Abstraction scheme is very important in network simulation modeling, especially in the case of large interconnected LAN via ATM backbone. It is almost impossible to simulate large-scale complex network without proper abstraction, because rapid prototyping and runtime is critical for the efficient analysis of the network design alternatives. Though burst level simulation has been thought to be a proper abstraction for ATM network simulation, it is not directly applicable to Ethernets interconnected via ATM backbone because Ethernet is based on the CSMA/CD (Carrier Sense Multiple Access with Collision Detection) that is characterized by traffic broadcasting and medium sharing. In this thesis, a new abstraction scheme for traffic model and its control scheme are proposed in order to apply the burst level simulation to the Ethernet and, as a result, to perform an integrated simulation of ATM and Ethernet. The traffic model consists of the four levels: Session, Offered burst, Carried-burst, and Packet. The KAIST campus network is analyzed as an example. It is implemented with MODSIM II, a general purpose object-oriented simulation language. According to the example, it is shown that the simulation modeling proposed in this thesis reflects the dynamic behaviors of the interconnected networks in an efficient way.