## 2 Related Works  
### SDN-Centered Security for IoT  
An architecture for furnishing network security services like an internet content filtering system, firewall, Intrusion Detection System (IDS), Intrusion Prevention System (IPS), and packet inspection using SDN is proposed. The network traffic can be routed through the services based on the needs of the user. The use of SDN for IoT networks to mitigate attacks by limiting the rate of suspicious traffic flow is proposed in [20]. An SDN-based framework for designing cyber resilience for the Industrial IoT (IIoT) is proposed in [21]. The ontology is designed to create pre-programmed failover paths that become activated in the event of failure. This maintains the equilibrium resilience of the IIoT network for effective failure recovery. A similar SDN-based ontology design for cyber resilience in smart manufacturing applications is proposed in [22]. To implement incident response in the IIoT, the use of SDN is proposed in [23] due to its dynamic routing policies. The preconfigured incident-response policy is enforced using SDN in the event of an attack. Invariant-based anomaly detection using SDN for IIoT is proposed in [24]. Invariant is a property of the IIoT network that remains the same in any situation. A change in this property is identified as an anomaly by adding the invariant algorithm to the SDN-controlled switches. An Intrusion Detection and Prevention System (IDPS) is proposed in [25] that exploits SDN and a Genetic Algorithm (GA) to extract features for effective intrusion detection in IoT applications. Advanced reservation-based access control using SDN is proposed in [26]. The advanced reservation of bandwidth for a certain period is employed using SDN. SDN extends the reservation from border routers to the end devices with tokens for authorization. Another SDN-based architecture for smart home networks is proposed in [27]. With SDN, all smart home devices are connected via a gateway. KNOT and Orchestrator are used with the aid of SDN to detect Advanced Persistent Threats and saturation attacks and mitigate them effectively. HanGaurd SDN-based fine-grained protection for a smart home from malicious apps running on authorized devices like a smartphone is proposed in [28]. An SDN-based firewall called FORTRESS is proposed in [29]. The stateful flow data are obtained from the data plane, and the Mealy machine is exploited to perform state table updations based on the routing decision made. An SDN-centered defense mechanism for IoT networks is proposed in [30]. The IoT devices are classified as easily patchable or non-patchable, vulnerable or hard-to-exploit, and a proactive defense mechanism is provided by changing the attack surface in case the device is vulnerable and non-patchable. The features of SDN are exploited to provide a honeypot as a service by steering the traffic through Virtualized Functions (VF) as proposed in [31]. The honeypot acts as a proactive as well as a reactive defense mechanism against attacks. The honeypots are virtualized and provided as a service using SDN. SDN for effective intrusion detection as well as for mitigation of attacks like Distributed Denial of Service (DDoS) in the habitat of the IoT is proposed in [32; 33]. DDoS detection system that exploits the convenience of SDN using machine learning techniques is proposed in [34]. The proposed work uses an adaptive multilayered feed-forwarding scheme that uses different algorithms in five layers. The third layer computes the live, real-time network traffic for DDoS attack detection, and SDN mitigates the attacks using Open Flow switches.