One of these groups, or other groups associated with alternate on-demand data streaming, may be stored at a remote location, while the other of the groups may be stored at a plurality...http://www.google.es/patents/US6868452?utm_source=gb-gplus-sharePatente US6868452 - Method for caching of media files to reduce delivery cost B???squeda avanzada de patentes N???mero de publicaci???nUS6868452 B1Tip