History of the Internet#From ARPANET to NSFNET
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{{Use mdy dates|date=June 2011}}
{{Internet|expanded=General}}
The history of the Internet originated in the efforts of scientists and engineers to build and interconnect computer networks. The Internet Protocol Suite, the set of rules used to communicate between networks and devices on the Internet, arose from research and development in the United States and involved international collaboration, particularly with researchers in the United Kingdom and France.{{harvnb|Abbate|1999|p=[https://books.google.com/books?id=9BfZxFZpElwC&pg=PA3 3] "The manager of the ARPANET project, Lawrence Roberts, assembled a large team of computer scientists ... and he drew on the ideas of network experimenters in the United States and the United Kingdom. Cerf and Kahn also enlisted the help of computer scientists from England, France and the United States"}}{{cite web|url=https://www.sri.com/newsroom/press-releases/computer-history-museum-sri-international-and-bbn-celebrate-40th-anniversary|title=The Computer History Museum, SRI International, and BBN Celebrate the 40th Anniversary of First ARPANET Transmission, Precursor to Today's Internet|date=27 October 2009|publisher=SRI International|archive-url=https://web.archive.org/web/20190329134941/https://www.sri.com/newsroom/press-releases/computer-history-museum-sri-international-and-bbn-celebrate-40th-anniversary|archive-date=March 29, 2019|access-date=25 September 2017|quote=But the ARPANET itself had now become an island, with no links to the other networks that had sprung up. By the early 1970s, researchers in France, the UK, and the U.S. began developing ways of connecting networks to each other, a process known as internetworking.}}{{cite web|url=http://elk.informatik.hs-augsburg.de/tmp/cdrom-oss/CerfHowInternetCame2B.html|title=How the Internet Came to Be|author1=by Vinton Cerf, as told to Bernard Aboba|date=1993|access-date=25 September 2017|quote=We began doing concurrent implementations at Stanford, BBN, and University College London. So effort at developing the Internet protocols was international from the beginning.|archive-date=September 26, 2017|archive-url=https://web.archive.org/web/20170926042220/http://elk.informatik.hs-augsburg.de/tmp/cdrom-oss/CerfHowInternetCame2B.html}}
Computer science was an emerging discipline in the late 1950s that began to consider time-sharing between computer users, and later, the possibility of achieving this over wide area networks. J. C. R. Licklider developed the idea of a universal network at the Information Processing Techniques Office (IPTO) of the United States Department of Defense (DoD) Advanced Research Projects Agency (ARPA). Independently, Paul Baran at the RAND Corporation proposed a distributed network based on data in message blocks in the early 1960s, and Donald Davies conceived of packet switching in 1965 at the National Physical Laboratory (NPL), proposing a national commercial data network in the United Kingdom.
ARPA awarded contracts in 1969 for the development of the ARPANET project, directed by Robert Taylor and managed by Lawrence Roberts. ARPANET adopted the packet switching technology proposed by Davies and Baran. The network of Interface Message Processors (IMPs) was built by a team at Bolt, Beranek, and Newman, with the design and specification led by Bob Kahn. The host-to-host protocol was specified by a group of graduate students at UCLA, led by Steve Crocker, along with Jon Postel and others. The ARPANET expanded rapidly across the United States with connections to the United Kingdom and Norway.
Several early packet-switched networks emerged in the 1970s which researched and provided data networking. Louis Pouzin and Hubert Zimmermann pioneered a simplified end-to-end approach to internetworking at the IRIA. Peter Kirstein put internetworking into practice at University College London in 1973. Bob Metcalfe developed the theory behind Ethernet and the PARC Universal Packet. ARPA initiatives and the International Network Working Group developed and refined ideas for internetworking, in which multiple separate networks could be joined into a network of networks. Vint Cerf, now at Stanford University, and Bob Kahn, now at DARPA, published their research on internetworking in 1974. Through the Internet Experiment Note series and later RFCs this evolved into the Transmission Control Protocol (TCP) and Internet Protocol (IP), two protocols of the Internet protocol suite. The design included concepts pioneered in the French CYCLADES project directed by Louis Pouzin. The development of packet switching networks was underpinned by mathematical work in the 1970s by Leonard Kleinrock at UCLA.{{Internet history timeline}}In the late 1970s, national and international public data networks emerged based on the X.25 protocol, designed by Rémi Després and others. In the United States, the National Science Foundation (NSF) funded national supercomputing centers at several universities in the United States, and provided interconnectivity in 1986 with the NSFNET project, thus creating network access to these supercomputer sites for research and academic organizations in the United States. International connections to NSFNET, the emergence of architecture such as the Domain Name System, and the adoption of TCP/IP on existing networks in the United States and around the world marked the beginnings of the Internet.{{Cite web|url=https://www.internethalloffame.org/blog/2015/10/19/untold-internet|title=The Untold Internet|date=October 19, 2015|website=Internet Hall of Fame|access-date=April 3, 2020|quote=many of the milestones that led to the development of the modern Internet are already familiar to many of us: the genesis of the ARPANET, the implementation of the standard network protocol TCP/IP, the growth of LANs (Large Area Networks), the invention of DNS (the Domain Name System), and the adoption of American legislation that funded U.S. Internet expansion—which helped fuel global network access—to name just a few.}}{{Cite journal |date=2014 |title=Study into UK IPv4 and IPv6 allocations |url=https://www.ofcom.org.uk/__data/assets/pdf_file/0031/37795/rtfm.pdf |journal=Reid Technical Facilities Management LLP |quote=As the network continued to grow, the model of central co-ordination by a contractor funded by the US government became unsustainable. Organisations were using IP-based networking even if they were not directly connected to the ARPAnet. They needed to get globally unique IP addresses. The nature of the ARPAnet was also changing as it was no longer limited to organisations working on ARPA-funded contracts. The US National Science Foundation set up a national IP-based backbone network, NSFnet, so that its grant-holders could be interconnected to supercomputer centres, universities and various national/regional academic/research networks, including ARPAnet. That resulting network of networks was the beginning of today's Internet.}}{{cite web | title=Origins of the Internet | website=www.nethistory.info | date=2 May 2005 | url=http://www.nethistory.info/History%20of%20the%20Internet/origins.html | archive-url=https://web.archive.org/web/20110903001108/http://www.nethistory.info/History%20of%20the%20Internet/origins.html | archive-date=3 September 2011 | url-status=live}} Commercial Internet service providers (ISPs) emerged in 1989 in the United States and Australia.{{cite web|url=http://www.rogerclarke.com/II/OzI04.html#CIAP|title=Origins and Nature of the Internet in Australia|last=Clarke|first=Roger|access-date=21 January 2014|archive-date=9 February 2021|archive-url=https://web.archive.org/web/20210209201253/http://www.rogerclarke.com/II/OzI04.html#CIAP|url-status=live}} Limited private connections to parts of the Internet by officially commercial entities emerged in several American cities by late 1989 and 1990.{{cite web |url=http://www.indra.com/homepages/spike/isp.html |title=The First ISP |publisher=Indra.com |date=1992-08-13 |access-date=2015-10-17 |archive-url=https://web.archive.org/web/20160305130609/https://www.indra.com/homepages/spike/isp.html |archive-date=March 5, 2016 }} The optical backbone of the NSFNET was decommissioned in 1995, removing the last restrictions on the use of the Internet to carry commercial traffic, as traffic transitioned to optical networks managed by Sprint, MCI and AT&T in the United States.
Research at CERN in Switzerland by the British computer scientist Tim Berners-Lee in 1989–90 resulted in the World Wide Web, linking hypertext documents into an information system, accessible from any node on the network.{{cite book |last1=Couldry|first1=Nick |title=Media, Society, World: Social Theory and Digital Media Practice |date=2012 |publisher=Polity Press |location=London|page=2|url=https://books.google.com/books?id=AcHvP9trbkAC&pg=PA2|isbn=978-0-7456-3920-8}} The dramatic expansion of the capacity of the Internet, enabled by the advent of wave division multiplexing (WDM) and the rollout of fiber optic cables in the mid-1990s, had a revolutionary impact on culture, commerce, and technology. This made possible the rise of near-instant communication by electronic mail, instant messaging, voice over Internet Protocol (VoIP) telephone calls, video chat, and the World Wide Web with its discussion forums, blogs, social networking services, and online shopping sites. Increasing amounts of data are transmitted at higher and higher speeds over fiber-optic networks operating at 1 Gbit/s, 10 Gbit/s, and 800 Gbit/s by 2019.{{Cite news|last=Nelson|first=Patrick|date=March 20, 2019|title=Data center fiber to jump to 800 gigabits in 2019.|work=Network World|url=https://www.networkworld.com/article/3374545/data-center-fiber-to-jump-to-800-gigabits-in-2019.html}} The Internet's takeover of the global communication landscape was rapid in historical terms: it only communicated 1% of the information flowing through two-way telecommunications networks in the year 1993, 51% by 2000, and more than 97% of the telecommunicated information by 2007.{{cite journal |last1=Hilbert |first1=Martin |last2=López |first2=Priscila |title=The World's Technological Capacity to Store, Communicate, and Compute Information |journal=Science |date=April 2011 |volume=332 |issue=6025 |pages=60–65 |doi=10.1126/science.1200970 |pmid=21310967 |bibcode=2011Sci...332...60H |s2cid=206531385 |doi-access=free }} The Internet continues to grow, driven by ever greater amounts of online information, commerce, entertainment, and social networking services. However, the future of the global network may be shaped by regional differences.{{cite news |author=The Editorial Board |title=There May Soon Be Three Internets. America's Won't Necessarily Be the Best. – A breakup of the web grants privacy, security and freedom to some, and not so much to others. |url=https://www.nytimes.com/2018/10/15/opinion/internet-google-china-balkanization.html |archive-url=https://ghostarchive.org/archive/20220102/https://www.nytimes.com/2018/10/15/opinion/internet-google-china-balkanization.html |archive-date=2022-01-02 |url-access=limited |url-status=live |date=15 October 2018 |work=The New York Times |access-date=16 October 2018 }}{{cbignore}}
Foundations
=Precursors=
== Telegraphy ==
:The practice of transmitting messages between two different places through an electromagnetic medium dates back to the electrical telegraph in the late 19th century, which was the first fully digital communication system. Radiotelegraphy began to be used commercially in the early 20th century. Telex became an operational teleprinter service in the 1930s. Such systems were limited to point-to-point communication between two end devices.
== Information theory ==
:Fundamental theoretical work in telecommunications technology was developed by Harry Nyquist and Ralph Hartley in the 1920s. Information theory, as enunciated by Claude Shannon in 1948, provided a firm theoretical underpinning to understand the trade-offs between signal-to-noise ratio, bandwidth, and error-free transmission in the presence of noise.
== Computers and modems ==
:Early fixed-program computers in the 1940s were operated manually by entering small programs via switches in order to load and run a series of programs. As transistor technology evolved in the 1950s, central processing units and user terminals came into use by 1955. The mainframe computer model was devised, and modems, such as the Bell 101, allowed digital data to be transmitted over regular unconditioned telephone lines at low speeds by the late 1950s. These technologies made it possible to exchange data between remote computers. However, a fixed-line link was still necessary; the point-to-point communication model did not allow for direct communication between any two arbitrary systems. In addition, the applications were specific and not general purpose. Examples included SAGE (1958) and SABRE (1960).
