I only know about UDP is unreliable and connectionless 
protocol.And TCP/IP protocol is connection oriented and 
reliable.i want some more advantages and disadvantages and 
UDP where its used.

UDP: It doesn't wait for acknowledgement as like TCP/IP so 
it is unreliable protocol.

UDP is usually used in where communication needs to be fast 
like in DNS and DHCP.

The first thing is UDP is connection less where as TCP is 
connection  oriented.The broadcasting and multicasting 
software is available in the UDP only.Why because it is 
connection less hence we can broadcast the packets very 
easily,no need to wait for connection like in tcp,which 
takes more delay.