functions of the application layer of the osi model
Application layer In the OSI model, the definition of the application layer is narrower in scope. The OSI model defines the application layer as the user interface responsible for displaying received information to the user. In contrast, the Internet Protocol Suite does not concern itself with such detail. OSI also explicitly distinguishes additional functionality below the application layer, but above the transport layer at two additional levels: the session layer, and the presentation layer. OSI specifies a strict modular separation of functionality at these layers and provides protocol implementations for each layer.
Transport layer In computer networking, the transport layer is a conceptual division of methods in the layered architecture of protocols in the network stack in the Internet Protocol Suite and the OSI model. The protocols of the transport layer provide host-to-host communication services for applications.[1] It provides services such as connection-oriented communication, reliability, flow control, and multiplexing.