Power over Ethernet
Power over Ethernet Standards and Development
Power over Ethernet (PoE) standards have evolved over the years with the IEEE standardizing techniques for PoE transmission since 2003. The development of PoE standards such as IEEE 802.3af-2003, IEEE 802.3at-2009 (PoE+), and IEEE 802.3bt-2018 (PoE++) has significantly increased power capabilities, allowing for applications like high-performance Wireless Access Points (WAPs) and surveillance cameras. The latest standard, 802.3bt, even supports higher data rates like 2.5GBASE-T, 5GBASE-T, and 10GBASE-T.
Power over Ethernet Implementation and Configuration
Power over Ethernet is typically implemented based on IEEE 802.3af-2003 or IEEE 802.3at standards, with three available modes: A, B, and 4-pair. Configuration is done through Ethernet layer 2 Link Layer Discovery Protocol (LLDP) for power negotiation. The PoE link stages include detection, classification, startup, and operation, where power levels and classifications determine the power requirements for connected devices.
Power over Ethernet Uses and Powered Devices
Power over Ethernet is commonly used to power devices such as VoIP phones, IP cameras, Wireless Access Points (WAPs), industrial control systems, and access control components. A powered device (PD) consumes energy from PoE, but many PDs also have auxiliary power connectors for external supply. The power supplied to PDs varies, and they can differ in the amount of power received from auxiliary ports.