VersaSync's NTP Service needs to be setup such that it utilizes the time source ("input reference") you want it to use. There are two options for an NTP Server to derive its time from:
- The NTP Service uses VersaSync's System TimeSystem Time is the time derived from the internal Timing System. The Timing System is the time server's central time processing engine. It consumes and processes time and 1PPS obtained from an external input reference e.g., typically GNSS., i.e. typically the GNSS reference (or IRIG, ASCII data input, etc.), and distributes that time over the NTP network. This is called Stratum 1 Operation, because VersaSync will be the Stratum 1 (or primary) server. This is the most common configuration.
- It is, however, also possible for NTP to utilize the time provided by another NTP Server as a reference. In this case the other server would be Stratum 1, and VersaSync would be Stratum 2 (or higher). This operating mode can be referred to as Stratum 2 operation, secondary server operation, or NTP Stratum Synchronization.
With a GNSS-capable time server it is possible to combine these two configurations e.g., by assigning a higher reference priority to (a.), and a lower "fallback" priority to (b.). For more information on reference priority configuration, see Configuring Input Reference Priorities.