At which OSI layer do routers operate?

Routers operate primarily at the Network Layer of the OSI model. This layer is responsible for packet forwarding, including routing through intermediate routers. The key function of routers is to determine the best path for data to travel across different networks, which involves managing logical addressing (IP addresses) and the routing of packets based on that addressing.

This layer ensures that data packets can successfully reach their destination from the source, even if they must traverse multiple routers along the way. By utilizing protocols such as IP (Internet Protocol), routers can facilitate communication between devices on different networks, helping users seamlessly connect and share information.

Other layers, such as the Application Layer or the Session Layer, serve different purposes, such as managing end-user services and establishing connections, respectively, while the Physical Layer deals with the actual hardware connections and transmission of bits over physical mediums. These functions are distinct from the routing capabilities provided at the Network Layer.