Introduction

Integration of Processes

SAP NetWeaver PI facilitates the integration of business processes that span different departments, organizations, or companies. Think of a process component being part of the value chain of a business application or a business process.

If we assume that a business application ranges over different departments of one company, then a process component usually represents one part of the process that is performed in one department. The following figure displays an integration scenario and shows the separation of a business application into its process components (blue icons), as well as the connections between those process components. In the example outlined in the figure, the process components run in three different departments of a company: A, B, and C. Process components can run on different systems, can be hosted in different departments of a company, or can be implemented in completely different companies that have a business relationship with each other. The process components exchange data with each other and thereby ensure that the value chain of the business process as a whole is maintained.

The focus of SAP NetWeaver PI is not on the inner-life of the individual process components, or how the business logic is implemented within a process component, but rather on how the process components exchange data with each other. Process integration is all about choreographing the exchange of data between process components.

Mediation

Technically, the business logic of different process components in an integration scenario is implemented on different systems. Let us assume that the systems involved in an integration scenario communicate directly with each other. For example, if the process components run on different SAP systems, one SAP system calls another using a remote function call. We call this kind of communication “point-to-point” or 'direct communication'. However, an upgrade to one part of the system landscape would, for example, entail that all individual connections that are affected also have to be adapted as part of the upgrade. In the case of large system landscapes, this approach could easily get out of control since the number of connections grows to the square of the number of systems.

However, consider a situation where a central instance or 'middleware' interconnects the systems. We call this type of communication 'mediated communication' and refer to the middleware as the SAP NetWeaver PI runtime engine. With a central instance interconnecting the systems, you then have the option to have all integration-relevant information accessible at one central location. In contrast to the point-to-point scenario (where there is a “spaghetti-like” arrangement of connections), in a mediated scenario the number and arrangement of connections remains manageable.

The following figure illustrates the difference between mediated and point-to-point communication:

Mediated communication is executed by exchanging XML messages. Accordingly, in the context of SAP NetWeaver PI we usually speak of message-based integration. The messages contain the business data exchanged between the systems involved in a cross-component process. The message protocol of SAP NetWeaver PI (which the runtime engine can process) is based on the W3C standard SOAP Messages with Attachments.

More information: Messages