General LLDP operating principles

LLDP and LLDP-MED use the services of the Data Link sublayers, Logical Link Control and Media Access Control, to transmit and receive information to and from other LLDP Agents (protocol entities that implement LLDP).

LLDP is a one-way protocol. An LLDP agent can transmit and receive information to and from another LLDP agent located on an adjacent device, but it cannot solicit information from another LLDP agent, nor can it acknowledge information received from another LLDP agent.