Service-Oriented Architecture

Service-oriented architecture (SOA) is one of those phrases that gets thrown around in everything from technical standards to business books.  Thomas Erl makes four key points in his books: ^[1]

• SOA can establish an abstraction of business logic and technology that allows a looser coupling between an organization's processes and its technology.
  
  
• SOA is an evolution of past approaches, preserving successful characteristics of traditional architectures and adding distinct new principles that foster service orientation.
  
  
• SOA is ideally standardized throughout an enterprise, but achieving this requires a planned transition and still-evolving technology.
  
  
• SOA is a technology architecture that supports and promotes service-oriented principles throughout an enterprise.

What SOA does, at a fundamental level, is allow the development of individual pieces of business functionality in a way that lets them be combined and modified effectively and without tightly coupling them to each other.

References

[1] Thomas Erl.  Service-Oriented Architecture (SOA):  Concepts, Technology, and Design.  Prentice-Hall (2005).