Which of the following represents the highest layer in the TCP/IP model?

The highest layer in the TCP/IP model is the Application layer. This layer is responsible for providing end-user services and facilitating communication between applications over the network. It enables applications to interact with the underlying network infrastructure and provides protocols for various services such as email, web browsing, file transfer, and remote login, among others.

In the TCP/IP model, the Application layer encompasses protocols that operate at this level, including HTTP (HyperText Transfer Protocol), FTP (File Transfer Protocol), and SMTP (Simple Mail Transfer Protocol). By functioning at the highest level, the Application layer directly supports user applications and manages processes such as data exchange and user interface interactions with networking protocols.

The other layers—Network Access, Internet, and Transport—serve different roles in process communication and data transmission. While Network Access deals with the physical and link-layer aspects of network connectivity, the Internet layer focuses on addressing and routing data. The Transport layer is responsible for end-to-end communication and reliability, such as ensuring that packets are delivered accurately and in order. However, these layers operate below the Application layer, making it the highest level of abstraction in the TCP/IP model.