WGU D415 Software-Defined Networking (SDN) — Actual Questions, Answers, /D415 Software-Defined Networking: Practice Exam and Topic Map

WGU D415 Software-Defined Networking (SDN) — Actual
Questions, Answers, /D415 Software-Defined Networking:
Practice Exam and Topic Map
Coverage

SDN Fundamentals and Architecture — 15% Control/data/management planes,
controller roles, logical centralization, hybrid models, intent vs imperative.

 Controllers and Controller Architectures — 15% Controller clustering, leader
election, east-west sync, hierarchical and sharded controllers, high availability.
 Southbound Protocols and Device Models — 12% OpenFlow basics and extensions,
NETCONF/YANG, RESTCONF, model-driven configuration, device adapters.
 Northbound APIs and Application Integration — 8% RESTful APIs, intent APIs,
event hooks, orchestration integration (Kubernetes, OpenStack).
 OpenFlow Mechanics and Flow Programming — 10% Match/action fields, flow
mods, packet-in/out, pipeline tables, group tables, meters, timeouts.
 Network Virtualization and Overlays — 12% VXLAN/GRE, VNIs, EVPN control
plane, vSwitch integration, tenant isolation, ARP suppression.
 NFV, Service Chaining, and VNFs — 6% NFV MANO, VNF lifecycle, service function
chaining, orchestration interplay with SDN.
 Telemetry, Monitoring, and Analytics — 6% Streaming telemetry (gNMI/gRPC), flow
counters, sampling, SIEM integration, anomaly detection.
 Security and Hardening — 8% mTLS for control channels, IAM for northbound, signed
rules, microsegmentation, secure onboarding/attestation.
 Orchestration and Automation — 6% IaC, declarative templates, CI/CD integration,
playbooks, autoscaling, snapshot/rollback strategies.
 Performance, Scalability, and Capacity Planning — 6% TCAM budgeting, flow
aggregation, controller placement, flow install throughput, batching, offload strategies.
 Troubleshooting, Testing, and Validation — 6% Emulation/testbeds, packet tracing,
synthetic transactions, topology visualization, audit logs and replay.




.

Section 1 — Q1 to Q40: SDN Fundamentals, Architecture, and Controllers

Q1. Which architectural component in SDN centralizes network intelligence and programs
forwarding behavior across devices?

,  A. Data plane switch

 B. Control plane controller

 C. Management plane agent

 D. Southbound API gateway

The controller implements control plane logic and programs data plane devices.

Q2. Which plane in SDN is responsible for actual packet forwarding and enforcement of flow
rules?

 A. Control plane

 B. Management plane

 C. Data plane

 D. Orchestration plane

The data plane handles forwarding based on rules installed by the controller.

Q3. Which interface type allows applications to request network services from the SDN
controller?

 A. Southbound API

 B. Northbound API

 C. East-west API

 D. CLI interface

Northbound APIs expose controller functions to applications and orchestration systems.

Q4. Which southbound protocol is most commonly associated with early SDN
implementations for programming switches?

,  A. NETCONF

 B. BGP

 C. OpenFlow

 D. RESTCONF

OpenFlow provides match/action flow programming between controller and switches.

Q5. Which SDN controller function maintains a global network view and topology
information for decision making?

 A. Southbound translation

 B. Network state database

 C. Packet forwarding engine

 D. CLI management

The controller’s network state database stores topology and device state for logic.

Q6. Which deployment model places the SDN controller as a logically centralized entity but
physically distributed for resilience?

 A. Fully distributed control plane

 B. Logically centralized, physically distributed

 C. Peer-to-peer control plane

 D. Device-embedded control plane

Controllers can be clustered across hosts while appearing centralized to applications.

Q7. Which northbound API style is most developer-friendly for modern orchestration and
automation tools?

,  A. SNMP MIBs

 B. RESTful JSON APIs

 C. Proprietary binary RPC

 D. CLI scripts

RESTful JSON APIs are widely used for programmability and integration with tools.

Q8. Which SDN concept separates the decision logic from the physical forwarding devices
to enable programmability?

 A. Network slicing

 B. Control and data plane separation

 C. VLAN segmentation

 D. Link aggregation

Separation allows centralized control logic to program forwarding devices dynamically.

Q9. Which controller architecture component translates high-level policies into low-level flow
rules for devices?

 A. Southbound connector

 B. Policy engine or compiler

 C. Packet buffer

 D. Flow table cache

Policy engines convert intents or policies into device-specific flow entries.

Q10. Which OpenFlow match field is commonly used to identify flows based on transport
layer port numbers?