The Research On Scalable And Backbone Topology-Aware Hybrid Multicast Protocol

With the great development of Internet, the demand of realizing group communication service conveniently and efficiently is increasing. IP multicast is the best efficient mechanism to implement group communication service, but it still can not be deployed in an operational network at the Internet because of its deficiency and the limit network support. As a promising alternative to the IP multicast, application layer multicast based on overlay networks solved the problem. However, most of existing application layer multicast protocols construct their overlay networks based on measurement with the end-to-end delay, and considering neither the physical network topology nor IP multicast efficiency in locality network. Thus, the huge probe measurement and computing might decrease the protocol's efficiency and affect its scalability.In this paper, according the information of Backbone, we present a new Scalable and Backbone Topology-Aware Hybrid Multicast~SHM, which combining application layer multicast and IP multicast. We studied SHM especially on how to management and maintenance Overlay Networks topology, and put forward the protocol architecture of SHM, including new group creation, inter-domain and intra-domain member join and leave algorithm, intra-domain topology optimize algorithm CDAF, data transfer model and the maintenance of all topology. Then, we have done some simulation experiment to illustrate the efficacy and performance of SHM with OPNET Modeler referring to CERNET Backbone. Simulation results show that CDAF algorithm can decrease the packets' retransmission times on intra-domain links, and the overhead on backbone links, moreover, compared with ESM, SHM is able to provide more efficient multicast with less maintenance overhead, higher flexibility and reliability, lower stress and stretch data path.SHM Protocol in this paper now only based on certain backbone topology, but it gives a new resolution for realizing the large and real-time group communication service, improves the development of group communication mechanism research.