Lawrence Gilman Roberts, who was known as Larry, was born and raised inWestport, Connecticut.[6] He was the son of Elizabeth (Gilman) and Elliott John Roberts, both of whom had doctorates inchemistry. It is said that during his youth, he built aTesla coil, assembled a television, and designed a telephone network built from transistors for his parents'Girl Scout camp.[7]
In late 1966, although at first reluctant due to the administrative nature of the role,[13] he was recruited byRobert Taylor in the ARPAInformation Processing Techniques Office (IPTO) to become the program manager for theARPANET. Roberts metPaul Baran in February 1967, but did not discuss networks.[14][15] He askedFrank Westervelt to explore the initial design questions for a network.[16] Roberts prepared a proposal that all host computers would connect to one another directly.[17] Taylor andWesley Clark disagreed with this design and Clark suggested the use of dedicated computers to create amessage switching network, which were later calledInterface Message Processors (IMPs).[16][18]
Roberts' plan for the ARPANET was the first wide area packet-switching network with distributed control, similar to Donald Davies' 1965 design.[28] ARPA issued arequest for quotation (RFQ) to build the system, which was awarded toBolt, Beranek and Newman (BBN). Significant aspects of the network's operation including routing, flow control, software design and network control were developed by the BBNIMP team, which includedBob Kahn.[11] Roberts managed its implementation and contracted withLeonard Kleinrock in 1968 to carry out mathematical modelling of the packet-switched network's performance.[29] Roberts engaged Howard Frank to consult on the topological design of the network. Frank made recommendations to increase throughput and reduce costs in a scaled-up network.[30] When Robert Taylor was sent toVietnam in 1969 and then resigned, Roberts became director of the IPTO. He hired Barry Wessler to oversee development of the ARPANET host-to-host protocol.[31][32]
Roberts became a champion of packet switching.[33] In 1970, he proposed toNPL's Donald Davies that the two organizations connect their networks via a satellite link. This original proposal proved infeasible, but in 1971Peter Kirstein agreed to Roberts' proposal to connect his research group atUniversity College London (UCL) instead. UCL provided interconnection withBritish academic networks, forming the first internationalresource sharing network.[34] Roberts anticipated in 1973 that it would be possible to use a satellite's 64 kilobit/second link as a medium shared by multiple satellite earth stations within the beam's footprint. This was implemented later by Bob Kahn, and resulted inSATNET.
ThePurdy Polynomial hash algorithm was developed for the ARPANET to protect passwords in 1971 at the request of Roberts.
Roberts approached AT&T in the early 1970s about taking over the ARPANET to offer a public packet switched service but they declined.[35]
In July 1972, he took the idea of READMAIL, which dumped all "recent" messages onto the user's terminal, and wrote a program forTENEX inTECO macros calledRD, which permitted access to individual messages.[36]
In early 1973, Roberts predicted the network would run out of capacity in nine months. In practice, it was found that the time-sharing host computers ran out of capacity before the network did.[37]
In 1973, Roberts left ARPA to join BBN's effort to commercialize the nascent packet-switching technology in the form ofTelenet,[38] the first FCC-licensedpublic data network in the United States. He was itsCEO from 1973 to 1980. Roberts joined the international effort to standardize a protocol for packet switching based onvirtual circuits shortly before it was finalized.[39][40] Telenet converted to theX.25 protocol, which was adopted byPTTs across North America and Europe forpublic data networks in the mid-late 1970s.[41] Roberts promoted this approach over thedatagram approach inTCP/IP being pursued by ARPA, which he described as "oversold" in 1978.[11]
In 1983 he joinedDHL Corporation as President. At the time, he predicted bandwidths would go down driven by voice compression technology.[42]
He was CEO of NetExpress, anAsynchronous Transfer Mode (ATM) equipment company, from 1983 to 1993. Roberts was president of ATM Systems from 1993 to 1998. He was chairman and CTO of Caspian Networks, but left in early 2004; Caspian ceased operation in late 2006.[43]
As of 2011[update], Roberts was the founder and chairman of Anagran Inc. Anagran continues work in the same area as Caspian: IP flow management with improvedquality of service for the Internet.[44]
Roberts claimed in the late 1990s that, by the time of the October 1967Symposium on Operating System Principles (SOSP), he already had the concept of packet switching in mind (although not yet named and not written down in his paper published at the conference, which a number of sources describe as "vague").[46][47][48][49][50] Furthermore, he claimed that his experiment with Thomas Marill in October 1965,[51] was based on packet switching;[52][53][54] and that their subsequent paper,Towards a Cooperative Network of Time-Shared Computers, published the following year, was a blueprint for the ARPANET.[55][56][57][58][59] In addition, he began describing himself as having been the "Chief Scientist" at ARPA.[60][61][62] These claims have been reflected in publications about the history of the ARPANET and the Internet, and became part of the packet switching 'paternity dispute'.[63]
