NetEgg: A Scenario-Based Programming Toolkit for SDN Policies

Recent emergence of software-defined networks offers an opportunity to design domain-specific programming abstractions aimed at network operators. In this paper, we propose scenario-based programming, a framework that allows network operators to program network policies by describing example behaviors in representative scenarios. Given these scenarios, our synthesis algorithm automatically infers the controller state that needs to be maintained along with the rules to process network events and update state. We have developed the NetEgg scenario-based programming tool, which can execute the generated policy implementation on top of a centralized controller, but also automatically infers flow-table rules that can be pushed to switches to improve throughput. We evaluate the performance of NetEgg based on the computational requirements of our synthesis algorithm as well as the overhead introduced by the generated policy implementation, and we study the usability of NetEgg based on a user study. Our results show that our synthesis algorithm can generate policy implementations in less than a second for all policies we studied, and the automatically generated policy implementations have performance comparable to their hand-crafted implementations. Our user study shows that the proposed scenario-based programming approach can reduce the programming time by 50% and the error rate by 32% compared with an alternative programming approach.