1. Tester #2 sleeping Model  Main Test Component: one MTC to create X PTCs. Parameter X is run-time configurable (in configuration file).  X PTC: ready to manage an incoming request. Initially only one PTC is listening the port but all the test components are deployed. MTC Tester #1 ready Create Connect Start Behavior #1 Tester #X sleeping Create Connect Create Connect System Under Test Listening Port #1= ip:tcp1 Listening Port #2= ip:tcp2......

2. Tester #2 sleeping Model  System Under Test send a CER to the Test System using the first port, for example.  PTC Tester #1 answer with a CEA and continues in ready state listening for CCR messages. MTC Tester #1 ready Create Connect Start Behavior #1 Tester #X sleeping Create Connect Create Connect System Under Test (1)...... Listening Port #2= ip:tcp2 CER (2) CEA

3. Tester #2 sleeping Model  System Under Test send a CCR to the Test System using the first port, for example.  PTC Tester #1 changes automatically its state from ready to busy, and wake up the next idle component, in this case PTC Tester #2 starting up Behavior #2. MTC Tester #1 busy Create Connect Start Behavior #1 Tester #X sleeping Create Connect Create Connect System Under Test (4)...... Listening Port #2= ip:tcp2 CCR (3) Start Behavior #2 (5)

4. Tester #2 ready Model  PTC Tester #2 now is ready to handle any incoming CCR while PTC Tester #1 is busy checking and answering to the CCR. MTC Tester #1 busy Create Connect Start Behavior #1 Tester #X sleeping Create Connect Create Connect System Under Test...... Listening Port #2= ip:tcp2 (7) CCA Listening Port #1= ip:tcp1 Listening Port #2= ip:tcp2 (6)

5. Tester #2 ready Model  Once PTC Tester #1 has sent the CCA to System Under Test it changes its status from busy to sleeping, and put into an idle mode until other PTC Tester wakes up again with Behavior #2 to handle potential incoming CCRs (in this case the load that the System Under Test is generating is not very heavy). MTC Tester #1 sleeping Create Connect Start Behavior #1 Tester #X sleeping Create Connect Create Connect System Under Test (8)...... Listening Port #1= ip:tcp1 Listening Port #2= ip:tcp2

6. Tester #2 busy Model  In heavy load conditions all the PTC Tester components may be in a busy state that means no incoming message will be processes (the Test System is working in the limit). This situation is similar to the clipping phenomenon in analog amplifiers. The solution is simple: to increase the number of PTCs modifying the run-time X param. MTC Tester #1 busy Tester #X busy System Under Test...... CLIPPING!!!