# Defining a loopback between port A and B is as follows:# Port = <PortA>,<PortB>,<delay>,<queue size>,<element (packet) size>[Defaults]Port= 0,1,1,10,1500Port= 501,502,1,10,1500Port= 503,504,10,10,1500Port= 505,506,100,10,1500Port= 507,508,1000,10,1500