Q-peer: A decentralized QoS registry architecture for Web services

Abstract

QoS (Quality of Service) is the key factor to differentiate web services with same functionality. Users can evaluate and select services based on their quality information. Traditionally, run-time QoS of web services is collected and stored in centralized QoS registry, which may have scalability and performance problem. More importantly, centralized registry can not operate across business boundaries to support global scale application of web services. In this paper, we propose a P2P (Peer-to-Peer) QoS registry architecture for web services, named Q-Peer. The architecture is a Napster-like P2P system, where query of QoS is naturally achieved by getting QoS storage address from service registry. Q-Peer employs object replication mechanism to keep load-balance of the whole system. We present two types of replication schemes and conduct comparison study. A prototype of Q-Peer has been implemented and tested on Planet-lab. Experimental results show that Q-Peer can automatically balance load among peers in different circumstances, so the system has good performance and scalability. © Springer-Verlag Berlin Heidelberg 2007.