Introduction

The TCP/IP model is a network protocol suite that is widely used for communication over the internet. It consists of five layers: the Application layer, Transport layer, Internet layer, Network Interface layer, and Physical layer. Each layer has its own set of protocols and functions. When data is sent from device A to device B, it goes through these layers in a specific order.

Explanation

When data is sent from device A to device B, it goes through the following layers in the TCP/IP model:

1. Application layer: The Application layer is responsible for providing network services to end-user applications. It includes protocols such as HTTP, FTP, SMTP, and DNS. This layer prepares the data to be sent over the network.

2. Transport layer: The Transport layer is responsible for the reliable delivery of data between hosts. It includes protocols such as TCP and UDP. TCP provides reliable, connection-oriented communication, while UDP provides unreliable, connectionless communication. In the case of data sent from device A to device B, the Transport layer at device A encapsulates the data and sends it to the Transport layer at device B.

3. Internet layer: The Internet layer is responsible for addressing, routing, and fragmentation of data packets. It includes protocols such as IP (Internet Protocol). The Internet layer at device A adds the source and destination IP addresses to the data packet and forwards it to the next hop in the network.

4. Network Interface layer: The Network Interface layer is responsible for the physical transmission of data packets over the network. It includes protocols such as Ethernet, Wi-Fi, and DSL. This layer converts the data packet into a format that can be transmitted over the physical medium.

5. Link layer: The Link layer is responsible for the logical communication between devices on the same network. It includes protocols such as ARP (Address Resolution Protocol) and Ethernet. The Link layer at device B receives the data packet from the Network Interface layer and prepares it for delivery to the Transport layer.

Conclusion

In conclusion, when data is sent from device A to device B in the TCP/IP model, the 5th layer to receive the data at device B is the Application layer. The data passes through layers such as Application, Transport, Internet, Network Interface, and finally the Link layer before reaching the Application layer at the receiving device.