Which component is essential for managing network traffic within a data centre?

The router is a vital component for managing network traffic within a data centre because it directs data packets between different networks and devices. It performs the essential function of determining the best path for data to travel, which helps in optimizing the flow of information and preventing bottlenecks in communication. Routers interact with switches and other networking devices to establish a clear pathway for data, ensuring that traffic is efficiently routed to its destination.

While a firewall is crucial for security, designed to control incoming and outgoing network traffic based on predetermined security rules, its primary function is not to manage traffic in terms of routing data across networks. A storage array focuses on managing data storage rather than network traffic, and a cooling unit deals with temperature regulation within the data centre, rather than contributing directly to network management. Therefore, among the listed options, the router stands out as the central hub for effective network traffic management.