This Recommendation is intended to promote interoperability among TMN elements that use Public Key Infrastructure (PKI) to support security-related functions. It applies to all TMN interfaces and applications. It is independent of which communications protocol stack or which network management protocol is being used. PKI facilities can be used for a broad range of security functions, such as, authentication, integrity, non-repudiation, and key exchange (ITU-T M.3016). However, this Recommendation does not specify how such functions should be implemented, with or without PKI.