Software-Defined Networking (SDN)

Correct Answer: SDN Controller

The SDN Controller is the right choice as it is the core component of the software-defined networking system that manages the flow control to the networking switches and translates instructions from applications down to the network and the data paths. It provides the centralized view and management of the network, which is the primary goal of the company. The SDN-enabled Switch is not the best answer because while it is an important component of an SDN infrastructure, it does not provide the centralized control that the company is looking for. SDN-enabled switches are more about forwarding traffic based on rules set by the SDN controller. API Gateway is also not the correct choice because it serves as an interface for microservice architecture rather than focusing on centralized management of network resources, which is the company's goal. Finally, the Service Mesh is a dedicated infrastructure layer for service-to-service communication, which is not the main focus of the company's goal to centrally manage its network resources.

Correct Answer: Northbound Interface

In an SDN (Software-Defined Networking) network architecture, the 'Northbound Interface' is the correct choice for incorporating third-party applications for monitoring the network. The Northbound Interface provides an open, programmable, and interactive session to the application layer, thus to the third-party applications. It allows these applications to read the network's state and make changes as needed, ensuring successful integration. On the other hand, the 'Southbound Interface' is used for communication between SDN controllers and network devices like switches and routers. It's not for integrating third-party applications. The 'Eastbound' and 'Westbound' interfaces don't exist in SDN architecture, so they're incorrect.

Correct Answer: Network Visibility and Monitoring

The function of the SDN controller that can help accomplish the observation of the flow of traffic across the network during peak hours is 'Network Visibility and Monitoring'. This feature of an SDN controller provides an identification and graphical representation of network utilization, traffic flows, and the network's overall performance metrics, allowing a network engineer to monitor and understand the flow of traffic in real-time. 'Managing Virtual Network Functions' is incorrect as it pertains to managing the network functions that run on virtual machines or containers, and not real-time traffic monitoring. 'Securing Communication Channels' is the capability of an SDN controller that helps in establishing secure data paths within the network but does not provide real-time monitoring of network traffic. 'Coordinating Service Function Chaining' pertains to the control of the order of network services, and not the real-time observation of network traffic.