Editing Router (computing) (section)

== History ==
[[File:ARPANET first router 2.jpg|thumb|upright=0.8|The first ARPANET router, the [[Interface Message Processor]], was delivered to UCLA August 30, 1969, and went online October 29, 1969.]]

The concepts of a ''switching node'' using software and an ''interface computer'' were first proposed by [[Donald Davies]] in 1966 for the [[NPL network]].<ref>{{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}}</ref><ref>{{cite web |last1=Roberts |first1=Dr. Lawrence G. |date=May 1995 |title=The ARPANET & Computer Networks |url=http://www.packet.cc/files/arpanet-computernet.html |url-status=live |archive-url=https://web.archive.org/web/20160324032800/http://www.packet.cc/files/arpanet-computernet.html |archive-date=24 March 2016 |access-date=13 April 2016 |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.}}</ref><ref>{{Cite book |last=Pelkey |first=James |url=http://www.historyofcomputercommunications.info/Individuals/abstracts/donald-davies.html |title=Entrepreneurial Capitalism & Innovation: A History of Computer Communications 1968 - 1988 |date=2007 |quote=paper dated June 1966 ... introduced the concept of an “interface computer” to sit between the user equipment and the packet network. |access-date=2020-02-18}}</ref> The same idea was conceived by [[Wesley A. Clark|Wesley Clark]] the following year for use in the [[ARPANET]], which were named [[Interface Message Processor|''Interface Message Processors'']] (IMPs).<ref name=":2">{{cite web |last=Pelkey |first=James |title=4.7 Planning the ARPANET: 1967-1968 in Chapter 4 - Networking: Vision and Packet Switching 1959 - 1968 |url=https://historyofcomputercommunications.info/section/4.7/planning-the-arpanet-1967-1968/ |url-status=dead |archive-url=https://web.archive.org/web/20221223230647/https://historyofcomputercommunications.info/section/4.7/planning-the-arpanet-1967-1968/ |archive-date=December 23, 2022 |access-date=May 9, 2023 |work=The History of Computer Communications}}</ref> The first interface computer was implemented at the [[National Physical Laboratory (United Kingdom)|National Physical Laboratory]] in the United Kingdom in early 1969, followed later that year by the IMPs at the [[University of California, Los Angeles]], the [[Stanford Research Institute]], the [[University of California, Santa Barbara]], and the [[University of Utah School of Computing]] in the United States.<ref name=":22">{{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}}</ref><ref>{{Cite conference |last=Scantlebury |first=Roger |date=2001 |title=A Brief History of the NPL Network |url=http://www.topquark.co.uk/conf/IAP2001.html |conference=Symposium of the Institution of Analysts & Programmers 2001 |archive-url=https://web.archive.org/web/20030807200346/http://www.topquark.co.uk/conf/IAP2001.html |archive-date=2003-08-07 |access-date=2024-06-13 |quote=The system first went 'live' early in 1969 |url-status=dead |website=}}</ref><ref>{{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}}</ref><ref name="C. Hempstead, W. Worthington">{{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=9781135455514 |editor1-last=Hempstead |editor1-first=C. |pages=573–5 |access-date=2015-08-15 |editor2-last=Worthington |editor2-first=W.}}</ref> All were built with the [[Honeywell 316|Honeywell 516]]. These computers had fundamentally the same functionality as a router does today.

