What is TCP 3 way handshake and why is it required?

TCP THREE - WAY HANDSHAKE : 

=> It is done to establish a virtual connection from source to destination.

=> It is maintaining a bi-directional communication between two devices .

* it is neccasary as per protocol tcp steps to cummunicate are : 

1> Connection Establishment   -   TCP Three Way Handshake

2> Data Transfer.

3> Connection Termination.

Hope It Helps !