The Full Form of OSI Meaning, and Definition 

On this page, We are going to learn about the full form of OSI and the meaning of OSI, As well as the meaning, definition, and acronym for OSI in different categories. So you should read this post till the end.

The Full Form of OSI: Open Systems Interconnection

OSI Stands for Open Systems Interconnection. Open Systems Interconnection (OSI) is a framework for transmitting messages between any pair of software entities in a communications network.

OSI model is used to Exchange or Transmit the data integrity from source to destination and prevent illegitimate messages from entering a network.

OSI is the seven-layered model that defines how to decode and transform data in computer networks. With this model, you can be sure your data are sent through the network reliably and quickly. Each layer handles its own type of data and has a number of functions behind them.

7 Layer of OSI Model network system

The 7-layer model of Open Systems Interconnection (OSI) is a reference model that describes how data traverses a computer network.

Each layer of the OSI Model performs a specific function, and each layer interacts with the layers immediately above and below it through interfaces called protocol handlers.

What is the meaning and full form of osi
7 Layer of OSI Model network system

The goal of the OSI model is to make data easier to transfer among computers or between networks, by ensuring that every application can access its destination directly.

SI Model network system is the most widely used networking model in the world. OSI framework for network communication that’s broken down into seven layers.

Each layer performs a specific role, building on previous layers and allowing a seamless flow of information between computers. Layers of the OSI Model –

1.Physical Layer

The physical layer is the first layer in the OSI model. This layer is also called a bit unit. This layer is responsible for physical and electrical connections such as – voltage, data rates, etc. 

In this layer, the digital signal is converted into an electrical signal. This layer also has the task of network layout ie network topology. The physical layer also describes whether the communication will be wireless or wired.

  • The main functionality of the physical layer is to transmit different bits from one node to another.
  • It is the lowest layer of the OSI model.
  • It establishes, maintains, and deactivates the physical connection.
  • It specifies mechanical, electrical, and procedural network interface specifications.

Functions of the Physical Layer

  • Line Configuration : It defines the way how two or more devices can be physically connected.
  • Data Transmission : It defines the transmission mode whether it is a simplex, half-duplex or full-duplex mode between two devices on the network.
  • Topology : It defines the way the network devices are arranged.
  • Signals : It determines the type of signal used to transmit the information.

2. Data Link Layer

The Data link layer is the second layer in the OSI model. This layer is also called the frame unit. In this layer, the packets of data sent by the Network Layer are decoded and encoded and this layer also confirms that these packets of data are error-free. Two protocols are used for data transmission in this layer.

  • High-level data link control (HDLC)
  • PPP (Point-to-Point Protocol)

important point

  • This layer is responsible for the error-free transfer of data frames.
  • It defines the format of data on the network.
  • It provides reliable and efficient communication between two or more devices.
  • It is mainly responsible for the unique identification of each device.

It consists of two sub-layers:

  • Logical Link Control Layer
    • It is responsible for transferring the packet to the network layer of the receiving receiver.
    • It identifies the address of the network layer protocol from the header.
    • It also provides flow control.
  • Media Access Control Layer
    • The Media Access Control Layer is the link between the Logical Link Control layer and the physical layer of the network.
    • It is used to transfer packets over the network.

3. Network Layer

The network layer is the third layer of the OSI model, this layer is also called the packet unit. Switching and routing techniques are used in this layer. 

Its function is to provide IP address. The data that is in the network layer is in the form of packets and the work of transporting these packets from source to destination is done by the network layer.

  • It is layer 3 that manages device addressing, and tracking the location of devices on the network.
  • It determines the best route to take data from source to destination based on network conditions, the priority of service, and other factors.
  • The data link layer is responsible for rooting and forwarding packets.
  • Routers are layer 3 devices, they are specified in this layer and used to provide routing services within the internetwork.
  • The protocol used to route network traffic is known as Network Layer Protocol. Examples of protocols are IP and Ipv6.

