Creating and Configuring Service Providers and Service Consumers 
SAP NetWeaver Application Server ABAP can be used both as a Web Services provider and as a service consumer. You can create, configure, publish, and consume services.
A Web service is a modularized, executable unit. It can be called in heterogeneous system landscapes and is not restricted to a single host system. Based on the given input parameters, output is determined by the system. This is subsequently passed back to the caller.
While Web services represent a technical concept, the service-oriented architecture enables you to design a complete solution for any business application.
The Web Services Framework comprises the development environment of SAP NetWeaver Application Server ABAP, the Enterprise Services Repository, tools to support UDDI registration in the form of the Services Registry, and an interoperable SOAP runtime environment.
SOAP requests are processed using the Internet Communication Framework. The http protocol of the Internet Communication Framework is used for communication between the consumer and the provider.
Web Service Standards
SOAP, WSDL, and UDDI are the core standards for all Web service approaches. SOAP provides standards for a general, application-independent format for XML messages. XML messages can be exchanged between the communication partners using different transport protocols. WSDL adds on the application-related component. Using this language, you can describe the interface for actual Web services. The latter consist of names of operations as well as input and output messages. At runtime, they are packed into SOAP messages and transmitted. UDDI provides the additional option of being able to publish and look for Web services.
The standards supported by SAP are described in the section Supported Standards.
Structure
Providing a Web Service
If the AS ABAP functions as a service provider, a service interface is created for the implemented function. This represents the Web service for the user. Based on this interface, the service is configured and can be called at runtime.
For more information, refer to: Providing a Web Service.
Consuming a Web Service
If the AS ABAP has the function of a service consumer, it is possible to generate a proxy – in just a few steps – using a WSDL document. The service can be called from a program.
For more information, refer to: Consuming a Web Service.
Configuring a Web Service
Both the service consumer and the service provider must be configured at runtime.
For more information, refer to Configuring the Web Service Runtime.
Making a Web Service Secure
To configure special security settings, you must configure security settings in the systems of the consumers and providers that communicate with one another.
For more information, refer to Making a Web Service Secure.
Publishing a Web Service
You can store released Web services in the Services Registry. Web services can be searched for and published in all registries that conform to the standard.
For more information, refer to Publishing a Web Service.
Managing the Web Service Runtime
To be able to use Web Services with Web Services Reliable Messaging, you must have the Web service runtime configured.
For more information, refer to: Configuring the Web Service Runtime.
In the AS ABAP, different tools for monitoring the Web service runtime are at your disposal.
For more information, refer to: Monitoring the Web Service Runtime.
More Information
SAP Developer Network (https://www.sdn.sap.com/irj/sdn) under SOA Middleware
Description of a delivered example application — SAP NetWeaver Demo Model (https://www.sdn.sap.com/irj/sdn/nw-demomodel) in the section SAP NetWeaver / Enterprise SOA.