Often scientists need to know how things will work in the real world. When the experiment that is being conducted is on a large scale and the risks are too high and the cost is too great, it is not possible to implement it in real life. This is where simulations come in useful, wherein the scientists are able to replicate the model that they expect to see in real life and obtain the results that will help them in their process.
There are many applications that are available that can allow researchers to simulate what they expect to see in real life. Those working in the field of networks would be familiar with NS2 or Network Simulator 2. It is what is called as a discrete event simulator. The simulator creates a model where the operations of a system act as a sequence of events and as the time changes the state of the system changes as well. There is another application called NS3 or Network Simulator 3 and this is open source software. That means it is publicly available and free for anyone to use and develop.
One of the benefits offered by the simulator is that it can also be an emulator. That means that it can be connected to a live network. Once it has been connected to a live network, it will receive data from the incoming network traffic allowing the researcher to work on it and analyse it.
There are two languages which are used to build this application. The first is C++. This is the language that is used to create the internal system of the simulator. The second is OTCL. This language controls the discrete events and simulations. The simulator gives results in both a text format as well as an animation format.