Hybrid Periodical Flooding in Unstructured Peer-to-Peer Networks

Blind flooding is a popular search mechanism used in current commercial P2P systems because of its simplicity. However, blind flooding among peers or superpeers causes large volume of unnecessary traffic although the response time is short. Some improved statistics-based search mechanisms can reduce the traffic volume but also significantly shrink the query coverage range. In some search mechanisms, not all peers may be reachable creating the so-called partial coverage problem. Aiming at alleviating the partial coverage problem and reducing the unnecessary traffic, we propose an efficient and adaptive search mechanism, Hybrid Periodical Flooding (HPF). HPF retains the advantages of statistics-based search mechanisms, alleviates the partial coverage problem, and provides the flexibility to adaptively adjust different parameters to meet different performance requirements. The effectiveness of HPF is demonstrated through simulation studies.