Software-Defined Networking (SDN) is a revolutionary approach to network management that simplifies and centralizes the control of network infrastructure through software applications. Traditionally, network devices like routers and switches have control plane functions embedded in their hardware, tightly coupling the control and data planes. In an SDN architecture, these planes are decoupled, allowing the control plane to be programmatically managed by software applications, often running on a centralized controller. This separation provides greater flexibility, agility, and scalability in managing networks. SDN enables administrators to dynamically adjust and optimize network behavior through software, allowing for more efficient resource utilization, improved traffic management, and rapid adaptation to changing network conditions. It enhances network programmability, making it easier to implement and deploy new services, protocols, and security measures. SDN has become a foundational concept in modern networking, particularly in large-scale data centers and cloud environments, offering a more agile and responsive approach to network management.