Application And Optimization Of Multicast In Distance Education System

Modern distance education system combines the knowledge of digital, network communications, multimedia, and computer technology. The architecture of current distance education system is concentration and IP unicast, which restricts its development. To reduce these shortcomings, this paper puts forward a systematic model of distance education system by making use of IP multicast. And excogitates a series of methods to solve and optimize some new problems due to IP multicast. In this paper, a new way has been inaugurated for the development of distance education system. Firstly, through our analyzing the problems of current distance education system, a blue print based on IP multicast has been designed in this paper, including both non-real-time and real-time. Further more, the realization method of IP multicast has been described in detail. Then, in the field of non-real-time system, the multicast-based scheduling policy and its optimization have been researched. Through our analyzing popular policies, a multicast-based scheduling policy has been put forward in this paper, which gives attention to many factors including quit ratio, fashion degree, wait-time and so on. In the field of real-time system, congestion control algorithm for IP multicast has been lucubrated. After our researching current popular congestion control algorithms, a congestion control algorithm for multimedia layered multicast has been put forward, which adapts to the peculiarity and request of real-time distance education system. The innovations of this paper lies in,on the one hand, putting forward a design pattern of distance education system based on IP multicast, on the other hand, putting forward optimize and solve methods in detail to the problems of multicast-based delivery policies and congestion control algorithm for IP multicast, and proving their validity, which reduces obstructions for the development of distance education systems.