Application Layer enable the user, whether human or software, to access the network. It provides user interfaces and support for services such as electronic mail,file access and transfer, access to system resource, surfing the world wide web, and network management.
Application layer is Responsible for Providing Services to the user.
- Application Layer is a term used in categorizing protocols and methods in architectural models of computer networking. Both the OSI model and the Internet Protocol Suite (TCP/IP) define application layers.
- In TCP/IP, the Application Layer contains all protocols and methods that fall into the realm of process-to-process communications via an Internet Protocol (IP) network using the Transport Layer protocols to establish underlying host-to-host connections.
- Provides a means for the user to access information on the network through an application. This layer is the main interface for the user to interact with the application and therefore the network.
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The application layer is the OSI layer closest to the end user, which means that both the OSI application layer and the user interact directly with the software application. This layer interacts with software applications that implement a communicating component. Such application programs fall outside the scope of the OSI model. Application layer functions typically include identifying communication partners, determining resource availability, and synchronizing communication. When identifying communication partners, the application layer determines the identity and availability of communication partners for an application with data to transmit. When determining resource availability, the application layer must decide whether sufficient network resources for the requested communication exist. In synchronizing communication, all communication between applications requires cooperation that is managed by the application layer.
Examples
Some examples of application layer implementations include Telnet, File Transfer Protocol (FTP), and Simple Mail Transfer Protocol (SMTP).
OSI Model
Points:
- Application Layer do Interaction (Providing Services to the user)
- 80% Application on internet do interact
- i.e google.com —–> will auto —–> www.google.com ——> Here www intract on port 80
- i.e for buy house property dealer do interact