Constructing the Robust and Efficient Small World Overlay Network for P2P Systems

The current P2P application protocols are usually constructed over the application-level overlay network. However, because the users in the P2P systems always follow a very dynamic mode, the overlay network with poor performance will leads to the problem of connectivity—the departures of peers often break the network into plenty of small parts, and results in the resource islands. Although increasing the links between peers can enhance the performance of connectivity by information redundancy. But it will lead to the severe cost of maintenance. Then there is an urgent need to integrate the online peers as a “giant component” as large as possible, so that the resources online can be shared completely; at the same time to guarantee the cost of maintenance as little as possible. And due to the prevalence and significance of small world in reality and theory, in this paper we analyzed the correlation between the shortcuts density and the connectivity, as well as the impact of shortcuts density to robustness over the popular WS Small World model. At last, numerical simulation was done to confirm our analytic results.