NPL network

The NPL Network or NPL Data Communications Network was a local area computer network operated by a team from the National Physical Laboratory in England that pioneered the concept of packet switching. Following a pilot experiment during 1967, elements of the first version of the network, Mark I, became operational during 1969 then fully operational in 1970, and the Mark II version operated from 1973 until 1986. The NPL network, followed by the wide area ARPANET in the United States, were the first two computer networks that implemented packet switching, and were interconnected in the early 1970s. The NPL network was designed and directed by Donald Davies.


In 1965, Donald Davies, who was later appointed to head of the NPL Division of Computer Science, proposed a national data network based on packet switching in Proposal for the Development of a National Communications Service for On-line Data Processing. After the proposal was not taken up nationally, during 1966 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.[1] The design was the first to describe the concept of an "Interface computer", today known as a router.[2]

The next year (1967) a written version of the proposal entitled NPL Data Network was presented by Roger Scantlebury at a conference at Gatlinburg of the proceedings of the Association for Computing Machinery, which described how equipment (nodes) used to transmit signals (packets) would be connected by electrical links to re-transmit the signals between and to the nodes, and interface computers would be used to link node networks to so-called time-sharing computers and other users. The interface computers would transmit multiplex signals between networks, and nodes would switch transmissions while connected to electrical circuitry functioning at a rate of processing amounting to mega-bits.[3][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][12][13]

Packet switching

The first theoretical foundation of packet switching was the work of Paul Baran, in which data was transmitted in small chunks and routed independently by a method similar to store-and-forward techniques between intermediate networking nodes. Davies independently arrived at the same model in 1965 and named it packet switching.[14][15] He chose the term "packet" after consulting with an NPL linguist because it was capable of being translated into languages other than English without compromise.[16] Packet switching was used to produce an experimental network using a Honeywell 516 node. According to Zakon, NPL under Davies was the earliest organisation that created a packet switching network.[3][17][9][18]


Following a pilot experiment during 1967,[19][20][21][22] Davies gave the first public demonstration of packet switching on 5 August 1968.[23] Elements of the first version of the network, Mark I, became operational during 1969 then fully operational in 1970, and the Mark II version operated from 1973.[3][4][24] The NPL team also carried out simulation work on the performance of packet networks.[25] The local area NPL network, followed by wide area ARPANET in the United States, were the first two computer networks that implemented packet switching.[26][27]

The NPL network was later interconnected with other networks, including the ARPANET in 1973.[3][28] The NPL network used a line speed of 768 kbit/s in 1967.[21][22] Influenced by this, the proposed line speed for ARPANET was upgraded from 2.4 kbit/s to 50 kbit/s and a similar packet format adopted.[29][30][31] In 1976, 12 computers and 75 terminal devices were attached,[32] and more were added. The network remained in operation until 1986, influencing other research in the UK and Europe.[33][25] Alongside Donald Davies, the NPL team included Derek Barber, Roger Scantlebury, Peter Wilkinson, Keith Bartlett, and Brian Aldous.[34]

