OSI MODEL for Networking.

       

The International Organization for Standardization (ISO) developed the Open System Interconnection (ISO) reference model.OSI model is most widely used for networking.OSI is a seven layer standard.

          OSI model does not specify the protocols required to be used to perform networking tasks but is a model for understanding and designing a network architecture.

The Seven layers of OSI model are as follows :

1. Physical Layer : It is the lowest layer of the OSI model.It co-ordinates the functions required to transmit a bit stream over a communication channel.

Functions of Physical layer:

-Physical characteristics of interface and media.

-Representation of bits.

-Data rate.

-Synchronization of bits.

2. Data link layer : This layer is responsible for transmitting frames from one node to another.

Functions :

-Framing.

-Physical Addressing.

-Flow control.

-Error control.

-Access control.

3. Network Layer : This layer is responsible for delivery of packets from source host to destination host.

Functions :

-Logical Addressing.

-Routing.

4. Transport Layer : This layer is responsible for delivery of messages from one process to another.

Functions: 

-Port addressing.

-Segmentation and reassembly.

-Flow control.

-Error control.

-Connection control.

5. Session Layer : This layer is responsible for dialog control and Synchronization.

Functions:

-Dialog Control.

-Synchronization.

6. Presentation Layer : This layer deals with the syntax and semantics of the information being exchanged.

Functions : 

-Translation.

-Encryption.

-Compression.

7. Application Layer : This layer is responsible for accessing the network by the user.

Functions :

-Network virtual terminal.

-Mail services.

-Directory services.

-File transfer,Access and management(FTAM).

 

These are the different layers present in the OSI Model and their associated functions.

Thank you for reading.

Vishwesh Wali from India.