What is the main function of a router?

The primary function of a router is to forward packets between different networks based on IP addresses. Routers operate within the network layer of the OSI model and are essential for directing data packets from the source network to the appropriate destination network. When a packet arrives at a router, it examines the destination IP address contained in the packet header. Based on this information, the router determines the best path to forward the packet to reach its destination. This process is known as routing.

Routers utilize routing tables and algorithms to make decisions about the most efficient pathways for data transmission. They facilitate communication across diverse networks, such as a home network connecting to the internet, by using protocols like RIP (Routing Information Protocol) and OSPF (Open Shortest Path First) to dynamically learn about network paths and changes.

Although creating and managing network topologies, encrypting data packets, and storing static information are important functions in certain contexts, they do not encapsulate the essence of what routers do. The critical task of packet forwarding is what distinguishes routers from other networking devices, making it the correct answer to the question.