Cost-based Proxy Caching

Caching has been used for decades as an effective performance enhancing technique in computer systems, among others. However, the traditional cache replacement algorithms are not easily applicable to WWW applications. Moreover, the frequently used hit-ratio and byte-hit ratio are not appropriate measures in WWW applications, because non-uniformity of the object sizes and non-uniformity cost of cache misses in WWW traffic. In this paper, we propose a cost efficient cache replacement algorithm, CERA. We define Cost Reduction Ratio (CRR), as the cost saved by using a cache divided by the total cost if no cache was used. We compare performance of CERA with other caching algorithms using CRR, hitratio and byte-hit ratio as performance metrics. Our experimental results indicate that CERA outperforms LRU, LFU and GDS.