Posting protocol for improved keyword search success in peer-to-peer file sharing systems

Decentralized peer-to-peer (P2P) file sharing systems, where peers query each other for content, are the most dominant in today's Internet. In the unstructured decentralized P2P systems, there is no direct connection between content location and system topology. Searches in such systems are typically broadcast within a limited region of the network and thus may not receive a response if the content is not within that region. Structured decentralized P2P systems provide a connection between content location and the system topology. There, queries can be directed to a peer who can respond definitively. Research in distributed computing has examined the problem of matching a client process to a desired server process. An approach to solving this distributed match-making problem is to have the server "post" or replicate information to other nodes in the system. We modify this approach to be used in the decentralized P2P file sharing environment. In this paper we propose a "posting" protocol to improve the success of searches in the decentralized P2P systems. By having peers replicate keyword information to other peers the search success rate can be increased. We evaluate different posting policies and compare the results for searching with and without posting,