How do you differentiate between BPMN message flows and sequence flows in a collaboration diagram?

1 Message flows

Message flows are dashed lines with arrows that show how messages are sent and received between participants. A message can be a document, a signal, a request, a response, or any other form of communication. Message flows can cross the boundaries of pools and lanes, which are the containers that separate different participants or roles in a collaboration diagram. Message flows can have different symbols at the ends of the arrows, such as envelopes, circles, or crosses, to indicate the type and direction of the message.

2 Sequence flows

Sequence flows are solid lines with arrows that show how activities and events are ordered and connected within a participant. A sequence flow can only exist within a pool or a lane, and it cannot cross the boundary of another participant. Sequence flows can have different symbols at the ends of the arrows, such as diamonds, bars, or circles, to indicate the type and outcome of the activity or event. Sequence flows can also have conditions or expressions attached to them, to specify the logic or rules that govern the flow.

3 How to differentiate

The easiest way to differentiate between message flows and sequence flows is to look at the style and location of the lines and arrows. Message flows are dashed and can cross participants, while sequence flows are solid and cannot cross participants. Another way to differentiate is to look at the symbols and labels of the flows. Message flows have symbols that represent messages, while sequence flows have symbols that represent activities or events. Message flows can also have labels that show the name or content of the message, while sequence flows can have labels that show the condition or expression of the flow.

4 Why it matters

Understanding the difference between message flows and sequence flows is important for creating and reading BPMN collaboration diagrams. By using the correct elements and notation, you can communicate the structure and logic of your business process more clearly and accurately. You can also avoid confusion and errors that might arise from mixing up or misinterpreting the flows. Moreover, you can leverage the power and flexibility of BPMN to model complex and dynamic processes that involve multiple participants and interactions.

6 How to learn more

If you want to learn more about BPMN message flows and sequence flows, and how to use them effectively in collaboration diagrams, there are many online and offline resources available. You can start by reading the official BPMN specification document, which provides the detailed definitions and rules for each element and notation. You can also explore various websites, blogs, books, courses, and videos that offer BPMN tutorials, tips, examples, and best practices. Additionally, you can join online forums, communities, or groups that discuss BPMN topics and issues, and share your questions and insights with other BPMN enthusiasts.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?