Preliminary Synchronization

Preliminary synchronization is a stage during which the system evaluates the initial time situation and decides how to proceed with longer-term synchronization. This stage involves the following steps:

1. The system obtains several readings of time data from NTP servers.
2. The system analyzes time data in the messages and compares the readings from different servers. Using this information, the system identifies the initial best time source (the best server).
3. The system calculates the difference between its own clock and the best server’s clock (the offset) and proceeds as follows:
   • If the offset is greater than 15 minutes, the system disables NTP and displays a message advising you to check the time zone and clock settings.
   • If the offset is less than 15 minutes, the system sets its clock to that of the best server.
4. Provided the system has not disabled NTP, it proceeds to the next stage:
   • If a frequency calibration is available, the system starts progressive synchronization.
   • If the system has never performed a frequency calibration or the calibration has been deleted, the system starts a frequency calibration.

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