Introduction

OSI model is a Set of Rules that explains how different computer networks communicate over a Network. It is a Seven-layer Plan (like Seven Stairs) that shows how data will e transferred from your device to the server, and each layer has a different job. The 7 Layers of OSI model is:

OSI Model Layers

Layer 1- Physical Layer

It is responsible for the actual physical connection between devices. In this layer, data is transferred in form of 0s and 1s. In this layer, bits are transferred one by one and while receiving data from any device, it firstly converts them into 0s and 1s and sends them to the Data link layer.

Layer 2- Data Link Layer (DLL)

It sends data to nearby devices connected on same Network like Ethernet and Wi-Fi and its one of the main feature is to keep the data error-free. Framing is also one of the main feature, it provides a way for a sender to transmit a set of bits that are meaningful to the receiver and it can accompanied by attaching special bit patterns to the beginning and end of each frame.

Layer 3- Network Layer

It works for the transmission of data from one host to other host located in the Internet. It finds the best route for packets to go to his destination like a postman choosing the best road for delivering the letter. And receiver’s Ip address is stored in the header by Network layer. Segments in the Network layer is referred to as Packets. And if the devices are on the same network then they don’t need to interact with thins layer.

Layer 4- Transport layer

It provides services to the application layer and receives services from Network layer. In this layer, data transferred are named as segments. It is responsible for the end-to-end delivery of complete message. Most popular protocols used in this layer are TCP(Transmission control protocol), UDP(User datagram Protocol). It also adds source, destination and port number in it header and forwards the segmented data(broken down of large data) into Network layer.

Layer 5- Session Layer

It is responsible making the connection, terminations, and preventing from overutilization or under-utilization of Resources like the teacher organizing class for parents meeting. It also provides authentication and security. Protocols used in this layer are NetBIOS and PPTP.

Layer 6- Presentation Layer

It is also called the Translation layer because data over the application layer is transported and manipulated(transformed/changed) as per the requirement. it performs features like Data transition, encryption and compression etc.. Protocols used in this layer are: Jpeg, png, SSL, mp4 etc. It also prepares data for application layer or server.

Layer 7- Application Layer

The application creates communication between the device with the network using protocols and data manipulation processes that transform computer readable data(0s and 1s) into Human readable data(like a,1). It also have function like FTAM(file transfer access and management) and features like e-mail service.

Data flows through OSI model in this step by step process:

• Application Layer: Applications create the data.

• Presentation Layer: Data is formatted and encrypted.

• Session Layer: Connections are established and managed.

• Transport Layer: Data is broken into segments for reliable delivery.

• Network Layer: Segments are packaged into packets and routed.

• Data Link Layer: Packets are framed and sent to the next device.

• Physical Layer: Frames are converted into bits and transmitted physically.

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