Test derivation for SDN-enabled switches: A logic circuit based approach

The paper is devoted to testing critical Software Defined Networking (SDN) components and in particular, SDN-enabled switches. A switch can be seen as a forwarding device with a set of configured rules and thus, can be modelled and analyzed as a ‘stateless’ system. Correspondingly, in this paper we propose to use appropriate logic circuits or networks to model the switch behavior. Both active and passive testing modes can benefit from such representation. First, this allows applying well-known test generation strategies such as for example, test derivation techniques targeting Single Stuck-at Faults (SSFs). We also specify a number of mutation operators for switch rules and propose an algorithm for eliminating equivalent mutants via SAT solving. Logic circuits simulating the behavior of the switches can be effectively utilized for run-time verification, and such logic circuit based approach is also discussed in the paper. Preliminary experimental results with Open vSwitch, on one hand, demonstrate the necessity of considering new fault models for logic circuits (apart from, for example well established SSFs) and on the other hand, confirm the efficiency of the proposed test generation and verification techniques.