In the OSI to TCP/IP model mapping, which OSI layer corresponds to the Internet layer in TCP/IP?

• A. OSI layer 3
• B. OSI layers 5–7
• C. OSI layer 4
• D. OSI layers 2–1

Answer: (A)

The network layer (Layer 3) in OSI handles routing and logical addressing, which is exactly what the Internet layer does in TCP/IP. The Internet layer is responsible for IP addressing and moving packets between networks, choosing routes, and enabling delivery across multiple hops. That alignment makes OSI Layer 3 the correct mapping for the TCP/IP Internet layer. The other layers map to different parts of TCP/IP: Transport in OSI corresponds to the TCP/IP Transport layer, while Session, Presentation, and Application in OSI map largely to the TCP/IP Application layer, and the OSI Data Link and Physical layers align with the TCP/IP Link (Network Interface) layer.