OSI Model leyers

1. Assignment on
OSI Model
Course Title : Data Communication
Course Code : CSE-313
Submitted To Submitted By
Pranab Bandhu Nath Lamya Mutassim
Lecturer ID: 1834902169
City University Batch:49(B)
B.Sc. in CSE

2. OSI Model
OSI stands for Open System Interconnection is a reference model that describes how information moves through
a physical medium from a software in a one computer to the software application in another computer. It has 7
layers.
1. Physical Layer
2. Data Link Layer
3. Network Layer
4. Transport Layer
5. Session Layer
6. Presentation Layer
7. Application Layer

3. Physical Layer (Level 1)
It is the lowest layer of OSI model. It contains information in the form of bits and responsible for physical
connection between devices. It receives signals as data and convert it into 0s and 1s and send them to Data Link
Layer.
Example: Hub, Repeater, Modem, Cables.

4. Data Link Layer (Level 2)
This layer is responsible for the error-free transfer of data frames. It defines the format of the data on the
network. It provides a reliable and efficient communication between two or more devices.
It contains two sub-layers :
Logical Link Control Layer : It identifies the address of the network layer protocol from the header.
Media Access Control Layer: A Media access control layer is a link between the Logical Link Control layer and
the network's physical layer.

5. Network Layer (Layer 3) :
Network layer works for the transmission of data from one host to the other located in different networks. It
determines the best path to move data from source to the destination based on the network conditions, the
priority of service, and other factors.

6. Transport Layer (Level 4)
Transport layer provides services to application layer and takes services from network layer. The main
responsibility of the transport layer is to transfer the data completely. It receives the data from the upper layer
and converts them into smaller units known as segments.

7. Session Layer (Level 5)
It is used to establish, maintain and synchronizes the interaction between communicating devices.

8. Presentation Layer (Level 6)
A Presentation layer is mainly concerned with the syntax and semantics of the information exchanged between
the two systems. This layer is a part of the operating system that converts the data from one presentation format
to another format. It is also called the Translation layer.

9. Application Layer(Level 7)
This layer serves as a window for the application services to access the network and for displaying the received
information to the user. It is not an application, but it performs the application layer functions.

10. Reference
https://www.geeksforgeeks.org/layers-of-osi-model/
https://www.javatpoint.com/osi-model