BitTorrent Protocol and TradeTorrent

Here are some things a former student, Karthik Tamilmani, wrote about the BitTorrent protocol.

The Bittorrent protocol - ( ppt ): A high level overview (07/15/03)
How does Bittorrent work? : A digramatic description of the components and working of a Bittorrent network.(Dt: 09/20/03)
Robustness of BitTorrent (Draft): A rough draft of Karthik's project proposal. It describes possible attacks on BT and a credit based trading mechanism to strengthen BT.(10/06/03)
SWIFT: System With Incentives For Trading: A paper published at the Second Workshop of Economics in Peer-to-Peer Systems that discusses a tit-for-tat choking and unchoking algorithm that is potentially better than the default in BitTorrent.
TradeTorrent software implementation of the SWIFT algorithm: the TradeTorrent client is a modified version of the BitTorrent-experimental client Ver 3.2.1b. It implements the trading mechanisms described in the above paper.

Here are some general references on Bittorrent.