At which OSI layer does a router operate?

A router operates at Layer 3 of the OSI model, which is the Network layer. This layer is responsible for routing packets between devices on different networks, determining the best paths for data traffic, and handling logical addressing (such as IP addresses). Routers analyze the destination IP address of incoming packets and use routing tables to decide where to forward the packets next, effectively allowing communication to take place across diverse networks.

Understanding this function is crucial in networking, as routers play a vital role in directing traffic efficiently. While devices that operate at Layer 1 (Physical) handle raw data transmission over various media and those that function at Layer 2 (Data Link) manage data framed for transmission on physical links, they lack the routing capabilities found at Layer 3. Similarly, the responsibilities of Layer 4 (Transport) involve end-to-end communication and flow control rather than routing between networks, further emphasizing the unique role of routers in networking.