The primary objective of service-oriented architecture (SOA) is to use information technology to address the key goals of business today: innovation, agility, and market value. Agility in SOA is achieved by use of the principles of encapsulation, modularity, and loose coupling, which facilitates a cleaner separation of concerns. While loose coupling enables customers to rapidly reuse services in new applications, strong coherency must be maintained to achieve the primary business objectives of the application. When applications are composed of loosely coupled services that are independent (owned by different parts of the organization, based on disparate technology assumptions, and evolving on independent schedules and with diverse priorities) the coherency of the composite application can be undermined. in this paper, we examine how coherency can be created and maintained in loosely coupled applications. We examine, in this context, various techniques and design approaches, such as service management, the use of service buses, the role of industry models and semantic ontologies, and governance, to achieve and maintain coherency of composite applications using SOA.

We introduce SOBA (Service Oriented Business Applications) Fabric, an architectural framework for Business Services Networks (BSN). BSNs extend the enterprise service bus concept beyond the boundaries of a single enterprise, enabling companies to build on each other's applications and create new loosely-coupled, network-centric business models. SOBA Fabric facilitates dynamic integration of people, processes, and information across business and technology boundaries by providing: 1) Dynamic provisioning and service personalization so that subscribers can quickly customize a business process to work with their systems and processes; 2) Industry-specific Service Level Agreements; 3) An industry-specific business services catalog supporting dynamic discovery and composition; 4) Business Process Management tools interface tailored to industry requirements; and 5) Visibility and exception handling across the BSN. Most importantly, SOBA Fabric provides industry-specific semantic "dial tones" that enable applications to plug and play at the business process level, using standardized XML business vocabularies. We describe the SOBA Architecture and present a case study from a successful deployment in the Insurance sector.