The Journal of Supercomputing, 20, 5–35, 2001 © 2001 Kluwer Academic Publishers. Manufactured in The Netherlands. An Active Organisation System for Customised, Secure Agent Discovery NICK ANTONOPOULOS N.Antonopoulos@surrey.ac.uk Department of Computing, University of Surrey, Guildford GU2 7XH, UK ALEX SHAFARENKO 1 a.shafarenko@herts.ac.uk Department of Computer Science, University of Hertfordshire, Hatfield AL10 9AB, UK Abstract. The area of software agents has experienced an exponential growth during the past decade, and is now being given a further boost by the introduction of global distributed computing services, such as Globus and Legion. The focus of the research has gradually shifted from single agent architectures to multi-agent systems and agent societies. In a Grid computing environment, agents should be able to discover efficiently other agents based on the computational services they offer or their characteristics (agent discovery). Existing systems either ignore this issue or use simplistic organisation models, which act as passive “yellow pages” thus keeping the discovery process separate from the computation. In this paper it is argued that the agent discovery can be coupled with several aspects of the computation such as access control and customisation resulting in a better sharing, use and management of the information held by the agent discovery system. A novel architecture is presented in which discovery messages and discovery paths are mutable, active entities, which interact with each other as peers making the organisation system dynamic in nature. Queries traversing the system can be reformulated while at the same time the system itself can change depending on the nature and volume of the query traffic. Furthermore it is shown that the organisation nodes of the proposed architecture can serve as re-usable components for building more complex, composite nodes from existing ones. Keywords: distributed systems, software agents, discovery, organisation, information retrieval, security 1. Introduction Mobile agents are becoming increasingly important in high-performance distributed computing. The main reason for mobility of software in systems such as computa- tional grids is the lack of mobility of large, persistent data objects, such as CERN particle collision data, which typically use Terabyte size datasets [21]. Processing, and especially visualising such objects by pulling them out to the user site is practi- cally impossible, not only at the transmission rates that are prevailing today, but also in the next few years, despite the explosive growth of the telecom industry. In the future datasets from scientific experiments, satellite remote sensing, bio-molecular sequencing, etc. are bound to continue to grow. As a result the ever-expanding research and high-tech-development communities will experience serious difficul- ties in gaining access to such information. 1 The work presented in this paper was carried out while the author was at the Department of Computing in the University of Surrey.