What is OSI Model ?

What is OSI Model ?

In this post we will try to understand you about osi model in very easy language and also learn about its advantages and disadvantages. So let's not start taking too much time: - The full name of the OSI model is Open Systems Interconnection. The osi layer consists of 7 layers. The OSI model is used for communication between two users in a network. It is a reference model. It involves the transmission of data from one layer to another.

OSI Model


Any data is sent or received through the network by the OSI model. The 7 layers in the OSI model have their own separate functions, due to which data can be easily sent from one device to another.

Layers of OSI Model

There are 7 layers in OSI model, so let's know about it in detail: -

Physical Layer

The physical layer is the lowest layer in the OSI model. This layer manages the physical and electrical connections. The digital signal in this layer is converted into an electrical signal. The physical layer also tells that the communication we have will be wireless or wired. This layer is also known as a bit unit.

It's Work

The physical layer determines how two or more systems will be physically connected. It also decides what transmission mode will be between two systems in the network.

Data Link Layer

The data link layer is the second-lowest layer of the OSI MODEL. This layer mainly consists of two sub layers - 

MAC (Media Access Control)

LLC (Logic Link Control)

In this layer, the data sent by the network layer is checked properly to ensure that there is no error in the data that is there. The data is then forwarded. There is also a framing of data in this layer.

Its work

Its main function is to control the transfer of data when our data is transferred. It also controls the error.

Network layer

The network layer is the third layer of the OSI model. Layer uses switching and routing techniques. Its function is to provide ip address. Our data in this layer is in the form of packets. The network layer performs the task of reaching these packets from source to destination. This layer is also called packet unit.

It's work

Its job is to select the best path to send data packets. When we send any data, where it is to be sent. That address is written as. Ip address.

Transport Layer

This layer is the fourth layer of the OSI model. Through this layer, data is transferred correctly by the network. This layer is used for communication between two computers.

It's work

The job of this layer is to send data between two computers. When this layer receives the data, it breaks it into segments. Which makes it easy to identify.

Session layer

The session layer is the fifth layer of the OSI model that controls connections between computers at the very top. It can also be understood in another language. The main function of the session layer is to see how the connection is maintained and terminated. 

It's work

 It synchronizes. Synchronization means that whenever an error occurs in the transmission, that transmission is repeated again.

Presentation layer

This layer is the sixth layer of the OSI model. Encryption and decryption of data is done through this layer. It is also used for the compression of data.

 It's work

 The function of this layer is to encrypt the data. It is also used for compression of data.

Application layer

This is the seventh layer of the OSI model. The function of this layer is to interface between our application and other layers.  In this layer, protocols like http, ftp, smtp and nfs etc. work together. 

functions

 Through the application layer, the user can access the files from the remote computer and retrieve the files. Through this we can forward and store email.

Characteristics of OSI Model

This layer is divided into two parts. upper layer and lower layer. The upper layer only applies to the application and handles any problem when it comes up. The lower layer handles the problem that occurs in the layer of data transport.

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