This read-only counter increments every time this PVC's link goes down for at least one second, and the description notes that if the circuit is not restored within the configured LINK TIMEOUT, the unit logs a LINK PVC DOWN alarm. An administrator watches it to catch circuits that are flapping even if they recover quickly enough to avoid triggering a full alarm. For example, a PVC with a growing statPvcRestart count but no LINK PVC DOWN alarms would tell the administrator the circuit is repeatedly bouncing just under the alarm threshold.