At what Open System Interconnect layer do routers operate?

Routers operate at the Network layer of the Open Systems Interconnection (OSI) model. This layer is responsible for determining the best path for data to travel across a network. It handles logical addressing, routing, and forwarding of packets. Routers use IP addresses to make forwarding decisions, enabling them to send data between different networks, which is a critical function in managing how data is transmitted from one endpoint to another across potentially diverse network infrastructures.

In contrast, other layers do not encompass the full functionality of a router. The Physical layer is focused on the transmission of raw bit streams over a physical medium, while the Data Link layer manages node-to-node data transfer and error detection. The Transport layer is responsible for end-to-end communication and flow control but does not deal with routing packets between different networks. This distinction is essential in understanding network architecture and the functionalities associated with each OSI layer.