A Lightweight Capability Communication Mechanism

Abstract

A persistent problem in managing the interaction between distributed agents is to be able to coordinate the communication between systems without having continually to ask each system for information about what it can do. One form of coordination is through the use of capability descriptions that are advertised by each agent and managed by a brokering mechanism. The task of the broker (which may be centralised or distributed among the agents) is to accept queries and to hypothesise the means of obtaining answers based only on the capability descriptions. This has the advantage that plans for coordinating answers can be constructed by the broker without having to contact the agents. Brokering, however, is not straightforward because capability descriptions can be complex and may be conditional on interactions with other agents. Brokering must also take into account the possibility that the ontologies used by each agent may differ, so some means of relating the terminology of capabilities of agents is needed. Many sophisticated systems exist for tackling parts of this problem but there have been comparatively few attempts to build lightweight engineering solutions by adapting well established methods. We describe a simple way of implementing a lightweight but powerful brokering mechanism.