The Application layer provides three basic services to applications:
- It makes sure the resources needed to carry out a session are present.
- It matches the application to the appropriate communication protocol or service.
- It synchronizes the tgransmission of data between the application and its protocol.
- File services – store, move control access to, and retrieve files
- Print services – send data to local or network printers
- Message services – transfer text, graphics, audio, and video over a network
- Application services – process applications locally or through distributed processing
- Database services – allow a local computer to access network services
In addition, the Application layer advertises any services that are being offered and determines whether requests made by the client should be processed locally or remotely (through another network resource).
The Application layer services and protocols you should know are: