SCs, GOAL observer cannot be tracked. B. In the Simulator, press the Watch button, then press States: as depicted in Figure 5.76, the state of the observer obs1 is displayed. Watch process dicbidio not created or stopped process dicaldlo not created or stopped dicaldispatch ! state = start dicbidispatch ! state = start process dicaldio not created or stopped process diabidio not created or stopped atob(1) ! state = start btoa(1)Lstate = start obs1 ! state = idle Figure 5.76 The state of observer obs1 C. Press the Start MSC button. D. Replay a Simulation scenario: select File > Scenario > Load, choose testl.scn, and press the Redo: All Simulator button: at Step 15, the simulation should stop, and display: stop condition: not verifying () and success (obs1 This means that observer obs1 has reached a success state: in the watch, you see that the state of obs1 is ok. The expression not verifying() prevents the Simulator from stopping during an exhaustive simulation. It proves that the SDL simulation performed matches the behavior expected in the observer MSC obs1 : you can check in the MSC trace that block DLCa has received L_EstabReq, then that signal L_EstabConf has been transmitted by block DLCa, and that the parameter of L_EstabConf, 0, is equal to the parameter of L_EstabReq. 5.3.6 More details on GOAL observers GOAL observers can read and change any SDL variable, including the contents of process queues, and have also access to constants and types defined in the observed SDL model. One .obs file can contain several GOAL observers. 162 Validation of Communications Systems with SDL 5.3.6.1 Ordinary and event GOAL observers By default, only one transition in each GOAL observer is executed after each SDL model transition. For example, the observer in Figure 5.78 will not detect any success in the SDL model represented in Figure 5.77, because the SDL model outputs the signals orange and red in the same transition; then the Simulator executes one transition only in the observer obs1 it goes from state waitOrange to s