400-007 Practice Questions

D (Enables innovation):SDN allows new services, business models, and automation capabilities.

E (OpEx/CapEx reduction):Automation reduces operational effort, and commodity hardware reduces CapEx.

Other options explained:

A: Redundancy depends on physical design.

B: SDN centralizes management.

C/F: SDN doesn ' t directly impact latency or capacity.

A (Redundant AAA servers): Protects control plane authentication services from becoming a single point of failure.

B (Control Plane Policing): Limits and controls control plane traffic to prevent CPU exhaustion attacks (DoS, reconnaissance).

F (Routing protocol authentication): Ensures control plane integrity by validating peer identity and preventing spoofed routing updates.

Why other options are incorrect:

C: Warning banners are part of management plane policies.

D: Enabling unused services weakens security posture.

E: SNMPv3 protects management plane, not control plane directly.

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The two most common challenges for organizations adopting container technologies are:

B (Security): Containers introduce unique security challenges, such as shared kernels, namespace isolation, image vulnerabilities, and orchestration exposure.

E (Skilled staff): Containerization requires specialized skills in orchestration (e.g., Kubernetes), CI/CD, and microservices design, which may not be readily available in many IT teams.

Other options explained:

A: Performance is generally good for containers; overhead is minimal.

C: Cost savings are often a driver for containerization.

D: Deployment is streamlined via orchestration platforms.

F: Compliance is important but less frequently cited as the initial adoption barrier.

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Software-Defined Networking (SDN) architecture is based on the logical decoupling of the control and data planes. According to the SDN reference model, the architecture typically includes the following planes:

Control Plane: This resides in the SDN controller and is responsible for decision-making, including route and policy calculations.

Application Plane: This layer contains business and network applications (e.g., firewalls, QoS policies) that communicate with the controller to request services and enforce policy.

These planes are essential in SDN architecture:

The control plane programs the forwarding behavior of network elements.

The application plane interacts via northbound APIs to define intent and service logic.

Options such as “Software plane” and “Network plane” are vague or not used in the SDN context. The “Management plane” is a separate functional layer and is not part of the architectural definition core to SDN as per CCDE v3.1.

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