Abstract
In this article we review contemporary multi-agent system architectures and implementations. We particularly focus on asynchronous message passing mechanisms. Our motivation is to explore two main areas in the context of multi-agent systems: the concept of micro-agents and the asynchronous message passing architectures. In the article we take a close look at the emerging area of micro-agent-based systems and contrast them with selected representatives from the general field of agent architectures. We provide historical references and examples of contemporary implementations supporting the hierarchical micro-agent-based software engineering paradigm. In addition, we also investigate various implementation mechanisms for efficient asynchronous message passing between large numbers of small interacting software components with regards to their use in the context of multi-agent systems. The results show a trade-off between performance, fairness and usability as key problem when selecting an appropriate solution. Future investigations into alternative concurrency handling mechanisms for better support of micro-agent architectures are suggested.