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What is OSI Model in Networking

OSI Model in computer network stands for Open System Interconnection Model, it is developed by the International Organization for Standardization (ISO) which describe the flow of information from one computer to another. OSI Model is also called the ISO OSI reference model.

There are seven Layers of OSI Model:

Application Layer
Session Layer
Presentation Layer
Transport Layer
Network Layer
Data Link Layer
Physical Layer

The top three layers (Application, Session, and Presentation) are called the upper layer of the OSI Model.

How OSI Model works:

Every time user is sending or receiving data in a network, the data travels from the different layers and it is well explained by OSI Reference Model.

Let’s take an example,

Sender:

There are 2 PCs in a network where PC 1 is sending data to PC 2. The data will first travel from the upper layer of the OSI Model (Application, Presentation, Session) to the Transport Layer.
Transport Layer will convert this data into segments and then forward it to the Network Layer.
Network Layer will convert this segment into packets and then forward it to the data link layer.
Data Link Layer will convert these packets into frames and then forward it to the physical layer.
The physical Layer will convert these frames into binary bits and then forward it to another physical layer that is on the receiver side.

Receiver:

Now, the data will flow in reverse order. The physical layer on the receiver side will forward its binary bits to the data link layer.
Data Link Layer is going to convert this binary bit into frames and then forward it to the network layer.
Now, Network Layer will convert these frames into packets and then forward it to Transport Layer.
Transport Layer will convert these frames into segments and then forward it to the upper layer (Application, Session, Presentation) of the OSI Model
And the user will receive the data from the application layer in a readable format. So, This is the basic concept of how data travels in a computer network and How OSI Model works.