See also


  1. ^ 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
  2. ^ Roberts, Dr. Lawrence G. (May 1995). "The ARPANET & Computer Networks". 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.
  3. ^ a b c d Hempstead, C.; Worthington, W., eds. (8 August 2005). Encyclopedia of 20th-Century Technology. Routledge. Retrieved 2015-08-15.
  4. ^ a b A Hey, G Pápay (8 December 2014). The Computing Universe: A Journey through a Revolution. Cambridge University Press. ISBN 0521766451. Retrieved 2015-08-16.(source: Roger Scantlebury - p.201)
  5. ^ B. Steil, Council on Foreign Relations (1 January 2002). Technological Innovation and Economic Performance. Princeton University Press. ISBN 0691090912. Retrieved 2015-08-15.
  6. ^ Oxford Dictionaries - word definition - relay & word definition - node published by Oxford University Press [Retrieved 2015-08-16]
  7. ^ J. Everard - STATES (p.14) published by Routledge 28 Feb 2013 (reprint), 176 pages, ISBN 1134692757 [Retrieved 2015-08-16]
  8. ^ F.E. Froehlich, A. Kent (14 November 1990). The Froehlich/Kent Encyclopedia of Telecommunications: Volume 1 - Access Charges in the U.S.A. to Basics of Digital Communications. CRC Press. p. 344. ISBN 0824729005., Volume 1 of Encyclopedia of Telecommunications|accessdate=2015-08-16}}
  9. ^ a b J. Gillies, R. Cailliau (2000). How the Web was Born: The Story of the World Wide Web. Oxford University Press. pp. 23–25. ISBN 0192862073.
  10. ^ "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
  11. ^ Naughton, John (2015). "8 Packet post". A Brief History of the Future: The origins of the Internet. Hachette UK. ISBN 1474602770. 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.
  12. ^ Barber, Derek (Spring 1993). "The Origins of Packet Switching". The Bulletin of the Computer Conservation Society (5). 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.
  13. ^ Abbate, Jane (2000). Inventing the Internet. MIT Press. p. 37. ISBN 0262261332. Although he was aware of the concept of packet switching, Roberts was not sure how to implement it in a large network.
  14. ^ Scantlebury, Roger (25 June 2013). "Internet pioneers airbrushed from history". The Guardian. Retrieved 1 August 2015.
  15. ^ "Packets of data were the key...". NPL. Retrieved 1 August 2015.
  16. ^ Harris, Trevor, Who is the Father of the Internet? The case for Donald Watts Davies, p. 6, retrieved 10 July 2013
  17. ^ T. Vickers (14 April 2005). Copeland, B. J., ed. Alan Turing's Automatic Computing Engine: The Master Codebreaker's Struggle to Build the Modern Computer. Oxford University Press. ISBN 0191625868. Retrieved 2015-08-15.
  18. ^ R.H. Zakon. Bidgoli, H., ed. The Internet Encyclopedia, G – O. published by John Wiley & Sons 2004, 840 pages,. ISBN 0471689963. Retrieved 2015-08-16.
  19. ^ Elliott, Geoffrey (2004). Global business information technology : an integrated systems approach. Financial Times Prentice Hall. p. 425. ISBN 9780321270122.
  20. ^ Winston, Brian (2002). Media,Technology and Society: A History: From the Telegraph to the Internet. Routledge. p. 327. ISBN 1134766327.
  21. ^ a b K.G. Coffman & A.M. Odlyzco. Optical Fiber Telecommunications IV-B: Systems and Impairments. published by Academic Press 22 May 2002, 1022 pages, Optics and Photonics, ISBN 0080513190, (edited by I. Kaminow & T. Li). Retrieved 2015-08-15. templatestyles stripmarker in |publisher= at position 84 (help)
  22. ^ a b "The History of the Internet". The History of Computing Project. 19 March 2001. Retrieved 13 April 2016.
  23. ^ "The accelerator of the modern age". BBC News. 5 August 2008. Retrieved 19 May 2009.
  24. ^ "UK National Physical Laboratory (NPL) & Donald Davies". Living Internet. Retrieved 13 April 2016.
  25. ^ a b C. Hempstead; W. Worthington (2005). Encyclopedia of 20th-Century Technology. Routledge.
  26. ^ Roberts, Lawrence G. (November 1978). "The Evolution of Packet Switching". Retrieved 9 April 2016.
  27. ^ "Donald Davies".; "Donald Davies".
  28. ^ M. Ziewitz & I. Brown (2013). Research Handbook on Governance of the Internet. Edward Elgar Publishing. p. 7. ISBN 1849805040. Retrieved 2015-08-16.
  29. ^ Abbate, Jane (2000). Inventing the Internet. MIT Press. p. 38. ISBN 0262261332.
  30. ^ "Brief History of the Internet". Internet Society. Retrieved April 9, 2016.
  31. ^ Roberts, Dr. Lawrence G. (May 1995). "The ARPANET & Computer Networks". Retrieved 13 April 2016.
  32. ^ "The National Physical Laboratory Data Communications Netowrk". 1974. Retrieved 5 September 2017.
  33. ^ Packet Switching
  34. ^ "Technology of the Internet". The National Museum of Computing. Retrieved 3 October 2017.

Further reading

External links


The Advanced Research Projects Agency Network (ARPANET) was an early packet-switching network and the first network to implement the TCP/IP protocol suite. Both technologies became the technical foundation of the Internet. The ARPANET was initially founded by the Advanced Research Projects Agency (ARPA) of the United States Department of Defense.The packet-switching methodology employed in the ARPANET was based on concepts and designs by Leonard Kleinrock, Paul Baran, Donald Davies, and Lawrence Roberts. The TCP/IP communications protocols were developed for the ARPANET by computer scientists Robert Kahn and Vint Cerf, and incorporated concepts from the French CYCLADES project directed by Louis Pouzin.

