In service-oriented architectures, everything is a service and everyone is a service provider. Web services (or simply services) are loosely coupled software components that are published, discovered, and invoked across the Web. As the use of Web service grows, in order to correctly interact with them, it is important to understand the business protocols that provide clients with the information on how to interact with services. In dynamic Web service environments, service providers need to constantly adapt their business protocols for reflecting the restrictions and requirements proposed by new applications, new business strategies, and new laws, or for fixing problems found in the protocol definition. However, the effective management of such a protocol evolution raises critical problems: one of the most critical issues is how to handle instances running under the old protocol when it has been changed. Simple solutions, such as aborting them or allowing them to continue to run according to the old protocol, can be considered, but they are inapplicable for many reasons (for example, the loss of work already done and the critical nature of work). In this article, we present a framework that supports service managers in managing the business protocol evolution by providing several features, such as a variety of protocol change impact analyses automatically determining which ongoing instances can be migrated to the new version of protocol, and data mining techniques inferring interaction patterns used for classifying ongoing instances migrateable to the new protocol. To support the protocol evolution process, we have also developed database-backed GUI tools on top of our existing system. The proposed approach and tools can help service managers in managing the evolution of ongoing instances when the business protocols of services with which they are interacting have changed.

We present a software tool and a framework for security protocol change management. While we focus on trust negotiation protocols in this paper, many of the ideas are generally applicable to other types of protocols. Trust negotiation is a flexible approach to access control that is well suited to dynamic environments typical of service-oriented applications. However, managing the evolution of trust negotiation protocols is a difficult problem that has not been sufficiently addressed, especially in situations where there are ongoing negotiations. By using our framework, the consequences of changing the protocol that applies to ongoing trust negotiations can be automatically determined. We have also implemented a database-backed GUI tool to manage the change process as an extension of an existing system, and we have performed experiments to test the efficiency of our management software. Our experimental results show that the techniques proposed can scale to applications with tens of thousands of simultaneous users even on commodity PCs.

A scalable approach to trust negotiation is required in Web service environments that have large and dynamic requester populations. We introduce Trust-Serv, a model-driven trust negotiation framework for Web services. The framework employs a model for trust negotiation that is based on state machines, extended with security abstractions. Our policy model supports lifecycle management, an important trait in the dynamic environments that characterize Web services. In particular, we provide a set of change operations to modify policies, and migration strategies that permit ongoing negotiations to be migrated to new policies without being disrupted. Experimental results show the performance benefit of these strategies. The proposed approach has been implemented as a container-centric mechanism that is transparent to the Web services and to the developers of Web services, simplifying Web service development and management as well as enabling scalable deployments.

Web services are emerging as a promising technology for the automation of inter-organizational interactions. As technology matures and the foundations of Web services become more solid, users will start to demand tools that facilitate the service development lifecycle. It is only when such tools become available that novel technologies become applied and enter the mainstream, since the complexity, cost and time necessary to deploy and manage solutions is dramatically reduced. In this paper, we present a framework and a tool that support the model-driven development of Web services. The idea consists in identifying key Web services abstractions, in addition to those of basic Web services standards, that enable the description of service policies and properties that are useful in practice. In this paper, we focus on service protocols, and specifically on conversation and trust negotiation protocols. These protocols are modeled by means of graphical tools and high-level languages so that they are easy to specify, understand, and evolve. The tools also support the automatic generation of service implementation skeletons based on these abstractions, manage the entire service lifecycle, and provide run-time support to verify that the interaction among clients and services occur in compliance with the specified policies.