What is a central advantage of centralized control over distribution in SD-WAN?

• A. Centralized consistency in policy and path decisions across the network.
• B. Centralized control is never scalable and is not used in modern SD-WAN.
• C. Centralized control never depends on the edge device state.
• D. Centralized control eliminates the need for policy at the edge.

Answer: (A)

Centralized control in SD-WAN provides a single, global view that enables consistent policy and path decisions across the entire network. The controller collects network telemetry and application requirements, computes optimal routing and security rules, and then pushes those uniform guidelines to all edge devices. With this centralized governance, every site follows the same policy, which greatly reduces configuration drift, simplifies management, and helps ensure end-to-end QoS, security, and predictable behavior across the fabric. Edge devices still enforce the rules locally and adapt to real-time conditions, but within the unified framework set by the controller.

The idea that centralized control is inherently unscalable is outdated; modern SD-WAN uses scalable controllers and distributed data planes to handle growth. Decisions do rely on edge state to reflect current conditions, so you don’t rely on a static view alone. And policy must be enforced at the edge; centralized control doesn’t remove edge policy needs, it standardizes and distributes them.