Transmission Control Protocol (TCP)

Whereas IP focuses on getting data across the vast network from one computer to another, TCP assures that the data gets sucked off the network connected computer and delivered to the receiving application and that the data is delivered in the correct sequence.

Recall that since IP chops messages up into packets, we need to assure that the messages are assembled correctly at the other end of transport. And if any errors occur during transport, such as message degradation or the loss of some packets, the sender will know to resend.

TCP also tries to optimize network bandwidth by controlling the flow of information dynamically, slowing down as network traffic becomes congested.