移动网格中负载自平衡的集群式边缘流媒体服务器

Cluster-Based Edge Streaming Server with Adaptive Load Balance in Mobile Grid

迅速发展的3G网络和覆盖范围可达整个城域的Wi-Fi网络的逐渐普及,使移动网络环境中对流媒体服务的需求迅速增长.由于移动用户主要依赖Internet上的流媒体服务资源提供服务,所以位于无线网络和Internet交界处的边缘流媒体服务器可以充当桥梁和缓冲区,对于降低网络负载和提高服务质量有显著的效果,因而提出一种新的集群架构的边缘流媒体服务器(CESS)的设计,而且针对集群服务器中最重要的负载均衡问题做了分析和测试,提出了一种新的MCLBS缓存替换算法来使CESS能够达到自适应的负载均衡.最后,实验测试和结果分析证明,相对于传统的缓冲替换算法,MCLBS算法更适合集群式的服务器体系结构,在同样的条件下,缓存命中率明显提高,大大降低远程服务器的带宽.

With the fast development of 3G network, and the gradual popularity of Wi-Fi which can cover the whole city area, the requirement of multimedia service in mobile grid has been growing significantly in recent years. Because the streaming media service on the Internet is the most important supplier for mobile multimedia users in mobile grid, the edge streaming servers which locate between the boundary of wireless network and the Internet, can act as bridges and buffers to achieve the notable effect on reducing the load of the Internet and improving the QOS of mobile multimedia service. Accordingly, a new design of clusterbased edge streaming server （CESS） is introduced; in the meanwhile, aiming at solving the most important problems of CESS, namely loading balance, some analysis and experiments are carried out. On the basis of such work, a new kind of caching replacement algorithm called MCLBS is brought out to make CESS an adaptive loading balance system. Finally, the experiment results and related analysis show that in comparison with the traditional cache replacement algorithm, the MCLBS algorithm which is more suitable for cluster server architecture makes the cache-hit-rate increase significantly and greatly reduces remote server＇s bandwidth requirements in the same environment.