Analyzing the reuse potential of migrating legacy components to a service-oriented architecture

An effective way of leveraging the value of legacy systems is to expose their functionality, or subsets of it, as services. In the business world, this has become a very popular approach because it allows underlying systems to remain largely unchanged, while exposing functionality to a larger number of clients through well-defined service interfaces. The U.S. Department of Defense (DoD) is also adopting this approach by defining service-oriented architectures (SOAs) that include a set of infrastructure common services on which organizations can build additional domain services or applications. When legacy systems or components are to be used as the foundation for domain services, there must be an analysis of how to convert the functionality in existing systems into services. This analysis should consider the specific interactions that is required by the SOA and any changes that need to be made to the legacy components. We have recently helped an organization evaluate the potential for converting components of an existing system into services that would run in a new and tightly constrained DoD SOA environment. This paper describes the process that was used and outlines several issues that need to be addressed in making similar migrations