TAON: A Topology-Oriented Active Overlay Network Protocol

Built upon overlay topologies, Peer-to-Peer (P2P) networks behave in an ad-hoc way, conduct application-layer routing, enable usercustomized decentralized resources sharing, and thus can be taken as an emerging representative of Active Networks. An important problem in current unstructured P2P networks is that, however, existing searching mechanisms do not scale well because they are either based on the idea of flooding the network with queries or because they know very little about the nature of the network topology. In this paper, we propose the Topology-oriented Active Overlay Network (TAON) which is an efficient, scalable yet simple protocol for improving decentralized resources sharing in P2P networks. TAON consists of three novel components: a Desirable Topology Construction and Adaptation algorithm to guide the evolution of the overlay topology towards a small-world-like graph, a Semanticbased Neighbor Selection Scheme to conduct an online neighbor ranking, and a Topology-aware Intelligent Search mechanism to forward incoming queries to deliberately selected neighbors. We deploy and compare TAON with a number of other distributed search techniques over static and dynamic environments, and the results indicate that TAON outperforms its competitors by achieving higher recall rate while using much less network resources, in both of the above environments.