Diameter Stack is general AAA framework for authentication, authorization, and accounting services which does not belong to a certain application.
Diameter Stack provides benefits such as error handling, message delivery reliability, reliable transport, and security support compared to the RADIUS(Remote Authentication Dial In User Service). It is configured in Peer-to-Peer architecture therefore functioning as a client or server. Unlike the RADIUS configured in Client-to-Server architecture, diameter server can initiate request messages.
Currently, the diameter protocol is widely used in the IMS architecture and supports various applications that require authentication and billing data