1_2 List-Process Command State start state AtoB:1 ready BtoA:1 ready dispatch:1 ready Démarrer 47 objet(s) 1.14Mo Figure 4.9 The Simulator is ready for MSC & SDL trace In the Command Window, you can see that the ready queue now contains process dispatch from block DLCa, ready to input signal L_EstabReq, as depicted in Figure 4.10. SimUI Command File Command List-Ready-Queue Command Entry PId State Signals Signal inst dispatch: 1 ready L_EstabReq <<Block DLCa>> Figure 4.10 The Simulator ready queue 4.2.2.2 Play and record the scenario DLC establishment You will simulate the SDL model, trying to play the scenario described in the MSC DLC establishment, shown in Figure 3.5. The Simulator will generate an MSC trace representing the actual SDL behavior, which you will compare with the expected MSC shown in Figure 3.5. Press three times the Transition 9 button in the Execute group until you see the Select Enter path window10: the Simulator executes the ready transitions (scheduled in the Simu- lator ready queue). If you had pressed on Go, the Simulator would have run automatically until the model is blocked. 10 This window appears because the Simulator reaches a decision containing text between quotes, called an informal decision: it asks you which answer you want to execute. 46 Validation of Communications Systems with SDL B. In the Select - Enter path window, select 1 /* "No" */ and press OK. It means that the signal v76frame is not lost. C. Press ONCE ONLY the Transition button. In the MSC trace, you see that process dispatch on side B has just sent L_EstabInd, and in the SDL trace, you see that timer T320 is ready to time-out. To avoid this, do NOT continue the execution: instead you will send an L_EstabResp to dispatch on side B. D. In the Simulator, press the Send To button: select L_EstabResp and press OK. E. Select the target process Block DLCb >> dispatch and press OK: the MSC Editor displays the trace11 represented in Figure 4.11, arranged for clarity. S MSC Editor - SimulatorTrace/1 Pages Diagrams Window Too