Toward the relief and safe car society, the in-vehicle network communication is evolving speedup and high capability, to connect the each information that ECU and sensor have, with the in-vehicle electronic systems continuing developing. The in-vehicle network developer designs it based on recommended network topology learned by experience or prescribed in ISO or CiA. However, with the evolution of the complicated degree of the network, it becomes difficult to develop it without a verification of an actual machine. On the other hand, as for the verification means at the logic level or physical level that is necessary for a network design, verification in the whole vehicle is difficult by a speedup and large of the system. Therefore it is applicable only for the system which limited to a domain or an area. Even if we cleared the problem mentioned above and was able to build verification environment, the flexible and timely utilization is difficult for the specifications change. Our approach to provide for the further advancement of the network design is to build the simulation environment for the network design at the physical layer and the network layer in the OSI reference model. In this paper, we explain verification technique of the bus load in the network layer and the ringing in the physical layer to arrive at recommended in-vehicle network topology. For the purpose of verifying communication in various network topologies, the model using in the simulation is expressed wire harnesses by a distributed constant circuit and combined it with a terminal circuit model. We show that we can perform virtually not only the verifying communication but also the verifying ringing suppressant effect of a transceiver and the terminator to adopt.