Emerging Network Technologies
Emerging Network Technologies
This domain tests how controllers, virtualization, cloud, and automation change network operations. Expect definitional questions plus design trade-offs.
Core rules
- SDN separates the control plane (decisions) from the data plane (forwarding). A controller computes and distributes policy; switches forward. This enables centralized intent, automation, and consistent policy.
- NFV virtualizes network functions such as firewalls and routers on commodity hardware. SDN and NFV are complementary, not synonyms.
- Overlay networks (VXLAN, GRE) tunnel Layer 2 frames over Layer 3. VXLAN uses a 24-bit VNI, supporting many segments.
- Cloud uses shared responsibility: the provider secures the cloud infrastructure; the customer secures identities, data, and configurations.
- Wi-Fi 6 (802.11ax) improves efficiency in dense environments; Wi-Fi 6E adds the 6 GHz band. 5G targets low latency and high density, not just peak speed.
- Infrastructure as code and APIs make changes repeatable; intent-based networking validates that configured state matches desired state.
Worked example A campus wants consistent segmentation policy across 200 switches. A controller-based SDN design can define intent once-for example, “guest VLAN cannot reach management”-and push it to fabric devices. The controller maintains topology and policy; switches enforce it in the data plane. This reduces per-device CLI drift, but requires resilient controller clustering and a clear out-of-band management path.
Traps Do not claim SDN eliminates the data plane; forwarding still happens on devices. Do not equate Wi-Fi 6 with 6 GHz-6E adds that band. Do not assume cloud providers secure customer IAM policies or data classification. Automation without validation can propagate errors faster, so testing and rollback matter.