As the project progressed, protocols for internetworking were developed by which multiple separate networks could be joined into a network of networks. Access to the ARPANET was expanded in 1981, when the National Science Foundation (NSF) funded the Computer Science Network (CSNET). In 1982, the Internet protocol suite (TCP/IP) was introduced as the standard networking protocol on the ARPANET. In the early 1980s the NSF funded the establishment of national supercomputing centers at several universities and provided interconnectivity in 1986 with the NSFNET project, which also created network access to the supercomputer sites in the United States from research and education organizations. The ARPANET was decommissioned in 1989.

BBN Technologies

BBN Technologies (originally Bolt, Beranek and Newman) is an American high-technology company that provides research and development services. BBN is based next to Fresh Pond in Cambridge, Massachusetts, United States. It is a military contractor, primarily for DARPA, and also known for its 1978 acoustical analysis for the House Select Committee on the assassination of John F. Kennedy. BBN of the 1950s and 1960s has been referred to by two of its alumni as the "third university" of Cambridge, after MIT and Harvard. In 1966, the Franklin Institute awarded the firm the Frank P. Brown Medal.

Ray Tomlinson of BBN is widely credited as having invented email in 1971. BBN registered the domain on April 24, 1985, making it the second oldest domain name on the internet. BBN became a wholly owned subsidiary of Raytheon in 2009. On February 1, 2013, BBN was awarded the National Medal of Technology and Innovation.


The CYCLADES computer network (French pronunciation: ​[siklad]) was a French research network created in the early 1970s. It was one of the pioneering networks experimenting with the concept of packet switching, and was developed to explore alternatives to the ARPANET design. The network supported general local network research.The CYCLADES network was the first to make the hosts responsible for the reliable delivery of data, rather than this being a centralized service of the network itself. Datagrams were exchanged on the network using transport protocols that do not guarantee reliable delivery, but only attempt best-effort. To empower the network leaves, the hosts, to perform error-correction, the network ensured end-to-end protocol transparency, a concept later to be known as the end-to-end principle. This simplified network design, reduced network latency, and reduced the opportunities for single point failures. The experience with these concepts led to the design of key features of the Internet protocol in the ARPANET project.The network was sponsored by the French government, through the Institut de Recherche en lnformatique et en Automatique (IRIA), the national research laboratory for computer science in France, now known as INRIA, which served as the co-ordinating agency. Several French computer manufacturers, research institutes and universities contributed to the effort. CYCLADES was designed and directed by Louis Pouzin.

Communications receiver

A communications receiver is a type of radio receiver used as a component of a radio communication link. This is in contrast to a broadcast receiver which is used to receive radio broadcasts. A communication receiver receives parts of the radio spectrum not used for broadcasting, that includes amateur, military, aircraft, marine, and other bands. They are often used with a radio transmitter as part of a two way radio link for shortwave radio or amateur radio communication, although they are also used for shortwave listening.

Core router

A core router is a router designed to operate in the Internet backbone, or core. To fulfill this role, a router must be able to support multiple telecommunications interfaces of the highest speed in use in the core Internet and must be able to forward IP packets at full speed on all of them. It must also support the routing protocols being used in the core. A core router is distinct from an edge router: edge routers sit at the edge of a backbone network and connect to core routers.

Donald Davies

Donald Watts Davies, (7 June 1924 – 28 May 2000) was a Welsh computer scientist who was employed at the UK National Physical Laboratory (NPL). In 1965 he developed the concept of packet switching, which is today the dominant basis for data communications in computer networks worldwide, and implemented it in the NPL network. This was independent of the work of Paul Baran in the United States who had a similar idea in the early 1960s. The ARPANET project, a precursor to the Internet, credited Davies for his influence.

Encyclopedia of Life

The Encyclopedia of Life (EOL) is a free, online collaborative encyclopedia intended to document all of the 1.9 million living species known to science. It is compiled from existing databases and from contributions by experts and non-experts throughout the world. It aims to build one "infinitely expandable" page for each species, including video, sound, images, graphics, as well as text. In addition, the Encyclopedia incorporates content from the Biodiversity Heritage Library, which digitizes millions of pages of printed literature from the world's major natural history libraries. The project was initially backed by a US$50 million funding commitment, led by the MacArthur Foundation and the Sloan Foundation, who provided US$20 million and US$5 million, respectively. The additional US$25 million came from five cornerstone institutions—the Field Museum, Harvard University, the Marine Biological Laboratory, the Missouri Botanical Garden, and the Smithsonian Institution. The project was initially led by Jim Edwards and the development team by David Patterson. Today, participating institutions and individual donors continue to support EOL through financial contributions.

Henry Sutton (inventor)

Henry Sutton (4 September 1855, Ballarat, Victoria – 28 July 1912) was an Australian designer, engineer, and inventor credited with contributions to early developments in electricity, aviation, wireless communication, photography and telephony.

