Part 4: Viewing an MSC trace

In the final part of this exercise on Viewing MSC traces, we will explore the capability of the KLOCwork MSC to SDL tool and the Telelogic Tau to produce graphical execution traces as MSCs.

1. Restart the current simulation. Click on the MSC button in the buttons panel of the Simulator UI.
2. Simulate the model by clicking the Transition button and selecting the appropriate path in the Path Selection dialog. The Tau MSC Editor appears, however, instead of highlighting events at the input MSC diagrams it displays the execution trace as a new MSC diagram in the Telelogic Tau MSC Editor.



Note that the MSC trace in the MSC Editor shows three instance axes. Instances with names USER_1_1 and SERVER_1_2 correspond to the instances of the input MSC model. The third instance, named env_0, corresponds to the environment of the system. This additional instance is not involved in MSC trace at this step.



3. Now we are ready to perform the rest of the simulation. Click the Go button in the Execute group of the Simulator. The Simulator performs all transitions of the model. The Path Selection dialog appears.
4. You must decide whether the User instance will send to the Server the Done message (choice 1) or the Request message (choice 2). Select choice 2 and click OK. Several events appear on MSC trace.



At its start transition, the User instance sends the Init message to the Server and then sends the message Request. Then it enters the state REQUEST_DATA_0 where it waits for the Server instance to reply. At the MSC trace diagram states are displayed as conditions.

At its start transition, the Server instance enters the state REQUEST_INIT_2, where it waits for connection request from the User instance. In this state, the Server receives the message Init from the User instance and performs transition to the state A_LOOP_1, which means that connection was successfully initialized.

Next, the Server receives message Request from the User and sends the Data message as the reply to the User. Then the Server returns to the state A_LOOP_1, where it waits for the next requests from the User.

The User receives the Data message from the Server, and this finishes the first data interchange between User and Server.

5. The Path Selection dialog appears again. Select 1 (send message Done to the Server instance to terminate the connection with the Information Server).

Events, which occur after this, are shown in the following figure.



The User instance sends the message Done to the Server and then stops its execution, which means that connection is terminated.

The Server instance receives the message Done from the User and performs transition to the state REQUEST_INIT_2, where it waits for the Init signal.

Summary

In this exercise we explored the KLOCwork MSC to SDL Synthesizer's capability for simulating MSCs.

In the next exercise we will produce and explore the SDL model, corresponding to the MSC model of our example.