This DisplayString field records the wall-clock timestamp at which this bin's counters were last cleared (reset to zero). Because this row is a closed, completed interval from the PTP performance-monitoring history table for this timing session, ClearTime tells you the true starting point of every count in this row — if it shows a recent time, an operator (or a reboot) reset the counters, so any counter that already looks large happened in a short span, not gradually. For example, if ClearTime shows a timestamp from ten minutes ago while a byte counter in the same row already reads several megabytes, that combination tells you the tunnel is carrying a very high rate, not that the counter has simply been accumulating for a long time.