Spectracom - Essential Ingenuity

"Ref ID" field for NTP references

Question

Why does the NTP reference ID change from my reference to ".PPS." in the NTP Status page in SecureSync/NetClock SW versions 5.2.0 and earlier? What does ".PPS." indicate?

Answer

The reference ID provided in NTP is intended to provide information on the source of the synchronization time for that system.  For Stratum 2 and higher devices, this will be the IP or hostname of the NTP server connected.  For Stratum 1 devices, the reference ID reports a character string identifying the reference source such as ".GPS." for a GPS reference.  If the SecureSync/NetClock has Stratum 1 operation enabled, an entry for the timing system reference is added to NTP.  In addition to that reference, a higher accuracy Stratum 1 1PPS reference is available that can be enabled separately.

Newer (black/charcoal background) web browser in software versions 5.1.2 and above
.gps

"Classic interface" (gray background) web browser
User-added image

If Stratum 1 Operation and Stratum 1 1PPS are both enabled, there are some impacts to the reference ID reported by NTP in SecureSync/NetClock SW versions 5.2.0 and earlier.  As NTP begins to synchronize to the system reference, either at startup or after a period of reference loss, NTP will use the standard timing reference.  After synchronizing to that reference, NTP will reports it's reference ID as the appropriate ID for that reference.  After that synchronization, it will transition to synchronizing to the 1PPS reference.  

Newer (black/charcoal background) web browser in software versions 5.1.2 and above
.pps


"Classic interface" (gray background) web browser
User-added image

Once it transitions to the 1PPS reference, NTP will now report the ID of the 1PPS reference instead, which is ".PPS.".  This has led to some confusion.  To determine the actual reference to the system, a user would need to look at the system reference ID reported by NTP.  Starting in SecureSync/NetClock SW version 5.2.1, when the transition occurs, the reference ID will be corrected to the system reference ID, so that NTP will report the actual reference.
 

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