how does application layer function to deliver services to the end user?

Answer 1

Application layer


DEFINITION - In the Open Systems Interconnection (OSI) communications model, the application layer provides services for an application program to ensure that effective communication with another application program in a network is possible. The application layer is not the application itself that is doing the communication. It is a service layer that provides these services:

* Makes sure that the other party is identified and can be reached
* If appropriate, authenticates either the message sender or receiver or both
* Makes sure that necessary communication resources exist (for example, is there a modem in the sender's computer?)
* Ensures agreement at both ends about error recovery procedures, data integrity, and privacy
* Determines protocol and data syntax rules at the application level

It may be convenient to think of the application layer as the high-level set-up services for the application program or an interactive user.