Task: Perform Subsystem Analysis
Identify the conceptual IT subsystems involved in the service solution, identity their dependencies, and identify the subsystem components that will be involved in realizing the service model.
Purpose
  • To establish the linkage between business models and IT implementations
  • To identify the service realization components that will be designed in detail
Relationships
RolesPrimary: Additional: Assisting:
InputsMandatory: Optional:
  • None
External:
  • None
Outputs
Main Description

Subsystem analysis establishes traceability from business functional areas to the IT subsystems that support each such area.  This process prepares for detailed design by building understandings of the dependencies between the IT subsystems.  Finally, you make initial decisions regarding which detailed components will be involved in realizing each service in the service model.   

This task marks the beginning of the transition from service solution specification into service realization design -- that is, identification and design of the components that underpin the services.  Prior to this point, you have finished the service model.  Now, begin focusing on component-based design.

The steps of this task are not necessarily performed in sequence -- and, sometimes, they need to be performed in concert with steps in other tasks.  For example, it is likely that some dependencies between subsystems will be discovered during the component specification task.

Steps
Identify IT subsystems

In the component model, create an IT subsystem for each business subsystem or business service interface that has been identified for each relevant functional area in the Functional Area model.

Model subsystem dependencies
Document subsystem dependencies in the component model.  See Considerations for Identifying Subsystem Dependencies to read more about reasons for doing this, dependency drivers, and how to model these dependencies.
Identify service component

In accordance with Concept: Service Component, define a service component in the component model to realize each service.  Allocate each service component to an IT subsystem. 

All the services that are provided by a given participant usually are realized by a single service component.  If this is not the case, the SOA Architect needs to revisit the service model and consider refactoring the participant. 

See Guideline: Service Component Patterns to learn more about how to transition from services to the components that implement the services.

Identify functional components

Identify the functional components that support each service component.  See Guideline: Identify Functional Components, Example: Functional Component, and Guideline: Service Component Patterns for additional advice and information.

Identify Technical Components

Identify the technical components that support each service component.  See Guideline: Identify Technical Components, Example: Technical Component, and Guideline: Service Component Patterns for additional advice and information.

Properties
Predecessor
Multiple Occurrences
Event Driven
Ongoing
Optional
Planned
Repeatable
More Information