== Time-sharing ==
:Christopher Strachey, who became Oxford University's first Professor of Computation, filed a patent application in the United Kingdom for time-sharing in February 1959.{{Cite web|url=https://history.computer.org/pioneers/strachey.html|title=Computer Pioneers - Christopher Strachey|website=history.computer.org|access-date=2020-01-23}}{{Cite web |title=Computer - Time-sharing, Minicomputers, Multitasking |url=https://www.britannica.com/technology/computer/Time-sharing-and-minicomputers |access-date=2023-07-23 |website=Britannica |language=en}} In June that year, he gave a paper "Time Sharing in Large Fast Computers" at the UNESCO Information Processing Conference in Paris where he passed the concept on to J. C. R. Licklider.{{cite book|first=F. J. |last=Corbató |display-authors=etal |url=http://www.bitsavers.org/pdf/mit/ctss/CTSS_ProgrammersGuide.pdf |title=The Compatible Time-Sharing System: A Programmer's Guide |publisher=MIT Press |year=1963 |isbn=978-0-262-03008-3}}. "the first paper on time-shared computers by C. Strachey at the June 1959 UNESCO Information Processing conference".{{harvnb|Gillies|Cailliau|2000|page=13}} Licklider, a vice president at Bolt Beranek and Newman, Inc. (BBN), promoted the idea of time-sharing as an alternative to batch processing. John McCarthy, at MIT, wrote a memo in 1959 that broadened the concept of time sharing to encompass multiple interactive user sessions, which resulted in the Compatible Time-Sharing System (CTSS) implemented at MIT. Other multi-user mainframe systems developed, such as PLATO at the University of Illinois Chicago.{{Cite web |title=Reminiscences on the Theory of Time-Sharing |url=http://jmc.stanford.edu/computing-science/timesharing.html |access-date=2020-01-23 |website=John McCarthy's Original Website |quote=in 1960 'time-sharing' as a phrase was much in the air. It was, however, generally used in my sense rather than in John McCarthy's sense of a CTSS-like object.}} In the early 1960, the Advanced Research Projects Agency (ARPA) of the United States Department of Defense funded further research into time-sharing at MIT through Project MAC.
=Inspiration=
J. C. R. Licklider, while working at BBN, proposed a computer network in his March 1960 paper Man-Computer Symbiosis:{{cite journal|author=J. C. R. Licklider|title=Man-Computer Symbiosis|journal=IRE Transactions on Human Factors in Electronics|volume=HFE-1|pages=4–11|date=March 1960|url=http://medg.lcs.mit.edu/people/psz/Licklider.html|doi=10.1109/thfe2.1960.4503259|access-date=January 25, 2014|archive-url=https://web.archive.org/web/20051103053540/http://medg.lcs.mit.edu/people/psz/Licklider.html|archive-date=November 3, 2005|author-link=J. C. R. Licklider}}
{{Blockquote|A network of such centers, connected to one another by wide-band communication lines [...] the functions of present-day libraries together with anticipated advances in information storage and retrieval and symbiotic functions suggested earlier in this paper}}
In August 1962, Licklider and Welden Clark published the paper "On-Line Man-Computer Communication"{{cite journal|author=J. C. R. Licklider and Welden Clark|title=On-Line Man-Computer Communication|journal=AIEE-IRE '62 (Spring)|pages=113–128|date=August 1962|url=http://cis.msjc.edu/courses/internet_authoring/CSIS103/resources/ON-LINE%20MAN-COMPUTER%20COMMUNICATION.pdf|access-date=October 31, 2014|archive-date=October 31, 2014|archive-url=https://web.archive.org/web/20141031214616/http://cis.msjc.edu/courses/internet_authoring/CSIS103/resources/ON-LINE%20MAN-COMPUTER%20COMMUNICATION.pdf}} which was one of the first descriptions of a networked future.
In October 1962, Licklider was hired by Jack Ruina as director of the newly established Information Processing Techniques Office (IPTO) within ARPA, with a mandate to interconnect the United States Department of Defense's main computers at Cheyenne Mountain, the Pentagon, and SAC HQ. There he formed an informal group within DARPA to further computer research. He began by writing memos in 1963 describing a distributed network to the IPTO staff, whom he called "Members and Affiliates of the Intergalactic Computer Network".{{cite web|author=Licklider, J. C. R.|title=Topics for Discussion at the Forthcoming Meeting, Memorandum For: Members and Affiliates of the Intergalactic Computer Network|date=23 April 1963|location=Washington, D.C.|publisher=Advanced Research Projects Agency|url=http://www.kurzweilai.net/memorandum-for-members-and-affiliates-of-the-intergalactic-computer-network|access-date=2013-01-26}}
Although he left the IPTO in 1964, five years before the ARPANET went live, it was his vision of universal networking that provided the impetus for one of his successors, Robert Taylor, to initiate the ARPANET development. Licklider later returned to lead the IPTO in 1973 for two years.{{cite web|url=http://www.livinginternet.com/i/ii_licklider.htm|title=J.C.R. Licklider and the Universal Network|work=The Internet|year=2000|access-date=February 16, 2010|archive-date=October 17, 2019|archive-url=https://web.archive.org/web/20191017134454/https://www.livinginternet.com/i/ii_licklider.htm}}
=Packet switching=
File:The idea of the data packet (Baran, 1964)-en.svg in 1962 and refined in 1964, is the first proposal of a data packet.{{Cite web |last=Press |first=Gil |title=A Very Short History Of The Internet And The Web |url=https://www.forbes.com/sites/gilpress/2015/01/02/a-very-short-history-of-the-internet-and-the-web-2/ |access-date=2020-01-30 |website=Forbes |language=en}}]]
{{Main|Packet switching}}
The infrastructure for telephone systems at the time was based on circuit switching, which requires pre-allocation of a dedicated communication line for the duration of the call. Telegram services had developed store and forward telecommunication techniques. Western Union's Automatic Telegraph Switching System Plan 55-A was based on message switching. The U.S. military's AUTODIN network became operational in 1962. These systems, like SAGE and SBRE, still required rigid routing structures that were prone to single point of failure.{{cite book |last1=Kim |first1=Byung-Keun |url=https://books.google.com/books?id=lESrw3neDokC&pg=PA52 |title=Internationalising the Internet the Co-evolution of Influence and Technology |date=2005 |publisher=Edward Elgar |isbn=978-1-84542-675-0 |pages=51–55}}
The technology was considered vulnerable for strategic and military use because there were no alternative paths for the communication in case of a broken link. In the early 1960s, Paul Baran of the RAND Corporation produced a study of survivable networks for the U.S. military in the event of nuclear war.{{Cite report |title=Reliable Digital Communications Using Unreliable Network Repeater Nodes |first=Paul |last=Baran |page=1 |date=May 27, 1960 |publisher=The RAND Corporation |url=http://www.rand.org/content/dam/rand/pubs/papers/2008/P1995.pdf |access-date=July 25, 2012}}{{cite web |title=About Rand |url=http://www.rand.org/about/history/baran.html |access-date=July 25, 2012 |work=Paul Baran and the Origins of the Internet}} Information would be transmitted across a "distributed" network, divided into what he called "message blocks".{{Cite book |last=Pelkey |first=James L. |title=Entrepreneurial Capitalism and Innovation: A History of Computer Communications 1968–1988 |chapter=6.1 The Communications Subnet: BBN 1969 |quote=As Kahn recalls: ... Paul Baran’s contributions ... I also think Paul was motivated almost entirely by voice considerations. If you look at what he wrote, he was talking about switches that were low-cost electronics. The idea of putting powerful computers in these locations hadn’t quite occurred to him as being cost effective. So the idea of computer switches was missing. The whole notion of protocols didn’t exist at that time. And the idea of computer-to-computer communications was really a secondary concern. |chapter-url=https://historyofcomputercommunications.info/section/6.1/the-communications-subnet-bbn-1969/}}{{cite journal |last1=Barber |first1=Derek |date=Spring 1993 |title=The Origins of Packet Switching |url=http://www.cs.man.ac.uk/CCS/res/res05.htm#f |journal=The Bulletin of the Computer Conservation Society |issue=5 |issn=0958-7403 |access-date=6 September 2017 |quote=There had been a paper written by [Paul Baran] from the Rand Corporation which, in a sense, foreshadowed packet switching in a way for speech networks and voice networks}}{{Cite book |last=Waldrop |first=M. Mitchell |url=https://books.google.com/books?id=eRnBEAAAQBAJ&pg=PT285 |title=The Dream Machine |date=2018 |publisher=Stripe Press |isbn=978-1-953953-36-0 |pages=286 |language=en |quote=Baran had put more emphasis on digital voice communications than on computer communications.}}{{Cite web |title=On packet switching |url=https://www.nethistory.info/Archives/packets.html |access-date=2024-01-08 |website=Net History |quote=[Scantlebury said] Clearly Donald and Paul Baran had independently come to a similar idea albeit for different purposes. Paul for a survivable voice/telex network, ours for a high-speed computer network.}} Baran's design was not implemented.{{cite magazine |last=Metz |first=Cade |date=3 September 2012 |title=What Do the H-Bomb and the Internet Have in Common? Paul Baran |url=https://www.wired.com/2012/09/what-do-the-h-bomb-and-the-internet-have-in-common-paul-baran/ |magazine=WIRED |quote=He was very conscious of people mistaken belief that the work he did at RAND somehow led to the creation of the ARPAnet. It didn't, and he was very honest about that.}}
In addition to being prone to a single point of failure, existing telegraphic techniques were inefficient and inflexible. Beginning in 1965 Donald Davies, at the National Physical Laboratory in the United Kingdom, independently developed a more advanced proposal of the concept, designed for high-speed computer networking, which he called packet switching, the term that would ultimately be adopted.{{Cite book |last=Yates |first=David M. |url=https://books.google.com/books?id=ToMfAQAAIAAJ&q=packet+switch |title=Turing's Legacy: A History of Computing at the National Physical Laboratory 1945-1995 |date=1997 |publisher=National Museum of Science and Industry |isbn=978-0-901805-94-2 |page=132-4 |language=en}}{{cite book |author=A Hey, G Pápay |url=https://books.google.com/books?id=NrMkBQAAQBAJ&pg=PA201 |title=The Computing Universe: A Journey through a Revolution |date=2014 |publisher=Cambridge University Press |isbn=978-0521766456 |pages=201 |access-date=2015-08-16}}{{Cite book |last=Roberts |first=Gareth Ffowc |url=https://www.google.co.uk/books/edition/For_the_Recorde/waCYEAAAQBAJ?hl=en&gbpv=1&pg=PA102&printsec=frontcover |title=For the Recorde: A History of Welsh Mathematical Greats |date=2022 |publisher=University of Wales Press |isbn=978-1-78683-917-6 |language=en}}{{Cite web |last=Dr. Ed Smith, FBCS, FITP, University of the Third Age; Mr Chris Miller BSc.; Prof Jim Norton OBE, FREng, University of Sheffield |title=Packet Switching: The first steps on the road to the information society |url=https://www.npl.co.uk/getattachment/about-us/History/Famous-faces/Donald-Davies/UK-role-in-Packet-Switching-(1).pdf |website=National Physical Laboratory}}
