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

The primary function of a router in a network is to route traffic between IP subnets. Routers operate at Layer 3 of the OSI model, dealing with IP addresses and ensuring that data packets are directed from one network segment to another. This involves determining the best path for the data to travel across the networks, making decisions based on the destination IP address and the routing table it maintains.

Routers facilitate communication between different networks, allowing devices on separate subnets to connect and exchange information. This routing capability is essential for larger networks and the Internet, where multiple IP subnets exist. By analyzing the information within the packets, routers can effectively determine how to forward them to the correct destination, whether locally or across the globe.

Other options, while related to networking, do not accurately capture the primary role of a router. For example, filtering traffic based on applications, extending networks to wireless, or enabling direct communication between devices might involve other equipment such as firewalls, access points, or switches, but are not the central functionality of routers.