Purpose

The landscape for Service Parts Management (SPM) requires an uninterrupted flow of information between system components. SPM uses asynchronous communication in all but exceptional cases, such as reading a status. In these exception cases, SPM uses synchronous communication.

Process Flow

In SPM, SAP CRM and SAP EWM communicate using the ERP system as an intermediary.

At any one point in time, only one system can be the owner of a process and therefore have permission to make changes to a document in that system. This principle is known as ‘owner of the process’.

The system that owns the process at a particular point in time handles changes from other systems as requests that it either accepts or rejects. The system that requests a change sends a change request to the ERP system. The ERP system either rejects the change immediately or if it cannot make a decision, acts as a dispatcher and forwards the change request to the system that currently owns the process. The owner of the process either accepts or rejects the request:

If the owner accepts the request, the ERP system makes the change in the document before forwarding the result of the request to the system that requested the change.

If the owner rejects the request, the ERP system forwards this message to the system that requested the change.

Example

The figure below shows how the ‘owner of the process’ principle works:

In this example from the outbound process, SAP CRM requests a change to a checked delivery that SAP EWM in turn accepts.

SAP CRM wants to change a sales order that SAP EWM owns.

The ERP system receives the change request from SAP CRM and dispatches the request to SAP EWM.

If the change is possible, SAP EWM updates the warehouse request (WR) and forwards this change to the ERP system.

If the change is not possible, SAP EWM sends a rejection message to the ERP system, which in turn sends a corresponding rejection message to SAP CRM.

On receiving the change from SAP EWM, the ERP system updates the checked delivery.

The ERP system communicates this to SAP CRM as a changed delivery.

SAP CRM updates the sales order.

The ERP system serves as the dispatcher and coordinator of the message flow in the system landscape.

To ensure that all systems have the same, up-to-date status, the ERP system distributes the results of any changes to the other SPM systems.