What is ARPANET?

By | April 25, 2020

In today’s world we cannot imagine a single day without the internet, from shopping to social media everywhere we require the internet. These days every device born smart and have the capability to linked over a network using the internet from smartwatches to smart television every household device using the internet and making a connection with each other by forming a small network. The world of internet is born from ARPANET, the internet which is available for everyone and not controlled by a single entity was not the same 5 decades ago when the predecessor of Internet ARPANET was introduced. Here in this article, we have provided information about what is ARPANET and how the internet born from it?

What is ARPANET?

It stands for Advanced Research Projects Agency Network and it is the predecessor of the Internet, it was a packet-switching network that first-ever implements and uses the protocols like TCP/IP, which were later on adopted by the Internet itself.


It was developed by the Advanced Research Project Agency(ARPA) in 1969 for the United States Department of Defence and only the US government had full control over the ARPA network. It was designed by Paul Baran, Donald Davies, Leonard Kleinrock, and Lawrence Roberts. At the early stages of ARPANET, it used the Network Control Program, but later on, with the development of TCP/IP in 1983, it adopted both the protocols for its network connections.

The initial idea was to build a system which can communicate and shear resources among different computers over a network, so mainly the scientific user of different institutes working on the project can communicate faster. The idea was similar to the telephone, but here information would send in small units called packets from source to the destination and form an end-to-end communication. Now it sounds very easy to set an end-to-end communication between two systems but in the early stages of networks this was the most difficult work and it became more difficult if we have various systems over a single network. In 1969 when ARPANET was under development it has four nodes connected over a single networks and all the four nodes are located at different universities of the USA, which were the University of California, Los Angeles (A Honeywell DDP 516 computer), Stanford Research Institute(An SDS-940 computer), University of California, Santa Barbara (An IBM 360/75), University of Utah (A DEC PDP-10).

Arpanet Logical maps


After the rapid development in the Networks and protocols, various new networks were joined in the Networks of Network. In 1981 National Science Foundation(NSF) fund the Computer Science Network(CSNET) and expand the access of the ARPANET, and by 1982 protocols like TCP/IP also introduced in the ARPANET network stack. It was 1990 when the government authorities stop funding the ARPANET project and telecommunication industries saw a future in ARPANET and fund it for commercialize purposes and make it a worldwide network so everyone uses it as the Internet.

Goal to design ARPANET

There was only one goal to design ARPANET, it was the time of cold war between USA and Russia after the second world war destruction and the threat of nuclear war USA defense wants to build a new computer technology which could meet to the military needs that can command and control the threats against nuclear forces.

Rules for using ARPNET when it was Funded by Government

It was a government project more specific it was a project of the Defence Department so there were some strict rules when ARPANET was under development and testing under various universities of the USA. As in ARPANET all the networks were ambiguous and by 1981 more than 213 hosts were joined into the network, so identify each network was a hectic task so some rules and restrictions were imposed by the defense department on using the ARPANET network.

Rules are as follow:

  • If ARPANET used for anything which is not in support of the Government business, then it would be considered Illegal
  • Friendly messages send over ARPANET would not consider harmful.
  • Could not send commercial or political profit email over ARPANET.

Birth of the Internet from ARPANET

Initially, It was isolated, and only the Government and Defence authorities of the USA knew about this project and general people were not aware of it. On 1st July 1957 DCA (Defence Communication Agency) took control over this project and all the funding was done under the military expenses, and by 1975 more than 57 systems were linked to this network. With the rapid development of ARPANET, more and more people were taking internet in it, that why every year many new systems getting linked to the network, by now only the authorized developers were allowed to connect to this network. With the rapid growth of the new system to the network was a threat to the national defense security and there was no proper framework to control the overall network, that’s why DCA impose some strict rules on the use of ARPANET.

In early 1980 the network gets opened for both authorized and authorized users, and It was divided into two networks ARPANET and MILNET. It was used for research purposes and MILNET for military usage. The privatization of ARPANET by DCA was a bold move and in 1984 NSF (National Science Foundation) start a new network and named it NFTNET backboned by ARPANET, and by 1988 NFS had started to use ARPANET for commercial purposes. In 1990 the government decommissioned the project and It has now become a distributed network and anyone was welcome to join it. In 1995 NSF shutdown the NFTNET and the new coined tossed in the market by name Internet.

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