Packet switching is a technique for transmitting computer data by splitting it into very short, standardized chunks, attaching routing information to each of these chunks, and transmitting them independently through a computer network. It provides better bandwidth utilization than traditional circuit-switching used for telephony, and enables the connection of computers with different transmission and receive rates. It is a distinct concept to message switching.{{Cite news |last=Ruthfield |first=Scott |url=http://dl.acm.org/citation.cfm?id=332198.332202&coll=portal&dl=ACM |archive-url=https://web.archive.org/web/20071018045734/http://www.acm.org/crossroads/xrds2-1/inet-history.html |archive-date=October 18, 2007 |url-status=live |title=The Internet's History and Development From Wartime Tool to the Fish-Cam |periodical=Crossroads |volume=2 |issue=1 |pages=2–4 |date=September 1995 |access-date=April 1, 2016 |doi=10.1145/332198.332202}}
Networks that led to the Internet
=NPL network=
{{Main|NPL network}}
Following discussions with J. C. R. Licklider in 1965, Donald Davies became interested in data communications for computer networks.{{cite journal |last1=Roberts |first1=L.G. |title=The evolution of packet switching |journal=Proceedings of the IEEE |date=1978 |volume=66 |issue=11 |pages=1307–1313 |doi=10.1109/PROC.1978.11141 |s2cid=26876676 }}{{cite web|last1=Roberts|first1=Dr. Lawrence G.|title=The ARPANET & Computer Networks|url=http://www.packet.cc/files/arpanet-computernet.html|access-date=13 April 2016|date=May 1995|archive-url=https://web.archive.org/web/20160324032800/http://www.packet.cc/files/arpanet-computernet.html|archive-date=March 24, 2016}} Later that year, at the National Physical Laboratory (NPL) in the United Kingdom, Davies designed and proposed a national commercial data network based on packet switching.{{Cite journal |last=Edmondson-Yurkanan |first=Chris |date=2007 |title=SIGCOMM's archaeological journey into networking's past |url=https://dl.acm.org/doi/10.1145/1230819.1230840 |journal=Communications of the ACM |language=en |volume=50 |issue=5 |pages=63–68 |doi=10.1145/1230819.1230840 |issn=0001-0782 |quote=In his first draft dated Nov. 10, 1965 [5], Davies forecast today’s “killer app” for his new communication service: “The greatest traffic could only come if the public used this means for everyday purposes such as shopping... People sending enquiries and placing orders for goods of all kinds will make up a large section of the traffic... Business use of the telephone may be reduced by the growth of the kind of service we contemplate.”}} The following year, he described the use of "switching nodes" to act as routers in a digital communication network.{{Cite web |last=Davies |first=D. W. |date=1966 |title=Proposal for a Digital Communication Network |url=https://www.dcs.gla.ac.uk/~wpc/grcs/Davies05.pdf |quote=Computer developments in the distant future might result in one type of network being able to carry speech and digital messages efficiently.}}{{cite web|last1=Roberts|first1=Dr. Lawrence G.|title=The ARPANET & Computer Networks|url=http://www.packet.cc/files/arpanet-computernet.html|access-date=13 April 2016|date=May 1995|quote=Then in June 1966, Davies wrote a second internal paper, "Proposal for a Digital Communication Network" In which he coined the word packet,- a small sub part of the message the user wants to send, and also introduced the concept of an "Interface computer" to sit between the user equipment and the packet network.|archive-url=https://web.archive.org/web/20160324032800/http://www.packet.cc/files/arpanet-computernet.html|archive-date=March 24, 2016}} The proposal was not taken up nationally but he produced a design for a local network to serve the needs of the NPL and prove the feasibility of packet switching using high-speed data transmission.{{cite book |url=https://books.google.com/books?id=TXhWJcsO134C&q=ARPANET&pg=PA29|author=K.G. Coffman & A.M. Odlyzco|title=Optical Fiber Telecommunications IV-B: Systems and Impairments|publisher=Academic Press|pages=1022 pages|series=Optics and Photonics (edited by I. Kaminow & T. Li) |access-date=2015-08-15|isbn=978-0-12-395173-1|date=2002-05-22}}{{cite book |url=https://books.google.com/books?id=ndiYguRu66oC&q=NPL+Network&pg=PA260|author=B. Steil, Council on Foreign Relations|title=Technological Innovation and Economic Performance|publisher=published by Princeton University Press 1 Jan 2002, 476 pages |access-date=2015-08-15|isbn=978-0-691-09091-7|year=2002}} To deal with packet permutations (due to dynamically updated route preferences) and to datagram losses (unavoidable when fast sources send to a slow destinations), he assumed that "all users of the network will provide themselves with some kind of error control",{{cite web|date=1967|title=A Digital Communication Network for Computers Giving Rapid Response at remote Terminals|url=https://people.mpi-sws.org/~gummadi/teaching/sp07/sys_seminar/how_did_erope_blow_this_vision.pdf|access-date=2020-09-15}} thus inventing what came to be known as the end-to-end principle. In 1967, he and his team were the first to use the term 'protocol' in a modern data-commutation context.{{Cite book|url=https://books.google.com/books?id=bbonCgAAQBAJ&pg=PT290|title=A Brief History of the Future|last=Naughton|first=John|date=2015-09-24|publisher=Orion|isbn=978-1-4746-0277-8|language=en}}
In 1968,{{cite conference|last=Scantlebury|first=R. A.|author2=Wilkinson, P.T.|year=1974|title=The National Physical Laboratory Data Communications Network|url=http://www.rogerdmoore.ca/PS/NPLPh/NPL1974A.html|pages=223–228|book-title=Proceedings of the 2nd ICCC 74|access-date=September 5, 2017|archive-date=October 20, 2013|archive-url=https://web.archive.org/web/20131020140205/http://rogerdmoore.ca/PS/NPLPh/NPL1974A.html|url-status=dead}} Davies began building the Mark I packet-switched network to meet the needs of his multidisciplinary laboratory and prove the technology under operational conditions.{{cite book |url=https://archive.org/details/EncyclopediaOf20thCenturyTechnologyAZMalestrom/page/n621/mode/2up?q=packet+switching |title=Encyclopedia of 20th-Century Technology |date=2005 |publisher=Routledge |isbn=978-1-135-45551-4 |editor1-last=Hempstead |editor1-first=C. |pages=573–5 |access-date=2015-08-15 |editor2-last=Worthington |editor2-first=W.}}{{cite news|url=http://news.bbc.co.uk/1/hi/technology/8331253.stm|title=Celebrating 40 years of the net|first=Mark|last=Ward|newspaper=BBC News|date=October 29, 2009}} The network's development was described at a 1968 conference.{{Cite web |last1=Smith |first1=Ed |last2=Miller |first2=Chris |last3=Norton |first3=Jim |title=Packet Switching: The first steps on the road to the information society |url=https://www.npl.co.uk/getattachment/about-us/History/Famous-faces/Donald-Davies/UK-role-in-Packet-Switching-(1).pdf.aspx |quote=Its development was described at a 1968 conference, two years before similar progress on ARPANET, the precursor to the Internet, was demonstrated}}{{cite news |date=5 August 2008 |title=The accelerator of the modern age |url=http://news.bbc.co.uk/1/hi/technology/7541123.stm |access-date=19 May 2009 |work=BBC News}} Elements of the network became operational in early 1969,{{Cite conference |last1=Rayner |first1=David |last2=Barber |first2=Derek |last3=Scantlebury |first3=Roger |last4=Wilkinson |first4=Peter |date=2001 |title=NPL, Packet Switching and the Internet |url=http://www.topquark.co.uk/conf/IAP2001.html |archive-url=https://web.archive.org/web/20030807200346/http://www.topquark.co.uk/conf/IAP2001.html |url-status=dead |archive-date=2003-08-07 |conference=Symposium of the Institution of Analysts & Programmers 2001 |access-date=2024-06-13 |quote=The system first went 'live' early in 1969 |website=}} the first implementation of packet switching,{{Cite journal |last1=John S |first1=Quarterman |last2=Josiah C |first2=Hoskins |date=1986 |title=Notable computer networks |journal=Communications of the ACM |language=EN |volume=29 |issue=10 |pages=932–971 |doi=10.1145/6617.6618 |s2cid=25341056 |quote=The first packet-switching network was implemented at the National Physical Laboratories in the United Kingdom. It was quickly followed by the ARPANET in 1969. |doi-access=free}}{{Cite AV media |url=https://www.inc.com/computerfreaks |title=Computer Freaks |date=June 22, 2023 |last=Haughney Dare-Bryan |first=Christine |type=Podcast |publisher=Inc. Magazine |series=Chapter Two: In the Air |minutes=35:55 |quote=Leonard Kleinrock: Donald Davies ... did make a single node packet switch before ARPA did}} and the NPL network was the first to use high-speed links.{{Cite journal|last=Cambell-Kelly|first=Martin|date=1987|title=Data Communications at the National Physical Laboratory (1965–1975)|url=https://archive.org/details/DataCommunicationsAtTheNationalPhysicalLaboratory|journal=Annals of the History of Computing|language=en|volume=9|issue=3/4|pages=221–247|doi=10.1109/MAHC.1987.10023|s2cid=8172150}} Many other packet switching networks built in the 1970s were similar "in nearly all respects" to Davies' original 1965 design. The Mark II version which operated from 1973 used a layered protocol architecture. In 1977, there were roughly 30 computers, 30 peripherals and 100 VDU terminals all able to interact through the NPL Network.{{Cite book |last=Copeland |first=B. Jack |url=https://www.google.co.uk/books/edition/Alan_Turing_s_Electronic_Brain/YhQZnczOS7kC?hl=en&gbpv=1&pg=PA349&printsec=frontcover |title=Alan Turing's Electronic Brain: The Struggle to Build the ACE, the World's Fastest Computer |date=2012-05-24 |publisher=OUP Oxford |isbn=978-0-19-960915-4 |page=275 |language=en}} The NPL team carried out simulation work on wide-area packet networks, including datagrams and congestion; and research into internetworking and secure communications.{{Cite thesis |last=Clarke |first=Peter |title=Packet and circuit-switched data networks |date=1982 |degree=PhD |publisher=Department of Electrical Engineering, Imperial College of Science and Technology, University of London |url=https://spiral.imperial.ac.uk/bitstream/10044/1/35864/2/Clarke-PN-1982-PhD-Thesis.pdf}} "As well as the packet switched network actually built at NPL for communication between their local computing facilities, some simulation experiments have been performed on larger networks. A summary of this work is reported in [69]. The work was carried out to investigate networks of a size capable of providing data communications facilities to most of the U.K. ... Experiments were then carried out using a method of flow control devised by Davies [70] called 'isarithmic' flow control. ... The simulation work carried out at NPL has, in many respects, been more realistic than most of the ARPA network theoretical studies."{{cite book|chapter-url=http://www.historyofcomputercommunications.info/Book/6/6.3-CYCLADESNetworkLouisPouzin1-72.html|title=Entrepreneurial Capitalism and Innovation: A History of Computer Communications 1968–1988|last=Pelkey|first=James|chapter=6.3 CYCLADES Network and Louis Pouzin 1971–1972|access-date=February 3, 2020|archive-date=June 17, 2021|archive-url=https://web.archive.org/web/20210617093154/https://www.historyofcomputercommunications.info/Book/6/6.3-CYCLADESNetworkLouisPouzin1-72.html|url-status=dead}} The network was replaced in 1986.
