Build two VoIP diagram as scenario using OPNET Modeler and GNS 3 and test the performance -- 2

Help me to create two VoIP diagram as scenario using OPNET Modeler and GNS 3. Test the performance of two scenario. Then using anyway(better can use Omnipeek, if not can tell me) to get the packet data like delay, packet loss and performance. After test this 2 scenario and Skype, need to compare 2 scenario and Skype ,which one is the best VoIP and which is the bad VoIP. Any don't understand, can ask me