Northbound API Purpose

A.

In a controller-based networking architecture, the network is managed by a central controller that provides a single point of management and configuration for all the network devices. A northbound API is an interface that allows external applications and services to communicate with the controller and access network information.

The purpose of a northbound API is to facilitate communication between the controller and the applications that run on top of it. This allows external applications to access network information and make changes to the network configuration. For example, an application could use the northbound API to request information about the network topology or to make changes to the network policies.

Option A, "facilitates communication between the controller and the applications," is the correct answer.

Option B, "reports device errors to a controller," is incorrect because this is the function of a southbound API, which allows the controller to communicate with the network devices.

Option C, "generates statistics for network hardware and traffic," is also incorrect because this is the function of a monitoring system, not a northbound API.

Option D, "communicates between the controller and the physical network hardware," is incorrect because this is the function of a southbound API, not a northbound API.