In recent years peer to peer networking (P2P) has become a popular method of file sharing. However there are several deficiencies in current P2P systems which make them difficult to use.

In this thesis I propose some new approaches to make these systems more efficient, and implement a new P2P system which incorporates these ideas. The system performs content matching instead of filename matching to improve search hit rate and accuracy. In addition, when downloading files, nodes can aggregate the bandwidth of multiple nodes, by downloading different portions of files from different nodes simultaneously. Searching for files by content further increases the opportunities for such bandwidth aggregation, as users can download the same file from nodes in parallel, even though filenames may differ on each of the nodes.

P2P networks make significant demands on every node’s bandwidth in both directions, and we show that TCP does not work well for bidirectional transfers. I propose a new transmission protocol called RTPF (Reliable Transmission Protocol using Forward Error Correction) which uses FEC to handle packet loss. We demonstrate that this protocol performs significantly better than TCP for bidirectional transfers and under relatively high packet loss conditions.


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Last updated: November 2001