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.