With the advent of many new multimedia applications with Quality of Service (QoS), the issue of multicast routing has become more and more important. Some previous researches in this area mainly take bounded end-to-end delay into account and neglect the ability of router in supporting multicasting, therefore a new multicast routing algorithm based on genetic algorithm (GA) is proposed to construct Degree-Delay-Constrained least-cost multicast routing Tree (DDCT problem). Our proposed algorithms adopt pruefer coding and decoding technique which is very suitable for crossover and mutation operation and can save runtime; Otherwise because pruning and grafting techniques are used to adjust node degree and repair tree structure, this algorithms may also be employed when taking dynamic adjusting tree or keeping load balance into consideration. Simulations were conducted on a random graph to evaluate the performance of the proposed algorithm compared with that of the other algorithms such as CSPT and Wang_GA. The experimental result shows that the proposed algorithm performs well.
With the emergence of new distributed multimedia applications upon secure group communication, Security becomes more important increasingly. Now most investigations about multicast security focus on key management problem. In this paper, an improved version of CBT is proposed for data communication and key management and named as Dynamic CBT(D-CBT). This approach accepts the advantages of Iolus and CBT approaches, its main characteristic is that D-CBT changes dynamically with group member join/removal frequently when cumulating influence of dynamic membership reaches certain threshold so that the bandwidth/cost of multicast is as least as possible, D-CBT is also very close to realistic application case. Performance analysis will be conducted compared with other methods.