OSI model easily explained

Open System Interconnection model (mostly known as OSI model)
SO it’s a seven-layer model used to visualize computer networks. The OSI model is beneficial for development and problem-solving. Each part of the seven layers goes-up in increments of one as it gets closer to the human user.
Layer seven is the application layer, is nearest to the person but
layer seven is the physical layer, where the network receives and transmits raw data.
In this article, each of the seven layers will be explained in a simple terms. The layers will be described from layer seven to layer one, because of this way, the data flow.
The seven layers of the OSI model

Layer 7 – Application
The application layer is where the users input their data, and data is output to the user. An application layer is mainly a software that is run off the local machine. However, this depends on the network architecture. The software could be cloud-based, meaning it runs off on a server in a remote location and data is transmitted over the internet, or the software may be run on a local server or a machine.
The application layer provides the services for email, Telnet, and file transfer
for example:- application layer can be an internet browser, or an FTP client, or Microsoft Word.

Layer 6 – Presentation layer
The presentation layer is an OSI model layer where the operating system stays, and the operating system can be Windows, OS X, a Unix based operating system, or other operating systems. Where the human (users) interacts with the application layer, which is described above, the application layer directly interacts with the presentation layer. This can be done through a runtime environment as like the Java Runtime Environment (JRE).

Layer 5 – Session layer
The session layer is mainly responsible for the creation and maintenance sessions between the OS (operation system) on the presentation layer or the other third party machines.
For example, whenever a user is surfing the internet, they are getting interacting with the application layer and the application layer is interacting with the presentation layer, and the session layer allows the operating system to interact with the webserver.

Layer 4 – Transport layer
The transport layer is responsible for the transportation of the session. As the example used above, the transport layer can be responsible for determining and detecting what and how much information is getting transferred between the operating system and the webservers.

Layer 3 – Network layer
The network layer is where routers operate. This is where users IP address comes from, and in the example which is used above,
the router is also responsible for sending packets of data or information out into the internet and receiving them. These packets origin and destination are determined by the IP address of your router.

Layer 2 – Datalink layer
The data link layer is the layer where switches operate and provide a reliable link between the two directly connected nodes. The data link layer is very much also responsible for detecting and also possibly fixing any packet errors that may cause on the physical layer.
The data link layer is distributed into two separate parts, first Media Access Control (MAC) and second is Logical Link Control (LLC) layers. The MAC part is responsible for controlling how devices connected to the network gain access and The LLC (logical link control) layer controls error checking, possible fixes, and packet synchronization.

Layer 1 – Physical layer
The physical layer is literally physical hardware that makes up the network.
This layer has several significant functions:-
Defining physical specifications
Defining protocols
Determining transmission mode (half-duplex & full-duplex)
Defines the network topology
Hardware, like the physical components of Ethernet cables and Bluetooth, is also an example of the physical layer.

Here’s the power tips from my side

If you wants to learn OSI model layers for life time for that you have to remember a sentence

Please do not through sausages and pizza away

Now remembers all the first word of the sentence

Please for p

Do for d

Not for n

Through for t

Sausages for s

Pizza for p

Away for a

Not the first letter is as same as the first word of each layer as following

P for physical layer

D for data link layer

N for network layet

T for transport layer

S for session layer

P for presentation layer

A for application layer

I hope you understand what is OSI layer and will never forget again

Thank you for reading this article hope you’ll like it

Regards

M kumar

VIEH Group

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