The TCP/IP model has four layers, which correspond with the OSI model's seven layers.

• A. True
• B. False
• C. Sometimes
• D. Only in theory

Answer: (A)

Understanding how TCP/IP and OSI relate helps you see why the four-layer TCP/IP model still maps to the seven-layer OSI model. The OSI reference model has seven layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application. The TCP/IP suite uses four layers: Link (or Network Interface), Internet, Transport, and Application. You can align them by functions: the TCP/IP Link layer corresponds to the OSI Physical and Data Link layers, Internet matches OSI Network, Transport maps to OSI Transport, and Application covers the OSI Application layer—and it also handles what OSI splits into Session, Presentation, and Application in many descriptions. Because OSI is a conceptual framework and TCP/IP is a practical protocol suite, the correspondence isn’t a strict one-to-one match, but a widely taught and used mapping shows that the four TCP/IP layers do align with the seven OSI layers in a meaningful way. That’s why the statement is true.