1.1 ISO/OSI Network Model
Layer 7 – Application Layer
The Application layer provides services to the software through which the user requests network services.
Your computer application software is not on the Application layer. This layer isn’t about applications and doesn’t contain any applications. In other words, programs such as Microsoft Word or Corel are not at this layer, but browsers, FTP clients, and mail clients etc.
A few of the most popular Application layer protocols are-
File Transfer Protocol (FTP): A protocol that enables a client to send and receive complete files from a server.
HyperText Transfer Protocol (HTTP): The core protocol of the World Wide Web.
Telnet: The protocol that lets you connect to another computer on the Internet in a terminal emulation mode.
Simple Mail Transfer Protocol (SMTP): One of several key protocols that are used to provide e-mail services.
Domain Name System (DNS): The protocol that allows you to refer to other host computers by using names rather than numbers.