Roberts' role at ARPA was largely administrative and managerial.[13][64] His early work, prior to SOSP, has been described as "extend[ing] the concept of a support graphics processor to the idea of a network" using "existing telegraphic techniques".[65][66] In his paper on "Packet Switching Economics" for the L.M. Ericsson prize for research in data communications, 1982, he referenced Davies' 1967 paper for SOSP, and no earlier papers.[67] Primary sources and historians recognize Baran and Davies for independently inventing the concept of digital packet switching used in modern computer networking including the ARPANET and the Internet.[68][69][70][71][72]
Roberts married and divorced four times. At the time of his death, his partner was physician Tedde Rinker.[6] Roberts died at his California home from a heart attack on December 26, 2018.[6][73]
IEEEHarry H. Goode Memorial Award (1976 ), "In recognition of his contributions to the architectural design of computer-communication systems, his leadership in creating a fertile research environment leading to advances in computer and satellite communications techniques, his role in the establishment of standard international communication protocols and procedures, and his accomplishments in development and demonstration of packet switching technology and the ensuing networks which grew out of this work."[74]
Member, National Academy of Engineering (1978)[75]
IEEEW. Wallace McDowell Award (1990), "For architecting packet switching technology and bringing it into practical use by means of the ARPA network."[75][76]
IEEE Internet Award (2000) For "early, preeminent contributions in conceiving, analyzing and demonstrating packet-switching networks, the foundation technology of the Internet."[75][78]
International Engineering Consortium Fellow Award (2001)[75]
Principe de Asturias Award 2002 in Spain "for designing and implementing a system that is changing the world by providing previously unthought of opportunities for social and scientific progress."[81]
NEC C&C Award (2005) in Japan "For Contributions to Establishing the Foundation of Today's Internet Technology through ... the Design and Development of ARPANET and Other Early Computer Networks that were Part of the Initial Internet."[82]
^Abbate, Jane (1999).Inventing the Internet. MIT Press. p. 3.ISBN978-0262261333.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.
^"A Flaw In The Design".The Washington Post. May 30, 2015.Historians credit seminal insights to Welsh scientist Donald W. Davies and American engineer Paul Baran
^Waldrop, M. Mitchell (2018).The Dream Machine. Stripe Press. pp. 285–6.ISBN978-1-953953-36-0.Oops. Roberts knew Baran slightly and had in fact had lunch with him during a visit to RAND the previous February. But he certainly didn't remember any discussion of networks. How could he have missed something like that?
^O'Neill, Judy (March 5, 1990)."An Interview with PAUL BARAN"(PDF). p. 37.On Tuesday, 28 February 1967 I find a notation on my calendar for 12:00 noon Dr. L. Roberts.
^Press, Gil (January 2, 2015)."A Very Short History Of The Internet And The Web".Forbes.Archived from the original on January 9, 2015. RetrievedFebruary 7, 2020.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.
^Naughton, John (2015).A Brief History of the Future: The origins of the Internet. Hachette.ISBN978-1474602778.they lacked one vital ingredient. Since none of them had heard of Paul Baran they had no serious idea of how to make the system work. And it took an English outfit to tell them. ... Larry Roberts paper was the first public presentation of the ARPANET concept as conceived with the aid of Wesley Clark ... Looking at it now, Roberts paper seems extraordinarily, well, vague.
^Tanenbaum, Andrew S.; Wetherall, David (2011).Computer networks(PDF) (5th ed.). Boston Amsterdam: Prentice Hall. p. 57.ISBN978-0-13-212695-3.Roberts bought the idea and presented a some what vague paper about it at the ACM SIGOPS Symposium on Operating System Principles held in Gatlinburg, Tennessee in late 1967
^Hafner, Katie; Lyon, Matthew (1996).Where wizards stay up late: the origins of the Internet. Internet Archive. Simon & Schuster. pp. 76–78.ISBN978-0-684-81201-4.Roger Scantlebury ... from Donald Davies' team ... presented a detailed design study for a packet switched network. It was the first Roberts had heard of it. ... Roberts also learned from Scantlebury, for the first time, of the work that had been done by Paul Baran at RAND a few years earlier.
^Abbate, Jane (2000).Inventing the Internet. MIT Press. pp. 37–8,58–9.ISBN978-0262261333.The NPL group influenced a number of American computer scientists in favor of the new technique, and they adopted Davies's term "packet switching" to refer to this type of network. Roberts also adopted some specific aspects of the NPL design.
^Rybczynski, Tony (2009). "Commercialization of packet switching (1975-1985): A Canadian perspective [History of Communications]".IEEE Communications Magazine.47 (12):26–31.doi:10.1109/MCOM.2009.5350364.ISSN1558-1896.S2CID23243636.
^Fang, Bingxing (2018).Cyberspace Sovereignty: Reflections on building a community of common future in cyberspace.Springer Nature. p. 154.ISBN978-9811303203.
^Naughton, John (2015).A Brief History of the Future: The origins of the Internet. Hachette.ISBN978-1474602778.they lacked one vital ingredient. Since none of them had heard of Paul Baran they had no serious idea of how to make the system work. And it took an English outfit to tell them. ... Larry Roberts paper was the first public presentation of the ARPANET concept as conceived with the aid of Wesley Clark ... Looking at it now, Roberts paper seems extraordinarily, well, vague.