Network Layer Functions

  • Internetworking : The main responsibility of a network layer is that it provides a logical connection between different devices.
  • Addressing : A network layer connects the source and destination addresses in the header of the frame. Addressing is used to identify devices on the Internet.
  • Routing : Routing is a key component of the Network Layer, and it determines the best optimal path among many paths from source to destination.
  • Packetizing : The network layer receives the frames from the upper layer and converts them into packets. This process is known as Packetizing. This is achieved by internet protocol (IP).

4. Transport Layer

The transport layer is the fourth layer of the OSI model. It is also called a segment unit. This layer is responsible for the reliable transfer of data. 

That is, the data reaches in order and error-free, it is the responsibility of this layer. The transport layer communicates in 2 ways, connection-less and connection-oriented.

This layer 4 ensures that messages are transmitted in the order in which they are sent and there is no duplication of data. 

This layer is known as the end-to-end layer as it provides a point-to-point connection between the source and destination to deliver the data.

Transmission Control Protocol

  • It is a standard protocol that allows systems to communicate over the Internet.
  • It establishes and maintains a connection between hosts.
  • When data is sent over a TCP connection, the TCP protocol divides the data into smaller units called segments. 
  • Each segment travels over the Internet using multiple routes, and they arrive at the destination in a different order. 
  • Transmission Control Protocol reorders the packets at the receiving end in the correct order.

5. Session Layer

Session Layer is the fifth layer of the OSI Model. The main function of the session layer is to see how the connection is established, maintained, and terminated.

the function of the Session layer

  • Dialog control: The session layer acts as a dialog control that creates a dialog between two processes or we can say that it allows communication between two processes which is either half-duplex or full-duplex could.
  • Synchronization: The session layer connects some checkpoints while transmitting data in a sequence. 
  • If an error occurs in the middle of the transmission of data, then there will be re-transmission from the checkpoint. This process is known as synchronization and recovery.

7. Presentation Layer

The Presentation Layer is the sixth layer of the OSI Model. This layer is related to the operating system. This layer is used for the encryption and decryption of data. 

It is also used for data compression. The presentation layer is mainly concerned with the syntax and semantics of the information exchanged between the two systems.

It acts as a data translator for a network. This layer is a part of the operating system that converts data from one presentation format to another.
The presentation layer is also known as the syntax layer.

functions of the Presentation layer

  • Translation: The processes occurring in two systems exchange information in the form of character strings, numbers, etc. Different computers use different encoding methods, the Presentation layer handles the differences between the different encoding methods. It converts data from a sender-dependent format to a common format and converts the common format to a receiver-dependent format at the receiving end.
  • Encryption: Encryption is required to maintain privacy. Encryption is a process of converting sender-transmitted information into another form and it sends the resulting message over the network.
  • Compression: Data compression is a process of compressing data, that is, it reduces the number of bits to be transmitted. Data compression-like text, audio, and video is very important in multimedia.

7. Application Layer

The Application Layer is the last layer of the OSI Model. The main function of the application layer is to interface between our actual application and other layers. 

The application layer is closest to the end user. The Application Layer controls how any application accesses the network.

The application layer acts as a window for users and application processes to access the network service. It handles issues like network transparency, resource allocation, etc. 

The application layer is not an application, it is a layer that performs some functions. This layer provides network services to the end users.

functions of the Application layer

  • File transfer, access, and management (FTAM) : The application layer allows a user to access files in a remote computer, retrieve files from the computer, and manage files in a remote computer.
  • Mail services : The application layer provides a facility for email forwarding and storage.
  • Directory services : Applications provide distributed database sources and are used to provide global information about various objects.

There are some of the most commonly used acronyms, abbreviations, full forms, and the OSI meaning are listed in different categories below the table.

TermsFull Forms
OSIAn Organization For Standards Institute
Governmental » Institutes
OSIOffice of Special Investigations
Governmental » US Government
OSIOil Stability Index
Economy » Report
OSIOnly Safe Internet
OSIOpen Source Indicators
Miscellaneous » Unclassified
OSIOpen System Interface
Computing » General Computing
OSIOptimal System Integration
Computing » Hardware
OSIOverflow Stack Immediate
Computing » IT
Meaning and full form of OSI