SDN and NFV Fundamentals
Key Takeaways
- SDN separates or centralizes network control from packet forwarding to improve programmability and policy consistency.
- Northbound interfaces connect controllers to applications; southbound interfaces connect controllers to devices.
- NFV runs network functions as software on general-purpose compute rather than dedicated appliances.
- SDN and NFV are complementary but not interchangeable.
- Huawei includes SDN and automation fundamentals in one 3% H12-811 V1.0 domain.
SDN and NFV Fundamentals
Software-defined networking (SDN) separates the logic that decides network behavior from the devices that forward traffic. A controller can provide a network-wide view, translate policy into device instructions, and help keep changes consistent across many devices. The physical or virtual switches and routers still forward packets; SDN does not eliminate the data plane.
Planes and interfaces
| Concept | Role |
|---|---|
| Control plane | Makes routing, topology, and policy decisions |
| Data plane | Forwards packets using installed tables and rules |
| Management plane | Supports configuration, monitoring, and administration |
| Northbound interface | Connects applications or orchestration to a controller |
| Southbound interface | Connects a controller to network devices |
Traditional networks often distribute control logic across individual devices. SDN can centralize or coordinate more of that logic, making policy changes and automation easier to apply consistently. Real deployments may be hybrid: local protocols can continue to run while a controller provides centralized management or intent.
NFV is a different idea
Network Functions Virtualization (NFV) moves functions such as firewalls, load balancers, or edge services from dedicated appliances into software running on general-purpose compute. SDN concerns how a network is controlled; NFV concerns where a network function runs. They can work together, but one does not require the other.
For H12-811, stay at the published fundamentals level. Understand the controller, the planes, northbound and southbound directions, the main benefits and trade-offs, and the SDN-versus-NFV distinction. Do not assume that an advanced protocol, controller product, or orchestration platform is examinable unless it appears in Huawei's current outline.
Which statement best defines SDN?
What does a northbound interface connect?
How does NFV differ from SDN?