Without Active Directory service integration, authentication is performed through an internal Metasys login process against a local Security database. With Active Directory service integration, authentication is performed for Active Directory service users against an Active Directory service authority called a Domain Controller. If you are logged in to the operating system with an Active Directory service user account that is privileged on the Metasys system, you proceed directly to the main Metasys SMP UI screen without stopping at the login screen. The Metasys system provides this SSO function for any Active Directory service user who is also a Metasys system user, regardless of how they accessed the Site Director (either locally at the Site Director computer itself or remotely from a client machine that is directly addressable on the network).