Application Layer Multicast Algorithm Analysis And Implementation Over IPv6 Networks

With the development of multimedia transmission applications over Internet, traditional end-to-end unicast has shown limitations in many ways, including lack of QoS support, waste of network resources, etc. IP layer multicast requires routers to save states of multicast groups, which complicates router design and implementation, adding potential problems of scalability and security. Internet does not support IP layer multicast for its heterogeneity. Application layer multicast has advantages of both unicast and IP layer multicast. It does not need to change design and implementation of underlying routers while constructs overlay networks in end systems. Current application layer multicast algorithms have two disadvantages, either having complicated group management mechanisms and large overhead, or requiring too much information such as complete underlying topology to start overlay network construction process.According to characteristics of IPv6 network CERNET2, this thesis brings up a new scalable application layer multicast algorithm based on topology information, called S-TAG, that is, Scalable Topology Aware Grouping, to transmit multi-view three-dimension TV programs. S-TAG can construct an efficient, flexible, scalable overlay network using detectable topology information and some QoS parameters. Each new node can use different metrics such as number of hops, end-to-end delay, available bandwidth in selecting parent nodes. Each node only needs to maintain nodes information that is related to itself, without knowing whole topology or performance parameters, which makes the algorithm scalable. The nodes can implement their own degree limitation according to their corresponding data forwarding and processing abilities. What's more, S-TAG can convert to P2P work mode to get streaming data from multiple nodes considering high bandwidth consumption of multi-view three-dimension TV programs.This thesis carried out simulation of S-TAG, and compared its performance with TAG, another topology information based application layer multicast algorithm. The results show that S-TAG can get higher data receiving rate and shorter first-packet delay than TAG giving the same number of participants. S-TAG is implemented in Windows system, and general rules and programming methods of multimedia transmission applications are described.