What is osi model in computer Network

An operating system interconnection model used for computer network communications is called the OSI Model, or simply OSI Model. Network communication is separated into seven OSI model levels, or levels, under this approach.

Each layer is in charge of carrying out particular duties and providing support for communication protocols. We will learn in-depth details about the various OSI Model layers in this essay.

What is osi model in computer Network

what is osi model in computer network

A conceptual framework known as the OSI (Open Systems Interconnection) model divides the operations of a computer or communications system into seven abstraction levels. The International Organisation for Standardisation (ISO) created it to guarantee compatibility and ease communication across various systems.

The OSI model’s levels each reflect a distinct set of functions, and these layers cooperate to allow devices in a network to communicate with one another. The OSI model’s seven levels, arranged from lowest to highest,

Network engineers and developers may better grasp the purposes of each layer and create interoperable communication protocols by using the OSI model as a reference framework.

Keep in mind that the OSI model is theoretical and that actual networking protocols, like the TCP/IP suite, might not precisely follow its seven-layer structure.

What is osi model

A reference model for communication in a network between two users is the OSI model. There are seven levels in this model, however they are not interconnected. In the OSI model, data is sent from one layer to another but is not dependant on any other layer.

7 Layers Of OSI Model

1). Physical Layer

The OSI Model’s Physical Layer is the lowest level. This layer handles network hardware and allows data to be sent and received between machines without being altered. It consists of several components, including a network card, repeater, hub, switch, and cable. Bits of data are transformed into electronic, radio, electrical, or infrared signals, among other forms, via the Physical Layer.

2). Data Link Layer 

The second layer of the OSI Model, the Data Link Layer, is located above the Physical Layer. This layer’s primary purpose is to transmit data flawlessly and securely between nodes. In order to send the data frames over the network, this layer separates the data into frames, adds logical addresses, and verifies messages. Error detection, error repair, and handshaking are handled by this tier.

3). Network Layer 

The third tier of the OSI Model, known as the Network Layer, is responsible for directing data packets between nodes. Logical addressing and routing are used to send the packets received through this layer to the appropriate node. This layer arranges transmitted packets based on the bandwidth allotted and controls network traffic.

4). Transport Layer 

The fourth tier of the OSI Model, the Transport Layer, is in charge of end-to-end acceleration and verification. This layer’s primary goal is to transfer data in a methodical and safe manner from one host to the other. This layer separates the data into segments, checks for faults using port numbers, regulates data transfer speed, and conducts segment validation.

5). Session Layer

The fifth tier of the OSI Model, the Session Layer, is in charge of creating and managing the transport connection. Between two hosts, this layer manages session activities and authentication. Between transport connections, the Session Layer creates a logical session, manages the session, and ends the session. Tokens, synchronisation points, and session data may all be stored with it.

6). Presentation Layer

The sixth tier of the OSI Model, the Presentation Layer, is in charge of formatting, decrypting, encrypting, and simplifying data. In order for a message sent to another host to be read and understood by another host, this layer converts data into machine-directed language. The data is compressed and decompressed by this layer as well.

7). Application Layer 

The OSI Model’s seventh and last level is the application layer. This layer includes several protocols, including HTTP, FTP, DNS, SMTP, and Telnet, among others, to manage users and user applications on the network. File transfers, network activities, and user interface are handled by this layer. Through the application layer, users interact with the network and conduct network operations.

Features Of OSI Model

The OSI Model is a thorough and all-inclusive networking architecture that offers level-wise systematisation and operation by adhering to universal principles. Among its primary attributes are:

  • Structural type: The OSI Model is divided into several tiers and is structurally ordered. It guarantees that each level carries out its duties and stays structured with appropriate activities.
  • Protocol stack: In the OSI model, different protocols are employed at different levels. This guarantees that when it comes to data transfer across various levels, the strictest guidelines may be adhered to.
  • Protocol Ratio: Every OSI Model level has a unique protocol ratio. This guarantees that data is handled appropriately and that supply-demand is used for communications at various levels.
  • Independent Level Development: In the OSI Model, every tier carries out its tasks autonomously and manages its own operational procedure. This guarantees that messages at any level don’t affect messages at any other level.
  • Protocol Testing: To test the protocols used at each OSI Model level, there is a dedicated protocol testing programme. This allows one to gauge the protocol’s ease of use and security.

These were a few of the key components that contribute to the OSI Model’s strength and security as a networking architecture. The OSI Model is now the most widely used networking architecture because of these characteristics.

Advantages Of OSI Model

The usage of the OSI Model has several benefits. Here are a few of the principal benefits:

  • Standardized structure: A standardised framework that may be used to help various networking devices communicate with one another is the OSI Model. This guarantees permanent strategic networking that can satisfy various devices’ communication requirements.
  • Supply-Demand Balance: Users are able to interact safely and effectively for the supply-demand balance because of the OSI Model’s level systematisation. The operation and administration of communications are made easy by the fact that circulation at one level has no bearing on circulation at another.
  • Development of new protocols: The OSI Model’s level systematisation makes it simpler to build and modify new protocols. It is feasible to design new and progressive protocols that enable secure, quicker, and more adaptable communications by assuring independent innovation of protocols at each level.
  • More Security: An essential component of the OSI Model is security. The networking architecture may be made more safe by putting security controls in place at every stage. Furthermore, the OSI model’s protocols and organisation aid in recognising and managing security threats.

The OSI model is a popular networking architecture that facilitates safe, standardised, and dependable communications because of these benefits.

Disadvantages Of OSI Model

The Open Systems Interconnection (OSI) Model has the following drawbacks:

  • Complexity: Because of its potential complexity, the OSI model can be challenging to comprehend and apply. Its seven layers mean that distinct procedures are needed for each level, some of which may be interdependent.
  • Worth: The cost of compliance might be significant since separate protocols are needed at each level of the OSI model. As such, adoption may be challenging for certain organisations or network engineers.
  • Organizational Conflict: The OSI Model’s potential to interfere with business protocols is another drawback. Delays in the creation and standardisation of a certain protocol might affect its maximum level of security and interoperability.
  • Utility Of More Levels: The OSI Model’s seven tiers may make it too beneficial for some small networks and users. Therefore, it could be highly unsuitable and challenging to use it in a commercial enterprise.

These are a few drawbacks of the OSI Model that need to be considered while using it.


An essential standardisation model that aids in guaranteeing network structure and functionality is the OSI Model in Hindi. Standardisation, structural segmentation, cross-platform compatibility, commercial marketing assistance, and organisational management are some of its advantages.

On the other hand, its drawbacks are sluggish performance, internal storage, delay in connections, complexity, and expense. This architecture can offer a dependable and secure network structure if it is used properly.


What is OSI Model?

A structural model called the OSI Model was created to comprehend and manage computer networks. According to this paradigm, there are seven distinct levels for communications protocols. The majority of levels utilise the services of the higher level, and each level carries out certain tasks.

How many layers are there in a computer?

A computer network has seven layers, which correspond to the seven OSI Model tiers.

Which layer is not in OSI Model?

None of the aforementioned seven levels in the OSI Model are the same as the layer designated as “Application.”

What are the 7 layers of OSI Model?

-Physical Layer
-Data link layer
-Network layer
-Transport layer
-Session layer
-Presentation layer
-Application layer

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