NPL network

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NPL network schematic

The NPL network, or NPL Data Communications Network, was a local area computer network operated by a team from the National Physical Laboratory (NPL) in London that pioneered the concept of packet switching.

Based on designs first conceived by Donald Davies in 1965, development work began in 1968. Elements of the first version of the network, the Mark I, became operational during 1969 then fully operational in January 1970, and the Mark II version operated from 1973 until 1986. The NPL network followed by the ARPANET in the United States were the first two computer networks that implemented packet switching and the NPL network was the first to use high-speed links. It, along with the ARPANET and the CYCLADES project, laid down the technical foundations of the modern Internet.

Origins

NPL network packet

During 1965-66, Donald Davies, who was later appointed to head of the NPL Division of Computer Science, proposed a commercial national data network based on packet switching in Proposal for the Development of a National Communications Service for On-line Data Processing.[1] After the proposal was not taken up nationally, he headed a team which produced a design for a local network to serve the needs of NPL and prove the feasibility of packet switching.[2] The design was the first to describe the concept of an "interface computer", today known as a router.[3]

A written version of the proposal entitled A digital communications network for computers giving rapid response at remote terminals was presented by

Mbit/s line rate).[4][5][6][7][8] In Scantlebury's report following the conference, he noted "It would appear that the ideas in the NPL paper at the moment are more advanced than any proposed in the USA".[9][10][11]

Packet switching

The first theoretical foundation of

kbit/s.[19] Influenced by this, the planned line speed for ARPANET was upgraded from 2.4 kbit/s to 50 kbit/s and a similar packet format adopted.[20][21] Louis Pouzin's CYCLADES project in France was also influenced by Davies' work.[22][6][23]

Implementation and further research

Network development

The NPL team used their packet switching concept to produce an experimental network using a Honeywell 516 node. Construction began in 1968. Coincidentally, this was the same computer chosen by the ARPANET to serve as Interface Message Processors.[24]

Elements of the first version of the network, Mark I NPL Network, became operational during 1969 (before the ARPANET installed its first node).[25][26] The network was fully operational in January 1970.[6] The local area NPL network followed by the wide-area ARPANET in the United States were the first two computer networks that implemented packet switching.[27][28] The network later used high-speed links, the first computer network to do so.[29][30] The Mark II version operated from 1973.[6][31]

The NPL team also carried out simulation work on the performance of wide-area packet networks, studying datagrams and network congestion.[6][32][33]

The NPL network was later interconnected with other networks, including the Post Office

European Informatics Network (EIN) in 1976.[6]

In 1976, 12 computers and 75 terminal devices were attached,[34] and more were added. The network remained in operation until 1986.[35]

Alongside Donald Davies, the NPL team included Derek Barber, Roger Scantlebury, Peter Wilkinson, Keith Bartlett, and Brian Aldous.[36][29][37]

Protocol development

NPL network model

The first use of the term protocol in a modern data-commutations context occurs in a memorandum entitled A Protocol for Use in the NPL Data Communications Network written by Roger Scantlebury and Keith Bartlett in April 1967.[29][38][39] A further publication by Bartlett in 1968 introduced the concept of an alternating bit protocol (later used by the ARPANET and the EIN)[40][41] and described the need for three levels of data transmission (roughly corresponding to the lower levels of the seven-layer OSI model that emerged a decade later). The Mark II version, which operated from 1973, used such a "layered" protocol architecture. The NPL team also introduced the idea of "protocol verification".[29]

Internetworking

The NPL network was a testbed for

International Networking Working Group (INWG) formed in 1972. Vint Cerf and Bob Kahn acknowledged Davies and Scantlebury in their 1974 paper A Protocol for Packet Network Intercommunication, which DARPA developed into the Internet protocol suite used in the modern Internet.[42]

Derek Barber was appointed director of the European COST 11 project played a leading part in proposing the

European Informatics Network (EIN) and led the project while Scantlebury led the UK technical contribution.[29][43][44][45] The EIN protocol helped to launch the INWG work,[41][46] which proposed an international end to end protocol in 1975, although this was not widely adopted.[47][48][49][50]

NPL investigated the "basic dilemma" involved in internetworking; that is, a common host protocol would require restructuring existing networks if they were not designed to use the same protocol. NPL connected with the European Informatics Network by translating between two different host protocols while the NPL connection to the Post Office Experimental Packet Switched Service used a common host protocol in both networks. This work confirmed establishing a common host protocol would be more reliable and efficient.[51]

