基于性能测量的分布式CDN负载均衡策略

为了能够使CDN根据网络和服务器的性能变化实现真正的全局负载均衡，并使其摆脱服务器的单点故障对全局的影响。本文借鉴P2P网络在分布式文件共享及定位等方面的巨大成功，取消CDN中心，使各POP节点成为对等实体，从而提出了完全分布式CDN(DCDN, Distributed CDN)模型。重点研究了负载均衡和服务定位等关键技术，提出了基于网络测量和服务性能测量的MBPP算法。从而在提高CDN的扩展性和健壮性的同时，能够更加精确定位最佳服务提供点。试验表明，基于MBPP算法的负载均衡策略以较低的通信开销和运算复杂度实现了真正的全局实时动态负载均衡。

Load Balancing Policy of Distributed CDN Model Based on Performance Measurement

In order to make CDN implement real global load balancing based on network and server performance variance and avoid influence of single point failure in server,by borrowing the successful P2P techniques for distributed file sharing and locating,we design a pure distributed CDN model that has no central node.Thus all PoP nodes are peers to each other.Key techniques such as load balancing and service locating are then studied in detail.A MBPP algorithm based on the network and service performance measurement is proposed.Scalability and robustness of CDN are improved,and the best service providing point can be located more precisely.Experiments show that,based on MBPP,global real-time dynamic load balance with small communication overhead and computing complexity can be achieved.