This paper present a new method for the forecasting of network traffic in heterogeneous environment. This research investigates performance evaluation of network interface port on heterogeneous services and technologies environment. We propose an enhanced equation to evaluate the performance of network interface port via Little Law and Queuing theories to improve the evaluation algorithm. To get accuracy results on the performance of simulation model, we measure (verify and validate) data from lab experiment and real network environment. We use network management tool to capture those data and Fluke Optiview device to generate traffic. As a result, this simulation model can provide a good approximation of the real traffic observed in the real network environment. The experimental results indicate that the present method is capable of approximating the performance of network traffic over heterogeneous services and techniques within a minimum error range.