A TCP three-way handshake is a method used by TCP networks to establish a socket connection between two computers over an Internet Protocol based network. This method is also referred to as "Syn-Syn/Ack-Ack" by IT professionals.
A requesting computer sends out a TCP synchronize packet (SYN) to a target computer. The target computer responds by sending back a synchronize-acknowledgement (SYN-ACK) packet to the requesting computer. The requesting computer receives the acknowledgement packet (ACK), and a TCP socket connection is established.The unique characteristic of this process allows computers to negotiate separate multiplex TCP socket connections at the same time. This allows a computer to send and receive multiple data streams simultaneously without flooding the network..