The service operations characterize the boundary between application modules (corresponding to a Service Domain) that should each be wholly contained within a business application - note: a typical business application will combine multiple Service Domains aligned ‘modules’. As a result the service operations either define the interfaces between Service Domain aligned modules within a business application or more interestingly the external interfaces between Service Domain aligned modules within one business application and the modules in other business applications. The characteristics of the service exchange represented by the service operation will depend on the technical environment. It could correspond to a hard wired interface or could map to a fully ‘service enabled’ exchange. A service operation will typically map to one or more underlying exchanged machine readable messages and this interaction may follow a simple request/respond choreography or could be a highly complex structured exchange of content dependent messages.