Using Proximity Information for Load Balancing in Geographically Distributed Web Server Systems
Many popular web sites get millions of hits everyday. To service a large number of requests, clusters of fully replicated web servers are used. In such a setup, the client’s request has to be directed to a cluster and then to a server within the cluster in a manner that the client receives the response in minimum time. In this paper, we propose an adaptive policy of selecting the nearest cluster for a request. Proximity is assessed by the round trip delay between the cluster and the client. An innovative idea is to measure this delay only for those clients who are sending a large number of requests. We have implemented this scheme, and using a test-bed which simulates the world wide web environment, compared the performance of the scheme with that of some existing schemes. The results indicate that the proposed scheme performs better, both in terms of average response time, as well as throughput.
KeywordsServer Selection Round Robin Average Response Time Client Request Request Rate
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