Security Encyclopedia

Transmission Control Protocol (TCP)

The Transmission Control Protocol (TCP) is an Internet protocol that connects a server and a client. Together, TCP and Internet Protocol (IP) are the set of networking protocols that enable computers to connect over the Internet. 

Data travels over the Internet in packets. For transit they are disassembled into packets, which are then reassembled at their destination. TCP manages the reliability of the rails on which they travel to ensure that no packets are lost, they are properly ordered, and that there are no delays in the journey that would affect data reassembly or quality. IP manages the addressing and forwarding of the data to and from its proper destinations. TCP/IP work together in a protocol stack, with one protocol working on top of the other. 

TCP was developed by the Defense Data Network of the US Department of Defense and today its wide adoption is responsible for the Internet’s ubiquitous commercial availability.


“TCP along with IP are two foundational protocols that make the Internet possible. TCP keeps the sending of data reliable, steady, and orderly. IP gets it to and from destinations accurately.”