^Tanenbaum, Andrew S.; Wetherall, David (2011).Computer networks(PDF) (5th ed.). Boston Amsterdam: Prentice Hall. p. 57.ISBN978-0-13-212695-3.Roberts bought the idea and presented a some what vague paper about it at the ACM SIGOPS Symposium on Operating System Principles held in Gatlinburg, Tennessee in late 1967
^Kirstein, Peter T. (2009). "The early history of packet switching in the UK".IEEE Communications Magazine.47 (2):18–26.doi:10.1109/MCOM.2009.4785372.S2CID34735326.It is more difficult to establish at this time, however, whether Larry intended to switch the fragments as independent packets in the ARPAnet before he heard of the NPL work; certainly he now claims that this was always his intention.
^technicshistory (June 2, 2019)."ARPANET, Part 2: The Packet".Creatures of Thought. RetrievedJune 21, 2024.The above description of how packet-switching came to be is the most widely-accepted one. However, there is an alternative version. Roberts claimed in later years that by the time of the Gatlinburg symposium, he already had the basic concepts of packet-switching well in mind, and that they originated with his old colleague Len Kleinrock, who had written about them as early as 1962, as part of his Ph.D. research on communication nets. It requires a great deal of squinting to extract anything resembling packet-switching from Kleinrock's work, however, and no other contemporary textual evidence that I have come across backs the Kleinrock/Roberts account.
^Katie Hafner (November 8, 2001),"A Paternity Dispute Divides Net Pioneers",New York Times,The Internet is really the work of a thousand people," Mr. Baran said. "And of all the stories about what different people have done, all the pieces fit together. It's just this one little case that seems to be an aberration.
^"Larry Roberts, Grandfather of the Internet, Dies at 81".Paleofuture. December 31, 2018. RetrievedMay 2, 2025.The work that Roberts contributed to the development of the internet is largely thought of as administrative and managerial as opposed to strictly technical
^Barber, Derek (Spring 1993)."The Origins of Packet Switching".The Bulletin of the Computer Conservation Society (5).ISSN0958-7403. RetrievedSeptember 6, 2017.Larry Roberts had extended the concept of a support graphics processor to the idea of a network, and he was then talking about multiple computer networks and inter-computer communication. Roger actually convinced Larry that what he was talking about was all wrong and that the way that NPL were proposing to do it was right. I've got some notes that say that first Larry was sceptical but several of the others there sided with Roger and eventually Larry was overwhelmed by the numbers. That actually gave birth to Arpanet
^Abbate, Jane (2000).Inventing the Internet. MIT Press. pp. 37–8,58–9.ISBN978-0262261333.The NPL group influenced a number of American computer scientists in favor of the new technique, and they adopted Davies's term "packet switching" to refer to this type of network. Roberts also adopted some specific aspects of the NPL design.
^Norberg, Arthur L.; O'Neill, Judy E. (1996).Transforming computer technology: information processing for the Pentagon, 1962-1986. Johns Hopkins studies in the history of technology New series. Baltimore: Johns Hopkins Univ. Press. pp. 153–196.ISBN978-0-8018-5152-0. Prominently cites Baran and Davies as sources of inspiration, and nowhere mentions Kleinrock's work.
^A History of the ARPANET: The First Decade(PDF) (Report). Bolt, Beranek & Newman Inc. April 1, 1981. pp. 13, 53 of 183.Archived from the original on December 1, 2012.Aside from the technical problems of interconnecting computers with communications circuits, the notion of computer networks had been considered in a number of places from a theoretical point of view. Of particular note was work done by Paul Baran and others at the Rand Corporation in a study "On Distributed Communications" in the early 1960's. Also of note was work done by Donald Davies and others at the National Physical Laboratory in England in the mid-1960's. ... Another early major network development which affected development of the ARPANET was undertaken at the National Physical Laboratory in Middlesex, England, under the leadership of D. W. Davies.
^"The Internet is one of the most eloquent examples of the benefits that accrue from scientific research and a commitment to technological innovation. A myriad of people and institutions were involved in this work. The jury wishes to acknowledge them all in awarding the prize to the four leaders of so extraordinary a development."José Luis Álvarez Margaride; Ernesto Carmona Guzmán; et al. (May 23, 2002)."Minutes of the Jury – Technical and Scientific Research 2002".Fundación Príncipe de Asturias. Archived fromthe original on November 21, 2008. RetrievedApril 10, 2008.
Oral history interview with Lawrence G. Roberts.Charles Babbage Institute, University of Minnesota. Roberts directed the Information Processing Techniques Office (IPTO) during 1968–1973 and was later chief operating officer of Network Express. The interview focuses on IPTO and the Advanced Research Projects Agency. Much of Roberts's description of the work of ARPA and IPTO is set within the context of his interactions with Congress on budget matters. Topics include J. C. R. Licklider, Ivan Sutherland,Stephen J. Lukasik, Wesley Clark, ARPA and IPTO support of research in computer science, computer networks, and artificial intelligence, the ARPANET, the involvement of universities with ARPA and IPTO.
