2.5.2 SOA Specific Cost Estimation Approachs

2.5.2 SOA specific cost estimation approaches
As the traditional cost estimation approaches failed to estimate the cost of SOA projects, SOA specific cost estimation approaches were proposed to address the SOA characteristics.
2.5.2.1 Linthicum Formula
This formula is one of the earliest approaches of SOA cost estimation‎[7]. The cost of SOA is calculated based on equation (1)
Cost of SOA = (Cost of Data Complexity + Cost of Service Complexity + Cost of Process Complexity + Enabling Technology Solution) (1)

Based on Linthicum formula, the SOA cost is affected by these factors :
• Number of data elements
• Complexity of data storage technology
• System complexity
• Service complexity
• Process Complexity
• New services needed
• Enabling technology
Also existence of updated detailed documentation of the legacy system and the quality of such documentation is vital information. Also Legacy dependencies have to be carefully identified and documented.
Describe Target SOA Environment:
In this step the target SOA environment has to be described in details .How services would interact with the SOA environment, QoS expectations and execution environment for new services is the main concern.
Analyze the Gap:
The gap between the existing legacy system and the target SOA system has to be cautiously analyzed.
Develop Migration Strategy:
Based on the gap between the existing legacy system and the target SOA system, the migration strategy is chosen and developed. The migration strategy has to address the migration issues and risks .Also considers the various migration strategies to follow. These migration strategies are wrapping, reengineering, replacement or migration, these migration strategies have been discussed