Routers operate at which layer of the OSI model?

• A. 4
• B. 3
• C. 1
• D. 5

Answer: (B)

Routers forward traffic between different networks by examining the destination IP address and using routing tables to decide the next hop. That ability sits squarely in the Network Layer, Layer 3 of the OSI model. The IP header carries logical addressing that routers use to determine where a packet should go next, enabling inter-network communication.

In contrast, Layer 1 covers the physical transmission media, Layer 2 handles local switching with MAC addresses, and Layer 4 concerns transport protocols and ports. Some devices or features may touch other layers (for example, firewalls or NAT affecting higher layers), but the fundamental routing function—deciding the path to a destination using IP addresses—is a Layer 3 activity.