All systems are treated as a black box the diagram places emphasis on events that cross the system boundary from actors to systems. Sequence diagrams are sometimes called event diagrams or event scenarios.įor a particular scenario of a use case, the diagrams show the events that external actors generate, their order, and possible inter-system events. Sequence diagrams are typically associated with use case realizations in the 4+1 architectural view model of the system under development.
The diagram depicts the processes and objects involved and the sequence of messages exchanged as needed to carry out the functionality.
In software engineering, a sequence diagram or system sequence diagram ( SSD) shows process interactions arranged in a time sequence.