Mahmoud wants to implement an AAA service. Which of the following services should he apply?

Remote Authentication Dial-in User Service (RADIUS) provides authentication, authorization, and accounting, which make up the three critical elements in AAA systems. OpenID is a protocol for authentication but does not provide authorization by itself. Lightweight Directory Access Protocol (LDAP) is a directory service, and Security Assertion Markup Language (SAML) is a markup language for making security assertions.