||Interaction and communication are fundamental abstractions of any distributed system, especially when cross-business and business-to-business systems are to be developed. Multi-agent systems (MAS) are the tools that currently better meet the needs emerging in this context because they offer proper abstractions: in an open MAS the interacting agents are typically designed and implemented by different parties, and may represent conflicting interests.
A key issue in designing MAS is to regulate the interaction between the autonomous parties so that it produces a desirable outcome. To this aim, a particularly interesting approach consists in adopting interaction protocols, meant as shared specifications of behavioral patterns which allow a set of agents to cooperate when they play their respective roles. Besides simplifying the coordination problems, protocols introduce the possibility of performing verification tasks. This aspect is very important because another key concern in this kind of systems is to have guaranties on how the interaction takes place, introducing also a notion of responsibility and of commitment.
Interaction protocols can be formally specified in different ways. Some representations have a procedural nature that captures the allowed interaction flows. Singh and colleagues criticize the use of procedural specifications as being too rigid and propose the more flexible commitment-based approach to protocol specification. The greatest advantage of the commitment-based protocols is that they do not over-constrain the behavior of the agents by imposing an ordering on the execution of the shared actions. Moreover, by giving a shared meaning to the social actions, they make it possible to work on common knowledge, rather than on beliefs about each others' mental state, as instead is done in mentalistic approaches to communication.