A software-defined network (SDN) is a network architecture that allows for the management of network policies from a central portal while maintaining a hardware-agnostic approach. SDN separates the control plane, which is responsible for making decisions about how to route traffic, from the data plane, which is responsible for forwarding traffic based on the control plane's instructions. SDN enables network administrators to configure, monitor, and manage network devices and services using a software application, regardless of the vendor or type of hardware. SDN also provides automation, programmability, scalability, and flexibility for network operations. A virtual private network (VPN) is a network technology that creates a secure and encrypted connection over a public network, such as the Internet. A VPN allows remote users to access a private network and its resources securely. A VPN is not related to the management of network policies from a central portal or the hardware-agnostic approach of SDN. Load balancing is a network technique that distributes traffic across multiple servers or devices to optimize performance, reliability, and availability. Load balancing can be implemented using hardware or software, but it does not provide the same level of centralized management and control as SDN. Direct Connect is a service offered by some cloud providers that allows customers to establish a dedicated network connection between their on-premises network and the cloud provider's network. Direct Connect bypasses the public Internet and provides lower latency, higher bandwidth, and more consistent network performance. However, Direct Connect is not a generic network architecture that supports a hardware-agnostic approach, and it does not offer the same degree of network programmability and automation as SDN. Reference: CompTIA Cloud Essentials+ CLO-002 Study Guide, Chapter 4: Cloud Design Principles, Section 4.2: Cloud Network Concepts, Page 1051 and What is software-defined networking (SDN)? | Cloudflare