What is a handshake protcol and how it works?

Handshake protocol is defined as, the process of communication between two entities and it begins when the one device send a message to another,  indicate that it want to establish a communication channel between the two devices. It works when, two devices send several message back and forth which enabled them to agree on a communication protocol.

In order to establish a connection between two devices handshaking take place. A classic example is the noises made when two dial-up modems connected top each other. It works on the principle of transmission control protocol.