Abstract: Based on feedback control theory, this paper designed a cache space controller through system identification.By dynamically reallocating cache space between different Web objects,the controller could guarantee the priority Web objects a higher hit rate and the proportions of hit rates between different kinds of Web objects constant The experimental results demonstrate the proposed approach achieves the proportional hit rate guarantee under UDSF, LRU and LFU cache replacement algorithms.

Key words: Proportional hit rate,Web caching,Differentiated service