Final answer:
The key characteristic of SDN architecture is the centralization of network control by separating the control and data planes, which enables more flexible and dynamic management of the network through a centralized SDN controller.
Step-by-step explanation:
A key characteristic of Software-Defined Networking (SDN) architecture is the centralization of network control and the decoupling of the control plane from the data plane. In traditional networks, the control and data planes are integrated within the network devices, such as routers and switches, leading to more complex and static configurations. SDN shifts the control aspect to a centralized entity called the SDN controller, which communicates with the underlying hardware using protocols like OpenFlow. This centralization allows for more dynamic and flexible network management and configuration.
Another significant characteristic is the programmability of the network. Administrators can programmatically configure, manage, and optimize network resources via software applications, which communicate with the SDN controller. This enables automation and makes it easier to implement and enforce policies consistently across the network. Additionally, SDN supports network abstraction, effectively creating a virtualized version of the network that can be more easily managed and configured.