This counter records the number of times a protection switchover occurred on this Ethernet port during the current interval. A rising count tells the admin that the port's redundancy/protection mechanism is being triggered repeatedly, which could indicate an unstable primary path rather than the occasional legitimate failover. For example, if cmEthernetTrafficPortStatsPSC increments several times in one day, the admin would investigate the primary link for a flapping or intermittent fault rather than assume protection switching is a one-time event.