2.1 Overview

RADIUS (Remote Authentication Dial In User Service) is an Authentication, Authorization and Accounting (AAA) protocol that is a predecessor to Diameter. RADIUS is still widely in use, especially in WLAN networks and even some 3G mobile data applications. DSR will be deployed in networks requiring support for both Diameter and RADIUS nodes as well in RADIUS-only networks.

RADIUS has some similarities to Diameter, but is significantly different in many ways. RADIUS is primarily supported on DSR by a new connection layer called the RADIUS Connection Layer (RCL), while using the existing routing services of the Diameter Routing Layer (DRL) and the existing Diameter-based message interface to/from the DRL.

• Ingress RADIUS Request/Response messages are encapsulated in Diameter Request/Answer messages respectively. Diameter Request message content is created by RCL based on a set of predefined rules using both configuration data and RADIUS message content. Diameter Answer message content is created by RCL based on a set of predefined rules using mostly the Diameter Request message content associated with the transaction.
• Because RADIUS Request message routing is based upon the associated Diameter Request message which encapsulates the RADIUS message, the user must be intimately familiar with the how the Diameter Request capsule is created so they can properly configure the DRL to route RADIUS Request messages.
• DRL provides required information to RCL to allow forwarding of RADIUS messages to the peer
• The RCL prevents accidental routing of non-RADIUS messages to a RADIUS connection due to misconfiguration.