BPMN Pool and Lanes
Swimlanes are one of the five basic categories of BPMN elements. They act as a container for partitioning a set of activities from other activities. BPMN 2.0 defines two different types of Swimlanes: Pools and Lanes.
A BPMN Pool represents a Participant in a business collaboration. In a BPMN diagram, a Participant can be a specific Partner Entity like a company or a Partner Role such as a buyer, seller, or manufacturer.
A Pool acts as a container for a full business process, and the process has to be fully contained within the Pool. The sequence flow cannot cross outside the boundaries.
A Pool has two basic representations: “white-box” and “black-box”. A white-box representation shows the internal details of the Pool, whereas a black-box representation hides any processes.
Black-box representations are best used when the Pool doesn’t reference a process but only an external process participant. Therefore, black-box pools are commonly named according to the process participant they represent, while white-box pools are commonly named according to the contained process.
A BPMN Lane is a sub-partition within a Pool and extends the entire length of the Pool, either horizontally or vertically.
Lanes are used to organize and categorize Activities within a Pool. In practice, Lanes are commonly used for allocating activities to roles, systems, or the organization’s departments.
In addition, Lanes can be nested or defined in a matrix. For example, in a Pool, there could be an outer set of Lanes for company departments and then an inner set of Lanes for roles within a department.
Although BPMN specification explicitly describes the possibility of “matrix” Lanes, they are rarely used. Nevertheless, the matrix structure of Lanes can enable optimal organization of process activities.
What is the difference between pools and lanes in BPMN 2.0?
At a glance, both swimlane elements look very similar. However, they have completely different meanings. A Pool represents a participant in a business collaboration and may act as a container for a single process, whereas a Lane represents an “activity-classifying mechanism”.