Davies and Barber published Communication networks for computers in 1973 and Computer networks and their protocols in 1979.[52][53][54] They spoke at the Data Communications Symposium in 1975 about the "battle for access standards" between datagrams and virtual circuits, with Barber saying the "lack of standard access interfaces for emerging public packet-switched communication networks is creating 'some kind of monster' for users".[55] For a long period of time, the network engineering community was polarized over the implementation of competing protocol suites, commonly known as the Protocol Wars. It was unclear which type of protocol would result in the best and most robust computer networks.[56]

Network security

Davies' later research at NPL focused on data security for computer networks.[57]

Legacy

The concept of packet switching developed at the NPL became the primary means of data communication in modern computer networks including the Internet.[4][58][59][60]

NPL sponsors a gallery, opened in 2009, about the "Technology of the Internet" at The National Museum of Computing at Bletchley Park.[37]

See also

References

  1. ISBN 978-0-901805-94-2
    .
  2. ^ Pelkey, James (2007), "NPL Network and Donald Davies 1966 - 1971", Entrepreneurial Capitalism and Innovation: A History of Computer Communications 1968-1988, retrieved 13 April 2016
  3. ^ Roberts, Dr. Lawrence G. (May 1995). "The ARPANET & Computer Networks". Archived from the original on 24 March 2016. Retrieved 13 April 2016. 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.
  4. ^
    ISBN 978-0-901805-94-2
    .
  5. S2CID 26876676
    . Both Paul Baran and Donald Davies in their original papers anticipated the use of T1 trunks
  6. ^
    ISBN 9781135455514
    . Retrieved 15 August 2015.
  7. ^ A History of the ARPANET: The First Decade (PDF) (Report). Bolt, Beranek & Newman Inc. 1 April 1981. pp. 53 of 183 (III-11 on the printed copy). Archived from the original on 1 December 2012.
  8. ISBN 978-0521766456
    . Retrieved 16 August 2015.
  9. ^ "Oral-History:Donald Davies & Derek Barber". Retrieved 13 April 2016. the ARPA network is being implemented using existing telegraphic techniques simply because the type of network we describe does not exist. It appears that the ideas in the NPL paper at this moment are more advanced than any proposed in the USA
  10. ISBN 978-1474602778
    . 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.
  11. ISSN 0958-7403
    . Retrieved 6 September 2017. 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.
  12. ISBN 1134766327
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  13. ^ Scantlebury, Roger (25 June 2013). "Internet pioneers airbrushed from history". The Guardian. Retrieved 1 August 2015.
  14. ^ Harris, Trevor, Who is the Father of the Internet? The case for Donald Watts Davies, p. 6, retrieved 10 July 2013
  15. ^ "The accelerator of the modern age". BBC News. 5 August 2008. Retrieved 19 May 2009.
  16. ^ "Computer Pioneers - Donald W. Davies". IEEE Computer Society. Retrieved 20 February 2020. In 1965, Davies pioneered new concepts for computer communications in a form to which he gave the name "packet switching." ... The design of the ARPA network (ArpaNet) was entirely changed to adopt this technique.; "A Flaw In The Design". The Washington Post. 30 May 2015. The Internet was born of a big idea: Messages could be chopped into chunks, sent through a network in a series of transmissions, then reassembled by destination computers quickly and efficiently. Historians credit seminal insights to Welsh scientist Donald W. Davies and American engineer Paul Baran. ... The most important institutional force ... was the Pentagon's Advanced Research Projects Agency (ARPA) ... as ARPA began work on a groundbreaking computer network, the agency recruited scientists affiliated with the nation's top universities.
  17. ISBN 0192862073
    .
  18. ISBN 0824729005
    . Although there was considerable technical interchange between the NPL group and those who designed and implemented the ARPANET, the NPL Data Network effort appears to have had little fundamental impact on the design of ARPANET. Such major aspects of the NPL Data Network design as the standard network interface, the routing algorithm, and the software structure of the switching node were largely ignored by the ARPANET designers. There is no doubt, however, that in many less fundamental ways the NPL Data Network had and effect on the design and evolution of the ARPANET.
  19. ISBN 978-0-08-051319-5
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  20. ISBN 0262261332
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  21. ^ Roberts, Dr. Lawrence G. (May 1995). "The ARPANET & Computer Networks". Archived from the original on 14 February 2019. Retrieved 16 June 2019.