=ARPANET=
{{Main|ARPANET}}
Robert Taylor was promoted to the head of the Information Processing Techniques Office (IPTO) at Advanced Research Projects Agency (ARPA) in 1966. He intended to realize Licklider's ideas of an interconnected networking system.{{harvnb|Hafner|Lyon|1998|pages=39–41}} As part of the IPTO's role, three network terminals had been installed: one for System Development Corporation in Santa Monica, one for Project Genie at University of California, Berkeley, and one for the Compatible Time-Sharing System project at Massachusetts Institute of Technology (MIT). Taylor's identified need for networking became obvious from the waste of resources apparent to him.
{{Blockquote|For each of these three terminals, I had three different sets of user commands. So if I was talking online with someone at S.D.C. and I wanted to talk to someone I knew at Berkeley or M.I.T. about this, I had to get up from the S.D.C. terminal, go over and log into the other terminal and get in touch with them....
I said, oh man, it's obvious what to do: If you have these three terminals, there ought to be one terminal that goes anywhere you want to go where you have interactive computing. That idea is the ARPAnet.{{cite news |last=Markoff |first=John |title=An Internet Pioneer Ponders the Next Revolution |work=The New York Times |url=https://archive.nytimes.com/www.nytimes.com/library/tech/99/12/biztech/articles/122099outlook-bobb.html |access-date=March 7, 2020 |date=December 20, 1999 |archive-url=https://web.archive.org/web/20050304045456/http://partners.nytimes.com/library/tech/99/12/biztech/articles/122099outlook-bobb.html |archive-date=March 4, 2005 |url-status=live}}}}Bringing in Larry Roberts from MIT in January 1967, he initiated a project to build such a network. Roberts and Thomas Merrill had been researching computer time-sharing over wide area networks (WANs).{{cite conference|last1=Roberts|first1=Larry|last2=Marrill|first2=Tom|date=October 1966|title=Toward a Cooperative Network of Time-Shared Computers|url=http://www.packet.cc/files/toward-coop-net.html|conference=Fall AFIPS Conference|archive-url=https://web.archive.org/web/20020401051508/http://www.packet.cc/files/toward-coop-net.html|archive-date=2002-04-01|access-date=2017-09-10|author-link1=Lawrence Roberts (scientist)}} Wide area networks emerged during the late 1950s and became established during the 1960s. At the first ACM Symposium on Operating Systems Principles in October 1967, Roberts presented a proposal for the "ARPA net", based on Wesley Clark's idea to use Interface Message Processors (IMP) to create a message switching network.{{Cite web|url=https://www.forbes.com/sites/gilpress/2015/01/02/a-very-short-history-of-the-internet-and-the-web-2/|title=A Very Short History Of The Internet And The Web|last=Press|first=Gil|date=January 2, 2015|website=Forbes|language=en|url-status=live|archive-url=https://web.archive.org/web/20150109145400/https://www.forbes.com/sites/gilpress/2015/01/02/a-very-short-history-of-the-internet-and-the-web-2/|archive-date=January 9, 2015|access-date=2020-02-07|quote=Roberts' proposal that all host computers would connect to one another directly ... was not endorsed ... Wesley Clark ... suggested to Roberts that the network be managed by identical small computers, each attached to a host computer. Accepting the idea, Roberts named the small computers dedicated to network administration 'Interface Message Processors' (IMPs), which later evolved into today's routers.}}{{Citation |url=https://web.stanford.edu/dept/SUL/library/extra4/sloan/mousesite/EngelbartPapers/B1_F20_CompuMtg.html|title=SRI Project 5890-1; Networking (Reports on Meetings) |year=1967|publisher=Stanford University|access-date=2020-02-15|quote=W. Clark's message switching proposal (appended to Taylor's letter of April 24, 1967 to Engelbart)were reviewed.|archive-date=February 2, 2020|archive-url=https://web.archive.org/web/20200202062940/https://web.stanford.edu/dept/SUL/library/extra4/sloan/mousesite/EngelbartPapers/B1_F20_CompuMtg.html}}{{Cite book|last=Roberts|first=Lawrence|date=1967|title=Multiple Computer Networks and Intercomputer Communications|chapter-url=https://people.mpi-sws.org/~gummadi/teaching/sp07/sys_seminar/arpanet.pdf|pages=3.1–3.6|doi=10.1145/800001.811680|quote=Thus the set of IMP's, plus the telephone lines and data sets would constitute a message switching network|chapter=Multiple computer networks and intercomputer communication|s2cid=17409102}} At the conference, Roger Scantlebury presented Donald Davies' work on a hierarchical digital communications network using packet switching and referenced the work of Paul Baran at RAND. Roberts incorporated the packet switching and routing concepts of Davies and Baran into the ARPANET design and upgraded the proposed communications speed from 2.4 kbit/s to 50 kbit/s.{{cite book |last1=Abbate |first1=Jane |author-link=Janet Abbate |url=https://books.google.com/books?id=E2BdY6WQo4AC&q=packet+switching&pg=PA125 |title=Inventing the Internet |date=2000 |publisher=MIT Press |isbn=978-0262261333 |pages=37–9, 57–9}}{{cite report |url=https://apps.dtic.mil/sti/pdfs/ADA115440.pdf |title=A History of the ARPANET: The First Decade |date=1 April 1981 |publisher=Bolt, Beranek & Newman Inc. |pages=53 of 183 (III-11 on the printed copy) |archive-url=https://web.archive.org/web/20121201013642/http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA115440 |archive-date=1 December 2012 |url-status=live}}
ARPA awarded the contract to build the network to Bolt Beranek & Newman. The "IMP guys", led by Frank Heart and Bob Kahn, developed the routing, flow control, software design and network control.{{cite book |author=F.E. Froehlich, A. Kent |url=https://books.google.com/books?id=gaRBTHdUKmgC&pg=PA344 |title=The Froehlich/Kent Encyclopedia of Telecommunications: Volume 1 - Access Charges in the U.S.A. to Basics of Digital Communications |date=1990 |publisher=CRC Press |isbn=0824729005 |page=344}} The first ARPANET link was established between the Network Measurement Center at the University of California, Los Angeles (UCLA) Henry Samueli School of Engineering and Applied Science directed by Leonard Kleinrock, and the NLS system at Stanford Research Institute (SRI) directed by Douglas Engelbart in Menlo Park, California at 22:30 hours on October 29, 1969.{{Cite web|date=2024-10-29 |title='We were just trying to get it to work': The failure that started the internet |url=https://www.bbc.com/future/article/20241028-the-failure-that-started-the-internet |access-date=2025-04-26 |publisher=BBC |language=en-GB}}{{cite web|url=http://computer.howstuffworks.com/arpanet1.htm|title=How ARPANET Works|publisher=HowStuffWorks|last=Strickland|first=Jonathan|date=December 28, 2007|archive-url=https://web.archive.org/web/20080112102002/http://computer.howstuffworks.com/arpanet1.htm|archive-date=January 12, 2008|url-status=live|access-date=March 7, 2020}}
{{Blockquote|"We set up a telephone connection between us and the guys at SRI ...", Kleinrock ... said in an interview: "We typed the L and we asked on the phone,
:"Do you see the L?"
:"Yes, we see the L," came the response.
:We typed the O, and we asked, "Do you see the O."
:"Yes, we see the O."
:Then we typed the G, and the system crashed ...
Yet a revolution had begun" ....{{Cite journal |last=Beranek |first=Leo |date=2000 |title=Roots of the Internet: A Personal History |url=https://www.jstor.org/stable/25081152 |journal=Massachusetts Historical Review |volume=2 |pages=55–75 |jstor=25081152 |issn=1526-3894}}{{cite web|url=http://www.netvalley.com/intval.html|title=Roads and Crossroads of Internet History|first=Gregory|last=Gromov|year=1995}} |author=|title=|source=}}
File:Stamps of Azerbaijan, 2004-683.jpg
By December 1969, a four-node network was connected by adding the Culler-Fried Interactive Mathematics Center at the University of California, Santa Barbara followed by the University of Utah Graphics Department.{{harvnb|Hafner|Lyon|1998|pages=154–156}} In the same year, Taylor helped fund ALOHAnet, a system designed by professor Norman Abramson and others at the University of Hawaiʻi at Mānoa that transmitted data by radio between seven computers on four islands on Hawaii.{{harvnb|Hafner|Lyon|1998|page=220}}
Steve Crocker formed the "Network Working Group" in 1969 at UCLA. Working with Jon Postel and others,{{Cite ietf|rfc=6529}} he initiated and managed the Request for Comments (RFC) process, which is still used today for proposing and distributing contributions. RFC 1, entitled "Host Software", was written by Steve Crocker and published on April 7, 1969. The protocol for establishing links between network sites in the ARPANET, the Network Control Program (NCP), was completed in 1970. These early years were documented in the 1972 film Computer Networks: The Heralds of Resource Sharing.
Roberts presented the idea of packet switching to the communication professionals, and faced anger and hostility. Before ARPANET was operating, they argued that the router buffers would quickly run out. After the ARPANET was operating, they argued packet switching would never be economic without the government subsidy. Baran faced the same rejection and thus failed to convince the military into constructing a packet switching network.{{Cite book |last=Roberts |first=L. |title=A history of personal workstations |date=1988-01-01 |publisher=Association for Computing Machinery |isbn=978-0-201-11259-7 |place=New York, NY, USA |pages=141–172 |chapter=The arpanet and computer networks |doi=10.1145/61975.66916 |doi-access=free}}{{Cite book |last1=Roberts |first1=Larry |title=Proceedings of the ACM Conference on the history of personal workstations |date=1986 |isbn=0897911768 |pages=51–58 |chapter=The Arpanet and computer networks |doi=10.1145/12178.12182 |doi-access=free}}
Early international collaborations via the ARPANET were sparse. Connections were made in 1973 to the Norwegian Seismic Array (NORSAR),{{cite web |title=NORSAR and the Internet |url=http://www.norsar.no/pc-5-30-NORSAR-and-the-Internet.aspx |archive-url=http://archive.wikiwix.com/cache/20090607094725/http://www.norsar.no/pc-5-30-NORSAR-and-the-Internet.aspx |archive-date=June 7, 2009 |access-date=June 5, 2009 |publisher=NORSAR }} via a satellite link at the Tanum Earth Station in Sweden, and to Peter Kirstein's research group at University College London, which provided a gateway to British academic networks, the first international heterogenous resource sharing network. Throughout the 1970s, Leonard Kleinrock developed the mathematical theory to model and measure the performance of packet-switching technology, building on his earlier work on the application of queueing theory to message switching systems.{{harvnb|Gillies|Cailliau|2000|page=26}} By 1981, the number of hosts had grown to 213.{{cite book|url=https://books.google.com/books?id=7XAZnpCfQnEC&q=1981+213+arpanet+hosts&pg=PT289|title=Communication Technology Update and Fundamentals|last1=Grant|first1=August E.|last2=Meadows|first2=Jennifer E.|place=Burlington, Massachusetts|publisher=Focal Press|year=2008|edition=11th|isbn=978-0-240-81062-1|page=289}} The ARPANET became the technical core of what would become the Internet, and a primary tool in developing the technologies used.
