The service model defines the functionality provided to the business, generally by the IT/IS function. As part of the SOA project a list of services is defined within System Architect as Service Definitions. These Services should be discrete and distinct with no overlap between them in terms of the functionality they provide.
Services are grouped into Service Component definitions. In turn Service Components are grouped into Component Categories. Both Service Components and Component Categories should be discrete and distinct with no overlap. A simple acid test to the degree of abstraction of Service Components and Component Categories is that over a circa 5 year period the service model at these levels of abstraction should not change significantly, if at all. Thus the Component Category and Service Component structure should remain static and are used to build a graphical landscape template of functional areas within the Application Landscape Diagram.
Once the service model has been defined as a structure of definitions the model is used to generate a hierarchical diagram within the Service hierarchy.
Services, and in some cases Service Components, are mappable to the Business process (BPMN) to show how the business uses services and also to the Application portfolio to show how services are supported by software.