Open Systems Interconnection/OSI Model

After Reading This you will be able to explane:

1. What is the creating reason of the OSI model?

2. OSI Model Hitory.
3. OSI Model 

There was a time when every computer company has there own Set of rule or Protocols to make the communication or maybe they have multiple Set of rules. But this is a problem, they can communicate only within their same company’s devices and there is no communication between each others devices because of difference in Set of rules. So, the time goes and goes like this and in 1984 the company name International Organization for Standardization (ISO) introduced a model name Open Systems Interconnection (OSI) Model.

The main idea is to prepare some Set of rules or Protocols and to use them step by step, in result they can communicate within and outside of their company’s devices. They actually prepare some layers which work step by step to establish a communication process.

The OSI model is actually the learning model and it consist of seven layers. The best learning practice about them layers is to group them in two. The upper four layers are used when a message is send by the sender and received by the receiver. The lower three layer are actually worked when the message is traveling on the internet from host to host. If receiving device finds out that it’s not their message they forward it to another host, until it finds out its real destination device. 

The OSI Model Layers:
1.Application Layer

2.Presentation Layer

3.Session Layer
4.Transport Layer
5.Network Layer
6.Data Link Layer
7.Physical Layer