混合内容分发网络及其性能分析模型

Hybrid Content Distribution Network and Its Performance Modeling

在大规模数字内容网络分发方面,占主导地位的CDN(Content Delivery Network)和P2P(Peer-to-Peer)网络具有显著互补优势.CDN网络可降低数据传输延迟,提高用户体验;P2P网络的部署成本低,可扩展性强.文章提出一种基于CDN和P2P技术的混合内容分发网络(Hybrid Content Distribution Network,HCDN),在骨干网部署CDN系统,在接入网构建P2P区域化网络,终端用户可同时通过CDN和P2P网络获取数据;阐述了HCDN网络模型及其内容分发处理流程,包括内容路由、副本放置和数据下载;给出了基于流模型的混合网络性能模型,并从节点数量变化、下载时间、服务能力和传输开销等方面进行综合性能评价.实验结果表明,HCDN能提高下载速率、降低服务器负载以及减小骨干网传输流量,既可克服CDN网络部署成本高的缺点,也可避免P2P网络在节点数量稀缺时的低性能.

CDN （Content Delivery Network） and P2P （Peer-to-Peer） are two dominant technologies for large-scale content distribution. CDN may reduce the end-user perceived latency, and P2P can decrease the deployment cost. In this paper, HCDN （Hybrid Content Distribution Network） is proposed to combine complementary advantages of CDN and P2P. In which, user node can retrieve content from both backbone CDN system and P2P autonomy. The network model and distribution operations are presented in detail, including content routing and replica placement. Also the performance evaluation based on fluid model is deseribed, and some metrics such as the evolution of nodes, average downloading time, and service capacity are analyzed. The clear performance benefits of the approach are shown with comparison of conventional CDN and P2P. As shown in the experimental results, HCDN has many advantages on decreasing overload of server, increasing downloading speed and reducing network transmission cost.