Data distribution system, data distribution method, the distribution side data relay apparatus, and the reception side data repeater

In the data distribution system for distributing content data in HTTP by MIME multipart format, the server side proxy, in accordance with the frequency or the like of the same request, it performs adaptive fragments split delivery using a communication path with the broadcasting path. On the client side proxy, following the response message of the communication path, information (path identification, synchronization information) of data from the data broadcast path from the communication path is adaptively deliver to merge processing.