Content delivery system, cache server, and cache control server

摘要

In a cache control assuming plural user terminals accessing identical content, cache delete priority assignment is performed from a position where a user finished playback based on whether the user intends to view the content later. A cache control server is provided, and a cache delete inhibit span is determined based on a playback stop position or a normal speed playback time. A cache server deletes the cache based on the delete inhibit span received from the cache control server. Traffic of the core network due to re-cache can thus be reduced.