By now, it should be abundantly clear that SOA is not the right answer for every situation. When you boil it down to the essentials, there are two reasons that SOA must be applied selectively:
The expense of service orientation cannot be recouped in every situation.
Service orientation can actually do more harm than good in certain situations.
Consequently, it is essential that the governance team put a methodology in place for determining when SOA makes sense and when it does not. The following methodology—Selective SOA™—has been successfully applied in a variety of SOA initiatives across different industries.
Phase 1: Bottom-Up Analysis
Selective SOA begins with a bottom-up analysis. What existing enterprise assets and resources are available for service orientation? This perspective looks at the current state of the enterprise from a people, process, and technology perspective to examine the assets and resources that are immediately available for use within an SOA. Exhibit 9.2 summarizes the key categories on which the bottom-up analysis focuses.
Typical questions that must be answered when performing a bottom-up analysis include:
What current business processes could benefit from service orientation?
What enterprise systems are available for service orientation? (e.g., customer relationship management [CRM], enterprise resource planning [ERP], custom finance package, etc.)
What is the state of the current technology infrastructure? (e.g., hardware/software, ...