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?
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?
