Toward a collaborative management of a P2P distribution protocol: Local vision vs. global vision

Peer to peer is a network approach where users (peers) act as client and server, depending on the request that it received. This double behavior client/server is a key pass to the offered service scale. The P2P allows sharing data and resources as well. An important parameter that will impact the protocol efficiency is the vision that a peer owns about the global network when acting in the swarm, through information exchanged with its neighbors. Current implemented policies in protocols as BitTorrent, eDonkey, Gnutella and Sopcast, etc. impose to peers a local vision that limits their decision-making and not allow them to actively act with their real level´s capacities. In this paper, we propose to manage in a global manner one of the network information : the rarest piece. The main objective of this proposal is to show the importance of information quality on peers´ status within the global performance of a P2P network. We implement this modification on a BitTorrent mainline client and we evaluate its efficiency in different cases on a test bed of dozen peers. Experimental results of the modified protocol demonstrate a homogeneous progress for all peers in the network and an improvement of the protocol performance in downloading time.