Cooperative caching methods and how to provide content with a request allocation device

The invention cooperative cache method and relates to a content providing method, the request assignment unit assigns the history information, server load information, and the critical load control information of each cache server in each cache cluster using the requested allocation unit-object service threshold cooperate with the load include the critical load - in the state of collecting and managing the allocation history information and the server load information using the first cache, the cache server with the first content from each of the cache servers in the cluster (the first cache server) determine the load rating for, and using the critical load management information when the first one of the cache servers to determine if that is the object services critical load greater than the cache server is present, is less than or equal to object services critical loads the first cache server does not exist, to the first cache server, the cache server of the cooperative critical loads or less (the second cache server), the zone If then identified whether the second server in a cache and to select the second cache server, a cache server (third cache server) of the. Next, the request assignment apparatus object services critical load is less than or equal to the first cache if the server does not exist using the allocated history information and the server load information in the in the first cache cluster of one is less than or equal to the object services critical load cache server ( fourth selecting a cache server) to the third cache server, and the fourth and be a cooperative cache for the first content implemented in the cache server, and it also provides the first content.