US Patent 8478836 Proxy cache technology

Proxy cache technology, in which a system determines a subset of content files to include in a proxy cache maintained by a network service provider that provides network service to user downloader devices included in a content delivery network. The system controls the network service provider to store the subset of content files in the proxy cache. The system also controls the user downloader devices to attempt to use the proxy cache as a peer to download a content file prior to using an external peer.