Build, Buy or Reuse: Services

The one of the most flaunted benefit of SOA is reuse of services. But it is one of the least used aspects of SOA. But Why so?

In enterprises there is no framework exist which can evaluate a service/service requirement which help in reach a decision of Build, Buy or Reuse. To fill up this gap, I have developed a framework. This framework has three aspects:

1. Appraisal Structure
2. Evaluation Criteria
3. Influencers

Appraisal Structure

The Appraisal Structure offers a classification for the types of considerations within the context of the business. The considerations and decision to build, buy or reuse fall into the following categories:

a. Strategic
b. Tactical
c. Operational
d. Business
e. Technical

Strategic considerations deal with the long-term vision and direction of an enterprise. These include:

• Market Share and Differentiation
• Growth
• Strategic Change Management

Tactical considerations deal with the short-term decisions and direction of an enterprise. These include:

• Current Project Portfolio
• Cash flow considerations
• Time consumption considerations

Operational considerations deal with the operational aspects of a project or a portfolio of enterprise. These include:

• Governance
• Change Management
• Skills
• Support and Maintenance

The business considerations are the ones that support the short- to medium-term objectives of the business. These include:

• Contract Management
• Depreciating of Assets
• Internal or External Provision

Enterprise have a technical strategy—one that states what technologies can be used and for what purposes. Considerations in this category include:

• Technology Considerations
• Technology Choice
• Interoperability/Integration
• Repository of Assets

Evaluation Criteria

There are eight Evaluation criteria identified eight attributes that affect Build, Buy or Reuse decision of services.

• Delivery Time
• Complexity
• Investment
• Expense
• Maturity
• Requirements compromise/match
• Maintenance
• Support




Influencers

There are five influencers. Each influencer has attractive and repulsive force field. Which force field will be more effective depends upon particular scenario – internal and external environmental conditions.

• Investment: It has one of the strongest force field – attraction as well as repulsive. This influencer has numerous aspects such as remaining cost-neutral RoI, profitability, affordability, and finally the cost implications of not doing it.

• Expenses: This influencer affect any decision on continuous basis. Investment and expenses in combination cover financial aspect of Build, Buy or Reuse decision. Like Investment, Expense also has multiple views – Cash Flow, ToC, etc.

• Quality: In market one with right quality wins keeping other parameters constant. Therefore Quality of Service (QoS) plays major role while making Build, Buy or Reuse decision. This influencer is also multi facet. Most of the abilities or non functional requirements are covered under Quality head.

• Time: In fast changing environment time is very critical. Time to market is one of the important parameter which affects Build, Buy or Reuse decision.

• Sustainability: Due to fast pace of technological and business environment evolution, obsolesce of a particular service and effort needed to keep it updated drives Build, Buy or Reuse decision.

The framework is very general in nature. It must be tweaked to a particular enterprise business environment, vision, goal, objectives and tactical needs.

Reference: The Architectural Journal (Microsoft) 20