Research Of Hybrid Application Layer Multicast Model Based On Load-balance

With the further development of the Internet application technologies, processing speed of network hardware equipment continues to accelerate, network bandwidth continues to grow, the need of information is not only limited to text and pictures, but more of real-time video live-cast from networks. However, with such a huge data processing, traditional unicast technology as the representative of multimedia applications, likely to cause network congestion, can not keep pace with the times, thus multicast technologies turn up which support such as network television, online broadcast and other new multimedia applications. Since IP multicast networks deploy network intricately and weak security, Application Layer Multicast (ALM) researches become the present hotspot to meet the multicast communications.In order to improve the network deployment flexibility, ALM moves multicast group communication functions from network layer routers into application layer end-hosts, which composes logical overlay Ad-hoc network with the group members. Due to the actual communication mode is in the bottom layer of the two end-hosts, the link is still a unicast IP path, so it can provide efficient, reliable services for the data transmission. ALM may give full play to the resource advantages of end-hosts, it is widely used for its flexibility and easy implement.Based on the analysis of a large number of ALM models suitable for real-time applications, one ALM model based on hybrid load balancing HMLB (Hybrid Model based on Load-balance) is proposed here in the paper to solve the instable host state and low data transmission efficiency problems. Adopting hybrid structure, HMLB divides the entire multicast tree into several clusters based on distance, each multicast group elects the core node on the basis of node overall performance, and one effective load-balance routing mechanism is adapted to make end-hosts full use of their resources to deal with service requests. Core nodes compose forwarding tree, which introduces data back-up mechanism to reduce the poor reliability of tree topology. Simulation results show that HMLB can be reliably applied to real-time multi-media business scenarios, and better average network delay, lower link stress, smaller degree of path stretch may be achieved to suit the dynamic stability of multicast group nodes joining and departure.