Service-Oriented Architecture (SOA)

Service-Oriented Architecture (SOA) is an architectural style that supports service orientation.

Service orientation is a way of thinking in terms of services and service-based development and the outcomes of services.

• Is a logical representation of a repeatable business activity that has a specified outcome (e.g., check customer credit; provide weather data, consolidate drilling reports)
• Is self-contained
• May be composed of other services
• Is a “black box” to consumers of the service

An architectural style is the combination of distinctive features in which architecture is performed or expressed.

The SOA architectural style has the following distinctive features:

• It is based on the design of the services – which mirror real-world business activities – comprising the enterprise (or inter-enterprise) business processes.
• Service representation utilizes business descriptions to provide context (i.e., business process, goal, rule, policy, service interface, and service component) and implements services using service orchestration.
• It places unique requirements on the infrastructure – it is recommended that implementations use open standards to realize interoperability and location transparency.
• Implementations are environment-specific – they are constrained or enabled by context and must be described within that context.
• It requires strong governance of service representation and implementation.
• It requires a “Litmus Test", which determines a “good service”.