OFf: bugspray for openflow.

The increasing complexity of software-defined (SDN) applications requires comprehensive methods and tools for debugging and analyzing program and network behavior. A key challenge in SDN application development is that programs can interact with network devices and configurations in unexpected ways, depending on traffic and application mix. In this paper, we describe OFf, a debugging and test environment for SDN program development. OFf leverages the fs-sdn simulator, which was designed to offer simple-to-use, accurate, and scalable evaluation of OpenFlow-based SDN applications. OFf offers a variety of commonly available debugging features such as stepping, breakpoints, watchpoints, and inspection and modification of program state. It also offers SDN-specific capabilities that facilitate network behavior analysis including packet tracing and replay, visualization features, and alerts that are triggered when, for example, configurations change.