Service Oriented Architecture (SOA) and Web services

Service Oriented Architecture (SOA) is based on a philosophy of how to connect systems and exchange data to solve business problems.

Rather than concentrating on a specific task or transaction, SOA addresses how to use data from various sources, reduce human involvement, and mitigate the effects of change in a business process and its supporting systems.

SOA defines the services to be provided. Web services are the means of implementing those services. Web services provide a platform-neutral technology to connect multiple systems in a flexible manner, where the platform-neutrality helps insulate the SOA from changes to the underlying systems.

An SOA's resilience to change is accomplished by adhering to good Web services design practices:

Building a Web service that performs a specific task
Having a rigid structure for the data