If the server is connected directly or indirectly to the public Internet, there is some danger that it can adversely affect the operation of unrelated clients.
Carefully read the Undisciplined Local Clock page and respect the stratum limit.
Ordinarily, the NTP selection algorithm chooses the best from among all sources, usually the best radio clock determined on the basis of stratum, synchronization distance and jitter.
The calibration function adjusts the values for all clock drivers are adjusted.
Some drivers depending on longwave and shortwave radio services need to know the radio propagation time from the transmitter to the receiver, which can amount to some tens of milliseconds.
This must be calculated for each specific receiver location and requires the geographic coordinates of both the transmitter and receiver.
Support for PPS signals is summarized in the Pulse-per-second (PPS) Signal Interfacing page.org Documentation Manpages GNU Info Debian document tree Whole document tree Trigance web page Public services User info Mailing lists Secure server Multilingual usage Copyright (C) 2000-2012 Philippe Troin program manual page.The following discussion presents Information on how to select and configure the device drivers in a running Unix system.Most of these clocks require support in the form of a serial port or special bus peripheral, but some can work directly from the audio codec found in some workstations.The particular device is normally specified by adding a soft link correspond to the unit number above.
Where the highest performance is required, generally better than one millisecond, additional hardware and/or software functions may be required.