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350-701 · Question #549

Which type of API is being used when a controller within a software-defined network architecture dynamically makes configuration changes on switches within the network?

The correct answer is D. southbound API. When a software-defined network (SDN) controller configures network devices like switches, it uses southbound APIs to communicate with the underlying network infrastructure.

Submitted by lukas.cz· Mar 30, 2026Software-Defined Networking

Question

Which type of API is being used when a controller within a software-defined network architecture dynamically makes configuration changes on switches within the network?

Options

  • Anorthbound API
  • Bwestbound API
  • Ceastbound API
  • Dsouthbound API

How the community answered

(38 responses)
  • A
    8% (3)
  • B
    3% (1)
  • C
    3% (1)
  • D
    87% (33)

Why each option

When a software-defined network (SDN) controller configures network devices like switches, it uses southbound APIs to communicate with the underlying network infrastructure.

Anorthbound API

Northbound APIs are used for communication between the SDN controller and applications or orchestration systems, allowing applications to request network services.

Bwestbound API

Westbound APIs are not a standard term in SDN architecture for communication between controllers and devices; East/Westbound APIs typically refer to controller-to-controller communication.

Ceastbound API

Eastbound APIs are not a standard term in SDN architecture for communication between controllers and devices; East/Westbound APIs typically refer to controller-to-controller communication.

Dsouthbound APICorrect

Southbound APIs are used by the SDN controller to communicate with and control the forwarding plane elements, such as switches and routers, enabling dynamic configuration changes and policy enforcement on the physical network devices.

Concept tested: SDN API types

Source: https://www.opennetworking.org/sdn-resources/sdn-definition/

Topics

#SDN architecture#Southbound API#Controller-device communication

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