  22. ^ Roberts, Dr. Lawrence G. (November 1978). "The Evolution of Packet Switching" (PDF). IEEE Invited Paper. Retrieved 10 September 2017. In nearly all respects, Davies' original proposal, developed in late 1965, was similar to the actual networks being built today.
  23. ^ Pelkey, James. "8.3 CYCLADES Network and Louis Pouzin 1971–1972". Entrepreneurial Capitalism and Innovation: A History of Computer Communications 1968–1988.
  24. ^ Scantlebury, R. A.; Wilkinson, P.T. (1974). "The National Physical Laboratory Data Communications Network". Proceedings of the 2nd ICCC 74. pp. 223–228.
  25. ^ Haughney Dare-Bryan, Christine (22 June 2023). Computer Freaks (Podcast). Chapter Two: In the Air. Inc. Magazine. 35:55 minutes in. Leonard Kleinrock: Donald Davies ... did make a single node packet switch before ARPA did
  26. S2CID 25341056
    . 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.
  27. ^ "Donald Davies". internethalloffame.org; "Donald Davies". thocp.net. Archived from the original on 5 November 2020. Retrieved 9 April 2016.
  28. ^ Roberts, Lawrence G. (November 1978). "The Evolution of Packet Switching". Archived from the original on 24 March 2016. Retrieved 9 April 2016.
  29. ^
    S2CID 8172150
    . the first occurrence in print of the term protocol in a data communications context ... the next hardware tasks were the detailed design of the interface between the terminal devices and the switching computer, and the arrangements to secure reliable transmission of packets of data over the high-speed lines
  30. ISSN 0261-3077
    . Retrieved 31 July 2020. This was the first digital local network in the world to use packet switching and high-speed links.
  31. ISBN 978-0521766456
    . Retrieved 16 August 2015.(source: Roger Scantlebury - p.201)
  32. ISSN 0958-7403
    .
  33. ^ Pelkey, James. "6.3 CYCLADES Network and Louis Pouzin 1971-1972". Entrepreneurial Capitalism and Innovation: A History of Computer Communications 1968-1988.
  34. ^ "The National Physical Laboratory Data Communications Netowrk". 1974. Retrieved 5 September 2017.
  35. S2CID 8172150
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  36. ISSN 0958-7403
    . Retrieved 6 September 2017.
  37. ^ a b "Technology of the Internet". The National Museum of Computing. Retrieved 3 October 2017.
  38. ISBN 978-1-4746-0277-8
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  39. ^ Pelkey, James L. "6.1 The Communications Subnet: BBN 1969". Entrepreneurial Capitalism and Innovation: A History of Computer Communications 1968–1988. As Kahn recalls: ... Paul Baran's contributions ... 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.
  40. ^ "ARPANET is now 50 years old | Inria". www.inria.fr. 22 October 2019. Retrieved 10 November 2022.
  41. ^
    ISBN 9780471997504
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  42. ISSN 1558-0857
    . 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.
  43. S2CID 28994436
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  44. ISBN 978-1-4831-6093-1
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  45. ^ "EIN (European Informatics Network)". Computer History Museum. Retrieved 5 February 2020.
  46. ISBN 978-3-540-00559-9
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  47. S2CID 206443072
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  48. S2CID 36954091
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  49. ^ Scantlebury, Roger (25 June 2013). "Internet pioneers airbrushed from history". The Guardian. Retrieved 1 August 2015.
  50. ^ Scantlebury, Roger (8 January 2010). "How we nearly invented the internet in the UK". New Scientist. Retrieved 7 February 2020.
  51. ISBN 978-0-262-51115-5
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  52. ^ "Donald Davies". thocp.net. Archived from the original on 5 November 2020. Retrieved 29 August 2012; "Donald Davies". internethalloffame.org.
  53. ISBN 9780471198741
  54. ISBN 9780471997504
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  55. ^ Frank, Ronald A. (22 October 1975). "Battle for Access Standards Has Two Sides". Computerworld. IDG Enterprise: 17–18.
  56. ISBN 978-3-527-32710-2
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  57. ISBN 978-0471921370
  58. ^ "Alan Turing and the Ace computer". BBC. 5 February 2010. Retrieved 13 February 2024.
  59. ^ "How the Brits invented packet switching and made the internet possible". www.computerweekly.com. Archived from the original on 31 August 2012. Retrieved 13 February 2024.
  60. ^ "The British invented much of the Internet". ZDNET. Retrieved 13 February 2024.

Further reading

Primary sources

External links

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