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

A router's primary function is to forward data packets between multiple networks. This is essential for directing traffic on the internet and allows devices from different networks to communicate with each other effectively. When a data packet arrives at a router, the device determines the best path for the packet based on its destination IP address. The router then forwards the packet to the appropriate next hop on its journey to reach the intended destination, making it a crucial component for inter-network communication.

The other options highlight important networking functions but do not represent the router's main role. Connecting devices within the same network pertains more to switches and hubs, which operate at a different layer of the OSI model and primarily handle local area networks. Monitoring network traffic for security is typically the responsibility of intrusion detection systems (IDS) or firewalls, not routers, though some advanced routers may have such capabilities. Assigning IP addresses to devices is generally the role of a DHCP (Dynamic Host Configuration Protocol) server, not the router itself, although routers can also perform DHCP functions.