Network Simulator NS-2

To model a real world process or system, simulators have been used. In telecommunication networks and computer networking, researchers use simulators to validate their protocols and algorithms. The most widely used simulator in the networking research community is Network Simulator NS-2. The network simulator NS-2 is an open source discrete event simulator which was incepted in 1989, in which the core backend libraries are developed in C++ programming language. NS-2 was further supported by Defense Advanced Research Project Agency (DARPA), USA under the VINT project. It is also used for education purposes for better understanding of the underlying network behavior. Additionally, it is also used for validating new and existing network related algorithms and protocols. These networks range from ZigBee, LANs, IEEE 802.11 to Vehicular Ad-Hoc Networks. Also, it is worth noted that new simulators or support in existing simulators are required whenever new technology is introduced. For example, when Cognitive Radio Network (CRN) was introduced, NS-2 existed at that time. Thus in order to simulate CRN, either a new simulator or CRN support in existing simulators is required. Since NS-2 is an open source simulator, therefore the community has contributed a lot for providing support of new technologies in NS-2 including CRN. While on the other hand, in commercialized simulators, only the company can provide support for new technologies and most of the time, they take extra charges for such support. Thus, this is one of the foremost benefits of NS-2 as being open source besides its widely adoption among the researchers.