SSD(System Sequence diagram for Alternative scenarios oof sameusecase

Hi all

Plz let me know that for Alternative scenarios of same usecase can we make separate System sequence diagram for each alternative scenario of same use case or make single system sequence diagram containing all alternatives and Main Sucess Scenario of same usecase as well?

Plz reply soon its urgent

Hi Safar,

Thanks for your question. It’s recommend to draw separate sequence diagrams for each alternative scenario of same use case.

Best regards,
Lilian Wong

Thanx a lot 4 ur reply and solving my pbl but i am taking about SSD(System Sequence Diagram). i have made separate Sequence diagram but confuse just coz of SSD.


Thanks for replying. Actually when I mean is the System Sequence Diagram, which representing interactions between actor(s) and the system. Everything described in System Sequence Diagram should be observable by the actor(s) and should not yet include any information on how the problem is to be solved.

If you have a complex system, you may need to create Subsystem-level Sequence Diagram, which is elaborated from System Sequence Diagram and showing the internal messages among subsystems.

For example, if we are modeling an ATM system, you may have the System Sequence Diagram and Subsystem Sequence Diagram for the activity "Withdraw Money"as shown as the image below.

Hope this helps you understand more on this issue.

Best regards,
Lilian Wong


Repected sir

i agree with u but the SSD u discussed other then ATM system, Bank and other system as well.The SSD i am making 4 my project is that the whole things take place inside the is not involving other system for its completetion…

To show the same system behave differently in alternative scenario i want to make different SSD…

Hi Safar,

Thanks for replying. The sequence diagram I picked as example is only in a different scope from yours, I illustrated the interactions that perform outside the ATM machine, but you can model the interaction between within the ATM machine (interactions between ATM machine, screen, cash dispenser, receipt printer, etc) in the sequence diagram. In a word, it depends on your requirements and scope in your system.

Best regards,
Lilian Wong