Constructing fixed-ratio superpeer-based overlay

In a self-organized unstructured P2P system, weak peers may become the bottleneck of the system, which causes the whole system shows low efficiency. Recently more and more unstructured P2P systems consider the heterogeneity between peers, utilizing powerful peers to provide services for other weak peers, which construct a super-peer peer-to-peer overlay. Typically peers are grouped by their capabilities, divided into two hierarchical layers, weak peers act as clients and powerful peers as servers. But in previous works, the ration of superpeers is an uncertain parameter, which causes the service quality cannot be guaranteed. In this paper, we propose a new superpeer overlay, in which we can define the ratio of superpeers. At the same time the latency is considered to be an important factor when building the relationship between a client peer and a superpeer. Simulations proved our method can construct a superpeer overlay with a fixed ratio of superpeers which can promise the service quality in the overlay. It is robust, efficient and quickly convergent.