History of the Internet

The history of the Internet begins with the development of electronic computers in the 1950s. Initial concepts of wide area networking originated in several computer science laboratories in the United States, United Kingdom, and France. The U.S. Department of Defense awarded contracts as early as the 1960s, including for the development of the ARPANET project, directed by Robert Taylor and managed by Lawrence Roberts. The first message was sent over the ARPANET in 1969 from computer science Professor Leonard Kleinrock's laboratory at University of California, Los Angeles (UCLA) to the second network node at Stanford Research Institute (SRI).

Packet switching networks such as the NPL network, ARPANET, Merit Network, CYCLADES, and Telenet, were developed in the late 1960s and early 1970s using a variety of communications protocols. Donald Davies first demonstrated packet switching in 1967 at the National Physics Laboratory (NPL) in the UK, which became a testbed for UK research for almost two decades. The ARPANET project led to the development of protocols for internetworking, in which multiple separate networks could be joined into a network of networks.

The Internet protocol suite (TCP/IP) was developed by Robert E. Kahn and Vint Cerf in the 1970s and became the standard networking protocol on the ARPANET, incorporating concepts from the French CYCLADES project directed by Louis Pouzin. In the early 1980s the NSF funded the establishment for national supercomputing centers at several universities, and provided interconnectivity in 1986 with the NSFNET project, which also created network access to the supercomputer sites in the United States from research and education organizations. Commercial Internet service providers (ISPs) began to emerge in the very late 1980s. The ARPANET was decommissioned in 1990. Limited private connections to parts of the Internet by officially commercial entities emerged in several American cities by late 1989 and 1990, and the NSFNET was decommissioned in 1995, removing the last restrictions on the use of the Internet to carry commercial traffic.

In the 1980s, research at CERN in Switzerland by British computer scientist Tim Berners-Lee resulted in the World Wide Web, linking hypertext documents into an information system, accessible from any node on the network. Since the mid-1990s, the Internet has had a revolutionary impact on culture, commerce, and technology, including the rise of near-instant communication by electronic mail, instant messaging, voice over Internet Protocol (VoIP) telephone calls, two-way interactive video calls, and the World Wide Web with its discussion forums, blogs, social networking, and online shopping sites. The research and education community continues to develop and use advanced networks such as JANET in the United Kingdom and Internet2 in the United States. Increasing amounts of data are transmitted at higher and higher speeds over fiber optic networks operating at 1 Gbit/s, 10 Gbit/s, or more. The Internet's takeover of the global communication landscape was almost instant in historical terms: it only communicated 1% of the information flowing through two-way telecommunications networks in the year 1993, already 51% by 2000, and more than 97% of the telecommunicated information by 2007. Today the Internet continues to grow, driven by ever greater amounts of online information, commerce, entertainment, and social networking. However, the future of the global internet may be shaped by regional differences in the world.

Interface Message Processor

The Interface Message Processor (IMP) was the packet switching node used to interconnect participant networks to the ARPANET from the late 1960s to 1989. It was the first generation of gateways, which are known today as routers. An IMP was a ruggedized Honeywell DDP-516 minicomputer with special-purpose interfaces and software. In later years the IMPs were made from the non-ruggedized Honeywell 316 which could handle two-thirds of the communication traffic at approximately one-half the cost. An IMP requires the connection to a host computer via a special bit-serial interface, defined in BBN Report 1822. The IMP software and the ARPA network communications protocol running on the IMPs was discussed in RFC 1, the first of a series of standardization documents published by the Internet Engineering Task Force (IETF).

Internet backbone

The Internet backbone may be defined by the principal data routes between large, strategically interconnected computer networks and core routers on the Internet.

These data routes are hosted by commercial, government, academic and other high-capacity network centers, the Internet exchange points and network access points, that exchange Internet traffic between the countries, continents and across the oceans. Internet service providers, often Tier 1 networks, participate in Internet backbone traffic by privately negotiated interconnection agreements, primarily governed by the principle of settlement-free peering.

The Internet, and consequently its backbone networks, do not rely on central control or coordinating facilities, nor do they implement any global network policies. The resilience of the Internet results from its principal architectural features, most notably the idea of placing as few network state and control functions as possible in the network elements, and instead relying on the endpoints of communication to handle most of the processing to ensure data integrity, reliability, and authentication. In addition, the high degree of redundancy of today's network links and sophisticated real-time routing protocols provide alternate paths of communications for load balancing and congestion avoidance.

