Which of the following is NOT a layer in the TCP/IP stack?

In the context of the TCP/IP stack, the layers are defined differently than those in the OSI model. The TCP/IP model consists of four primary layers: Application, Transport, Internet (which is sometimes referred to as the Network layer), and Link.

The Application layer encompasses network protocols that applications use to communicate, such as HTTP, FTP, and SMTP. The Transport layer is responsible for end-to-end communication and includes protocols like TCP and UDP. The Network layer, often referred to as the Internet layer in TCP/IP terminology, deals with routing and forwarding of packets across networks, with the Internet Protocol (IP) being the most notable protocol in this layer.

The Session layer, however, does not exist within the TCP/IP model. Instead, session management and control functions are typically handled within the Application layer. As a result, identifying the Session layer as not being part of the TCP/IP stack accurately reflects the distinction between TCP/IP and the OSI model. Understanding this framework is crucial for comprehending how data is transmitted over the internet and helps clarify the roles of different protocols in network communications.