A Research On Application Layer Multicast Topology-aware Overlay Network Construction Protocol

Unlike IP multicast, application layer multicast requires no infrastructure support and can be easily deployed in Internet. It is the very idea that the famous "end-to-end argument" advocate.The foundation of application layer multicast is the construction of the overlay networks. The efficiency of the overlay network will directly or indirectly influences the upper multicast protocols. The present protocols' overlay networks have not utilize the physical network topology but adopted the simple Ping RTT among hosts, which induce frequently low-efficiency connection in the overlay network. Furthermore, the whole multicast system will be lacking in its efficiency.The Internet has the small world effect, and the information will be delivered faster in such small worlds. With the topology information of physical network, we can construct a similar clustering overlay network. It can enhance the delay performance of the entire multicast system. After taking all situations mentioned above into consideration, this thesis firstly analyses the characteristic of network structure, and then put forward the tree model of Internet structure by combining the distribution mechanism of IP address space registration. The information saved in the model is all-round and authorized selected and aggregated from the internet registration information base. The model is simple and distinctively layered. It can provide coarse granularity topology information for the overlay construction.This thesis also put forwards a Scalable Hybrid Multicast system-SHM based on the research of present protocols. SHM is consisted of three parts: Topology-aware overlay construction protocol (T-SHM), multicast Management protocol (M-SHM) and Reliable data transmission protocol (R-SHM). T-SHM protocol is designed on the base of the tree model. It includes overlay construction algorithms, access node selecting algorithms and the discussion of partition mechanism of SHM domain. T-SHM can construct a topology-aware overlay network. Moreover, for the sake of proving the generalization of the tree model, we modify the ALMI protocol, and design the T-ALMI(topology-aware ALMI) overlay construction algorithms.Finally, we adopt the topology generated by the generator and the delay of real nodes in internet respectively to evaluate the T-ALMI and the T-SHM protocol. The experiment results show that the T-ALMI overlay improve performance preferably and the T-SHM is able to construct a topology-aware overlay network with preferably link delay performance.