Consistent Process Execution in Peer-to-Peer Information Systems

The proliferation of Internet technology resulted in a high connectivity between individuals and companies all over the world. This technology facilitates interactions within and between enterprises, organizations, etc. and allows for data and information exchange. Automating business interactions on this platform requires the execution of processes. This process execution has to be reliable, i.e., guarantees for correct concurrent and fault tolerant execution are vital. A strategy enforcing these properties must take into consideration that large-scale networks like the Internet are not always reliable. We deal with this by encapsulating applications within mobile agents. Essentially, this allows users to be temporary disconnected from the network while their application is executing. To stress the aspect of guarantees, we use the term transactional agents. They invoke services provided by resources, which are responsible for logging and conflict detection. In contrast, it is the transactional agents' task to ensure globally correct concurrent interactions by means of communication. The used communication pattern is a sample implementation of our newly developed protocol. It is, to our best knowledge, the first distributed protocol that addresses the global problem of concurrency control and recovery in a truly distributed way and that, at the same time, jointly solves both problems in a single framework. Because (i) processes are long running transactions requiring optimistic techniques and (ii) large networks require decentralized approaches, this protocol meets the demands of process-based applications in large scale networks.