| The development of computer technology, broadband technology, network technology has laid a good foundation for the development of P2P streaming media technology. P2P streaming media technology has been widely used. In the P2P streaming network, the transmission mechanism of streaming media data has great influence on the playing quality. But domestic and foreign researches on the technology of P2P streaming media network still has the problem of topology mismatch, transmission quality can not be guaranteed. So how to guarantee the transmission quality of streaming media data and ensure the smooth playback has become a hot research topic in P2P streaming media technology.Node selection mechanism has an important influence on the transmission quality of P2P streaming media system, traditional random selection method, network topology aggregation mechanism, priority bandwidth selection mechanism does not solve the impact of heterogeneity of nodes on the system performance, they did not comprehen-sive consider the node’s ability value and the problem of mismatch between the logical structure of the system and the underlying physical topology. It makes the data in the transmission easily across the backbone network, resulting in more traffic, and resulting in larger delay. Aiming at this problem, according to the distribution characteristics of the network IP address, we proposed a static network distance algorithm in this paper, it assess the node location information and service capabilities comprehensively. A P2P node selection mechanism with distance awareness is proposed in this paper, the distance between the node and the request node and the node with strong ability is preferred. At the same time, considering the distance factor, the algorithm based on the network distance between nodes is proposed.In addition, in order to ensure the reliability of data transmission in P2P streaming media network, the existing researches generally use the reliable mechanism in the TCP protocol to UDP, which makes the UDP protocol more complex. Aiming at this problem,It is proposed light load transmission protocol which can not only keep the low overhead of UDP, but also be suitable for the streaming media transmission in this paper. In the sending and receiving ends, realize the mechanism of unpacking and the reorganization of the package, to maintain data synchronization and prevent packet loss caused by the packet disorder due to the use of UDP transmission. When the packet loss occurs, according to the continuity of the packet loss, the mass retransmission mechanism is proposed, which only retransmit the start and end number of packet loss Consecutively, reduce the size of the packet, prevent the heavy packet from taking up too much link bandwidth. Besides, in order to prevent the network from entering the congestion state, a kind of congestion control mechanism is proposed, which is suitable for the characteristics of streaming media transmission. We propose divide network load condition based on packet loss rate and one-way delay, a rate dynamic adjustment strategy is proposed in this paper, which adjusts the transmission rate according to the state of the network, and dynamically updates the packet loss rate threshold.In order to respond to the network state in time, an adaptive feedback period strategy is proposed.The algorithm proposed in this paper is applied to the P2P streaming media system, and the simulation experiments are carried out on the proposed algorithm and the improved mechanism. The experimental results show that the proposed algorithm is feasible. And compared and analyzed the improved transmission protocol, results show that it can improve the transmission rate of streaming media data and improve the quality of service. |
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