Dual-Kad: Kademlia-Based Query Processing Strategies for P2P Data Integration

The P2P data integration system aims to combine the advantages of P2P technologies and data integration to overcome centralized data integration systems´ shortcomings. Kademlia, as a widely used and efficient network protocol for P2P files sharing system, has a very clear logical structure, and with its unique identifying pattern of nodes and XOR metric for distance, it can provide O(logn) lookup to locate the node closest to a given key. In this paper, we put forward a method of applying Kademlia to the P2P data integration system, and propose a new P2P data integration model, Dual-Kad, combing the Kademlia network over the Peer layer with that over the Super-Peer layer. Dual-Kad can process queries based on semantic logic which is a limitation of the original Kademlia, and shorten the query routing path, cache the query results, and as a result, speed the whole query routing. We describe the detailed structures of Dual-Kad and its query routing algorithms. Our query routing strategies are proved effective in our case studies mentioned in this paper.