A novel method to anti-free-rider in the unstructured P2P networks

In P2P network, free riding is so prevalent that it is harmful or even seriously threatened to the normal P2P applications. A novel distributed algorithm, called as DAMR, to alleviate the impacts of free-riding is proposed, in which free-riders´ location is mainly concerned. In the algorithm, each peer monitors its neighbors and reaches its own judgment whether a neighbor is a free-rider or not. In our algorithm each node stores the messages coming from its neighbors and maintains a set of counters. We proposed a mathematical model to evaluate the DAMR incentive mechanism and draw the conclusion that the incentive mechanism can make P2P network system to reach and keep a positive equilibrium.