 SHM(1)

peer offset SHM(1) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Offset SHM(1) -93.599 -73.725 -17.630 -0.784 41.837 89.323 112.195 59.467 163.048 20.937 2.279 µs -2.243 13.52

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.



Server Jitter 2001:470:e815::23 (pi3.rellim.com)

peer jitter 2001:470:e815::23 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 2001:470:e815::23 (pi3.rellim.com) 4.806 8.087 10.056 32.477 101.297 144.319 148.115 91.241 136.232 28.857 40.329 µs 2.623 7.82

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 2001:470:e815::8 (spidey.rellim.com)

peer jitter 2001:470:e815::8 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 2.651 5.117 8.958 26.567 75.302 98.072 2,434.368 66.344 92.955 96.918 36.367 µs 21.41 525.7

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 204.17.205.1

peer jitter 204.17.205.1 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 204.17.205.1 3.166 3.839 6.227 22.013 69.615 91.957 152.976 63.388 88.118 20.431 27.966 µs 2.715 9.615

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 204.17.205.17

peer jitter 204.17.205.17 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 204.17.205.17 0.000 5.076 7.448 22.969 84.538 99.040 124.495 77.090 93.964 24.217 31.927 µs 2.205 6.008

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 204.17.205.27

peer jitter 204.17.205.27 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 204.17.205.27 2.209 3.737 5.928 20.491 77.882 101.775 152.696 71.954 98.038 23.041 29.009 µs 2.271 7.282

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 204.17.205.30

peer jitter 204.17.205.30 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 204.17.205.30 2.534 3.589 6.182 23.349 75.655 103.212 143.395 69.473 99.623 22.646 30.206 µs 2.504 8.058

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 2606:4700:f1::123 (time.cloudflare.com)

peer jitter 2606:4700:f1::123 plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter 2606:4700:f1::123 (time.cloudflare.com) 0.247 0.273 0.373 0.762 1.489 20.819 27.899 1.116 20.546 2.822 1.196 ms 5.298 42.05

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 SHM(0)

peer jitter SHM(0) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter SHM(0) 0.149 0.389 0.552 1.815 8.174 12.873 39.225 7.622 12.485 2.901 2.881 ms 3.338 25.31

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.



Server Jitter SHM(1)

peer jitter SHM(1) plot

Percentiles...... Ranges...... Skew- Kurt-
Name Min1%5%50%95% 99%Max   90%98%StdDev  MeanUnits nessosis
Server Jitter SHM(1) 0.047 0.099 0.148 0.735 19.105 35.211 53.480 18.957 35.112 6.798 3.201 µs 1.76 10.41

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 -2.996 -2.971 -2.859 -1.936 -0.061 0.238 0.411 2.798 3.209 0.754 -1.855 ppm -50.62 203
Local Clock Time Offset -93.598 -73.725 -17.629 -0.783 41.836 89.322 112.194 59.465 163.047 20.936 2.279 µs -2.243 13.52
Local RMS Frequency Jitter 0.054 0.111 0.191 1.014 12.957 21.310 25.536 12.766 21.199 4.344 2.772 ppb 1.663 7.816
Local RMS Time Jitter 0.083 0.125 0.151 0.288 5.363 7.712 11.519 5.212 7.587 1.757 1.099 µs 1.19 5.462
Server Jitter 2001:470:e815::23 (pi3.rellim.com) 4.806 8.087 10.056 32.477 101.297 144.319 148.115 91.241 136.232 28.857 40.329 µs 2.623 7.82
Server Jitter 2001:470:e815::8 (spidey.rellim.com) 2.651 5.117 8.958 26.567 75.302 98.072 2,434.368 66.344 92.955 96.918 36.367 µs 21.41 525.7
Server Jitter 204.17.205.1 3.166 3.839 6.227 22.013 69.615 91.957 152.976 63.388 88.118 20.431 27.966 µs 2.715 9.615
Server Jitter 204.17.205.17 0.000 5.076 7.448 22.969 84.538 99.040 124.495 77.090 93.964 24.217 31.927 µs 2.205 6.008
Server Jitter 204.17.205.27 2.209 3.737 5.928 20.491 77.882 101.775 152.696 71.954 98.038 23.041 29.009 µs 2.271 7.282
Server Jitter 204.17.205.30 2.534 3.589 6.182 23.349 75.655 103.212 143.395 69.473 99.623 22.646 30.206 µs 2.504 8.058
Server Jitter 2606:4700:f1::123 (time.cloudflare.com) 0.247 0.273 0.373 0.762 1.489 20.819 27.899 1.116 20.546 2.822 1.196 ms 5.298 42.05
Server Jitter SHM(0) 0.149 0.389 0.552 1.815 8.174 12.873 39.225 7.622 12.485 2.901 2.881 ms 3.338 25.31
Server Jitter SHM(1) 0.047 0.099 0.148 0.735 19.105 35.211 53.480 18.957 35.112 6.798 3.201 µs 1.76 10.41
Server Offset 2001:470:e815::23 (pi3.rellim.com) -128.156 -126.437 -77.658 -0.056 94.138 126.072 173.037 171.796 252.509 50.738 0.796 µs -3.64 9.14
Server Offset 2001:470:e815::8 (spidey.rellim.com) -0.970 -0.930 -0.822 0.064 0.942 1.198 1.292 1.764 2.128 0.493 0.078 ms -3.173 7.651
Server Offset 204.17.205.1 -1.335 -1.249 -1.104 -0.003 0.578 0.733 0.813 1.682 1.983 0.428 -0.012 ms -5.293 16.49
Server Offset 204.17.205.17 -262.533 -233.897 -113.447 2.948 88.450 140.240 227.233 201.897 374.137 68.288 -2.625 µs -4.687 14.3
Server Offset 204.17.205.27 -187.172 -115.510 -78.953 -8.608 70.915 117.071 138.165 149.868 232.581 45.265 -7.656 µs -5.036 13.72
Server Offset 204.17.205.30 -247.807 -199.693 -114.862 -21.380 72.188 138.437 202.151 187.050 338.130 61.369 -21.959 µs -6.76 19.96
Server Offset 2606:4700:f1::123 (time.cloudflare.com) 0.550 0.732 0.851 1.252 1.654 1.876 2.284 0.803 1.144 0.253 1.242 ms 72.11 335.6
Server Offset SHM(0) -64.529 -32.142 -25.966 -16.380 -12.646 -11.353 -8.099 13.320 20.789 4.608 -17.541 ms -127.6 726.3
Server Offset SHM(1) -93.599 -73.725 -17.630 -0.784 41.837 89.323 112.195 59.467 163.048 20.937 2.279 µs -2.243 13.52
TDOP 0.490 0.560 0.610 0.840 1.270 1.660 3.720 0.660 1.100 0.237 0.886 30.62 134.2
Temp ZONE0 46.160 47.236 47.236 50.464 66.604 69.832 70.908 19.368 22.596 5.435 52.168 °C
nSats 7.000 8.000 9.000 12.000 16.000 17.000 18.000 7.000 9.000 1.902 12.458 nSat 187.6 1136
Summary as CSV file


This server:

Motherboard: Raspberry Pi 3
OS: Gentoo stable
GPS; Adafruit GPS HAT
GPS/PPS server: gpsd
NTP server: NTPsec
../ntp.conf

Notes:

22:00 29 Nov 2017 SD card crash, start over

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.



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