Multi-Constrained QoS Multi-Cast Routing Optimization And Simulation

With the expansion of the Internet real-time distributed stream media and video application such as video conference, video on demand and remote education, the QoS multicast technology has been getting more and more attention. IP multicast is a mechanism which can supports multi-point communication efficiently. It utilizes a tree delivery structure, on which data packets are duplicated only at fork nodes and are forwarded only once over each link. This approach makes IP multicast resource-efficient in delivering data to a group of members simultaneously and scalable in supporting very large multicast groups. The QoS multicast is the special multicast which should guarantee some QoS constraints such as bandwidth ,delay and packet loss rate, et al. So QoS multicast is the important basis of high- bandwidth and shared Internet applications,such as stream media and video.Recent research showes that the multicast routing algorithm plays a very important role in the network quality of service guarantee and that the research on QoS multicast routing algorithm has become a hotspot in the network research area. In the previous research , QoS multicast routing problem is usually attributed to the minimum cost steiner tree problem with some constraints which has been proved to be NP-Complete. So the QoS multicast routing problem has no solution method within polynomial time and often been solved with heuristic algorithms. With the increasing demand for the network QoS and the increasing network scale, it is very important and also significative that we do some researches on the QoS multicast routing algorithm with multi-constraints in order to attain nice quality of network service and better utilization of the network resource.In this paper, three different algorithms are proposed to solve the QoS multicast routing problem after achieving extensive and intensive research on the area of solving multicast routing problem using ant colony algorithm.They are called ACA-O, AC AT and ACAT-0 seperately:(1)Ad Hoc network are obtaining more and more attention due to its excellent characteristics and special application. This paper proposes the concept of "orientation factor" on the basis of analyzing the statistic characteristic of the Ad Hoc network, the wide application of GPS technology and the essentiality of ant colony algorithm. Then a new algorithm called ACA-0 (Ant Colony Algorithm considering Orientation) is designed and realized by applying orientation factor to ant colony algorithm, which is aimed to solve the QoS multicast routing problem in the Ad Hoc network. In the algorithm of ACA-O, orientation factor affects the searching behavior of the ants, leads the ants to reach the destination more rapidly and make the algorithm convergerapidly.The simulation results show that the algorithm ACA-0 can get better solution with less time,less packets and less energy.(2)Another algorithm called ACAT(Ant Colony Algorithm based on Tree) is proposed to solve multicast routing problem. Comparing the traditional fashion of combining the paths into a tree, AC AT generates the tree using the fashion of growing tree directly, simplifies the process of searching for multicast tree and improves the efficiency of algorithm.(3)Considering the multicast routing characteristic in the Ad Hoc network, we proposes a new algorithm called ACAT-O(ACAT considering Orientation) by adding new version of the orientation factor to ACAT The new orientation factor can leads the tree to "grow" in the shape of radiation, restrains the "reverse growing" of tree and improves the efficiency of algorithm furtherly. Simulation results proves that comparing with ACAT, ACAT-O can converge more rapidly with a good solution in terms of the Ad Hoc network topology.