A graph transformation system model of reliable dynamic communication networks for location transparent mobile agents

Mobile agent technology has been the subject of much attention in the last few years, mainly due to the proliferation of distributed software technologies in future telecommunication networks. Currently, it is beginning to make the transition from research lab to mainstream software development practice. Requirements for this technology include the dynamic modifiability to adapt to the evolutional nature of the Internet and network applications. In particular, location transparency of mobile agents is one of the functionalities required for such a dynamic nature. It is assumed that two or more mobile agents are communicating to each other for some kind of cooperation. In this circumstance, it is desired that the communications will not result in failure even after some agents have moved to other places without any notice to other agents. Agent systems that satisfy this condition is said to be ´location transparent´. Several location transparent schemes have been proposed in the literature, but none of them consider the reliability of the communication networks. In addition, all of them discuss their systems in terms of imprecise descriptions or specific implementation. This makes it difficult to design and analyze complex mobile agent systems rigorously. We present a new class of reliable communication networks, called ´proxy networks´, for location transparent mobile agent systems. The dynamic nature of the networks is modeled formally in terms of a graph transformation system, which makes it easier to design and analyze the reliability and the soundness of the system in a rigorous but conceptually clear framework.