What Is TCP/IP?

Written by Coursera Staff • Updated on

TCP/IP, or transmission control protocol/internet protocol, is a protocol that sends data between two computers.

[Featured image] An IT support specialist looks up TCP/IP on their phone.

TCP/IP stands for transmission control protocol/internet protocol. It's an internet protocol that allows computers to communicate with one another and transfer data across long distances. The protocol breaks data down into little packets and transmits them to its destination. Once it arrives, it puts them back together into one clear message. 

Technically, TCP and IP are two different protocols, but they both have important roles. TCP organizes and sorts all of the data, while IP is responsible for sending and receiving it. IP can work with other protocols, but TCP must always have IP to work. In order to work, TCP/IP goes through a four-layer process twice.  

History of TCP/IP

TCP/IP originated in the 1970s when two Defense Advanced Research Projects Agency (DARPA) scientists, Vinton Cerf and Bob Kahn, created it. It was initially the standard protocol for the Advanced Research Projects Agency Network (ARPANET) and is sometimes referred to as the internet protocol suite. ARPANET is the predecessor of the internet. 


Read more: Information Technology (IT) Terms: A to Z Glossary

What is the four-layer process for TCP/IP?  

The four layers of the TCP/IP protocol are datalink, internet, transport, and application. 

  • The datalink layer is sometimes called the link layer, network interface layer, network access layer, or physical layer. It involves the physical components of computer-to-computer communication, like the wireless network, Ethernet cable, and network interface card.  

  • The internet layer ensures data arrives safely and accurately. Internet traffic can affect the speed. 

  • The transport layer is what divides the data into packets and ensures they reach their destination. 

  • The application layer involves the parts of the communications that the user sees, such as email or a messaging app. 

Is TCP/IP the only internet protocol? 

In addition to TCP/IP, several other types of internet protocols exist, though most of them work in conjunction with TCP/IP. For example, hypertext transfer protocol (HTTP) involves websites and web browsers. File transfer protocol (FTP) involves sending files across a network. Simple mail transfer protocol (SMTP) focuses on sending and receiving emails. 

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