What is Unstructured Peer-to-Peer Networks

In order to improve the scalability and reduce the traffic of Gnutella-like unstructured peer-to-peer networks, index caching and controlled flooding mechanisms had been an important research topic in recent years. In this chapter the authors will describe and present the current state of the art about index management schemes, interest groups and data clustering for unstructured peer-to-peer networks. Index caching mechanisms are an approach to reducing the traffic of keyword querying. However, the cached indices may incur redundant replications in the whole network, leading to the less efficient use of storage and the increase of traffic. They propose a multiplayer index management scheme that actively diffuses the indices in the network and groups indices according to their request rate. The peers of the group that have indices with higher request rate will be placed in layers that receive queries earlier. Their simulation shows that the proposed approach can keep a high success query rate as well as reduce the flooding size.