| Network simulators play a significant role in network research that involves the validation of the behavior of existing protocols, the development of new protocols, and performance comparison of different algorithms and architectures. A number of commercial and academic simulators are currently available for network research and development, including REAL, GlomoSim, JavaSim, NS (Network Simulator), SSFNet and OPNET (Optimized Network Engineering Tool). They are used for modeling, simulation, data collection and analysis of various types of network products, protocols and system architectures. This work investigates two popular discrete-event simulators used in the network community, NS and OPNET. The architecture, modeling efficiency, simulation performance, analytical capability, protocols and applications of NS and OPNET are compared. This work is significant because a comparative study between NS and OPNET has not been undertaken in much detail before. It provides a guide to researchers for choosing the appropriate simulator depending on their simulation requirements. |
