Research On Multipath Transmission Path Selection Method With Application-layer QoS Policy Decision

IMS Media Transfer Mode entirely adopts dependence on Single-path Transmission Mode of Carrier Network, existing difficulty of ensuring end-to-end QoS, prominent bandwidth bottleneck effect, and inefficient transmission, seriously restricting the development of IMS business. Using the application layer relay to achieve IMS media multipath transmission, can help to overcome bandwidth bottleneck effect, at the same time, through the path redundancy to realize transmission of QoS guarantee, is an important means to enhance the IMS application media transmission capacity and efficiency. Building an multipath transmission based on application relay, needs to consider the overlay network organization of application relay node、selection of multipath transmission、evaluation of application-layer QoS and QoE, and multipath transmission control mechanisms and protocols. This thesis focuses on the overlay network organization model of application relay and the research of path selection algorithm, for supporting multipath transmission control.Nowaday, in the overlay network organization of application relay, there is no impacted model on the research. This thesis proposes the R-Cluster Network organization model, considered the typical P2P network organization models, and combined media application requirements and characteristics. Divided the relay node in the model is in accordance with the different ISP or AS, and relay node are divided into management node, super relay node and ordinary relay node. It discusses the joining and leaving algorithms of network topology and nodes. The organization of the network model conducive to the generation and management of relay path, on the other hand, that is as much as possible to support the path diversity.On the path selection algorithms, this thesis proposes the multipath selection algorithm to supporting QoE prediction. Except meeting the bandwidth and delay conditions of paths, the algorithm tries to choose disjoint-paths, to improve the path redundancy. By OMNET++simulation software testing and evaluating R-Cluster Network Organization and Multipath selection algorithm, the results show that the network model and path selection algorithm are reasonable and feasible.