Because of its logically centralized design, Software-defined Networking (SDN) is vulnerable to a variety of adversarial attacks. These attacks have the possibility of degrading the coordinated network's efficiency or, in the most severe scenario, bring it down. As a result, SDN efficiency must be assessed and estimated to ascertain its performance through reliability, mean time to failure (MTTF), cost, MTTF sensitivity and availability.In this paper, a system with four subsystems, (subsystem-1, subsystem-2, subsystem-3 and subsystem-4) is studied. All the four subsystems are connected in a series configuration. Subsystem- 1 has only one unit, subsystem-2 has three units connected in parallel working under 1-out-of-3: G; policy, subsystem-3 has two units connected in series, and subsystem-4 has two units connected in parallel working under 1-out-of-2: G; policy. The system is assumed to work in good operating conditions with different failure rates and repair rates. Laplace transforms and Supplementary variable techniques were used to study the system. Availability, reliability, mean time to failure (MTTF), sensitivity, and cost analysis has been evaluated for particular values of the failure and repair rates. Tables and figures were used to demonstrate the evaluated results.