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Difficulty: HardComparing Traditional Networks with Controller-Based Networking

An organization is auditing its infrastructure operational model as it migrates from per-device management to a software-defined controller-based deployment (such as Cisco DNA Center). The network engineering team needs to clarify the architectural and management operational differences between these two models for their automation workflows. Which of the following statements correctly compare traditional networks with controller-based networking? (Select TWO.)

  1. Controller-based architectures centralize network management and control plane intelligence, using Northbound APIs to expose abstraction layers to management applications, whereas traditional architectures require individual node management and distributed control planes.Answer
  2. Controller-based deployments leverage Southbound APIs (such as NETCONF, RESTCONF, or OpenFlow) to program network devices dynamically, replacing manual per-device CLI updates used in traditional networking.Answer
  3. C
    Traditional network architectures rely on agent-based centralized controllers to pull configuration updates via SSH, whereas controller-based networks eliminate controllers and process all control plane logic locally on each edge switch.
  4. D
    In a controller-based architecture, Northbound REST API interactions use the HTTP GET verb exclusively to create and update fabric configurations across managed network switches.

Answer

The correct statements are that controller-based architectures centralize management and control plane intelligence using Northbound APIs while traditional networks rely on per-device management and distributed control planes, and that controller-based deployments use Southbound APIs (such as NETCONF, RESTCONF, or OpenFlow) to dynamically program network devices.
The correct statements accurately contrast the two paradigms. Controller-based architectures centralize network intelligence and expose Northbound REST APIs for management applications while delegating downstream device orchestration to Southbound APIs like NETCONF, RESTCONF, or OpenFlow. Traditional networks require per-device management with distributed control plane execution on each router and switch.

Step-by-Step Solution

1
Analyze control and management plane distribution in traditional vs. controller-based models.
Traditional networks execute control plane logic locally on each device and require individual CLI/SNMP configuration. Controller-based networks centralize control/management logic into a single software controller.
Separation of control and data planes is a core tenant of Software-Defined Networking (SDN).
2
Evaluate API directional roles (Northbound vs. Southbound).
Northbound APIs connect the controller to upper-tier management apps/scripts. Southbound APIs connect the controller downstream to network hardware nodes.
Northbound interfaces use REST APIs (HTTP GET/POST/PUT/DELETE) for abstraction, while Southbound interfaces use protocols like NETCONF, RESTCONF, or OpenFlow for device programming.
3
Evaluate distractors for architectural or REST verb inaccuracies.
The statement claiming traditional networks use controllers while SDN processes everything locally reverses the definitions. The statement claiming HTTP GET creates/updates configuration incorrectly maps HTTP GET to CRUD create/update operations.
HTTP GET is read-only in RESTful API architectures.

Key Concept

Centralized vs. Distributed Control Planes and Interface Roles (Northbound vs. Southbound APIs)
Estimated Time:2m 0s
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Topics

Comparing Traditional Networks with Controller-Based Networking

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