This invention treats of a two-level cache management method for continuous media files of a proxy server. In the first level, the method reserves collapsed buffers in the cache for every active client attended by the proxy server. To save bandwidth and memory space collapsed buffers can be concatenated and overlapped when content belongs to the same continuous media file. The proxy manages collectively the collapsed buffers of each client, which cooperate by making its content available to the whole system, reducing traffic over the communication network and on the media-on-demand server. In the second level, the method allows proxy servers to cooperate between themselves, by concatenating collapsed buffers when necessary, increasing the amount of available shared media in the cache, saving bandwidth both on the media-on-demand server and on the communication network backbone.