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An Open Systems Interconnection Model, commonly known as an OSI Model, is an effective conceptual setup that has been created by the International Organization for Standardization. This system is very effective to communicate with other network systems as well. Due to the creation of these standardized protocols, each diverse network can communicate with each networking system with ease, as the same set of protocols is followed by all the other systems as well.
One major use of OSI models is in the resolving of troubleshooting network issues. As an OSI model has been divided into seven different layers, it becomes quite easy to precisely detect the stage at which the root of the networking problem lies and gets solved accordingly.
Layers of the OSI Model
We begin with a broader classification of the OSI model. The system is broadly divided into two upper and lower layers.
Upper layer: This layer usually figures out issues based on application. They are used in the software only. It carries out functions related to the host.
Lower layer: This layer usually figures out issues of data transport. They are used both in the software as well as the hardware. It carries out functions related to the network.
Now, going to the different layers of the OSI model, they are:
Physical: Situated at the bottom position of the model setup. It has the function of establishing hardware with respect to electrical and mechanical devices, such as cables or switches.
Data Link: It is primarily involved in the transfer of data between two same types of network systems. Depends on the types of intra-network system communication. It facilitates error-free flow and maintenance of data.
Network: Involved in the transfer of data between two different network systems. It uses the method of routing, which means that the data transfer method would zone in the most feasible way of transferring data.
Transport: It is involved in the function of transferring data and communicating between two devices. It performs an end-to-end control and maintenance of the flow of data. This layer majorly uses the routing method.
Session: Primarily involved in the communication between two devices. A session in this context is defined as the time period during which the lines of communication are opened or closed accordingly. The session tries to optimize the opening time maximally so as to achieve complete communication without any errors.
Presentation: Also known as the syntax layer, this layer is a prerequisite for the last layer of the OSI model,i.e., the application layer. Simply put, it is used to make data presentable enough and uses the semantics and syntax accordingly of the data exchanged to enable effective representation of the data.
Application: This is the last and the topmost layer of the OSI model. The application acts as an intermediate between the device and the user and is in direct contact with the user. Examples include emails, file transfers, etc.
Conclusion
In this article, we saw an overview of the OSI model. An OSI model is basically a model created according to international standards and protocols to facilitate communication between various network systems. The model is divided into seven layers based on its roles and functions. The seven layers are also broadly categorized into two divisions: upper and lower layers. The OSI model is very effective in solving troubleshooting network problems.
