ptp-clock-holdover-note.adoc

Note

During holdover, the T-GM or T-BC uses the internal system clock to continue generating time synchronization signals as accurately as possible based on the last known good reference. You can set the time holdover specification threshold controlling the time spent advertising ClockClass values 7 or 135 to 0 so that the T-GM or T-BC advertises a degraded ClockClass value directly after losing traceability to a PRTC. In this case, after initially advertising ClockClass values between 140–165, a clock can still be within the holdover specification.

For more information, see "Phase/time traceability information", ITU-T G.8275.1/Y.1369.1 Recommendations.