Utilizing Web Services in an Agent Based Transaction Model

Abstract

The Web services paradigm is an opportunity for a universal programmatic interface to the Internet, one that could parallel the web-browser, human user-centered interface, in scope and adoption. However, there remains a great challenge in being able to reliably perform transactions in the loosely coupled Web services environment, hosted by independent Web service providers, running on heterogeneous systems. The ACID properties in traditional transaction models cannot be guaranteed in this environment, due to unreliable communication, the uncertain duration of individual services and the decentralized nature of server management. We draw lessons from the long history of research into distributed transactional systems. The recent WS-Coordinate protocol draws upon some but not all of those lessons. Unlike WS-Coordinate, we are interested in being able to incorporate independent take-it or leave-it Web services, into orchestrated systems — not just those that agree at the outset, to provide a particular service, with a mutually agreed quality-of-service regime. To address these issues, we call upon the flexibility of the agent-oriented paradigm, and propose an agent-based transactional model (ABT) that orchestrates multiple, often independent Web services, into new robust services. We assert that the use of multi-agent technology to manage and orchestrate transactions is the right choice in the Web services environment — the choice most-likely to propel the Web services paradigm to levels of adoption that approach those of the web-browser interface.