Enabling Enterprise Services 

This scenario shows you how you can develop services on the basis of Web service standards, and how you can apply these services.

Service Concept

The complexity of heterogeneous system landscapes based on different platforms, computer languages, and proprietary APIs makes the integration of processes and applications a difficult task. Using Web services enables you to integrate applications without the need for complicated, expensive development projects. The following concepts are fundamental for the development of these services:

·        A service is a routine that can be called and executed. It hides the implementation and the actual accessing of the data. Unlike proprietary APIs, services have a standardized interface. To make an existing function of a system available to the outside world, you can encapsulate the function as a service

·        Services are based on the W3C standard WSDL (Web Service Description Language). WSDL is independent of a specific computer language. Consumers of a service use this description to call the service. You can either create a WSDL description for existing functions, or create services directly in WSDL.

·        When developing and modeling cross-system processes, it is essential that the description of a service is available centrally, for example on a UDDI server (Universal Description, Discovery, and Integration). However, developers still implement the service in the application systems.

·        Developing according to the service concept is the key to the flexibility of an Enterprise Service Architecture (ESA).

Service Provider and Service Consumer

This scenario differentiates between the service provider that implements and provides services, and the consumer who calls these services:

·        Services are developed based on a universally-valid philosophy, regardless of how the services are used.

·        The way each service can be used is not fixed and there are different variants, which are dependent on the requirements of the application. The variants define the way in which the service is called and by whom.

Integration with Other IT Scenarios

This scenario uses processes from the scenarios enabling application-to-application integration, enabling business-to-business processes and business process management.

Scenario Variants

The scenario consists of the following scenario variants:

Variant	Description
Point-to-Point Service-Based Integration	In this variant, you make the functions of an application server (ABAP or Java) available as a Web service to enable direct communication between a Web service client and the service provider.
Brokered Service-Based Integration	Enhances the previous variant by enabling the Integration Broker to be used as broker between the service provider and the service consumer to make use of additional integration functions.