Optimizing topology in Bit Torrent based networks

In this paper, we discuss the importance of the network connectivities of the peers in Bit Torrent based systems in determining the download performance of the peers. In this context, assuming that the fraction of the peers of each bandwidth are known, we derive optimal connectivities of the peers that help to improve the average latency of the peers. We represent the topology of a Bit Torrent based system as a weighted graph, where the average edge weight of the graph directly relates to the download latency of the peers. We formulate the average edge weight of the whole system as a linear function of the fraction of the edges that connect peers of different bandwidth and derive the topology that maximizes the average edge weight of the network. Simulation results based on the Bit Torrent protocol validates the fact that in the optimal topology, peers have 13% better download latency as compared to topologies formed in the normal Bit Torrent based systems. Further the obtained topology also improves the fairness of the system as compared to normal Bit Torrent significantly.