THE 7 LAYERS OF THE OSI MODEL

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The 7 Layers of the OSI model describes how communication between computers and other networking devices will develop. That is, the standard for providing communication between different companies’ networking devices is called the OSI model.

7 Layers of the OSI model
Figure: 7 Layers of the OSI model

Communication from one computer to another is the main purpose of sharing information. The two computers are located in different locations and these two computers want to exchange information. Then when a computer sends data, the data will reach the destination through many media. There are some rules set out to ensure that data is not a problem when moving from source to destination so that it can access an error-free way. These rules are called protocols. And the model built using these protocols is called the OSI model. This model defines the ISO.

The OSI model is divided into seven layers. The layers are:

  1. Application Layer
  2. Presentation Layer
  3. Session Layer
  4. Transport Layer
  5. Network Layer
  6. Data Link Layer
  7. Physical Layer

Application Layer

These are the 7 layers of the OSI model. This works in the window between the user and the network service. To act as a user corner application in the network service from the OSI model it can send to the next layer. For example, if you want to compose and send mail to a mail client. First, it will go to the application layer. Some of the network applications that work at this level are Email, Web Browser, Hypertext Transfer Protocol (HTTP), File Transfer Protocol (FTP) and Network File System (NFS).

application layer

What this layer does:

  • The application layer provides the user interface and processes the network data.
  • The sender creates network data for sending the application layer to Hast.
  • Resource sharing and device redirection.
  • Remote file access.
  • Remote Procedure Call (RPC) Support.
  • Network management.
  • Directory Services.
  • Electronic messaging.

When you want to browse the webpage in the corner and click on the link in the corner, give the browser one give the command. This command tells the browser to file from a computer at a certain angle on the Internet to collect. When your computer is waking up to that computer, it’s yours the source of the computer shake and the destination of the computer shaking of the Internet. In the application layer, the service area will be used first.

Presentation Layer

This layer acts as a data translator for network services. On the transmitting computer, this layer converts the data received from the application layer into a legible format of the following layers. Once again, the presentation layer on the destination computer converts the data into an unobtrusive format of the application layer.

 presentation layer

The presentation layer does the following:

  • Character code translation, such as conversion from ASCII to EBCDIC format.
  • Data conversion, such as converting an integer to a floating-point.
  • Data compression, so that data can be transmitted faster over the network.
  • Data encryption and decryption, so that the data transmitted over the network is secure.

We should try to avoid these things better. Let’s first come up with a character conversion. When we create data in an application, such as e-mail messages, it does not exist in all service or application format. As such, all computers can understand such a format as ASCII or the American Standard Code for Information Interchange. It has 96 characters and digits, as well as 32 non-printing characters Presentation Layer Application Converts data from a layer to this ASCII format.

Session Layer

The session layer works by connecting the source and the destination device to the connection, maintaining that connection and disconnecting the connection at the end of the transmission. It also works for message-mode data transfer.

The Session Layer does the following:

  • For each application process, a unique address register, such as NetBIOS, can do this. The session layer with these addresses can separate each process from the address of the network adapter.
  • Session Layer works by creating a combination of two processes between two different devices by creating a unique process address, protecting that connection, and separating the connection between the two devices. This creates a virtual circuit that is created between two processes on two devices.
  • The beginning and end of a message data can be identified. This allows the receiver to know if the session layer is fully up to the message. He will not send the message data of the upper layer until the whole massage session reaches the layer.
  • Session Layer works on message synchronization. After sending a number of data packets, the session layer of the source device waits for the receiver to receive an acknowledgment message (called ACK) from the session layer of the device. After receiving the ACK message from the session layer of the receiving device, the source sends the message data again, thus synchronizing the message at a certain time.
  • Different processes require the support of the network to work, such as username and password verification, resource security verification, etc. session layer.

Transport Layer

The fourth layer of the OSI model is the transparent layer. Its job is to ensure that the data from the session layer reliably reach another device. To do this, the Transparent Layer Session breaks down the data available from the Layer into smaller pieces so it can send subsequent layers to another network. The transparent layer uses two types of transmission to ensure data is transmitted from one device to another.

  1. connection-oriented
  2. Connectionless
transport layer

This transport layer also determines what the communication speed between the two devices will be. This is called flow control. Regardless of the type of transmission used, the transport layer will see the maximum size of any data packet that both devices can accept. Based on this, the data packet is shared and sent.  Suppose computer 1 can send 5 bytes of data packets, and computer 2 can send 10 bytes packets. Now if Computer 2 sends a packet of 10 bytes to Computer 1, then Computer 1 cannot accept it. Therefore, the Transport Layer will determine through flow control that both computers will send only 5 bytes of data packets to each other in communication.

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