This tutorial compares the OSI reference model with the TCP/IP model. Learn the similarities and differences between the OSI reference model and the TCP/IP model.
The TCP/IP and OSI are network reference models. The process of developing both models began in the early 1970s and ended in the late 1970s. Both models were published in the early 1980s. Manufacturers manufactured devices to support one model or both models in the 1990s. By the late 1990s, the TCP/IP model became a common option and the OSI model was rejected due to a slower formal standardization process than the TCP/IP model. Leading manufacturers abandoned their proprietary networking model in favor of the TCP/IP model in the 2000s. Nowadays, only the TCP/IP model is used. Almost all modern computer networks are built using the TCP/IP model. All modern networking devices support the TCP/IP model.
Why is the OSI model still taught in networking courses?
In terms of explanation and documentation, the TCP/IP model stands nowhere near the OSI model. The OSI model is one of the best explained and well-documented models ever created. It describes complex networking concepts, protocols, and terms in such a manner that is not only easy to understand but also easier to remember.
Since both models were built to achieve the same goal, they both use the same set of standard protocols and similarly describe networking concepts. By learning one model, you can easily learn another model.
For this reason, even though the OSI model is not supported and used by hardware manufacturers, it is still taught in almost all networking courses. Once students learn the OSI model, they are introduced to the TCP/IP model. Since they have already learned the foundation topics and the layered approach from the OSI model, learning the TCP/IP model becomes easier for them.
This article also follows the same approach. The first two parts of this article explain the OSI model and its layers. This part explains the differences and similarities between the TCP/IP model and the OSI model. And the next two parts explain the TCP/IP model and its layers.
This tutorial is the third part of the article "Networking reference models explained in detail with examples". Other parts of this article are the following.
OSI Model Advantages and Basic Purpose ExplainedThis tutorial is the first part of the article. It briefly explains why the OSI model created was and what the advantages of the OSI model are.
OSI Seven Layers Model Explained with ExamplesThis tutorial is the second part of the article. It explains the seven layers of the OSI model in detail.
TCP/IP Reference Model ExplainedThis tutorial is the fourth part of the article. It explains the five layers of the TCP/IP model in detail.
Data Encapsulation and De-encapsulation ExplainedThis tutorial is the fifth part of the article. It explains how data is encapsulated and de-encapsulated when it passes through the layers.
Similarities between the TCP/IP model and the OSI model
- Both are logical models.
- Both define standards for networking.
- Both provide a framework for creating and implementing networking standards and devices.
- Both divide the network communication process into layers.
- In both models, a single layer defines a particular functionality and sets standards for that functionality only.
- Both models allow a manufacturer to make devices and network components that can coexist and work with the devices and components made by other manufacturers.
- Both models simplify the troubleshooting process by dividing complex functions into simpler components.
- Instead of defining the already defined standards and protocols, both models referenced them. For example, the Ethernet standards were already defined by IEEE before the creation of these models. So instead of defining them again both models used them as IEEE Ethernet standards.
Differences between the OSI model and the TCP/IP model
- The OSI Layer model has seven layers while the TCP/IP model has four layers.
- The OSI Layer model is no longer used while the TCP/IP is still used in computer networking.
- To define the functionalities of upper layers, the OSI model uses three separate layers (Application, Presentation, and Session) while the TCP/IP model uses a single layer (Application).
- Just like the upper layers, the OSI model uses two separate layers (Physical and Data-link) to define the functionalities of the bottom layers while the TCP/IP uses a single layer (Link layer) for the same.
- To define the routing protocols and standards, the OSI model uses the Network layer while the TCP/IP model uses the Internet layer.
- The OSI model is well documented than the TCP/IP model.
- The OSI model explains every standard and protocol in detail while the TCP/IP model provides a summarized version of the same.
Differences between the original TCP/IP model and the updated TCP/IP model
The TCP/IP model which we use nowadays is slightly different from the original TCP/IP model. The original TCP/IP model has four layers while the updated TCP/IP model has five layers.
The original version uses a single layer (Link layer) to define the functionalities and components that are responsible for data transmission. The updated version uses two layers (Data Link and Physical) for the same.
It defines the functions that are directly related to the data transmission in the Physical layer and defines the functions that are indirectly related to the data transmission in the Data-link layer.
In the updated version, the name of the Internet layer is changed to the Network layer.
The following figure compares the OSI reference model, the original TCP/IP model, and the updated TCP/IP model.
No matter which model you study or learn first, once you learned one, you can easily correlate it with another. In general comparison, the updated TCP/IP model is much or less similar to the OSI model except for the Application layer. For learning, you can think that the Application layer of the TCP/IP model does what the top three layers (Application, Presentation, and Session) of the OSI model do.
That’s all for this part. In the next part of this article, we will learn the TCP/IP model and its layers in detail. If you like this tutorial, please don’t forget to share it with friends through your favorite social site.