Page 88 - NetWork-En-V3

12.1 Application Layer

The applications in this layer generate user data to send to other applications over
the network to another device. The Application layer contains several protocols, the
most notable of which are:
• HTTP protocol, which we use daily while browsing the Internet.
• File Transfer Protocol (FTP).
• Simple Mail Transfer Protocol (SMTP), which manages the process of sending

email over computer networks.

12.2 Transport Layer

The primary function of this layer is data transfer, along with optional functions such
as ensuring error-free and orderly access to the other party. There are two protocols
in this layer: TCP and UDP.
The TCP protocol sends data and ensures its arrival by controlling the data flow and
detecting errors. On the other hand, the UDP protocol sends data without ensuring
its arrival. In reality, both protocols have their uses, as TCP is characterized by
accuracy, while UDP is known for its speed .

12.3 Internet Layer

This layer is primarily concerned with transferring data packets between network
devices. It includes definitions for device addresses, mechanisms for routing packets
between devices, and the selection of the fastest routes for delivery. The Internet
Protocol (IP) is the fundamental protocol operating in this layer, defining the IP
addresses for each device on the network. Special devices, called routers, operate in
this layer to route packets from one network to another.

81 Central Unit for Information Technology Training - Supreme Council of Universities © Intellectual Property Rights 2024