Layer 7 - The application layer

The application layer is the topmost layer of the OSI model, and has no upper-layer protocols. The software applications that need communication with other systems interact directly with the OSI application layer. This layer is not to be confused with the application software, which is the program that implements the software; for example, HTTP is an application layer protocol, while Google Chrome is a software application.

The application layer provides services directly to user applications. It enables the users and software applications to access the network and provides user interfaces and support for services such as email, remote file access and transfer, shared database management, and other types of distributed information services.

Some examples of application layer protocols are HTTP, SMTP, SNMP, FTP, DNS, LDAP, Telnet, and so on.