Peer to peer video on demand system selectively using client and server to forward the requested video program to another client

A method used in a peer to peer video-on-demand system for providing video programs among a video program providing apparatus and a plurality of clients which are connected through a peer to peer network, said method comprising the steps of:

• (a) in response to a request for a video program from a first client among said plurality of clients, transmitting the requested video program to said first client on a first channel;
• (b) in response to a request for the same video program from a second client among said plurality of clients, allocating a second channel for transmitting video program;
• (c) notifying said first client which receives the same video program on said first channel prior to said second client, to forward said video program to said second client on said second channel from the beginning of said video program which has been received from the video program providing apparatus and stored by said first client;
• (d) controlling said second client to receive and store the said video program transmitted from the video program providing apparatus on said first channel in synchronization with said first client;
• (e) in response to a notification that the video program received from said first client by said second client reaches a starting point of the program which was received from the video program providing apparatus and stored by said second client, merging said second channel into said first channel, and notifying said first client to stop forwarding said video program to said second client.