Netsim Standard is a proprietary/commercial software which can be bought by your university/institute. You can write to them at [email protected] for further product information. Visit www.tetcos.com for more information.
I highly recommend NetSim for research compared to other simulators like NS-2, as it so far the best network simulation and emulation software where you can design, run and analyse the results/animation. NetSim works on latest technologies like IoT, WSN, MANET, Cognitive Radio etc.
My friend had a huge difficult using NS-2 for his undergraduate research, when he had to work on 802.15.4 networks and NS-2 is not so compatible for 802.15.4 networks. Most importantly NetSim saves time, yet with most precise results.