Lane (swimlane)

How to read it

BPMN 2.0.2 defines a lane as a sub-partition of a process, usually within a Pool, running its whole length either horizontally or vertically. The standard leaves the meaning of lanes to the modeller; it names internal roles such as a manager, systems such as an enterprise application and departments such as shipping or finance as common uses. Each step sits in the lane of whoever carries it out, and sequence flows can cross from one lane to another. Lanes can be nested, for example roles within departments.

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What a swimlane diagram is

Stephen White of IBM, introducing BPMN 1.0 in 2004, wrote that many process modelling methods use swimlanes to organise activities into separate visual categories showing different responsibilities, and that BPMN supports them with two constructs, pools and lanes. Lanes, he wrote, are the closer of the two to the traditional swimlane methods.

Pool or lane

A pool is a separate participant, such as another company, and only messages pass between pools. Lanes divide one participant’s process. Politecnico di Milano’s exercise book says a lane has the same shape as a pool and stands for a role or an actor within that participant. Camunda’s BPMN reference lists positions such as an accounting clerk, departments such as sales and IT applications such as a CRM system as things lanes often stand for, while noting that BPMN does not specify it.