Abstract: The centralized control layer was introduced into the Web Cache architecture. The centralized control was used to watch the status of all the caches, through a overall and effective control of their memory and w orkload to make the storage structure reasonable and the workload balance. We realized the arithmetic of workload balance, the arithmetic of prefetch based on the Pull mechanism, the arithmetic of wash out based on the combination of the TTL and the life modulus. The arit hmetic of workload balance helps to resolve the bottleneck of caches, and the ot her two increase the hitrate and system efficiency. By introduce the arithmetic, the control lay can control the Cache layer effectively, it can increase the hi trate of the architecture and decrease the response time of the architecture.

Key words: Web Cache, centralized control, workload balance, prefetch based on the Pull mechanism, wash out arithmetic