TCP/IP model stands for Transmission Control Protocol and Internet Protocol.
The TCP/IP model consists of five layers: the application layer, transport layer, network layer, data link layer and physical layer.
The first four layers provide physical standards, network interface, internetworking, and transport functions that correspond to the first four layers of the OSI model and these four layers are represented in TCP/IP model by a single layer called the application layer.
TCP/IP is a hierarchical protocol made up of interactive modules, and each of them provides specific functionality.
Below there is a table with all layers given with their individual task.
| Layer 4 | Application | Allow access to network resources |
| Layer 3 | Transport | Provides process to process message delivery and error handling |
| Layer 2 | Internet | Move packets from source to destination |
| Layer 1 | Link/Network Interface | Responsible for transmission of data between two devices in a same network. |
Here below a visual difference between OSI and TCP/IP protocol.
Note : The higher you go up in the model the headers are stripped away until you have the main data left for your application.
Internet Layer
This layer is consist of different protocol like TCP or UDP. It has a thing called headers and the headers has certain properties as well –
- Version – It describes the IP address type IPV4 or IPV6
- Header Length – It specifies the size of the header. Usually it is 32 bit.
- Differentiated Services Code Point (DSCP) – It contains data of bandwidth sensitive application like VOIP.
- Time To Live (TTL) – Some time error happens and a Ip packets travels through the routers infinitely and to prevent we use this.
- Protocol – It specifies the protocol type. E.G. – TCP or UDP.
Aniruddha Basak 