You can use systems event/trace descriptions, sometimes called sequence diagrams, event scenarios, and timing diagrams, to trace actions in a scenario or critical sequence of events.

You can use systems event/trace descriptions by themselves or in conjunction with systems state transition descriptions to describe dynamic behavior. The systems event trace descriptions in the systems architecture view can reflect system-specific aspects or refinements of critical sequences of events described in the operational architecture view.

The event trace description is captured in a system event/trace diagram, which shows interactions in terms of messages, or information transfers, between system nodes that are arranged in time sequence.

The event/trace diagram shows the system nodes involved in the scenario by vertical dashed lines, which are called system node event timelines. Horizontal line symbols between the system node event timelines represent the messages, or system events, that pass between the system nodes. The system events are drawn chronologically from the top of the diagram to the bottom; the horizontal placing or spacing of objects is arbitrary.