 in Figure 4.22. The information displayed here is more synthetic as it only shows the transitions not executed. But even if it indicates that all the transitions have been executed, a branch after an answer to a decision could remain uncovered: this can only be detected by the symbol coverage tree. As we have only replayed the scenario testl.scn, it is normal that two transitions that are not executed are displayed in Figure 4.22, one in process dispatch corresponding to the input of DLCstopped, the other in process DLC corresponding to the input of timer T320; to sim- ulate them, we also need to replay retryl.com, and then press on Transition to execute one more transition. 4.2.5 Validate against more scenarios After simulation of the main scenarios, described in Section 4.3.2, it is wise to play more scenarios to check the reaction of the SDL model. Those scenarios can be Interactive Simulation 59 more complex: for example, two simultaneous connections, beyond limits: for example, creation of more connections than allowed. 4.2.5.1 Simulate two simultaneous connections You will simulate to check that the SDL model can handle two connections in parallel. A. In the Simulator, select File > Restart and press OK. B. Type the command Define-MSC-Trace-Channels on (or type d-m-t-c on) to get two envi- ronment instances. C. Select Trace > MSC Trace: Start: a Select window appears. In the Select window, select 0 /* Basic MSC */ and press OK. Select Execute > Command Script, choose cnx1.com and press OK; the Simulator executes the commands contained in cnxl.com one instance of process DLC exists on each side of the system. Now establish one more connection: E. Press the Send To button: select L_EstabReq and press OK. Enter the value 1 for the parameter of signal L_EstabReq and press OK. Select the target process < < Block DLCa > > dispatch and press OK. F. Press several times the Transition button until you see the Select - Enter path window. A new instance of process DLC is created. G. In the Select - Enter path window,