Question: Before a browser can request for a webpage, A TCP connection is required to be established. What is the necessity of 3 way handshake in interacting with a server computer? why can't we simply send a web request and wait for the response?

Shouldn't the resolution of IP address be enough for this purpose?

Basically, I need to know the reason for establishing TCP connection.

thanks in advance

Answer: 
You are using a device named A and server is named B

Host A sends a TCP SYNchronize packet to Host B 

Host B receives A's SYN

Host B sends a SYNchronize-ACKnowledgement

Host A receives B's SYN-ACK

Host A sends ACKnowledge

Host B receives ACK. 
TCP socket connection is ESTABLISHED.

* See more at: <http://www.inetdaemon.com/tutorials/internet/tcp/3-way_handshake.shtml#sthash.F2f4b8Xn.dpuf>
Because you need a TCP connection to send HTTP over, and TCP has a 3-way handshake.

> 
> Basically, I need to know the reason for establishing TCP connection.
> 
> 
> 

Because HTTP runs over TCP. It doesn't exist in a vacuum.