NS4: Enabling Programmable Data Plane Simulation

Network simulation plays a crucial role in the field of network research, education, and industry. However, before conducting a simulation on traditional network simulators, operators need to develop a simulative behavioral model, which requires intimate knowledge of the simulator implementation. Besides, the behavioral model cannot be migrated directly into real-world devices due to its tight coupling with the simulator platform, resulting in redundant and error-prone codes rewriting. Recently, P4, a high-level domain specific language (DSL), has attracted great attention from both academia and industry for its advantages of enabling operators to define behaviors of the programmable data plane. Inspired by the idea of DSL, we present NS4, a P4-driven network simulator supporting simulation of P4-enabled networks to address the problems existing in traditional simulators. Taking advantage of P4, NS4 simplifies the development of a behavioral model and bridges the gap between simulation and deployment. Furthermore, to the best of our knowledge, NS4 is the first research effort to enable simulation of a P4-enabled network, providing a useful tool for P4 research and development. In this paper, we designed and implemented NS4, consisting of data plane models integrated with ns-3, the state-of-the-art network simulator, and control plane models to interact with the P4 pipeline. Then we evaluated its effectiveness and efficiency by simulating several representative P4 programs. Results show that NS4 can simulate large-scale P4-enabled networks at a low cost.