In the field of mobile communication, not only has the scale of network environments increased over the last few years, but there has also been a steady increase in the diversity of mobile communication protocols and service applications due to the spread of mobile Internet applications. To enable these networks to be designed and developed efficiently, it is therefore necessary to have some way of simulating entire systems in order to evaluate different schemes, predict the traffic levels and try out alternative designs. In this study, we simulate a large-scale wide-area mobile Internet environment by allowing multiple existing simulators to cooperate with each other. Specifically, by calling wireless data link protocol software simulator on an OPNET from an ns-2 simulator running a wide-area network simulation, we have conducted a simulated evaluation of a TCP/IP communication protocol suite including a W-CDMA environment, thereby confirming the validity of this approach.