WGU D415 OBJECTIVE ASSESSMENT AND PRE -
ASSESSMENT LATEST 2026 TEST BANK| D415
SOFTWARE DEFINED NETWORKING AO & PA EXAM
WITH 300 REAL EXAM QUESTIONS AND CORRECT
VERIFIED ANSWERS/ ALREADY GRADED A+ (MOST
RECENT!!)
Q1. What is the primary architectural change introduced by
Software-Defined Networking (SDN)?
A. Combining the control and data planes into a single device
B. Decoupling the network control (control plane) from the
forwarding functions (data plane)
C. Eliminating all network protocols
D. Replacing IP addresses with MAC addresses
Correct Answer: B
Rationale: SDN fundamentally decouples the control plane
(decision-making) from the data plane (packet forwarding). This
separation allows the control plane to be centrally managed and
programmed directly, while the data plane remains responsible
for high-speed packet forwarding based on instructions from the
controller .
1
,Q2. In SDN architecture, which plane is responsible for
making forwarding decisions?
A. Data plane
B. Management plane
C. Control plane
D. Application plane
Correct Answer: C
Rationale: The control plane is the "brain" of the SDN
architecture. It makes all forwarding decisions and communicates
these decisions to the data plane devices (switches/routers) via
southbound interfaces like OpenFlow .
Q3. Which plane in SDN architecture consists of switches and
routers that forward packets based on controller instructions?
A. Application plane
B. Control plane
C. Orchestration plane
D. Data plane
Correct Answer: D
2
,Rationale: The data plane consists of forwarding devices
(switches, routers) that do not make independent routing
decisions. Instead, they follow flow rules provided by the SDN
controller, which allows for simpler and faster forwarding
hardware .
Q4. What protocol is commonly used for communication
between SDN controllers and switches?
A. SNMP
B. BGP
C. OSPF
D. OpenFlow
Correct Answer: D
Rationale: OpenFlow is the foundational SDN protocol that
enables communication between the controller and network
devices. It allows the controller to define how packets should be
handled by switches, supporting centralized traffic management
and dynamic flow control .
3
, Q5. Which API allows applications to communicate with the
SDN controller?
A. Southbound API
B. East-West API
C. Northbound API
D. Management API
Correct Answer: C
Rationale: Northbound APIs enable communication between SDN
applications and the controller. They allow applications to define
policies such as security rules or traffic prioritization. This
abstraction simplifies network automation .
Q6. What is the primary role of the southbound API in SDN?
A. Connect controllers together
B. Interface with applications
C. Communicate with network devices
D. Provide network monitoring
Correct Answer: C
Rationale: Southbound APIs enable communication between the
SDN controller and data plane devices like switches and routers.
4
ASSESSMENT LATEST 2026 TEST BANK| D415
SOFTWARE DEFINED NETWORKING AO & PA EXAM
WITH 300 REAL EXAM QUESTIONS AND CORRECT
VERIFIED ANSWERS/ ALREADY GRADED A+ (MOST
RECENT!!)
Q1. What is the primary architectural change introduced by
Software-Defined Networking (SDN)?
A. Combining the control and data planes into a single device
B. Decoupling the network control (control plane) from the
forwarding functions (data plane)
C. Eliminating all network protocols
D. Replacing IP addresses with MAC addresses
Correct Answer: B
Rationale: SDN fundamentally decouples the control plane
(decision-making) from the data plane (packet forwarding). This
separation allows the control plane to be centrally managed and
programmed directly, while the data plane remains responsible
for high-speed packet forwarding based on instructions from the
controller .
1
,Q2. In SDN architecture, which plane is responsible for
making forwarding decisions?
A. Data plane
B. Management plane
C. Control plane
D. Application plane
Correct Answer: C
Rationale: The control plane is the "brain" of the SDN
architecture. It makes all forwarding decisions and communicates
these decisions to the data plane devices (switches/routers) via
southbound interfaces like OpenFlow .
Q3. Which plane in SDN architecture consists of switches and
routers that forward packets based on controller instructions?
A. Application plane
B. Control plane
C. Orchestration plane
D. Data plane
Correct Answer: D
2
,Rationale: The data plane consists of forwarding devices
(switches, routers) that do not make independent routing
decisions. Instead, they follow flow rules provided by the SDN
controller, which allows for simpler and faster forwarding
hardware .
Q4. What protocol is commonly used for communication
between SDN controllers and switches?
A. SNMP
B. BGP
C. OSPF
D. OpenFlow
Correct Answer: D
Rationale: OpenFlow is the foundational SDN protocol that
enables communication between the controller and network
devices. It allows the controller to define how packets should be
handled by switches, supporting centralized traffic management
and dynamic flow control .
3
, Q5. Which API allows applications to communicate with the
SDN controller?
A. Southbound API
B. East-West API
C. Northbound API
D. Management API
Correct Answer: C
Rationale: Northbound APIs enable communication between SDN
applications and the controller. They allow applications to define
policies such as security rules or traffic prioritization. This
abstraction simplifies network automation .
Q6. What is the primary role of the southbound API in SDN?
A. Connect controllers together
B. Interface with applications
C. Communicate with network devices
D. Provide network monitoring
Correct Answer: C
Rationale: Southbound APIs enable communication between the
SDN controller and data plane devices like switches and routers.
4
