| With the continuous improvement of network bandwidth, multimedia contents such as video and audio began to spread to the Internet. Internet-based applications and services like Internet video conferencing, TV broadcasting, Video-On-Demand steaming become very hot in recent years. These applications and services essentially belong to the one-to-many content delivery mode which traditionally realized by unicast or IP multicast technology. In this paper, we firstly gave a brief review of these two technologies, and then focused on the research of ALM (application-layer multicast) technology, concrete work is as follows:1) Read a large number of domestic and international ALM related papers and documents. Classified the existing ALM protocols from different perspective, and analyzed several typical ALM protocols which had been designed for live video streaming in recent years, summarized their characteristics and pointed out their deficiencies. Finally concluded the future research ideas of ALM.2) Proposed a simple and practical ALM protocol for single source live video streaming applications. It uses a novel hybrid Push-Pull interleaved transmission mechanism which adopts priority-based algorithm for chip selection to deliver data packets. Proposed an innovative priority calculation method according to the importance of different video data. This ALM protocol optimized video transmission while ensured better scalability and lower control overheads.3) Designed and implemented a prototype system based on the above ALM protocol. It includes stream reading, video data slicing and packaging, connection management and data forwarding function modules, etc. We tested the prototype system in local area network, system function modules worked correctly. In the test, the new ALM protocol showed a good topological self-organizing capacity, and could effectively alleviate the source server's bandwidth stress. |
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