What is Business Process Modeling Notation? (BPMN)

The Business Process Modeling Notation (BPMN) is a standardized graphical notation for drawing business processes in a workflow.

Business Process Modeling Notation was developed by Business Process Management Initiative, and is now being maintained by the Object Management Group since their merger in 2005. The primary goal of BPMN is to provide a notation that is readily understandable by all business users, from the business analysts who create the initial drafts of the processes, to the technical developers responsible for implementing the technology that will perform those processes, and finally, to the business people who will manage and monitor those processes. Thus, BPMN creates a standardized bridge for the gap between the business process design and process implementation. Currently, there are scores of process modeling tools and methodologies. BPMN will also advance the capabilities of traditional business process notations by inherently handling B2B business process concepts, such as public and private processes and choreographies, as well as advanced modeling concepts, such as exception handling and transaction compensation.

Business Process Modeling Notation (BPMN) scope

BPMN is constrained to support only the concepts of modeling that are applicable to business processes. This means that other types of modeling done by organizations for business purposes are out of scope for BPMN. For example, the modeling of the following will not be a part of BPMN:

  • Organizational structures
  • Functional breakdowns
  • Data models

In addition, while BPMN shows the flow of data (messages), and the association of data artifacts to activities, it is not a data flow diagram.

Uses of BPMN

Business process modeling is used to communicate a wide variety of information to a wide variety of audiences. BPMN is designed to cover this wide range of usage and allows modeling of end-to-end business processes to allow the viewer of the Diagram to be able to easily differentiate between sections of a BPMN Diagram.

There are three basic types of sub-models within an end-to-end BPMN model:

  • Private (internal) business processes
    • These are internal to a specific organization and are the types of processes that have been generally called workflow or BPM processes. If swim lanes are used then a private business process will be contained within a single Pool. The Sequence Flow of the Process is therefore contained within the Pool and cannot cross the boundaries of the Pool. Message Flow can cross the Pool boundary to show the interactions that exist between separate private business processes.
  • Abstract (public) processes
    • This represents the interactions between a private business process and another process or participant. Only those activities that are used to communicate outside the private business process are included in the abstract process. All other “internal” activities of the private business process are not shown in the abstract process. Thus, the abstract process shows to the outside world the sequence of messages that are required to interact with that business process. Abstract processes are contained within a Pool and can be modeled separately or within a larger BPMN Diagram to show the Message Flow between the abstract process activities and other entities. If the abstract process is in the same Diagram as its corresponding private business process, then the activities that are common to both processes can be associated.
  • Collaboration (global) processes
    • Depicts the interactions between two or more business entities. These interactions are defined as a sequence of activities that represent the message exchange patterns between the entities involved. Collaboration processes may be contained within a Pool and the different participant business interactions are shown as Lanes within the Pool. In this situation, each Lane would represent two participants and a direction of travel between them. They may also be shown as two or more Abstract Processes interacting through Message Flow. These processes can be modeled separately or within a larger BPMN Diagram to show the Associations between the collaboration process activities and other entities. If the collaboration process is in the same Diagram as one of its corresponding private business process, then the activities that are common to both processes can be associated.

Types of Business Process Diagrams

Within and between these three BPMN sub-models, many types of Diagrams can be created. The following are the types of business processes that can be modeled with BPMN:

  • High-level private process activities (not functional breakdown)
  • Detailed private business process
  • As-is or old business process
  • To-be or new business process
  • Detailed private business process with interactions to one or more external entities (or “Black Box” processes)
  • Two or more detailed private business processes interacting
  • Detailed private business process relationship to Abstract Process
  • Detailed private business process relationship to Collaboration Process
  • Two or more Abstract Processes
  • Abstract Process relationship to Collaboration Process
  • Collaboration Process only (e.g., ebXML BPSS or RosettaNet)
  • Two or more detailed private business processes interacting through their Abstract Processes
  • Two or more detailed private business processes interacting through a Collaboration Process
  • Two or more detailed private business processes interacting through their Abstract Processes and a Collaboration Process

BPMN is designed to allow all the above types of Diagrams. However, it should be cautioned that if too many types of sub-models are combined, such as three or more private processes with message flow between each of them, then the Diagram may become too hard for someone to understand. Thus, we recommend that the modeler pick a focused purpose for the BPD, such as a private process, or a collaboration process.

Elements

Models in Business Process Modeling Notation are made by simple diagrams with a small set of graphical elements. It should make it easy for business users as well as developers to understand the flow and the process. The four basic categories of elements are:

  • Flow objects
    • Flow Objects consist of only three core elements:
    • Event: An Event is represented with a circle and is something that happens. It could be Start, Intermediate or End. This element is a trigger or a result.
    • Activity: An Activity is represented with a rounded-corner rectangle and shows us the kind of work which must be done. It could be a task or a sub-process. A sub-process also has a plus sign in the bottom line of the rectangle.
    • Gateway: A Gateway is represented with a diamond shape and will determine different decisions. It will also determine forking, merging and joining of paths.
  • Connecting objects
    • The Flow Objects are connected to each other with Connecting Objects. There are three different Connecting Objects:
    • Sequence Flow: A Sequence Flow is represented with a solid line and arrowhead and shows in which order the activities will be performed.
    • Message Flow: A Message Flow is represented with a dashed line and an open arrowhead. It tells us what messages flow between two process participants.
    • Association: An Association is represented with a dotted line and a line arrowhead. It is used to associate an Artifact, data or text to a Flow Object.
  • Swimlanes
    • A Swimlane is a visual mechanism of organizing different activities into categories of the same functionality. There are two different swimlanes, and they are:
    • Pool: A Pool is represented with a big rectangle which contains many Flow Objects, Connecting Objects and Artifacts.
    • Lane: A Lane is represented as a sub-part of the pool. The lanes are used to organize the Flow Objects, Connecting Objects and Artifacts more precisely.
  • Artifacts
    • Artifacts allow developers to bring some more information into the model/diagram. In this way the model/diagram becomes more readable. There are three pre-defined Artifacts and they are:
    • Data Objects: Data Objects are used to show the reader which data is required or produced in an activity.
    • Group: A Group is represented with a rounded-corner rectangle and dashed lines. The Group is used to group different activities but does not affect the flow in the diagram.
    • Annotation: An Annotation is used to give the reader of the model/diagram an understandable impression.