=Merit Network=
{{Main|Merit Network}}
The Merit NetworkThe Merit Network, Inc. is an independent non-profit 501(c)(3) corporation governed by Michigan's public universities. Merit receives administrative services under an agreement with the University of Michigan. was formed in 1966 as the Michigan Educational Research Information Triad to explore computer networking between three of Michigan's public universities as a means to help the state's educational and economic development.{{cite web | title=A Chronicle of Merit's Early History | website=merit.edu | date=1 August 2006 | url=http://merit.edu/about/history/article.php | archive-url=https://web.archive.org/web/20090207130720/http://merit.edu/about/history/article.php | archive-date=7 February 2009 }} With initial support from the State of Michigan and the National Science Foundation (NSF), the packet-switched network was first demonstrated in December 1971 when an interactive host to host connection was made between the IBM mainframe computer systems at the University of Michigan in Ann Arbor and Wayne State University in Detroit.{{cite web | title=Timeline: The 1970s | website=merit.edu| date=11 July 2013 | url=http://www.merit.edu/about/history/timeline_1970.php | archive-url=https://web.archive.org/web/20160101025735/http://www.merit.edu/about/history/timeline_1970.php | archive-date=1 January 2016 }} In October 1972 connections to the CDC mainframe at Michigan State University in East Lansing completed the triad. Over the next several years in addition to host to host interactive connections the network was enhanced to support terminal to host connections, host to host batch connections (remote job submission, remote printing, batch file transfer), interactive file transfer, gateways to the Tymnet and Telenet public data networks, X.25 host attachments, gateways to X.25 data networks, Ethernet attached hosts, and eventually TCP/IP and additional public universities in Michigan join the network.{{cite web | title=Timeline: The 1980's | website=merit.edu | date=11 July 2013 | url=http://www.merit.edu/about/history/timeline_1980.php | archive-url=https://web.archive.org/web/20160101025735/http://www.merit.edu/about/history/timeline_1980.php | archive-date=1 January 2016 }} All of this set the stage for Merit's role in the NSFNET project starting in the mid-1980s.
=CYCLADES=
{{Main|CYCLADES}}
The CYCLADES packet switching network was a French research network designed and directed by Louis Pouzin. In 1972, he began planning the network to explore alternatives to the early ARPANET design and to support internetworking research. First demonstrated in 1973, it was the first network to implement the end-to-end principle conceived by Donald Davies and make the hosts responsible for reliable delivery of data, rather than the network itself, using unreliable datagrams.{{Cite book |last=Green |first=Lelia |url=https://www.worldcat.org/title/504280762 |title=The internet: an introduction to new media |date=2010 |publisher=Berg |isbn=978-1-84788-299-8 |series=Berg new media series |page=31 |oclc=504280762 |quote=The original ARPANET design had made data integrity part of the IMP's store-and-forward role, but Cyclades end-to-end protocol greatly simplified the packet switching operations of the network. ... The idea was to adopt several principles from Cyclades and invert the ARPANET model to minimise international differences.}}{{cite web |last1=Bennett |first1=Richard |date=September 2009 |title=Designed for Change: End-to-End Arguments, Internet Innovation, and the Net Neutrality Debate |url=https://www.itif.org/files/2009-designed-for-change.pdf |access-date=11 September 2017 |publisher=Information Technology and Innovation Foundation |pages=7, 9, 11 |quote=Two significant packet networks preceded the TCP/IP Internet: ARPANET and CYCLADES. The designers of the Internet borrowed heavily from these systems, especially CYCLADES ... The first end-to-end research network was CYCLA
DES, designed by Louis Pouzin at IRIA in France with the support of BBN’s Dave Walden and Alex McKenzie and deployed beginning in 1972.}} Concepts implemented in this network influenced TCP/IP architecture.{{cite web|url=http://www.cs.utexas.edu/users/chris/think/Cyclades/index.shtml|title=A Technical History of CYCLADES|work=Technical Histories of the Internet & other Network Protocols|publisher=Computer Science Department, University of Texas Austin|archive-url=https://web.archive.org/web/20130901092641/http://www.cs.utexas.edu/users/chris/think/Cyclades/index.shtml|archive-date=September 1, 2013}}{{Cite news |date=2013-11-30 |title=The internet's fifth man |url=https://www.economist.com/news/technology-quarterly/21590765-louis-pouzin-helped-create-internet-now-he-campaigning-ensure-its |access-date=2020-04-22 |newspaper=The Economist |quote=In the early 1970s Mr Pouzin created an innovative data network that linked locations in France, Italy and Britain. Its simplicity and efficiency pointed the way to a network that could connect not just dozens of machines, but millions of them. It captured the imagination of Dr Cerf and Dr Kahn, who included aspects of its design in the protocols that now power the internet.}}
=X.25 and public data networks=
{{Main|X.25|public data network}}
File:ABC Clarke predicts internet and PC.ogv by the Australian Broadcasting Corporation, in which he describes a future of ubiquitous networked personal computers]]
Based on international research initiatives, particularly the contributions of Rémi Després, packet switching network standards were developed by the International Telegraph and Telephone Consultative Committee (ITU-T) in the form of X.25 and related standards.{{Cite journal |last=Rybczynski |first=Tony |date=2009 |title=Commercialization of packet switching (1975–1985): A Canadian perspective [History of Communications] |journal=IEEE Communications Magazine |volume=47 |issue=12 |pages=26–31 |doi=10.1109/MCOM.2009.5350364 |s2cid=23243636 }}{{Cite journal|last=Schwartz|first=Mischa|date=2010|title=X.25 Virtual Circuits - TRANSPAC IN France - Pre-Internet Data Networking [History of communications]|journal=IEEE Communications Magazine|volume=48|issue=11|pages=40–46|doi=10.1109/MCOM.2010.5621965|s2cid=23639680 }} X.25 is built on the concept of virtual circuits emulating traditional telephone connections. In 1974, X.25 formed the basis for the SERCnet network between British academic and research sites, which later became JANET, the United Kingdom's high-speed national research and education network (NREN). The initial ITU Standard on X.25 was approved in March 1976.{{cite web|author=tsbedh |url=http://www.itu.int/ITU-T/studygroups/com17/history.html |title=History of X.25, CCITT Plenary Assemblies and Book Colors |publisher=Itu.int |access-date=June 5, 2009}} Existing networks, such as Telenet in the United States adopted X.25 as well as new public data networks, such as DATAPAC in Canada and TRANSPAC in France. X.25 was supplemented by the X.75 protocol which enabled internetworking between national PTT networks in Europe and commercial networks in North America.{{harvnb|Davies|Bressan|2010|pp=[https://books.google.com/books?id=DN-t8MpZ0-wC&pg=PA2 2, 9]}}{{cite thesis |last1=Ikram |first1=Nadeem |date=1985 |title=Internet Protocols and a Partial Implementation of CCITT X.75 |id={{OCLC|663449435|1091194379}} |url=https://www.proquest.com/openview/678d6e16a1f0ac0470e12db67623ce91/1 |page=2 |quote=Two main approaches to internetworking have come into existence based upon the virtual circuit and the datagram services. The vast majority of the work on interconnecting networks falls into one of these two approaches: The CCITT X.75 Recommendation; The DoD Internet Protocol (IP).}}{{Cite journal |last1=Unsoy |first1=Mehmet S. |last2=Shanahan |first2=Theresa A. |date=1981 |title=X.75 internetworking of Datapac and Telenet |journal=ACM SIGCOMM Computer Communication Review |volume=11 |issue=4 |pages=232–239 |doi=10.1145/1013879.802679 }}
The British Post Office, Western Union International, and Tymnet collaborated to create the first international packet-switched network, referred to as the International Packet Switched Service (IPSS), in 1978. This network grew from Europe and the US to cover Canada, Hong Kong, and Australia by 1981. By the 1990s it provided a worldwide networking infrastructure.{{cite web |title=Events in British Telecomms History |work=Events in British TelecommsHistory |url=http://www.sigtel.com/tel_hist_brief.html |archive-url=https://web.archive.org/web/20030405153523/http://www.sigtel.com/tel_hist_brief.html |archive-date=April 5, 2003 |access-date=November 25, 2005}}
Unlike ARPANET, X.25 was commonly available for business use. Telenet offered its Telemail electronic mail service, which was also targeted to enterprise use rather than the general email system of the ARPANET.
The first public dial-in networks used asynchronous teleprinter (TTY) terminal protocols to reach a concentrator operated in the public network. Some networks, such as Telenet and CompuServe, used X.25 to multiplex the terminal sessions into their packet-switched backbones, while others, such as Tymnet, used proprietary protocols. In 1979, CompuServe became the first service to offer electronic mail capabilities and technical support to personal computer users. The company broke new ground again in 1980 as the first to offer real-time chat with its CB Simulator. Other major dial-in networks were America Online (AOL) and Prodigy that also provided communications, content, and entertainment features.{{Cite book|last1=Council|first1=National Research|url=https://books.google.com/books?id=Jh1pORpfvrQC&pg=PA148|title=The Unpredictable Certainty: White Papers|last2=Sciences|first2=Division on Engineering and Physical|last3=Board|first3=Computer Science and Telecommunications|last4=Applications|first4=Commission on Physical Sciences, Mathematics, and|last5=Committee|first5=NII 2000 Steering|date=1998-02-05|publisher=National Academies Press|isbn=978-0-309-17414-5|language=en}} Many bulletin board system (BBS) networks also provided on-line access, such as FidoNet which was popular amongst hobbyist computer users, many of them hackers and amateur radio operators.{{Citation needed|date=June 2009}}
=UUCP and Usenet=
{{Main|UUCP|Usenet}}
In 1979, two students at Duke University, Tom Truscott and Jim Ellis, originated the idea of using Bourne shell scripts to transfer news and messages on a serial line UUCP connection with nearby University of North Carolina at Chapel Hill. Following public release of the software in 1980, the mesh of UUCP hosts forwarding on the Usenet news rapidly expanded. UUCPnet, as it would later be named, also created gateways and links between FidoNet and dial-up BBS hosts. UUCP networks spread quickly due to the lower costs involved, ability to use existing leased lines, X.25 links or even ARPANET connections, and the lack of strict use policies compared to later networks like CSNET and BITNET. All connects were local. By 1981 the number of UUCP hosts had grown to 550, nearly doubling to 940 in 1984.{{Cite web|url=http://www.faqs.org/faqs/uucp-internals/|title=UUCP Internals Frequently Asked Questions|website=www.faqs.org}}
Sublink Network, operating since 1987 and officially founded in Italy in 1989, based its interconnectivity upon UUCP to redistribute mail and news groups messages throughout its Italian nodes (about 100 at the time) owned both by private individuals and small companies. Sublink Network evolved into one of the first examples of Internet technology coming into use through popular diffusion.
