Date and Time parameters
Digi TransPort User Guide
617
NTP parameters
Use NTP for greater accuracy
Selecting this checkbox expands the page to show the NTP settings, described below.
NTP is much more accurate than SNTP, with NTP an accuracy of 200 microseconds (1/5000
second) can be achieved. The NTP functionality is in accordance with RFC1305.
Up to 4 remote peers can be configured, all the peers are polled at intervals and the best peer
is selected for using as the time source. SNTP should be configured prior to using NTP. The
router calculates the accuracy of the NTP time servers over a period of time, up to 2 hours.
Once the drift compensation is calculated, the NTP client will be used. The drift compensation
value is stored in NVRAM and written to the
config.da0
file. If the router loses power or is
rebooted, it does not need to re-calculate the accuracy of the NTP servers again. The
compensation value is constantly monitored to make sure it remains correct.
Note
Using SNTP achieves an accuracy of around 1 second.
Using NTP achieves an accuracy of 200 microsecond.
Not all models support NTP; this option only appears for models that do.
Initial Drift Compensation n ppm
NTP incorporates compensation for clock drift. If this parameter is known, it can be entered
here. Otherwise, the router calculates this value over a period of time. Once calculated, the
value is displayed in the text box.
Clock Precision Limit
Select the clock precision limit from the drop-down selection box.
Disable NTP when interface x,y is out of service
If the specified interface is out of service, the NTP is disabled until the interface is available
again.
