What is the primary function of a router in a network?

The primary function of a router in a network is to route packets between different networks based on IP addresses. This function is crucial for enabling communication between diverse networks, allowing data to transfer efficiently from a source in one network to a destination in another. Routers examine the destination IP address of incoming packets and determine the best path through various networks to ensure the packets reach their intended location. This intelligent decision-making process is what differentiates routers from other network devices that handle traffic within the same local network.

In this context, extending the range of the network, switching local traffic, or monitoring network performance are not the main roles of a router. While some devices can perform these functions, those tasks are typically associated with access points, switches, or network management tools, respectively, rather than the routing function of separating and directing data traffic across distinct networks.