Performance Evaluation of a Load Balancing Routing Algorithm for Clustered Multiple Cache Servers

Hiroyoshi MIWA
Kazunori KUMAGAI
Takeo ABE

IEICE TRANSACTIONS on Communications   Vol.E85-B    No.1    pp.147-156
Publication Date: 2002/01/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Internet Technology II -- Traffic Control and Performance Evaluation in the Internet)
load balancing,  cache server,  routing algorithm,  request locality,  period of validity,  

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The explosive growth of World Wide Web usage is causing a number of performance problems, including slow response times, network congestion, and denial of service. Web site that has a huge number of accesses and requires high quality of services, such as a site offering hosting services, or content delivery services, usually uses a cache server to reduce the load on the original server offering the original content. To increase the throughput of the caching process and to improve service availability, multiple cache servers are often positioned in front of the original server. This requires a switch to direct incoming requests to one of the multiple cache servers. In this paper, we propose a routing algorithm for such a switch in front of clustered multiple cache servers and evaluate its performance by simulation. The results show that our routing algorithm is effective when content has request locality and a short period of validity, for example, news, map data, road traffic data, or weather information. We also identify points to consider when the proposed algorithm is applied to a real system.