Enterprise Services Architecture (ESA) is SAP's enhanced version of service-oriented architecture (SOA). ESA facilitates deployment of Web services at the business level. This streamlines the conception and development of innovative application programs within the existing infrastructure of an enterprise, minimizing the cost while allowing timely implementation of new business processes.
The term SOA refers to the underlying structure supporting communications among units of work, also called services, executed on behalf of computing entities such as human users or applications. SOA defines how these entities can interact, allowing one to perform a specific service for another. The interactions are defined using a description language such as Unified Modeling Language (UML).