The Study And Implementation Of The Streaming Media Oriented Application Level Multicast System

Along with the computer network and multimedia technologies having been developing rapidly, multimedia applications , such as video conference, distance learning and etc, which have multicast transmission characteristic, are used more and more widely at Intranet. And the next improvement stage is to be deployed at Internet, which is also motivated by the customer requirements. But because of the unsolved issues in technology and market, Traditional IP multicast can not be widely deployed at Internet. Under this background, the researchers turn to the application layer to implement all the multicast functions, and application level multicast is such an alternative technology.In application level multicast, multicast functions are moved from routers to end systems, such as the multicast group denotation, membership management, multicast tree generation, the duplication and distribution of data packets. All the group members is set up to be an overlay network on the top of the IP network, and then construct multicast tree by the application level multicast routing protocol.The research of the thesis focused on the application level multicast system, especially on the design of the prototype and the hop by hop congestion control. The following are the detailed content:Study on the research status of the application level multicast, summarize the research production of multicast system architecture and application level multicast routing protocol. In order to support streaming media application, large group membership and quality of service, the thesis proposed a new hybrid system design based on the P2P overlay network and tree-first application level routing protocol, which is called HMT-ALMS.To be adaptive to the dynamic change of the overlay link's bandwidth, a new rate based application level multicast hop by hop congestion control-RHBHCC is proposed, which is streaming oriented and the multimedia data is single layer adaptive coded in it. RHBHCC apply the mature end-to-end congestion control mechanism within one hop, and apply adaptive adjustment between upstream and downstream hops.Based on the HMT-ALMS design, realize the application level multicast prototype and develop the streaming media multicast application. This prototype adopts the proxy-based architecture, including access network and overlay network. At access network, it fulfils the service customization, at overlay network, it fulfils the RHBHCC.Test about the HMT-ALMS prototype. The function test result shows that the system works well and reaches the design objective. The performance test under star and linear representative structures shows that it can support large group membership multicast service.