Using callbacks and traces for inspection of ns-3 nodes and protocols

In simulations, it is very important to inspect the working of protocols and applications. ns-3 offers an important feature called tracing to inspect a variety of nodes and their installed protocols and applications. Before using the ns-3 tracing feature in your simulation, it is important to learn how tracing works. In ns-3 simulations, nodes are the important building blocks to understand where we install protocols and applications. In ns-3, tracing can be viewed as the implementation of event handling at sources and sinks. In ns-3, nodes are major event sources, where protocols and applications generate a variety of events, such as packets received and dropped and congestion window changed. These events carry important details related to protocols and applications from sources. In ns-3, trace sources are implemented using the ns-3 TracedCallback class.

On the other hand, while running the simulation, we are...