The CCNA exam requires knowledge of the OSI reference model's application layer. This layer represents the various network applications such as e-mail reader, Web browser, Hypertext Transfer Protocol (HTTP), File Transfer Protocol (FTP), and Network File System (NFS).

  • The application layer provides a user interface and processes network data.

  • The application layer on the sending host produces the network data to be transmitted from the sender host.

  • The application layer on the receiving host consumes the network data produced and transmitted by the sender host.