The RADIUS (Remote Authentication Dial-In User Service) networking protocol supports Authentication, Authorization, and Accounting (AAA) management for users. One of the Internet Engineering Task Force (IETF) standards, RADIUS is a client/server protocol that manages network access.
The RADIUS protocol uses access credentials (like a username and password) to authenticate and authorize (via a RADIUS server) access to the requested network for a user or an equipment. After the access request is accepted, an Accounting Start message is transmitted by the network access server (NAS) to the RADIUS server to indicate the start of the network access for the user or equipment.
When the user or equipment closes the network session, the NAS sends an Accounting Stop message to the RADIUS server including information for billing, like usage time and packets/data transferred.
The Policy Management system uses the RADIUS protocol to connect PGW-to-DPI and subscriber profile repositories.