1973–1989: Merging the networks and creating the Internet
File:Internet map in February 82.png test network in February 1982]]
=TCP/IP=
{{Main|Internet protocol suite}}
{{See also|Transmission Control Protocol|Internet Protocol}}
File:First Internet Demonstration, 1977.jpg, PRNET, and SATNET on November 22, 1977]]
With so many different networking methods seeking interconnection, a method was needed to unify them. Louis Pouzin initiated the CYCLADES project in 1972,{{Cite conference |last=Pouzin |first=Louis |date=1973 |title=Presentation and major design aspects of the CYCLADES computer network |url=http://portal.acm.org/citation.cfm?doid=800280.811034 |language=en |publisher=ACM Press |pages=80–87 |doi=10.1145/800280.811034 |doi-access=free |book-title=DATACOMM '73: Proceedings of the third ACM symposium on Data communications and Data networks}} building on the work of Donald Davies and the ARPANET.{{cite book |last=Pelkey |first=James |title=Entrepreneurial Capitalism and Innovation: A History of Computer Communications 1968–1988 |chapter=8.3 CYCLADES Network and Louis Pouzin 1971–1972 |chapter-url=https://historyofcomputercommunications.info/section/8.3/CYCLADES-Network-and-Louis-Pouzin-1971-1972/}} An International Network Working Group formed in 1972; active members included Vint Cerf from Stanford University, Alex McKenzie from BBN, Donald Davies and Roger Scantlebury from NPL, and Louis Pouzin and Hubert Zimmermann from IRIA.{{Cite journal|last=McKenzie|first=Alexander|date=2011|title=INWG and the Conception of the Internet: An Eyewitness Account|journal=IEEE Annals of the History of Computing|volume=33|issue=1|pages=66–71|doi=10.1109/MAHC.2011.9|s2cid=206443072 }}{{cite journal |last1=Russell |first1=A. L. |title=The internet that wasn't |journal=IEEE Spectrum |date=August 2013 |volume=50 |issue=8 |pages=39–43 |doi=10.1109/MSPEC.2013.6565559 |s2cid=11259224 |url=https://spectrum.ieee.org/osi-the-internet-that-wasnt }}{{Cite web|title=Vinton Cerf: How the Internet Came to Be|url=http://www.netvalley.com/archives/mirrors/cerf-how-inet.html|access-date=2021-12-21|website=www.netvalley.com}} Pouzin coined the term catenet for concatenated network. Bob Metcalfe at Xerox PARC outlined the idea of Ethernet and PARC Universal Packet (PUP) for internetworking. Bob Kahn, now at DARPA, recruited Vint Cerf to work with him on the problem. By 1973, these groups had worked out a fundamental reformulation, in which the differences between network protocols were hidden by using a common internetworking protocol. Instead of the network being responsible for reliability, as in the ARPANET, the hosts became responsible.{{cite journal |last=Hauben |first=Ronda |year=2004 |title=The Internet: On its International Origins and Collaborative Vision |url=http://www.ais.org/~jrh/acn/ACn12-2.a03.txt |journal=Amateur Computerist |volume=12 |issue=2 |access-date=May 29, 2009}}
Cerf and Kahn published their ideas in May 1974,{{cite journal |last1=Cerf |first1=V. |last2=Kahn |first2=R. |title=A Protocol for Packet Network Intercommunication |journal=IEEE Transactions on Communications |date=May 1974 |volume=22 |issue=5 |pages=637–648 |doi=10.1109/TCOM.1974.1092259 |quote=The authors wish to thank a number of colleagues for helpful comments during early discussions of international network protocols, especially R. Metcalfe, R. Scantlebury, D. Walden, and H. Zimmerman; D. Davies and L. Pouzin who constructively commented on the fragmentation and accounting issues; and S. Crocker who commented on the creation and destruction of associations.}} which incorporated concepts implemented by Louis Pouzin and Hubert Zimmermann in the CYCLADES network.{{Cite book |last=Green |first=Lelia |url=https://www.worldcat.org/title/504280762 |title=The internet: an introduction to new media |date=2010 |publisher=Berg |isbn=978-1-84788-299-8 |series=Berg new media series |page=31 |oclc=504280762 |quote=The original ARPANET design had made data integrity part of the IMP's store-and-forward role, but Cyclades end-to-end protocol greatly simplified the packet switching operations of the network. ... The idea was to adopt several principles from Cyclades and invert the ARPANET model to minimise international differences.}}{{cite news|date=13 December 2013|title=The internet's fifth man|work=Economist|url=https://www.economist.com/news/technology-quarterly/21590765-louis-pouzin-helped-create-internet-now-he-campaigning-ensure-its|access-date=11 September 2017|quote=In the early 1970s Mr Pouzin created an innovative data network that linked locations in France, Italy and Britain. Its simplicity and efficiency pointed the way to a network that could connect not just dozens of machines, but millions of them. It captured the imagination of Dr Cerf and Dr Kahn, who included aspects of its design in the protocols that now power the internet.}} The specification of the resulting protocol, the Transmission Control Program, was published as {{IETF RFC|675}} by the Network Working Group in December 1974.{{cite ietf |author1=Vint Cerf |author2=Yogen Dalal |author3=Carl Sunshine |date=December 1974 |RFC=675 |title=Specification of Internet Transmission Control Protocol}} It contains the first attested use of the term internet, as a shorthand for internetwork. This software was monolithic in design using two simplex communication channels for each user session.
With the role of the network reduced to a core of functionality, it became possible to exchange traffic with other networks independently from their detailed characteristics, thereby solving the fundamental problems of internetworking. DARPA agreed to fund the development of prototype software. Testing began in 1975 through concurrent implementations at Stanford, BBN and University College London (UCL). After several years of work, the first demonstration of a gateway between the Packet Radio network (PRNET) in the SF Bay area and the ARPANET was conducted by the Stanford Research Institute. On November 22, 1977, a three network demonstration was conducted including the ARPANET, the SRI's Packet Radio Van on the Packet Radio Network and the Atlantic Packet Satellite Network (SATNET) including a node at UCL.{{cite web |url=http://www.computerhistory.org/about/press_relations/releases/20071101/ |access-date=November 22, 2007 |title=Computer History Museum and Web History Center Celebrate 30th Anniversary of Internet Milestone }}{{cite news|url=http://news.cnet.com/Internet-van-helped-drive-evolution-of-the-Web/2100-1033_3-6217511.html|title='Internet van' helped drive evolution of the Web|first=Erica|last=Ogg|work=CNET|date=2007-11-08|access-date=2011-11-12}}
The software was redesigned as a modular protocol stack, using full-duplex channels; between 1976 and 1977, Yogen Dalal and Robert Metcalfe among others, proposed separating TCP's routing and transmission control functions into two discrete layers,{{cite book|last1=Panzaris|first1=Georgios|url=https://books.google.com/books?id=9yMhAQAAIAAJ|title=Machines and romances: the technical and narrative construction of networked computing as a general-purpose platform, 1960–1995|date=2008|publisher=Stanford University|page=128|quote=Despite the misgivings of Xerox Corporation (which intended to make PUP the basis of a proprietary commercial networking product), researchers at Xerox PARC, including ARPANET pioneers Robert Metcalfe and Yogen Dalal, shared the basic contours of their research with colleagues at TCP and Internet working group meetings in 1976 and 1977, suggesting the possible benefits of separating TCPs routing and transmission control functions into two discrete layers.}}{{cite book|last1=Pelkey|first1=James L.|title=Entrepreneurial Capitalism and Innovation: A History of Computer Communications, 1968–1988|date=2007|chapter=Yogen Dalal|access-date=5 September 2019|chapter-url=http://www.historyofcomputercommunications.info/Individuals/abstracts/yogen-dalal.html|archive-date=September 5, 2019|archive-url=https://web.archive.org/web/20190905162105/http://www.historyofcomputercommunications.info/Individuals/abstracts/yogen-dalal.html}} which led to the splitting of the Transmission Control Program into the Transmission Control Protocol (TCP) and the Internet Protocol (IP) in version 3 in 1978.{{cite web|title=BGP Analysis Reports|url=http://bgp.potaroo.net/index-bgp.html|access-date=2013-01-09}} Version 4 was described in IETF publication RFC 791 (September 1981), 792 and 793. It was installed on SATNET in 1982 and the ARPANET in January 1983 after the DoD made it standard for all military computer networking.{{Cite web|title=TCP/IP Internet Protocol|url=https://www.livinginternet.com/i/ii_tcpip.htm|access-date=2020-02-20|website=www.livinginternet.com|archive-date=July 26, 2020|archive-url=https://web.archive.org/web/20200726154118/https://www.livinginternet.com/i/ii_tcpip.htm}}{{cite ietf |author=Jon Postel |title=NCP/TCP Transition Plan |RFC= 801}} This resulted in a networking model that became known informally as TCP/IP. It was also referred to as the Department of Defense (DoD) model or DARPA model.{{Cite web|title=The TCP/IP Guide – TCP/IP Architecture and the TCP/IP Model|url=http://www.tcpipguide.com/free/t_TCPIPArchitectureandtheTCPIPModel.htm|access-date=2020-02-11|website=www.tcpipguide.com}} Cerf credits his graduate students Yogen Dalal, Carl Sunshine, Judy Estrin, Richard A. Karp, and Gérard Le Lann with important work on the design and testing.{{cite web|date=24 April 1990|title=Smithsonian Oral and Video Histories: Vinton Cerf|url=https://americanhistory.si.edu/comphist/vc1.html|access-date=23 September 2019|website=National Museum of American History|publisher=Smithsonian Institution}} DARPA sponsored or encouraged the development of TCP/IP implementations for many operating systems.
Image:IPv4 address structure and writing systems-en.svg value]]
=From ARPANET to NSFNET=
{{Main|2 = NSFNET}}
File:InetCirca85.jpg TCP/IP Internet map of early 1986]]
After the ARPANET had been up and running for several years, ARPA looked for another agency to hand off the network to; ARPA's primary mission was funding cutting-edge research and development, not running a communications utility. In July 1975, the network was turned over to the Defense Communications Agency, also part of the Department of Defense. In 1983, the U.S. military portion of the ARPANET was broken off as a separate network, the MILNET. MILNET subsequently became the unclassified but military-only NIPRNET, in parallel with the SECRET-level SIPRNET and JWICS for TOP SECRET and above. NIPRNET does have controlled security gateways to the public Internet.
The networks based on the ARPANET were government funded and therefore restricted to noncommercial uses such as research; unrelated commercial use was strictly forbidden.{{Cite web |date=December 1985 |title=ARPANET Information Brochure |url=https://apps.dtic.mil/sti/pdfs/ADA164353.pdf |publisher=Defense Communication Agency}} This initially restricted connections to military sites and universities. During the 1980s, the connections expanded to more educational institutions, and a growing number of companies such as Digital Equipment Corporation and Hewlett-Packard, which were participating in research projects or providing services to those who were. Data transmission speeds depended upon the type of connection, the slowest being analog telephone lines and the fastest using optical networking technology.
Several other branches of the U.S. government, the National Aeronautics and Space Administration (NASA), the National Science Foundation (NSF), and the Department of Energy (DOE) became heavily involved in Internet research and started development of a successor to ARPANET. In the mid-1980s, all three of these branches developed the first Wide Area Networks based on TCP/IP. NASA developed the NASA Science Network, NSF developed CSNET and DOE evolved the Energy Sciences Network or ESNet.