The idea for a router (called a ''[[Gateway (telecommunications)|gateway]]'' at the time) initially came about through an international group of computer networking researchers called the [[International Network Working Group]] (INWG).<ref>Davies, Shanks, Heart, Barker, Despres, Detwiler and Riml, "Report of Subgroup 1 on Communication System", INWG Note No. 1.</ref> These gateway devices were different from most previous [[packet switching]] schemes in two ways. First, they connected dissimilar kinds of networks, such as [[serial line]]s and [[local area network]]s. Second, they were [[connectionless]] devices, which had no role in assuring that traffic was delivered reliably, leaving that function entirely to the [[host (network)|hosts]].<ref>{{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=INWG#1: Report of Subgroup 1 on Communication System Requirements by Davies, Shanks, Heart, Barker, Despres, Detwiler, and Riml. They wrote: “It was agreed that interworkingbetween packet switching networks should not add complications to the hosts, considering that networks will probably be different and thus gateways between networks will be required.  These gateways should be as uncomplicated as possible, whilst allowing as much freedom as possible for the design of individual networks”. INWG#1 clarified that gateways and simplicity were accepted concepts when INWG was formed.|url-access=subscription }}</ref> This particular idea, the [[end-to-end principle]], was contained in the work of Donald Davies.<ref name=":5">{{cite conference |last1=Davies |first1=Donald |last2=Bartlett |first2=Keith |last3=Scantlebury |first3=Roger |last4=Wilkinson |first4=Peter |date=October 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 |conference=ACM Symposium on Operating Systems Principles |archive-url=https://ghostarchive.org/archive/20221010/https://people.mpi-sws.org/~gummadi/teaching/sp07/sys_seminar/how_did_erope_blow_this_vision.pdf |archive-date=2022-10-10 |access-date=2020-09-15 |quote=It is thought that all users of the network will provide themselves with some kind of error control and that without difficulty this could be made to show up a missing packet. Because of this, loss of packets, if it is sufficiently rare, can be tolerated. |url-status=live}}</ref><ref name="Pelkey8.3">{{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 |quote=The inspiration for datagrams had two sources. One was Donald Davies’ studies. He had done some simulation of datagram networks, although he had not built any, and it looked technically viable. The second inspiration was I like things simple. I didn’t see any real technical motivation to overlay two levels of end-to-end protocols. I thought one was enough. |chapter-url=https://historyofcomputercommunications.info/section/8.3/CYCLADES-Network-and-Louis-Pouzin-1971-1972/}}</ref> 

The concept was explored in practice by various groups, with the intention to produce a working system for [[internetworking]]. There were three notable contemporaneous programs. The first was an implementation directed by [[Louis Pouzin]] of the [[CYCLADES]] network, which was designed and developed during 1972-3.<ref name=":3">{{Cite journal |last1=Russell |first1=Andrew L. |last2=Schafer |first2=Valérie |date=2014 |title=In the Shadow of ARPANET and Internet: Louis Pouzin and the Cyclades Network in the 1970s |url=https://www.jstor.org/stable/24468474 |journal=Technology and Culture |volume=55 |issue=4 |pages=880–907 |doi=10.1353/tech.2014.0096 |issn=0040-165X |jstor=24468474|url-access=subscription }}</ref><ref>{{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.}}</ref><ref name="Bennett2009">{{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 CYCLADES, designed by Louis Pouzin at IRIA in France with the support of BBN’s Dave Walden and Alex McKenzie and deployed beginning in 1972.}}</ref> The second was program at [[Xerox PARC]] to explore new networking technologies, which produced the [[PARC Universal Packet]] system. Some time after early 1974, the first Xerox routers became operational. Due to corporate intellectual property concerns, it received little attention outside Xerox for years.<ref>{{Citation |last=Taylor |first=Bob |title=Oral History of Robert (Bob) W. Taylor |date=October 11, 2008 |journal=Computer History Museum Archive |volume=CHM Reference number: X5059.2009 |page=28 |url=http://archive.computerhistory.org/resources/access/text/2013/05/102702015-05-01-acc.pdf}}</ref><ref>David Boggs, John Shoch, Edward Taft, Robert Metcalfe, [https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=1094684 "Pup: An Internetwork Architecture"], IEEE Transactions on Communications, Volume 28, Issue 4, April 1980, pp. 612- 624.</ref> The third was a [[DARPA]]-initiated program, which began during 1973-4. This drew on the work of the other two programs,''<ref name="Cerf-1974">{{Cite journal |last1=Cerf |first1=V. |last2=Kahn |first2=R. |date=1974 |title=A Protocol for Packet Network Intercommunication |url=https://www.cs.princeton.edu/courses/archive/fall06/cos561/papers/cerf74.pdf |journal=IEEE Transactions on Communications |volume=22 |issue=5 |pages=637–648 |doi=10.1109/TCOM.1974.1092259 |issn=1558-0857 |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.}}</ref>'' expanded significantly, and went on to create the [[TCP/IP]] architecture in use today.<ref>{{Cite IETF|rfc=1087|title=Ethics and the Internet|date=January 1989|quote=At great human and economic cost, resources drawn from the U.S. Government, industry and the academic community have been assembled into a collection of interconnected networks called the Internet.}}</ref><ref>{{Cite IETF|rfc=2555|title=30 Years of RFCs|date=7 April 1999|quote=Reflections - Joyce K. Reynolds: A very long time ago when I was dabbling in IP network number and protocol parameter assignments with Jon Postel, gateways were still "dumb", the Exterior Gateway Protocol (EGP) was in its infancy and TOPS-20 was in its heyday.}}</ref> [[University College London]] (UCL) provided a gateway between [[Internet in the United Kingdom#Early years|British research groups]] and the ARPANET from 1973 until the late 1980s, latterly using [[SATNET]].<ref name=":9">{{cite journal |last1=Kirstein |first1=P.T. |date=1999 |title=Early experiences with the Arpanet and Internet in the United Kingdom |journal=IEEE Annals of the History of Computing |volume=21 |issue=1 |pages=38–44 |doi=10.1109/85.759368 |s2cid=1558618}}</ref><ref>{{Cite IETF|title=Routing and Access Control in UK to US Services|ien=190}}</ref><ref>{{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}}</ref>

