Research On Technology Of P2P Streaming Media Delivery And Service

CDN (Content Delivery Network) and P2P (Peer-to-Peer) are two dominant technologies for large-scale streaming media delivery. CDN-based solutions for streaming media, the major challenge are its scalability and deployment costs. The advantage of P2P streaming media distribution scheme lies in its scalability and lower cost of services. In P2P streaming media distribution systems, peers communicate directly with each other for the media content by sharing their terminals'resources such as cache and bandwidth. It can effectively decrease the load on the media server, and improve the scalability of system. However, pure P2P streaming solutions are also more fragile due to the churn and relatively frequent node failures, and the service capabilities of peer nodes are limited.There exist many challenging issues that need to be addressed in P2P streaming media system,include how to optimally select multiple senders and optimally allocate streaming rate and media data among multiple senders, how to deal with the leave or failure behaviors of peer nodes, and so on. These challenges actually constitute the key problems in P2P streaming media distribution research area. Currently, hybrid distribution architecture (HDA), is proposed where content CDN and P2P techniques are brought together to take advantage of the individual benefits of each solution (i.e., to combine the system stability/reliability and quality of service (QoS) advantages of CDN with the cost and service scalability advantages of P2P), has been a hot research topic in content distribution service research.This dissertation focuses on the following aspects: how to optimally select multiple senders, how to improve the service scalability of streaming media distribution system, and the key flow routing adjustment algorithm (KFRA). In summary, the major contributions of this dissertation are as below.1. In P2P media streaming with the pattern of multiple senders and single receiver, to minimize transmission delay of streaming videos,a new algorithm DRAA is proposed. Firstly, this paper models the optimal rate allocation problem as a non-linear optimization problem by applying queueing theory, and derives the optimal rate allocation formula that computes the optimal solution. Then, a new optimal rate allocation algorithm (ORAA) based on the formula is proposed. The ORAA algorithm can produce the optimal solution and the optimality of its solution is proved. Finally, based on the ORAA algorithm, the dynamic rate allocation algorithm (DRAA) is proposed, which can dynamically adapt to network fluctuation and optimally allocate streaming rate and media data among multiple senders. Because of its short running time, the DRAA algorithm can be used in real time. Extensive simulation results using NS2 shows that the proposed DRAA algorithm effectively reduces calculation and communication overheads, and achieves a better performance than the related works with different parameters.2. In P2P media streaming with the pattern of multiple senders and single receiver, to effectively reduce the packet loss probability of aggregated bandwidth,a new algorithm (MSRDA) is proposed. Firstly, the problem is modelled as a linear optimization problem, and then the MSRDA algorithm is presented. The MSRDA selects senders according to the sort ascending of selected path's ratios of packet loss probability to available bandwidth, which is distinct from existing algorithms which select paths only by the packet loss probability of selected paths. Theory analysis and simulation results using NS2 show that the proposed algorithm can effectively reduce the packet loss probability of aggregated bandwidth,dynamically adapt to network fluctuation and achieve a better performance than the related works with different parameters.3. A key flow routing adjustment algorithm(KFRA) based on queueing theory is proposed. Firstly, the optimal flow allocation model is established by applying queueing theory, which gives the method of computing the optimal solution ,and the relation between optimal flow allocation of path and maximal available bandwidths of path set. Then, KFRA algorithm based on the model is proposed. Finally, the theoretical analysis proves that the computational complexity of KFRA is O(nlogn), which is better than that of a majority of methods nowaday.The simulation results using NS2 shows that the proposed KFRA algorithm can optimally allocate flows among multiple paths with delay guaranteed, minimize flow transmission delay , maximize its quality , and achieve a better performance than the related works.4. This paper presents BTAHVDM, a hybrid streaming media scheme that combines the BitTorrent peer-to-peer file-transfer technology with dedicated streaming server to increase the service scalability of the system and reduce the operational costs. Firstly control mechanism based on both fluid model and stability theory of differential equation is proposed, then based on both control mechanism and signaling game model the service scalability of the system is achieved by adding more seeds. Finally, the control mechanism and service scalability of the proposed scheme are validated by simulation.