NASA developed the TCP/IP based NASA Science Network (NSN) in the mid-1980s, connecting space scientists to data and information stored anywhere in the world. In 1989, the DECnet-based Space Physics Analysis Network (SPAN) and the TCP/IP-based NASA Science Network (NSN) were brought together at NASA Ames Research Center creating the first multiprotocol wide area network called the NASA Science Internet, or NSI. NSI was established to provide a totally integrated communications infrastructure to the NASA scientific community for the advancement of earth, space and life sciences. As a high-speed, multiprotocol, international network, NSI provided connectivity to over 20,000 scientists across all seven continents.
In 1981, NSF supported the development of the Computer Science Network (CSNET). CSNET connected with ARPANET using TCP/IP, and ran TCP/IP over X.25, but it also supported departments without sophisticated network connections, using automated dial-up mail exchange. CSNET played a central role in popularizing the Internet outside the ARPANET.
In 1986, the NSF created NSFNET, a 56 kbit/s backbone to support the NSF-sponsored supercomputing centers. The NSFNET also provided support for the creation of regional research and education networks in the United States, and for the connection of university and college campus networks to the regional networks.{{cite web |author1=David Roessner |author2=Barry Bozeman |author3=Irwin Feller |author4=Christopher Hill |author5=Nils Newman |title=The Role of NSF's Support of Engineering in Enabling Technological Innovation |year=1997 |url=http://www.sri.com/policy/csted/reports/techin/inter2.html |access-date=May 28, 2009 |archive-url=https://web.archive.org/web/20081219114437/http://www.sri.com/policy/csted/reports/techin/inter2.html |archive-date=December 19, 2008 }} The use of NSFNET and the regional networks was not limited to supercomputer users and the 56 kbit/s network quickly became overloaded. NSFNET was upgraded to 1.5 Mbit/s in 1988 under a cooperative agreement with the Merit Network in partnership with IBM, MCI, and the State of Michigan. The existence of NSFNET and the creation of Federal Internet Exchanges (FIXes) allowed the ARPANET to be decommissioned in 1990.
NSFNET was expanded and upgraded to dedicated fiber, optical lasers and optical amplifier systems capable of delivering T3 start up speeds or 45 Mbit/s in 1991. However, the T3 transition by MCI took longer than expected, allowing Sprint to establish a coast-to-coast long-distance commercial Internet service. When NSFNET was decommissioned in 1995, its optical networking backbones were handed off to several commercial Internet service providers, including MCI, PSI Net and Sprint.{{cite report | title=Internet Traffic Exchange | series=OECD Digital Economy Papers | publisher=Organisation for Economic Co-Operation and Development (OECD) | date=1 April 1998 | doi=10.1787/236767263531| doi-access=free }} As a result, when the handoff was complete, Sprint and its Washington DC Network Access Points began to carry Internet traffic, and by 1996, Sprint was the world's largest carrier of Internet traffic.{{cite press release |title=Sprint Boosts Fiber-Optic Network Capacity 1600 Percent |url=https://www.ciena.com/about/newsroom/press-releases/sprint-boosts-fiber-optic-network-capacity-1600-percent-prx.html |location=Kansas City, MO |publisher=Ciena Corporation |date=June 11, 1996 |access-date=December 20, 2022}}
The research and academic community continues to develop and use advanced networks such as Internet2 in the United States and JANET in the United Kingdom.
=Transition towards the Internet=
The term "internet" was reflected in the first RFC published on the TCP protocol (RFC 675:{{cite ietf|rfc=675 |title=RFC 675 – Specification of internet transmission control program |year=1974 |doi=10.17487/RFC0675 |access-date=May 28, 2009|last1=Cerf |first1=V. |last2=Dalal |first2=Y. |last3=Sunshine |first3=C. }} Internet Transmission Control Program, December 1974) as a short form of internetworking, when the two terms were used interchangeably. In general, an internet was a collection of networks linked by a common protocol. In the time period when the ARPANET was connected to the newly formed NSFNET project in the late 1980s, the term was used as the name of the network, Internet, being the large and global TCP/IP network.{{cite book |last=Tanenbaum |first=Andrew S. |author-link=Andrew S. Tanenbaum |title=Computer Networks |url=https://archive.org/details/computernetwork000tane |url-access=registration |year=1996 |publisher=Prentice Hall |isbn=978-0-13-394248-4 }}
Opening the Internet and the fiber optic backbone to corporate and consumers increased demand for network capacity. The expense and delay of laying new fiber led providers to test a fiber bandwidth expansion alternative that had been pioneered in the late 1970s by Optelecom using "interactions between light and matter, such as lasers and optical devices used for optical amplification and wave mixing".{{Cite book|last1=Saleh|first1=Bahaa EA|title=Fundamentals of Photonics|last2=Teich|first2=Malvin Carl|publisher=John Wiley and Son|year=2019|pages=Preface xxii}} This technology became known as wave division multiplexing (WDM). Bell Labs deployed a 4-channel WDM system in 1995.{{cite journal | last1=Winzer | first1=Peter J. | last2=Neilson | first2=David T. | last3=Chraplyvy | first3=Andrew R. | title=Fiber-optic transmission and networking: the previous 20 and the next 20 years | journal=Optics Express | publisher=The Optical Society | volume=26 | issue=18 | date=31 August 2018 | pages=24190–24239 | doi=10.1364/oe.26.024190 |pmid=30184909|s2cid=52168806|doi-access=free}} To develop a mass capacity (dense) WDM system, Optelecom and its former head of Light Systems Research, David R. Huber formed a new venture, Ciena Corp., that deployed the world's first dense WDM system on the Sprint fiber network in June 1996. This was referred to as the real start of optical networking.{{cite book | last1=Cvijetic | first1=M. | last2=Djordjevic | first2=I. | title=Advanced Optical Communication Systems and Networks | publisher=Artech House | series=Artech House applied photonics series | year=2013 | isbn=978-1-60807-555-3}}
As interest in networking grew by needs of collaboration, exchange of data, and access of remote computing resources, the Internet technologies spread throughout the rest of the world. The hardware-agnostic approach in TCP/IP supported the use of existing network infrastructure, such as the International Packet Switched Service (IPSS) X.25 network, to carry Internet traffic.
Many sites unable to link directly to the Internet created simple gateways for the transfer of electronic mail, the most important application of the time. Sites with only intermittent connections used UUCP or FidoNet and relied on the gateways between these networks and the Internet. Some gateway services went beyond simple mail peering, such as allowing access to File Transfer Protocol (FTP) sites via UUCP or mail.{{cite web|url=http://ftp.cac.psu.edu/pub/internexus/ACCESS.PROVIDRS|archive-url=https://web.archive.org/web/20020112024958/http://ftp.cac.psu.edu/pub/internexus/ACCESS.PROVIDRS|archive-date=January 12, 2002|title=Internet Access Provider Lists|access-date=May 10, 2012}}
Finally, routing technologies were developed for the Internet to remove the remaining centralized routing aspects. The Exterior Gateway Protocol (EGP) was replaced by a new protocol, the Border Gateway Protocol (BGP). This provided a meshed topology for the Internet and reduced the centric architecture which ARPANET had emphasized. In 1994, Classless Inter-Domain Routing (CIDR) was introduced to support better conservation of address space which allowed use of route aggregation to decrease the size of routing tables.{{cite ietf|rfc=1871 |title=RFC 1871 – CIDR and Classful Routing |date=November 1995 |access-date=May 28, 2009|last1=Postel |first1=Jon |doi=10.17487/RFC1871 }}
=Optical networking=
The MOS transistor underpinned the rapid growth of telecommunication bandwidth over the second half of the 20th century.{{cite book |last1=Jindal |first1=R. P. |title=2009 2nd International Workshop on Electron Devices and Semiconductor Technology |chapter=From millibits to terabits per second and beyond – over 60 years of innovation |date=2009 |chapter-url=https://events.vtools.ieee.org/m/195547 |pages=1–6 |doi=10.1109/EDST.2009.5166093 |isbn=978-1-4244-3831-0 |s2cid=25112828}} To address the need for transmission capacity beyond that provided by radio, satellite and analog copper telephone lines, engineers developed optical communications systems based on fiber optic cables powered by lasers and optical amplifier techniques.
The concept of lasing arose from a 1917 paper by Albert Einstein, "On the Quantum Theory of Radiation". Einstein expanded upon a conversation with Max Planck on how atoms absorb and emit light, part of a thought process that, with input from Erwin Schrödinger, Werner Heisenberg and others, gave rise to quantum mechanics. Specifically, in his quantum theory, Einstein mathematically determined that light could be generated not only by spontaneous emission, such as the light emitted by an incandescent light or the Sun, but also by stimulated emission.
