The OSI model is a logical model that describes the different layers and their functions in the process of transmitting data over a network. It is not a physical model and does not specify the exact protocols or technologies used at each layer.
On the other hand, the TCP/IP model, also known as the Internet Protocol Suite, is a physical model that describes the actual protocols used on the internet and other networks that use the Internet Protocol (IP). The TCP/IP model has four layers:
- Link Layer: This layer corresponds to the Physical and Data Link Layers of the OSI model. It deals with the physical connections between devices and the low-level details of transmitting data.
- Internet Layer: This layer corresponds to the Network Layer of the OSI model. It is responsible for routing packets of data between devices on the network, using IP addresses.
- Transport Layer: This layer corresponds to the Transport Layer of the OSI model. It is responsible for ensuring that data is delivered reliably and in the correct order, using protocols such as TCP and UDP.
- Application Layer: This layer corresponds to the Session, Presentation, and Application Layers of the OSI model. It provides interfaces and protocols that applications use to communicate over the network, such as HTTP, FTP, and SMTP.