Cdn Backbone Multicast Routing Optimazation And Simulation Based On Artificial Immune Algorithm

With the explosive development of the Internet and users, people become more and more reliable on multimedia applications to get information. The multimedia streaming system represented by IPTV has been projected as "killer-app" for the Internet now, and people can access the media content from the Internet anytime and anywhere. Streaming the media content to a large number (usually millions) of people stably and continuously has become a hot research topic no matter in academia or in industry.There are two alternative technologic ways for delivering media content to end users:one way is CDN (Content Delivery Network), and the other way is multicast networks, and each has its inherent advantage and disadvantage. CDN deploys many edge servers around the country or the world, and it enables the media content provider to deal with much larger user requests, the end users to get the content through the shortest packet delivery paths from appropriate edge servers, and the ISPs to avoid congestion in backbone. Since there are many edge servers in CDN, the operation cost is also very high; and because of its traditional client-server approaches, it cannot efficiently solve the problem of scalability and address the flash crowd phenomena, especially in live streaming systems. In multicast networks, media content can be shared among users by means of replication, which allows the network to obtain higher scalability while keeping a small server load. However, the establishment in the application layer multicast packet forwarding rules from the network layer does not consider the topology of the network, therefore, the application layer multicast in delay performance is poor; what’s more, due to the repeated transfer factors, the application layer multicast will add extra burden to the network layer, in this way. the network quality of service (QoS) is difficult to guarantee.Based the basis of in-depth study of multicast technology and CDN technology, we propose an IPTV transmission network combining multicast and CDN technology, it incorporates the advantages of both CDN and multicast technology, and at the same time make up for their shortcomings as we use artificial immune algorithm to optimize the transmission system of the QoS, and designs an improved artificial immune algorithm which can adapt to different sizes of topology, automatically adjust the parameters, no longer rely on artificial selection.(1) For IPTV streaming media real-time transmission is high, but multicast algorithm convergence time is relatively long in large-scale topological problems, we introduce artificial immune algorithm in optimization of multicast routing, a multicast routing optimization algorithm based on artificial immune algorithm with typical multicast tree construction algorithm, the proposed algorithm is based on the multicast tree merge and transformation to achieve the result of evolution, which will greatly reduce the convergence time of the algorithm. It can be proved by a large number of experiments, artificial immune routing algorithm has a good adaptability in large topologies.(2) For different topology size, classic algorithms depend entirely on the choice of parameters in a large number of artificial adjustments. We introduce swarm optimization algorithm based on the artificial immune algorithm, through the particles search, the parameter can be adaptive to current topology size, in this way to aid the immune algorithm converge to the optimal solution.