From NS-2 to NS-3 - Implementation and evaluation

NS-2 is the most famous simulator among other network simulators. Most of researchers use NS-2 to evaluate their new protocols/architectures. Although NS-2 has much resource and many available tools to generate different characteristics and network scenarios, source codes created on NS-2 is not able to be reused for real implementation. The releasing of NS-3 changes the way researchers work. NS-3 allows the researchers to work on both simulations and emulations with the same implementation and source codes. These can help researchers to evaluate their works on a single computer for simulation or on a real system without wasting their time to implement their works twice; one in NS-2 simulation and the other in real system. In this paper, we elaborate different points of protocol implementation between NS-2 and NS-3. We recommend a setting for mobility trace in order to obtain correct results between NS-2 and NS-3. Then, as a case study, we use DECA, which is a reliable broadcasting protocol for VANETs and previously implemented on NS-2. How to transfer DECA from NS-2 to NS-3 and how to validate its performance are shown. Moreover, an emulation of DECA on real system using NS-3 is described. The emulation results show a problem caused by asymmetric links which is not concerned in most of literatures. In this paper, therefore, we also propose a simple solution to help protocols' operation in the asymmetric link scenarios. The simulation results show that our solution can improve protocol performance.