The TCP/IP application layer corresponds with the top four layers of the OSI model.

• A. True
• B. False
• C. It maps to top three layers
• D. It maps to bottom three layers

Answer: (B)

Understand how the two models relate. The OSI model has seven layers, while the TCP/IP model has four. The Application layer in TCP/IP does not span four OSI layers; it covers the OSI’s upper layers—Session, Presentation, and Application. The Transport layer is a separate OSI layer and isn’t included in the TCP/IP Application layer. So the statement that the TCP/IP application layer corresponds with the top four OSI layers is false. In practice, the TCP/IP Application layer aligns with OSI’s top three layers, with the lower TCP/IP layers mapping to the lower OSI layers.