The Research And Simulation Of Special Line On The Internet

With the rapid spreading of the Internet, network has been closely connected with people' s lives and work. With the increasing number of Internet users, more and more relevant problems rise to be solved. Except of the lack of IP addresses, another serious problem is that the quality of service can not be guaranteed yet. The current Internet provides best-effort services. In this service model, all of service traffics fairly occupy network resources, and any reliability and delay for IP packets are not guaranteed.With the development of multimedia services, various network special line services are obviously insufficient for those applications with some special demands such as bandwidth, delay, delay jitter and so on. Hence network QoS guaranteeing becomes a problem that needs to be tackled immediately. Although it is difficult to fulfill QoS all over the world at present, some differential services are possible in a local area even based on TCP/IP.This paper points out that the necessity of limited differential services still exits in spite of the increasing bandwidth today. A flexible and safe HD-EDN(Highest Director-Enterprise Direct Network) special line is presented for differential services, and a fast authentication method is used. This line is designed for important people to transmit important information within a limited region, such as an enterprise. In this paper, firstly, the status of cryptography and related key algorithms, as well as the key management, are discussed. Then the background and definition of VPN(Virtual Private Network), its classification, and its relevant characteristics are introduced. Through the study of the VPN technique, the safety,flexibility and QoS features of the HD-EDN line are analyzed. Detail methods for solving possible problems existed in various sections in the special line are given, the focus is on the guaranteeing of the security and QoS of the special line. Finally, simulation is made with professional OPNET software in order to prove these methods. During the process of simulation, the basic functions of a HD-EDN special line are mostly implemented. Various experimental data are compared, and results apparently show the special line mechanism described above.