Radius Overview

Remote Authentication Dial-In User Service (Radius) refers to protocols, standards, clients and servers used to provide central Authentication, Authorization and Accounting (AAA) services for computer networks.

Authentication verifies a user’s identify whereas Authorization determine what rights, actions or service are allowed for a user. In order to utilize Radius, devices in a network must support Radius (include a Radius client). This is most often done in customer premise equipment (CPE) or in the case of wireless Internet, at the Access Point.

https://en.wikipedia.org/wiki/RADIUS