Patent ID: 7904562

Claim:
A cache server for caching content of a content server according to a request from a client and distributing the content to the client, comprising: a cache control unit configured to determine whether the load is overloaded by measuring a load of the cache server, the overload being caused by a load source cache server, and comparing a value of the load with a predetermined overload setting value, wherein the cache server and the load source cache server belong to a first layer and a second layer lower than the first layer, respectively, the load source cache server in the second layer is connected to the cache server in the first layer, and the load source cache server caches content of the cache server in the first layer, to select content to switch and content to be switched by another cache server or content server such that a total load after switching can become equal to or less than the overload setting value, to generate connecting destination retrieve request information including a request for retrieving a connecting destination of the load source cache server from the content server or the other cache server and information about each piece of selected content, and to generate a request requesting the load source cache server to switch its connection to a connecting destination indicated by connecting destination information on the basis of the connecting destination information indicating a connecting destination retrieved from the content server or the other cache server that has received the connecting destination retrieve request information via the content server or the other cache server; and a communication management unit configured to transfer information about a cache to the cache control unit.