Which protocol does an access point use to obtain power information from a connected switch?

Cisco Discovery Protocol (CDP) is a proprietary Layer 2 protocol used by Cisco devices to share information about themselves with other directly connected Cisco equipment. This includes details like device type, capabilities, and, crucially for access points, power requirements for Power over Ethernet (PoE). An access point uses CDP to advertise its power needs to a connected Cisco switch, allowing the switch to allocate the correct amount of power. Internet Group Management Protocol (IGMP) is used for managing multicast group memberships. Adaptive Wireless Path Protocol (AWPP) is a routing protocol used in some wireless mesh networks, not for power negotiation. Neighbor Discovery Protocol (NDP) is an IPv6 protocol used for address resolution, router discovery, and other functions, similar to ARP in IPv4, but not for PoE power negotiation.