Unstructured P2p System Search Mechanism

In the field of application of file sharing, unstructured P2P system has gained great success because of its simplicity and robustness. But, badly scalability of unstructured P2P system restricted its rapid development.In this paper, we studied Gnutella searching optimisation techniques in the recent years. Based on characteristics of modern Gnutella, we proposed a new searching mechanism better for scalability of unstructured P2P system: InitialFlood. The searching procedure in InitialFlood is divided into two stages according to TTL of message.In the first stage, a message is propogated by using the standard flooding scheme. In the second stage, the message propagating is only conducted through the neighbor servent whose degree is the least. Our simulation results show that InitialFlood could greatly minimize the number of redundant messages and retain the same message propagating scope as that of standard flooding scheme, improve searching efficiency and scalability of modern Gnutella.We introduced the notion of preferential neighbor node in order to address the mismatch of topology between Gnutella's overlay network and the Internet. Selecting topologically close node to join Gnutella network could alleviate the pression on underlying infrastructure when a node initiates the connection.