PoE++ is a high-power version of Power over Ethernet. It lets a switch send both network data and much more electrical power over the same Ethernet cable, enough for devices such as wireless access points, IP cameras, sensors, and some access-control hardware. Compared with lower-power PoE standards, PoE++ is designed for endpoints that need a larger power budget to operate reliably.
In cyber security, PoE++ matters because it can keep critical infrastructure alive even when separate power sources are unavailable, and it can also create hidden failure points. A switch may still forward traffic while its PoE++ function is degraded, leaving powered devices offline without an obvious link failure. Attackers may target PoE infrastructure to disrupt cameras or access points, while defenders monitor PoE status, power draw, and port behavior to detect faults, overloads, or tampering.