Balanced distributed web service lookup system

Abstract

Web Services (WS) constitute an essential factor for the next generation of application integration. An important direction, apart from the optimization of the description mechanism, is the discovery of WS information and WS search engines lookup capabilities. In this paper, we propose a novel decentralized approach for WS discovery based on a new distributed peer-based approach. Our proposed solution builds upon the Domain Name Service decentralized approach majorly enhanced with a novel efficient lookup up system. In particular, we work with peers that store WS information, such as service descriptions, which are efficiently located using a scalable and robust data indexing structure for Peer-to-Peer networks, the Balanced Distributed Tree (BDT). BDT provides support for processing (a) Exact match Queries of the form “given a key, map the key onto a node” and (b) Range Queries of the form “map the nodes whose keys belong to a given range”. BDT adapts efficiently update queries as nodes join and leave the system, and can answer queries even if the system is continuously changing. Results from our theoretical analysis point out that the communication cost of both lookup and update operations scaling in sub-logarithmic (almost double-logarithmic) time complexity on the number of nodes. Furthermore, our system is also robust on failures.