The Research On A NAS Model Based On Diameter Protocol

Authentication, Authorization and Accounting (AAA) protocols such as TACACS and RADIUS were initially deployed to provide dial-up PPP and terminal server access. With the growth of the Internet and the introduction of new access technologies, including wireless, DSL, Mobile IP and Ethernet, routers and network access servers (NAS) have increased in complexity and density, putting new demands on AAA protocols. TACACS and RADIUS protocols are not competent for demands on current AAA services of networks based on IP, especially in NGN era in the future.Taking into account the amalgamation between PSTN, computer network and cable TV network, and the development of Internet, the next generation AAA technology based on IP is needed to solve many existing problems in AAA services. Diameter protocol has been appointed AAA protocol standard by IETF.In this dissertation, the primary work includes:Firstly, the thorough research and analysis of Diameter, EAP and PANA protocols is done. Diameter protocol not only keeps compatibility with RADIUS protocol, but also overcomes many shortcomings of RADIUS protocol. Diameter protocol is adopted not only by Internet, but also by the next generation mobile communication network (3G). EAP provides a peer-to-peer authentication mechanism, which supports various authentication methods and has high expansibility. PANA is a link-layer agnostic transport protocol for EAP to enable network access authentication between clients and access networks.Secondly, the NAS model based on Diameter, EAP and PANA protocols is designed. The model consists of NASREQ and EAP application of Diameter protocol, PAA and EP function of PANA protocol, and authenticator function of EAP protocol.Finally, the NAS prototype system is designed and implemented, and the system is tested. The result proves that the system basically satisfies requirement of a NAS defined by Diameter, EAP and PANA protocols.