The Base Definition of Service Oriented Architecture (SOA)

This is the definition of SOA from the Glossary in Appendix A.

Service Oriented Architecture is a paradigm for organizing and utilizing distributed capabilities that may be under the control of different ownership domains. It provides a uniform means to offer, discover, interact with and use capabilities to produce desired effects consistent with measurable preconditions and expectations.

The key elements are:

• Capabilities - things a service can do
• Ownership Domains - different players and stakeholders, generally a service provider and a consumer, but may include multiple providers and consumers.
• Offer, Discover, Interact and Use - these are the activities and phases in the lifecycle of a service.
• Desired Effects - the intended results of the service consumer.
• Preconditions - the necessary conditions for the successful activation and completion of a service, in other words things that must happen first.
• Expectations - expectations seem to be similar to desired effects, but they include the expectations of the service provider as well as the service consumer.

The idea of measurements is introduced in the defnition above. Presumably, this would consist of measures of success or failure in terms of task completion, integrrity of the transaction, relevance of information and other measurements of the appropriateness of the real-world effects versus the desired effects.

Later in the document, it says: "in support of the dynamics of interacting with services are a set of concepts that are about services themselves". Those concepts are the foundation of the architecture.