Software-Defined Networking (SDN) is an approach to networking that separates the control plane from the data plane in network devices, allowing for centralized control and programmability of network infrastructure. By decoupling the network control from the network hardware, SDN enables greater flexibility, scalability, and automation in network management. Researchers in the field of SDN focus on developing new network architectures, protocols, and algorithms to improve network performance, security, and efficiency. Additionally, they explore the use of SDN in various applications such as cloud computing, Internet of Things (IoT), and virtualized networks.