P2P下的大型流媒体文件分发共享机制研究

Study of distribution and sharing scheme on large media file in P2P network

利用CDN网络进行大型流媒体的分发会由于代理服务器存贮空间的有限性而造成应用性能的下降。基于文件分段共享方案的提出从一定程度上缓解了这种矛盾,但并没有从根本上解决它。而P2P网络的提出及基于P2P主机来构建CDN网络却为这个问题的解决提供了可行性。正是基于这一观点提出了一种在基于P2P节点主机构建的CDN网络上进行大型流文件分发共享的方案。由于是基于P2P节点主机构建,因此这种网络的存贮容量接近于"无限",而CDN网络中节点主机的"动态性"促使在选择文件段的存贮位置及其后的流文件调度机制中都需考虑节点的"剩余寿命"。与原有的基于代理服务器构建的CDN网络上的文件段共享方案相比,本方案具有更好的性能,主要体现在具有更加稳定的系统服务容量和更高的服务完成率。模拟实验证明了这一点。

Large media streaming presents new ehallenge to content distribution network because of its unique features,such as large file size.The appearance of segmentation-based fine-grained proxies sharing technique has mitigated the problem to some extent,but can not solve it.To improve the service capabilities of resource-constrained proxy servers,a peer sharing technique of P2P systems at proxies is proposed.The lifespan of peers is considered in selecting and scheduling destination of operations.Com- pares with traditional segmentation-based proxies-based CDN proposal,it has advantages such as more stable system service ca- pabilities,higher service completion percentage.Simulation prove it.