Network Layers

Introduction to Layers

A network is usually split into layers to help organize and manage complex tasks.
These layers are part of a protocol stack, which allows for different types of hardware and software to work together in a network.

The Application Layer represents the level where users interact with the network, using applications such as web browsers and email clients.
The Transport Layer is responsible for ensuring end-to-end communication between devices, managing flow control, error checking and packet sequencing.
The Internet Layer is responsible for data routing and addressing. This layer ensures packets of data are sent to the right destination.
The Link Layer directly interacts with the network hardware, facilitating communication with other devices on the same network.

Dividing the network into layers allows for better management and control over the network.
Each layer is independent and can be developed and updated separately, as long as it continues to perform its required task.
This modularity allows for greater flexibility and prevents small errors from affecting the entire network.
It also allows for protocol independence, as each layer can use different protocols to achieve their specific purposes.

When a user interacts with a network application (like a web browser), data is sent through these layers before reaching the network.
At each layer, specific information (header or footer) is added to the packet. This is called encapsulation.
Once the data reaches its destination, each layer’s information is read and removed. This process is known as decapsulation.

Each layer supports particular protocols that dictate how data should be formatted, transmitted, encapsulated, and decapsulated.
TCP/IP is one of the most commonly used sets of protocols and closely aligns with the four-layer model.
The use of protocols ensures compatibility between different devices and allows communication over the network.