RADIUS
Remote Authentication Dial-In User Service
Remote Authentication Dial-In User Service is a system of distributed security that secures remote access to networks and network services against unauthorized access. RADIUS includes the authentication server which is installed on a central computer within the network core and the client protocols used to access the server. RADIUS is designed to simplify the security process by separating security technology from communications technology. RADIUS servers are deployed extensively in support of DSL services and mobile broadband architectures, although there are many more instances of RADIUS usage for AAA.