The TCP/IP model, also known as the Internet Protocol Suite, is a conceptual framework used for the design and implementation of computer network protocols. It's the set of communications protocols that underpins the Internet and many private networks. The TCP/IP model does not have as many layers as the OSI model but aligns closely with it. The TCP/IP model consists of four layers, from the bottom to the top:
Link Layer (or Network Interface Layer):
Functions: This layer is responsible for the physical connection between devices and the local network's medium. It deals with the addressing of devices on the local network and the framing of data for transmission.
Protocols: Ethernet, Wi-Fi, PPP (Point-to-Point Protocol).
Internet Layer:
Functions: This layer is responsible for routing packets of data between different networks, and it provides logical addressing to devices on the network.
Protocols: IP (Internet Protocol), ICMP (Internet Control Message Protocol).
Transport Layer:
Functions: The transport layer ensures end-to-end communication, segmentation, and reassembly of data. It also provides error detection and correction, as well as flow control.
Protocols: TCP (Transmission Control Protocol), UDP (User Datagram Protocol).
Application Layer:
Functions: The application layer interacts directly with end-user applications. It provides network services directly to applications and supports communication between software applications.
Protocols: HTTP (Hypertext Transfer Protocol), FTP (File Transfer Protocol), SMTP (Simple Mail Transfer Protocol).
The TCP/IP model is widely used for networking, and the protocols associated with it are fundamental to the operation of the Internet. Unlike the OSI model, the TCP/IP model has become the de facto standard for networking, and most modern networks are based on it. The four layers of the TCP/IP model provide a conceptual framework for understanding how network protocols work together to enable communication between devices across diverse networks.