The USSR launches Sputnik, the first artificial Earth satellite. In the late 1960s the United States military was desperately afraid of a nuclear attack by the Soviet Union. The United States formed the Advanced Research Projects Agency (ARPA) within the Department of Defense to create a bomb-proof network to connect military bases. The ARPANET physical network was created in 1969 to allow universities and research organizations to freely exchange information. The first two nodes that formed the ARPANET were UCLA and Stanford Research Institute, shortly after the University of Utah was added to the ARPANET. The Network Control Protocol (NCP) was initially used as the ARPANET protocol, starting in 1970. By 1971, a total of 23 hosts in 15 locations were connected to the ARPANET. The following year the first international connections occurred, connecting University College London (UK) and the Royal Radar Estabilishment (Norway) to the ARPANET. The way the ARPANET was set up is such that if one of the network links was disrupted by an enemy attack, the traffic on it could be automatically redirected to other links. Fortunately, the Network has rarely been attacked by the enemy. In the 1970s, ARPA also sponsored further research into applications of packet switching technologies. This included the extension of packet switching to ships at sea and land mobile units, and the use of radio for packet switching. Ethernet was created in the course of research into using radio for packet switching, and it was discovered that coaxial cable could support the movement of data at extremely high speeds. The development of Ethernet was crucial to the growth of local computer networks. The success of the ARPANET has made it difficult to manage, particularly with the large and growing number of university sites on it. So it was split into two parts. The two parts consisted of MILNET, which had the military sites, and the new, smaller ARPANET, which had the non-military sites. On January 1, 1983, every machine connected to the ARPANET had to use TCP/IP. TCP/IP became the primary Internet protocol and completely replaced NCP (the old ARPANET language). Thanks to TCP/IP, MILNET and ARPANET remained connected through a technical scheme called IP (Internet Protocol); which allows traffic to be routed from one network to another as needed. All networks connected to the Internet speak IP, so they can all exchange messages. Although only two networks existed at the time, IP was designed to allow tens of thousands of networks. An unusual fact about IPdesign is that every computer on an IP network is just as capable as any other, then any other