A BitTorrent topology measurement system

BitTorrent (BT) is a widely used P2P file-sharing system, and its performance is a hot research topic. It is important to design an efficient BT topology measurement system for BT performance research. Some studies use the BT clients to collect the information of BT topology, which may be incomplete due to their limitation. In this paper, combining the passive and active approaches, we design a BT topology measurement system. We evaluate the peer coverage ratio by comparing the number of nodes achieved by the measurement system with that registered to the tracker. And we evaluate the connection coverage ratio by comparing the connection number extracted from PEX messages with that of BT clients. The results show that the average peer coverage ratio can reach above 95%, which is much higher than that of μTorrent, and the connection coverage ratio reaches above 90%. Overall, the performance of our measurement system is better than that of BT clients.