Testing stateful and dynamic data planes with FlowTest

Many recent efforts have leveraged Software-Defined Networking (SDN capabilities to enable new and more efficient ways of testing the correctness of a network's forwarding behaviors. However, realistic network settings induce two additional sources of complexity that fall outside the scope of existing SDN testing frameworks: (1) complex nature of real-world data planes (e.g., stateful firewalls, dynamic behaviors of proxy caches), and (2) complexity of intended network policies (e.g., service chaining). In this paper, we outline FlowTest, a high-level vision for testing such stateful and dynamic network policies. FlowTest systematically explores the state space of the network data plane to verify its behavior w.r.t. policy goals. We show the early promise of our approach and discuss open challenges in realizing this vision in practice.