At design time, all objects that are the foundation for Web services are modeled in the Enterprise Services Repository (outside-in mode).

It is also possible in the inside-out mode to make service provider functions available as Web services. In an AS ABAP service provider system, you can publish independent function modules that were implemented as RFC-enabled function modules, functions groups, or BAPIs as Web services.

The provider proxy is generated and implemented in the service provider system and the service definition is configured. The Web service is then classified and published in the Services Registry, if a Service Registry is available in your system landscape.

The service consumer finds the Web service in the Services Registry and generates and implements the consumer proxy in the service consumer system.