What is the relationship between BPMN and BPEL?
BPEL is an XML-based language for describing a business process in which most of the tasks represent interactions between the process and external Web services. The BPEL process itself is represented as a Web service, and is realized by a BPEL engine which executes the process description. BPMN is a standard set of diagramming conventions for describing business processes. It is designed to visualize a rich set of process flow semantics within a process and the communication between independent processes. It is intended to support capture of sufficient detail to allow it to be the source of an executable process description. Since BPEL is currently considered the most important standard for execution languages, a translation to BPEL is specified in the BPMN standard. By design there are some limitations on the process topologies that can be described in BPEL, so it is possible to represent processes in BPMN that cannot be mapped to BPEL. There are a few concepts, such as Ad-Hoc sub-pro
BPMN is a visual notation for business process modeling, whereas BPEL is a text-based (XML-based) business process modeling language which includes precise execution semantics. BPMN defines a mapping of its visual notation to BPEL execution semantics, so the best features of both these standards can be combined.
