There are two main networking models which are available to communicate the different devices over the internet.
Keep in mind OSI and TCP/IP are two different models which built in almost same period and their functionality is almost similar.
1. OSI Model
The OSI (Open System Interconnection) is a Theoretical (or Reference) Model which holds seven layers as given below.
- This Model is not practically implemented anywhere in the world because It defines just rules.
- As this model defines the way through which two devices can communicate easily over internet. That’s why, the hardware manufacturers and software developers produce the hardware’s and software’s according to OSI layered model.
2. TCP/IP Model
TCP/IP is a practical model and in functionality it is just like OSI model. In mostly books TCP/IP holds 5 layers and in some syllabus it holds 4 layers. Reason behind 4 or 5 layers is explained in TCP/IP tutorial.
This model is the combination of TCP and IP. The TCP is implemented on transport layer and IP is implemented at network layer.
Differences Between OSI & TCP/IP Model
|OSI Model||TCP/IP Model|
|The OSI proposal model was first defined in raw form in Washington, DC in 1978 but later it was published by the (International Organization for Standardization (ISO) in 1980.||In the late 1970’s TCP/IP was developed by The Defense Data Network (DDA), part of the Department of Defense, for its Advanced Research Projects Agency Network (ARPANet).|
|It is just a theoretical (referenced) model.||It is practical model.|
|The structure of OSI model was developed first and then the protocols in each layer were developed.||In the TCP/IP, the protocols were developed first and then the model was developed.|
|The OSI has seven layers.||TCP/IP has four or five layers in different books. It is because TCP/IP is not a theoretical Model.|