Load Balancing Routing Algorithm for Reverse Proxy Servers

Satosi KATO  Hidetosi OKAMOTO  Toyofumi TAKENAKA  

IEICE TRANSACTIONS on Communications   Vol.E88-B   No.9   pp.3693-3700
Publication Date: 2005/09/01
Online ISSN: 
DOI: 10.1093/ietcom/e88-b.9.3693
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Internet
load balancing,  reverse proxy server,  routing algorithm,  zipf-like law,  cache hit rate,  

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We propose a novel routing algorithm for reverse proxy servers, called load balancing content address hashing (LB-CAH), and evaluate the performance of the proposed routing algorithm compared with that of the content address hashing (CAH) and the hash and slide (HAS) routing algorithms. The proposed LB-CAH routing algorithm calculates the popularity of pages in the load balancer using an LFU caching technique and periodically makes a popularity list. Using this popularity list, the proposed routing algorithm selects a reverse proxy server as follows. When the requested page appears in the popularity list, the request is routed according to the round robin method; otherwise, it is routed according to the content address hashing method. We evaluate and compare the LB-CAH, CAH and HAS routing algorithms by simulation experiments from the viewpoints of load balancing, consumed cache space and cache hit rate. Simulation experiments show that the proposed LB-CAH routing algorithm achieves almost the same degree of load balancing as the HAS algorithm and the same cache hit rate as the CAH algorithm for reverse proxy servers in various web site environments.