In 1969 ,Arpanet was started to connect computer situated in different Universities and US Defense .
In 1970s, the NSF created a common network called CS NET
IN 1980 a new high capacity and more speedy network called NSF net was developed
IN 1992 a new network called ANS NET was developed provided by NSF NET
IN 1995 all the above network were combined to create a common large network called the internet