A fundamental challenge in Peer-To-Peer (P2P) systems is how to locate objects of interest, namely, the look-up service problem. In the distributed hash table (DHT), including Chord, CAN, Pastry and Tapestry, among others, both object id and network node are randomly hashed to a same id space, so that “locality-awareness” is not inbullt in the basic DHT design. Therefore, objects are referred to in a location-independent manner.

In this paper, we propose a semantic approach to build a P2P system called SemanticChord which aims to integrate and organize the datalinformation resources based on the domain of interest to route requests to the most likely physical location of data. We apply the Topic maps approach as a semantic layer in aggregating and organizing ressources based on the domain of interest on top of the Chord Protocol. Experimental results show that SemanticChord improves the traditional DHT-based Chord in terms of average number of messages per lookup (11 ), the average success rate for content location ( 6) and response time.