This technology is referred to as PD Alive Check, PD Device Alive Check, Powered Device Monitor or PoE Watchdog. At the core of each, regardless of the specifics of the implementation by different switch manufacturers and chipset vendors, is the same basic function: Monitor connected PoE devices and, if they stop responding, power cycle the PoE device by briefly cutting power to it and forcing it to restart. After the restart, the PoE device will function again without the intervention of the network technician.