The largest providers, known as tier 1 providers, have such comprehensive networks that they never purchase transit agreements from other providers. As of 2016 there were six tier 1 providers in the telecommunications industry. Current Tier 1 carriers include CenturyLink (Level 3), Telia Carrier, NTT, GTT, Tata Communications, and Telecom Italia.

List of military inventions

A military invention is an invention that was first created by a military. There are many inventions that were originally created by the military and subsequently found civilian uses.

List of the oldest currently registered Internet domain names

This is a list of the oldest extant registered generic top-level domains used in the Domain Name System of the Internet.


In telecommunications and computer networks, multiplexing (sometimes contracted to muxing) is a method by which multiple analog or digital signals are combined into one signal over a shared medium. The aim is to share a scarce resource. For example, in telecommunications, several telephone calls may be carried using one wire. Multiplexing originated in telegraphy in the 1870s, and is now widely applied in communications. In telephony, George Owen Squier is credited with the development of telephone carrier multiplexing in 1910.

The multiplexed signal is transmitted over a communication channel such as a cable. The multiplexing divides the capacity of the communication channel into several logical channels, one for each message signal or data stream to be transferred. A reverse process, known as demultiplexing, extracts the original channels on the receiver end.

A device that performs the multiplexing is called a multiplexer (MUX), and a device that performs the reverse process is called a demultiplexer (DEMUX or DMX).

Inverse multiplexing (IMUX) has the opposite aim as multiplexing, namely to break one data stream into several streams, transfer them simultaneously over several communication channels, and recreate the original data stream.

Nepal Telecom

Nepal Doorsanchar Company Ltd. (Nepali: नेपाल दूरसञ्चार कम्पनी लिमिटेड), popularly known as Nepal Telecom (Nepali: नेपाल टेलिकम) is state owned telecommunication service provider in Nepal with 91.49% of the government share. The company was a monopoly until 2003, when the first private sector operator United Telecom Limited(UTL) started providing basic telephony services. The central office of Nepal Telecom is located at Bhadrakali Plaza, Kathmandu. It has branches, exchanges and other offices in 184 locations within the country.

It is the sole provider of fixed line, ISDN and leased-line services in Nepal. Following the entry of Ncell (previously called Mero Mobile) into Nepal's telecommunications industry in 2005, it is no longer the only provider of GSM mobile service. With more than 5,400 employees, it is one of the largest corporations of Nepal. It has a total of 262 telephone exchanges in various parts of the country serving 603,291 PSTN lines, more than 5 million GSM cellular phones and more than a million CDMA phone line as of July 2011. According to recent data, there are about 10 million users of Nepal Telecom including all those of fixed landline, GSM mobile, CDMA and internet service. Nepal Telecom Launched 4G LTE Service on 1 January 2017. It is the first operator to provide 4G LTE service in Nepal on technology neutral frequency band of 1800 MHz as standard for 4G in Nepal.till the date 4G is only available in kathmandu and pokhara Network information

Outline of the Internet

The following outline is provided as an overview of and topical guide to the Internet.

Internet – worldwide, publicly accessible network of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol (IP). It is a "network of networks" that consists of millions of interconnected smaller domestic, academic, business, and government networks, which together carry various information and services, such as electronic mail, online chat, file transfer, and the interlinked Web pages and other documents of the World Wide Web.

It allows other services

Router (computing)

A router is a networking device that forwards data packets between computer networks. Routers perform the traffic directing functions on the Internet. Data sent through the internet, such as a web page or email, is in the form of data packets. A packet is typically forwarded from one router to another router through the networks that constitute an internetwork until it reaches its destination node.A router is connected to two or more data lines from different networks. When a data packet comes in on one of the lines, the router reads the network address information in the packet to determine the ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey.

The most familiar type of routers are home and small office routers that simply forward IP packets between the home computers and the Internet. An example of a router would be the owner's cable or DSL router, which connects to the Internet through an Internet service provider (ISP). More sophisticated routers, such as enterprise routers, connect large business or ISP networks up to the powerful core routers that forward data at high speed along the optical fiber lines of the Internet backbone. Though routers are typically dedicated hardware devices, software-based routers also exist.

Voice of Russia

The Voice of Russia (Russian: Голос России, tr. Golos Rossii), commonly abbreviated VOR, was the Russian government's international radio broadcasting service from 1993 until 2014, when it was reorganised as Radio Sputnik. Its interval signal was a chime version of 'Majestic' chorus from the Great Gate of Kiev portion of Pictures at an Exhibition by Mussorgsky.

Network topology
and switching

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