| As Internet develops rapidly, the number of Internet users grows quickly. Managing large numbers of users can create the need for significant administrative support. Besides, ISPs require careful attention to users access authorization, usage accounting, billing and charging to gain operating earning. These bring forward users access management and billing issues.The kernel of users access management is AAA (Authentication,Authorization,Accounting), which realize identification of access users, as well as authorize network resource and services to them and record their network usage.Now the main implementation way of AAA is Radius. Radius (Remote Authentication Dial In User Service) is a dial in user authentication protocol. Doing research on Radius, develops and re-develops it has great meaning. There are currently many free software releases of Radius implementation, such as FreeRADIUS. But these open sources have many shortcomings in business application. Therefore, re-development of Radius makes sense. Although Radius has been running on Internet for many years, it hasn't come into being a standard. On the one hand, the development of Internet technologies calls for new requests to AAA protocols. On the other hand, Radius protocol itself still needs to be improved. In this article, AAA architecture will be discussed. Then on the base of FreeRADIUS release, the software implementation is extended and polished up.The article is part of a concrete project. The whole project is to develop an AAA system, which satisfies the demand of IP access network. Firstly, the requirements of AAA system are discussed and preliminary design of the system is given. Then among at FreeRADIUS, composing modules are decomposed and modules functions are interrelated. Interfaces between modules and database structure are designed as well. Then in the following section, detailed implementation way of Radius server is described, including data process flow, system security, redundancy and fault-tolerance, system exceptional handle, system management platform, end users deal interface. In the end, tests of AAA system functions and performance are given and results are educed.The emphasis of this article is how to improve the data process flow of Radius server and how to improve database structure, so that the whole server will has a high process speed. Furthermore, to enhance the security level of the system is an important part of this article. |
