A Node Selection Algorithm for Many-to-Many Mappings in Peer-to-Peer Networks

To achieve high performance and resilience to failures, many peer-to-peer (P2P) systems have begun to use striping and collaborative downloading, where each peer can download the file or pieces of the file from a number of peers in parallel, and at the same time, serve them to some other peers. These P2P systems intrinsically involve many-to-many mappings from the servers to the clients (or peers to peers) as well as many-to-one mappings from the clients to the server. In this paper, we present a node selection algorithm that generates an optimal server set with respect to the worst link stress (WLS) criterion for a single client and evaluates its network performance metrics for many- to-many mappings and many-to-one mappings. Simulation results show that our system is simple yet effective in achieving the design goals. In particular, it minimizes the level of congestion at the bottleneck link, and it consumes less network resources in terms of total bandwidth usage. The objectives of this in-depth examination are to raise awareness and concern for these issues and to provide alternatives or improved designs that can be incorporated into many P2P systems.