PROPOSED REQUIREMENT: If the VNF or PNF is using Certificate Authentication, the VNF or PNF MUST support mutual TLS authentication and the Subject Name in the end-entity certificate MUST be used according to RFC 5280.
Note: In mutual TLS authentication, the client (VNF or PNF) must authenticate the server (DCAE) certificate and must provide its own X.509v3 end-entity certificate to the server for authentication.

REASON: Add NF requirements for Certification Authentication for HTTPS.  Certificates are more secure and more scalable.