LDP (Label Distribution Protocol) advertises labels per Forwarding Equivalence Class (FEC), which means it associates particular labels with specific paths or groups of paths that data packets may travel. It also uses Forwarding Equivalence Classes, which are groups of IP packets that are forwarded in the same manner, over the same path, and with the same forwarding treatment. Therefore, the functions of LDP include both advertising labels per FEC and utilizing FECs.