Comparison of SDN OpenFlow network simulator and emulators: EstiNet vs. Mininet In this paper, we compare and evaluate the correctness, performance, and scalability of EstiNet OpenFlow simulator, EstiNet OpenFlow emulator, and Mininet OpenFlow emulator over a set of grid networks. The popular Floodlight OpenFlow controller is used without any modification to control the simulated/emulated OpenFlow switches created in these tools. We performed experiments over a set of N × N grid networks, where N = 5, 6, …, 31 and used the real-world ping program to observe whether the average RTTs reported by these ping packets are correct or not over these tools. We found that in EstiNet simulation, the simulated results of the average RTT are always correct and repeatable, but EstiNet simulator needs more time to finish the simulation when the network size becomes larger. As for emulation, we found that Mininet emulator generated strange results that cannot be explained over some network sizes. In addition, Mininet emulator spends a huge amount of time on its program launch, network setup, and resource releasing when the network size is large. As for EstiNet emulator, we found that it generated good performance and scalability and it used less time to obtain results.