Adaptive load balancing content address hashing routing for reverse proxy servers

We propose a novel routing algorithm for reverse proxy servers, called adaptive loud balancing content address hashing (AH), and evaluate the performance of the proposed routing algorithm compared with that of the content address hashing (SH) and the hash and slide (HS) routing algorithms. The proposed AH 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 AH, SH and HS routing algorithms by simulation experiments from the viewpoints of load balancing, consumed cache space and cache hit rate. Simulation experiments show that the proposed AH routing algorithm achieves almost the same degree of load balancing as the HS algorithm and the same cache hit rate as the SH algorithm, for reverse proxy servers in various web site environments.