Business processes and information systems have become so tightly intertwined that it is no longer possible to design one without designing the other. Business processes do not simply depend on information systems—they define the services required.

Altering business processes inevitably requires system changes. Conversely, system changes inexorably alter business processes. Herein we find the SOA challenge—designing systems in such a way that accommodating most business process changes simply requires rearranging existing business services.