The first true IP router was developed by [[Ginny Travers]] at [[BBN Technologies|BBN]], as part of that DARPA-initiated effort, during 1975–1976.<ref>{{Cite web |title=Virginia Travers |url=https://www.internethalloffame.org/inductee/virginia-travers/ |access-date=2024-06-16 |website=Internet Hall of Fame |language=en-US}}</ref><ref>{{cite web |date=21 December 2015 |title=Ms. Ginny Strazisar |url=http://www.ithistory.org/honor-roll/ms-ginny-strazisar |url-status=live |archive-url=https://web.archive.org/web/20171201034131/http://www.ithistory.org/honor-roll/ms-ginny-strazisar |archive-date=1 December 2017 |access-date=21 November 2017 |website=IT History Society}}</ref> By the end of 1976, three [[PDP-11]]-based routers were in service in the experimental prototype Internet.<ref>Craig Partridge, S. Blumenthal, [https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=1603444 "Data networking at BBN"]; IEEE Annals of the History of Computing, Volume 28, Issue 1; January–March 2006.</ref> Mike Brecia, Ginny Travers, and Bob Hinden received the [[IEEE Internet Award]] for early IP routers in 2008.<ref>{{Cite web |title=IEEE INTERNET AWARD RECIPIENTS |url=https://corporate-awards.ieee.org/wp-content/uploads/internet-rl.pdf}}</ref>

The first multiprotocol routers were independently created by staff researchers at [[MIT]] and [[Stanford]] in 1981 and both were also based on PDP-11s. Stanford's router program was led by [[William Yeager]] and MIT's by [[Noel Chiappa]].<ref>[https://www.pbs.org/cringely/pulpit/1998/pulpit_19981210_000593.html Valley of the Nerds: Who Really Invented the Multiprotocol Router, and Why Should We Care?] {{webarchive|url=https://web.archive.org/web/20160303172753/http://www.pbs.org/cringely/pulpit/1998/pulpit_19981210_000593.html|date=2016-03-03}}, Public Broadcasting Service, Accessed August 11, 2007.</ref><ref>[http://www.networkworld.com/supp/2006/anniversary/032706-routerman.html?t5 Router Man] {{webarchive|url=https://web.archive.org/web/20130605195255/http://www.networkworld.com/supp/2006/anniversary/032706-routerman.html?t5|date=2013-06-05}}, NetworkWorld, Accessed June 22, 2007.</ref><ref>David D. Clark, "M.I.T. Campus Network Implementation", CCNG-2, Campus Computer Network Group, M.I.T., Cambridge, 1982; pp. 26.</ref><ref>Pete Carey, "A Start-Up's True Tale: Often-told story of Cisco's launch leaves out the drama, intrigue", San Jose Mercury News, December 1, 2001.</ref> Virtually all networking now uses TCP/IP, but multiprotocol routers are still manufactured. They were important in the early stages of the growth of computer networking when protocols other than TCP/IP were in use. Modern routers that handle both IPv4 and IPv6 are multiprotocol but are simpler devices than ones processing AppleTalk, DECnet, IPX, and Xerox protocols.

From the mid-1970s and in the 1980s, general-purpose [[minicomputer]]s served as routers. Modern high-speed routers are [[network processor]]s or highly specialized computers with extra [[hardware acceleration]] added to speed both common routing functions, such as packet forwarding, and specialized functions such as [[IPsec]] encryption. There is substantial use of [[Linux]] and [[Unix]] software-based machines, running [[Open-source software|open source]] routing code, for research and other applications. The [[Cisco IOS]] operating system was independently designed. Major router operating systems, such as [[Junos]] and [[NX-OS]], are extensively modified versions of Unix software.