SAP Exchange Infrastructure
SAP Exchange Infrastructure (SAP XI) is an integration technology and platform. XI uses by default an extended SOAP protocol for connecting applications. In addition, other protocols, such as JMS, JDBC, RFC and IDOC, can be used with adapters. XI provides communication services such as message routing and mapping of messages between different formats and contains a component for cross-component business process management (ccBPM). This component makes it possible to model and execute business processes on XI.
SAP XI provides, among other things, reliable messaging for asynchronous communication. Therefore, the SAP application does not implement such functionality on its own for the asynchronous invocation of Web services but requires SAP XI-based communication in this scenario.
The figure below shows the XI scenario for invoking Web services by refining the architecture introduced in the previous sections. The different types of proxies described in the section Proxy Type are not shown (for clarity reasons).
XI Based Web Service Invocation
More Information
For more information about SAP XI, see the SAP help portal at 
help.sap.com 
SAP NetWeaver.
