I’ve wanted to define this term for a while, but, someone beat me to it several years ago. I generally agree with what these guys have to say. These terms are still in use today at client sites where DataPower and the IBM SOA stack is being deployed. Service Mediation logic is the application of service virtualization, schema validation, data transformations, protocol transformations, message routing, security, and others-let’s call this abstracting integration logic into an ESB (possibly implemented through WebSphere DataPower). Service Orchestration is the coordination and composition of Web Services to facilitate a complex business process-think WS-BPEL-you generally don’t want to do this in your ESB.
It is noted that there is a fair amount of gray area between these two when it comes to what should and should not be in an ESB tier. Each situation needs to be judged on its own merits.
Service Mediation is what I deal with far more often on a day-to-day bases. When I use the term I am referring to the application of some combination of the following:
- Data Transformation
- Protocol Transformations
- Schema Validation