LLDP is the acronym for Link Layer Discovery Protocol, an open and vendor-neutral protocol that is part of the Internet Protocol Suite used in IEEE 802 (specifically, it's defined by standard IEEE 802.1AB). This protocol allows devices on a local network, mainly wired Ethernet, to communicate their identities and characteristics.

LLDP has the same features of othery proprietary protocols like CDP by Cisco or LLTD by Microsoft.