The BPMN Specification defines a Web Service as a combination of a participant, an interface and an operation. Because those objects have their origin in the BPEL world the ARIS BPEL objects are being reused to represent Participant, Interface and Operation.

The concrete mapping (which BPEL Operation is represented by which BPMN Task) is done inside a BPMN Allocation Diagram. The following figure is the overall view of a BPMN Task that is a representation of a BPEL Operation.

Task 1 has a Web Service Implementation; The Participant that provides the Web Service is WebServices (Pool) – the definition which operation is being executed is done inside the allocation diagram which is assigned behind Task1 (See following figure).

The allocation Diagram behind Task1 – Task 1 executes the Operation SendEMail from the Interface MailHandling on the PartnerLink internal

The BPMN Web Service Pool Object provides the Internal PartnerLink, this partner Link provides the Interface MailHandling, which provides the operation SendEMail This is modeled inside the BPMN Allocation Diagram which has to be assigned behind the WebService(Pool) Object.