Arpanet

The USSR launches Sputnik, the first artificial earth satellite. In the late 1960's the

U.S. military was desperately afraid of a nuclear attack from the Soviet Union. The

United States formed the Advanced Research Projects Agency (ARPA) within the Department

of Defense to establish a bombproof network to connect military bases. ARPANET's physical

network was established in 1969 to enable universities and research organizations to

exchange information freely. The first two nodes that formed the ARPANET were UCLA and

the Stanford Research Institute, shortly after the University of Utah was added to

ARPANET.

The Network Control Protocol (NCP) was initially used as the ARPANET protocol, beginning

in 1970. By 1971, a total of 23 hosts at 15 locations were connected to the ARPANET. The

following year, the first international connections occurred, linking the University

College of London (UK) and the Royal Radar Establishment (Norway) to the ARPANET.

The way ARPANET was set up is so that if one of the network links became disrupted by

enemy attack, the traffic on it could automatically be rerouted to other links.

Fortunately, the Net rarely has come under enemy attack. In the 1970s, ARPA also

sponsored further research into the applications of packet switching technologies. This

included extending packet switching to ships at sea and ground mobile units and the use

of radio for packet switching. Ethernet was created during the course of research into

the use of radio for packet switching, and it was found that coaxial cable could support

the movement of data at extremely fast rates of speed. The development of Ethernet was

crucial to the growth of local area computer networks.

The success of ARPANET made it difficult to manage, particularly with the large and

growing number of university sites on it. So it was broken into two parts. The two parts

consisted of MILNET, which had the military sites, and the new, smaller ARPANET, which

had the nonmilitary sites. On January 1,1983, every machine connected to ARPANET had to

use TCP/IP. TCP/IP became the core Internet protocol and replaced NCP (old ARPANET

language) completely. Thanks to TCP/IP MILNET and ARPANET remained connected through a

technical scheme called IP (Internet Protocol); which enables traffic to be routed from

one network to another as necessary. All the networks connected to the Internet speak IP,

so they all can exchange messages. Although there were only two networks at that time, IP

was designed to allow for tens of thousands of networks. An unusual fact about the IP

design is that every computer on an IP network is just as capable as any other, so any