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What is OSI Model in Computer Network?

In this tutorial, you will learn what is OSI Model in computer network, how it works, and more!

Introduction to the OSI Model

The OSI model is a standard for networking protocols. It is a seven-layer reference model that is used to describe and standardize networking between computer systems, commonly referred to as a “stack”. The OSI model divides the functions of a network into seven layers: application, presentation, session, transport, network, data link, and physical.

Each layer can be thought of as a separate “blueprint” for how information is transmitted from one computer to another over a network. Each layer has its own specific set of rules and specifications about how data should be organized and transmitted.

Every connection between two devices in a network has all seven OSI layers operating simultaneously. However, different layers are more dominant in certain connections than in others.

Purpose of OSI model in computer network

The OSI model can be used to communicate between two computers anywhere in the world, regardless of the types of networks or technologies used to connect them. It is a standard that has been adopted by many different organizations and industries and has become the accepted way to describe and implement data communication.

The OSI model provides a consistent approach to communication between computers and can be used as a troubleshooting tool to identify where a network problem is occurring. It can also be used as a guide for setting up networks and designing new systems.

Networking Process using OSI Model in Computer Network

The following are the networking process of the OSI model in a computer network:

  1. Connection: The data link layer provides the hardware and software to establish a connection between the sending and receiving devices. This includes the use of an electrical signal that is sent through the network cable to signal that a connection has been established.
  2. Encoding: The application layer performs the encoding of data. Data encoding is the process of taking information and translating it into a format that can be understood and used by another system or device.
  3. Packaging: The transport layer takes data that has been encoded by the application layer and packages it into smaller segments that are sent to the network layer. The network layer then divides the data into smaller pieces, called packets. Packets are a group of data that is transmitted and received as a single unit.
  4. Transmission: The data link layer adds additional information to each packet to indicate where it should be sent. Once the data link layer has added this information, the packets are ready to be sent and transmitted through the network. The data link layer also resends any packets that are not acknowledged by the receiving device.

Layers of OSI Model in Computer Network

There are 7 layers of the OSI model in the computer network. Take a look at each of them in a little detail below:

Layer 1: The Physical Layer

The physical layer is responsible for the actual connection between devices. The physical layer includes the equipment and physical media that are used to establish a connection between two devices. It specifies the type of network cables and connectors, voltage, and other physical properties that are used in a connection. This layer does not define any logical information and operates on a “simplicity” basis. If the two devices are connected, they are connected on this layer.

Layer 2: The Data Link Layer

The data link layer is responsible for getting data from one computer to another over a network. It is primarily responsible for the data transmission between two devices on a network and it specifies the type of network topology that is being used. The data link layer determines the best way for the data to be transmitted between the devices and it specifies the type of network protocol that will be used.

Layer 3: The Network Layer

The network layer is responsible for routing data between networks. This layer determines the best route for the data to travel from one network to another. It considers the available networks and which one will provide the best path for the data to follow. The network layer specifies the type of routing protocol that will be used and how the data will be forwarded between networks.

Layer 4: The Transport Layer

The transport layer is responsible for end-to-end connections between devices, or hosts. It ensures that the data is delivered to the correct host and that it is received accurately and completely. The transport layer is also responsible for ensuring that the data is securely transferred between the hosts. It manages any errors that occur during the transmission and resends any data that has been lost or damaged.

Layer 5: The Session Layer

The session layer is responsible for setting up and managing the communication between two hosts. It is used for securing the data transmission between two hosts and for managing the end-to-end connection. It is also used for controlling the amount of bandwidth that is required for the connection. The session layer is often used for real-time applications, such as Voice over Internet Protocol (VoIP) and video conferencing.

Layer 6: The Presentation Layer

The presentation layer is responsible for the translation of data between different systems. It is responsible for the translation of data from the application layer that has been encoded by the application layer into a format that can be used by the receiving system. The presentation layer is also responsible for the encryption and decryption of data that is being transmitted between systems.

Layer 7: The Application Layer

The application layer is responsible for managing the end-user applications, such as word processors and email. It is responsible for the end-user devices and the user request for the data. It receives the request from the user, passes it to the transport layer, and then receives the data from the transport layer and sends it to the appropriate application.

Final Words on OSI Model in The Computer Network

The OSI model in the computer network is a helpful model for understanding how data is transmitted and received in a network. It also provides a guide for troubleshooting and designing new systems. The OSI model is commonly used in computer science education, network engineering, and communication.