Efficient server cooperation mechanism in content delivery network

Content delivery network (CDN) plays an important role in today´s Web services. More and more content providers use CDNs to lower the server overhead, reduce client perceived latency and decrease network traffic. More research papers have been published in recent years addressing CDN system performance issues. However, most of them are concentrated on server placement policy, content distribution mechanism and request routing algorithm. In this paper, we propose a new CDN architecture to improve system performance by grouping the content servers which are topologically close into server clusters and exploiting the benefits of server cooperation. In our approach, when a server receives a request and cannot fulfil this request, it will forward the request to other nearby servers in this cluster. If there is a cache bit, the data can be fetched immediately. Only in case none of the servers can satisfy this request, the data will be fetched from the original server. Furthermore, with the server coordination, system workload can be well balanced on several servers. We conduct extensive simulations and the results show that our solution achieves significant improvement over the conventional CDN architecture