Agents and the Grid

Abstract

The Grid is a large-scale computer system, capable of coordinating resources that are not subject to centralised control, while using standard, open, general-purpose protocols and interfaces, and delivering non-trivial qualities of service. In this chapter, we argue that Grid applications very strongly suggest the use of agent-based computing, and we review key uses of agent technologies in Grids: user agents, able to customise and personalise data, agent communication languages offering a generic and portable communication medium, and negotiation allowing multiple distributed entities to reach service-level agreements. In the second part of the chapter, we focus on Grid service discovery, which we have identified as a prime candidate for the use of agent technologies: we show that Grid services need to be located via personalised, semantic-rich discovery processes, which must rely on arbitrary metadata about services that originates from both service providers and service users. We present UDDI-M^T, an extension to the standard UDDI service directory approach that supports the storage of such metadata via a tunnelling technique that ties the metadata store to the original UDDI directory. The outcome is a flexible service registry that is compatible with existing standards and also provides metadata-enhanced service discovery.