Forty years later, on November 13, 1957, Columbia University physics student Gordon Gould first realized how to make light by stimulated emission through a process of optical amplification. He coined the term LASER for this technology—Light Amplification by Stimulated Emission of Radiation.{{cite book | last=Taylor | first=Nick | title=Laser: The Inventor, the Noble Laureate, and the Thirty-Year Patent War | publisher=Kensington Publishing Corporation | year=2000 | isbn=978-0-8065-2471-9 | url=https://books.google.com/books?id=VZ3dsdWRz6kC&pg=PA212 | page=212}} Using Gould's light amplification method (patented as "Optically Pumped Laser Amplifier"),{{cite patent |country=US |number=4053845A |title=Optically pumped laser amplifiers |status=patent}} Theodore Maiman made the first working laser on May 16, 1960.{{cite book | editor-last1=Garwin | editor-first1=Laura |editor-last2=Lincoln |editor-first2=Tim | title=A Century of Nature: Twenty-One Discoveries that Changed Science and the World |chapter=The first laser: Charles H. Townes | publisher=University of Chicago Press | year=2010 | isbn=978-0-226-28416-3 | page=105}}
Gould co-founded Optelecom in 1973 to commercialize his inventions in optical fiber telecommunications,{{Cite book|last=Bertolotti|first=Mario|title=Masers and Lasers: An Historical Approach|publisher=CRC Press|year=2015|edition=2nd|location=Chicago|page=151}} just as Corning Glass was producing the first commercial fiber optic cable in small quantities. Optelecom configured its own fiber lasers and optical amplifiers into the first commercial optical communication systems which it delivered to Chevron and the US Army Missile Defense.{{cite book | last=Taylor | first=Nick | title=Laser: The Inventor, the Nobel Laureate, and the Thirty-Year Patent War | publisher=Kensington | year=2000 | isbn=978-0-8065-2471-9 | url=https://books.google.com/books?id=VZ3dsdWRz6kC&pg=PA225 | pages=225–226}} Three years later, GTE deployed the first optical telephone system in 1977 in Long Beach, California.{{cite book | last=Kangovi | first=S. | title=Peering Carrier Ethernet Networks | publisher=Elsevier Science | year=2016 | isbn=978-0-12-809249-1 | url=https://books.google.com/books?id=8kLQDAAAQBAJ&pg=PA46 | page=46}} By the early 1980s, optical networks powered by lasers, LED and optical amplifier equipment supplied by Bell Labs, NTT and Perelli{{clarify|reason=Pirelli is a tyre company. Were they really involved in telecoms? If so, why is this spelling retained?|date=February 2025}} were used by select universities and long-distance telephone providers.{{cn|date=February 2025}}
=TCP/IP goes global (1980s)=
==SATNET, CERN and the European Internet==
{{See also|Protocol Wars}}
In 1982, Norway (NORSAR/NDRE) and Peter Kirstein's research group at University College London (UCL) left the ARPANET and reconnected using TCP/IP over SATNET.{{Cite IETF|title=Routing and Access Control in UK to US Services|ien=190}} There were 40 British research groups using UCL's link to ARPANET in 1975;{{cite journal |last1=Kirstein |first1=P.T. |title=Early experiences with the Arpanet and Internet in the United Kingdom |journal=IEEE Annals of the History of Computing |date=1999 |volume=21 |issue=1 |pages=38–44 |doi=10.1109/85.759368 |s2cid=1558618 }} by 1984 there was a user population of about 150 people on both sides of the Atlantic.{{Cite paper |last=Kirstein |first=P. T. |date=December 1984 |title=The University College London International Computer Communications Interconnection Service |url=https://discovery.ucl.ac.uk/id/eprint/10076375/1/pub-102-D.pdf |journal=Internal Working Paper}}
Between 1984 and 1988, CERN began installation and operation of TCP/IP to interconnect its major internal computer systems, workstations, PCs, and an accelerator control system. CERN continued to operate a limited self-developed system (CERNET) internally and several incompatible (typically proprietary) network protocols externally. There was considerable resistance in Europe towards more widespread use of TCP/IP, and the CERN TCP/IP intranets remained isolated from the Internet until 1989, when a transatlantic connection to Cornell University was established.{{Cite journal|last=Fluckiger|first=Francois|date=February 2000|title=The European Researchers' Network|url=https://fluckiger.web.cern.ch/Fluckiger/Articles/F.Fluckiger-The_European_Researchers_Network.pdf|journal=La Recherche|issue=328|access-date=February 20, 2020|archive-url=https://web.archive.org/web/20180929121140/https://fluckiger.web.cern.ch/Fluckiger/Articles/F.Fluckiger-The_European_Researchers_Network.pdf|archive-date=September 29, 2018}}{{Cite web|url=https://www.internethalloffame.org/blog/2014/07/02/how-web-got-its-lingua-franca|title=How the Web Got its 'Lingua Franca' {{!}} Internet Hall of Fame|website=www.internethalloffame.org|date=July 2, 2014 |access-date=2020-04-03}}{{Cite web |title=The Internet—From Modest Beginnings |url=https://www.nsf.gov/about/history/nsf0050/internet/modest.htm |archive-url=https://web.archive.org/web/20161007113705/https://www.nsf.gov/about/history/nsf0050/internet/modest.htm |archive-date=2016-10-07 |work=NSF website |access-date=September 30, 2011}}
The Computer Science Network (CSNET) began operation in 1981 to provide networking connections to institutions that could not connect directly to ARPANET. Its first international connection was to Israel in 1984. Soon after, connections were established to computer science departments in Canada, France, and Germany.{{Cite web|url=https://www.livinginternet.com/i/ii_csnet.htm|title=CSNET, Computer Science Network}}
In 1988, the first international connections to NSFNET was established by France's INRIA,{{cite book |doi=10.4324/9781315748962-6 |chapter=From the Minitel to the Internet: The Path to Digital Literacy and Network Culture in France (1980s–1990s) |title=The Routledge Companion to Global Internet Histories |date=2017 |last1=Schafer |first1=Valérie |last2=Thierry |first2=Benjamin G. |pages=77–89 |isbn=978-1-315-74896-2 |chapter-url=https://books.google.com/books?id=rlwlDgAAQBAJ&pg=PT191 }}{{Cite web|title=A brief history of the internet|url=http://thetechnologytrend.blogspot.com/2012/03/brief-history-of-internet.html|last=Andrianarisoa|first=Menjanirina|date=March 2, 2012}}{{user-generated inline|date=September 2023}} and Piet Beertema at the Centrum Wiskunde & Informatica (CWI) in the Netherlands.{{Cite web|url=https://www.cwi.nl/about/history/cwi-achievements-details|title=CWI History: details|website=CWI|language=en-gb|access-date=2020-02-09}} Daniel Karrenberg, from CWI, visited Ben Segal, CERN's TCP/IP coordinator, looking for advice about the transition of EUnet, the European side of the UUCP Usenet network (much of which ran over X.25 links), over to TCP/IP. The previous year, Segal had met with Len Bosack from the then still small company Cisco about purchasing some TCP/IP routers for CERN, and Segal was able to give Karrenberg advice and forward him on to Cisco for the appropriate hardware. This expanded the European portion of the Internet across the existing UUCP networks. The NORDUnet connection to NSFNET was in place soon after, providing open access for university students in Denmark, Finland, Iceland, Norway, and Sweden.{{Cite book|last=Lehtisalo|first=Kaarina|url=http://www.nordu.net/history/TheHistoryOfNordunet_simple.pdf|title=The history of NORDUnet: twenty-five years of networking cooperation in the noridic countries|date=2005|publisher=NORDUnet|isbn=978-87-990712-0-3|language=en|access-date=May 2, 2020|archive-date=March 4, 2016|archive-url=https://web.archive.org/web/20160304031416/http://www.nordu.net/history/TheHistoryOfNordunet_simple.pdf}}
In January 1989, CERN opened its first external TCP/IP connections.{{Cite book |last=Segal |first=Ben |author-link=Ben Segal (computer scientist) |title=A short history of Internet protocols at CERN |publisher=CERN |year=1995 |location=Geneva |publication-date=April 1995 |language=English |doi=10.17181/CERN_TCP_IP_history}} This coincided with the creation of Réseaux IP Européens (RIPE), initially a group of IP network administrators who met regularly to carry out coordination work together. Later, in 1992, RIPE was formally registered as a cooperative in Amsterdam.
The United Kingdom's national research and education network (NREN), JANET, began operation in 1984 using the UK's Coloured Book protocols and connected to NSFNET in 1989. In 1991, JANET adopted Internet Protocol on the existing network.{{Cite journal|date=January 1991|title=FLAGSHIP|url=http://www.chilton-computing.org.uk/ccd/literature/ccd_newsletters/flagship/p012.htm|journal=Central Computing Department Newsletter|issue=12|access-date=February 20, 2020|archive-url=https://web.archive.org/web/20200213100220/http://www.chilton-computing.org.uk/ccd/literature/ccd_newsletters/flagship/p012.htm|archive-date=February 13, 2020}}{{Cite journal|date=September 1991|title=FLAGSHIP|url=http://www.chilton-computing.org.uk/ccd/literature/ccd_newsletters/flagship/p016.htm|journal=Central Computing Department Newsletter|issue=16|access-date=February 20, 2020|archive-url=https://web.archive.org/web/20200213100222/http://www.chilton-computing.org.uk/ccd/literature/ccd_newsletters/flagship/p016.htm|archive-date=February 13, 2020}} The same year, Dai Davies introduced Internet technology into the pan-European NREN, EuropaNet, which was built on the X.25 protocol.{{Cite web|url=https://www.internethalloffame.org/inductee/dai-davies/ |title=Dai Davies |website=Internet Hall of Fame }}{{Cite web|url=https://www.internethalloffame.org/2015/01/16/protocol-wars/ |title=Protocol Wars |website=Internet Hall of Fame |date=January 16, 2015 }} The European Academic and Research Network (EARN) and RARE adopted IP around the same time, and the European Internet backbone EBONE became operational in 1992.
Nonetheless, for a period in the late 1980s and early 1990s, engineers, organizations and nations were polarized over the issue of which standard, the OSI model or the Internet protocol suite would result in the best and most robust computer networks.{{cite journal |last1=Russell |first1=A.L. |title='Rough Consensus and Running Code' and the Internet-OSI Standards War |journal=IEEE Annals of the History of Computing |date=July 2006 |volume=28 |issue=3 |pages=48–61 |doi=10.1109/MAHC.2006.42 |s2cid=206442834 }}{{cite web |url={{Google books|DN-t8MpZ0-wC|page=106|plainurl=yes}} |title=The Protocol Wars |pages=106–107 }} in {{cite book |doi=10.1002/9783527629336.ch4 |chapter=Different Approaches |title=A History of International Research Networking |date=2010 |pages=73–110 |isbn=978-3-527-32710-2 |first1=Howard |last1=Davies |first2=Beatrice |last2=Bressan }}
==The link to the Pacific==
Japan, which had built the UUCP-based network JUNET in 1984, connected to CSNET, and later to NSFNET in 1989, marking the spread of the Internet to Asia.
South Korea set up a two-node domestic TCP/IP network in 1982, the System Development Network (SDN), adding a third node the following year. SDN was connected to the rest of the world in August 1983 using UUCP (Unix-to-Unix-Copy); connected to CSNET in December 1984; and formally connected to the NSFNET in 1990.{{cite web |url=https://net.its.hawaii.edu/history/Korean_Internet_History.pdf |title=A Brief History of the Internet in Korea |author=Kilnam Chon |author2=Hyunje Park |author3=Kyungran Kang |author4=Youngeum Lee }}{{Cite web |title=A Brief History of the Internet in Korea (2005) – 한국 인터넷 역사 프로젝트 |url=https://sites.google.com/site/koreainternethistory/publication/brief-history-korea-eng-ver |access-date=2016-05-30 |website=sites.google.com}}{{Cite book |last1=Shrum |first1=Wesley |url=https://books.google.com/books?id=cNFOD_g7xXIC&pg=PA55 |title=Past, Present and Future of Research in the Information Society |last2=Benson |first2=Keith |last3=Bijker |first3=Wiebe |last4=Brunnstein |first4=Klaus |date=2007-12-14 |publisher=Springer Science & Business Media |isbn=978-0-387-47650-6 |page=55 |language=en}}
In Australia, ad hoc networking to ARPA and in-between Australian universities formed in the late 1980s, based on various technologies such as X.25, UUCPNet, and via a CSNET. These were limited in their connection to the global networks, due to the cost of making individual international UUCP dial-up or X.25 connections. In 1989, Australian universities joined the push towards using IP protocols to unify their networking infrastructures. AARNet was formed in 1989 by the Australian Vice-Chancellors' Committee and provided a dedicated IP based network for Australia.
New Zealand adopted the UK's Coloured Book protocols as an interim standard and established its first international IP connection to the U.S. in 1989.{{Cite web|title=History of University of Waikato: University of Waikato|url=https://www.waikato.ac.nz/about/history.shtml|url-status=live|archive-url=https://web.archive.org/web/20200801155046/https://www.waikato.ac.nz/about/history.shtml|archive-date=2020-08-01|access-date=2020-02-09|website=www.waikato.ac.nz}}
==A "digital divide" emerges==
Source: International Telecommunication Union.{{citation |url=http://www.itu.int/en/ITU-D/Statistics/Documents/statistics/2013/Individuals_Internet_2000-2012.xls |title=Percentage of Individuals using the Internet 2000–2012 |publisher=International Telecommunication Union |location=Geneva |date=June 2013 |format=XLS}}]]{{Main|Global digital divide|Digital divide}}
File:FixedBroadbandInternetPenetrationWorldMap.svg
as a percentage of a country's population