Power-over-Ethernet (PoE) allows Ethernet cables to carry both data and electrical power, simplifying deployment of devices like IP phones and access points by eliminating the need for separate power supplies. PoE provides flexibility by allowing devices to be placed anywhere within the reach of an Ethernet cable, improves safety by consolidating wiring, is more eco-friendly by reducing energy usage and waste from power adapters, and offers durable operation by delivering continuous power to devices.