The Research Of Application Layer Multicast Routing Algorithm Based On Bacterial Foraging Optimization

With the developing of multimedia, communication and storage technology, various new applications and diversified business appeared in the Internet. The integration of IT and other fields attracted more massive online population, which put increasing pressure on the computer networks. Especially the businesses which have a high requirement for bandwidth and delay like the teleconferencing, live online and real-time monitoring, need more efficient network technology. Theoretically the IP multicast can effectively ease the pressure on network, it was considered as a good solution to solve the real-time multi receiving point of large flow data transmission, but its limitations in expansion, hardware upgrading, billing and security made it failed to be the mainstream scheme. However, the idea of multicast is reasonable, the present situation of network demands such services, so researchers proposed application layer multicast scheme.In application layer multicast scheme, network layer routers still follow the basic function of unicast. The end hosts burden duplication and forwarding of data stream and all the QoS functions, which surfer large pressure. So in the multicast tree building stage, the delay and cost need optimized as well as the degree constraint, in this case, the key point in application layer multicast scheme is to design a minimum spanning tree with the delay and degree constrained. This is a proven NP-C problem, so we consider using intelligent algorithm to solve the problem, which is the main focus of this research.This paper focuses on the research of bacterial foraging algorithm(BFO). The BFO algorithm has three basic operations, including Chemotaxis, Reproduction and Elimination & Dispersal. This algorithm has strong searching ability and not easy to fall into local optimal solution. It performs well in convergence speed and robustness as a new stochastic optimization algorithm. This paper analyzed the BFO algorithm optimization mechanism, combined it to the application layer multicast forwarding tree optimization. We made experiment on the simulation platform, and compared the results with other algorithms’.Additionally, aiming at the deficiency existing in the bacterial foraging algorithm, this paper proposed a hybrid bacterial foraging algorithm strategy, modified the particle position update steps of particle swarm operation(PSO) into the Chemotaxis operation of BFO, which accelerated the global optimization efficiently. Further, this paper made the revision in Elimination & Disposal steps of BFO, ensuring the diversity of solutions and avoided mis-killing good solutions. The simulation and experiment results show that, the proposed algorithm has better efficiency in solving the degree and delay constrained minimum spanning tree problem, is a feasible optimization method.