Study On Resource Discovering And Searching Method In Unstructured Peer-To-Peer Networks

With the network technology advances and enhancing power of PCs, the traditional client/server computing model is being transformed into a peer-to-peer (P2P) topology. The decentralized and unstructured peer-to-peer networks such as Gnutella are attractive for some certain applications since they require no the centralized directories and no precise control over the network topology or data placement On the one hand, for the flooding-based search algorithm used in Gnutella, the query can flood the whole network rapidly and get the maximum search results; on the other hand, each query generates a large amount of network traffic and the large systems quickly become overwhelmed by a query-induced load. For the scalability problem of the Gnutella-like decentralized and unstructured peer-to-peer networks, how to reduce their message packets and improve searching efficiency is very important.To avoid a large volume of unnecessary network traffic incurred by the flooding-based search, many improved statistics-based search mechanisms have been proposed. Instead of flooding to all immediate overlay neighbors, a peer selects only a subset of its neighbors to query based on some statistics information and heuristic algorithms. The statistics-based search mechanisms may reduce the query coverage range. At this time, not all peers can be reachable for a query, hence the so-called partial coverage problem is produced. BCDS (Broadcast based on Connected Dominating Set) algorithm, by finding a minimum Connected Dominating Set (CDS) in each node's two-hop topology, reduces the redundant messages greatly while maintaining as the same coverage...