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Home , Cable modem, Donald Davies, Micronet 800, Openreach, Packet switching, Prestel

Professor Nigel Linge

FROM TO THE CLOUD

Telecommunication engineers have always drawn a picture of a cloud to represent a network. Today, however, the cloud has taken on a new meaning, where IT becomes a utility, accessed and used in exactly the same on-demand way as we connect to the National Grid for electricity. Yet, only 50 years ago, this vision of universal access to an all- encompassing and powerful network would have been seen as nothing more than fanciful science fiction.

he first electronic, digital, network - a figure that represented a concept of packet switching in which stored-program 230% increase on the previous year. data is assembled into a short se- was built in 1948 and This clear and growing demand for quence of data bits (a packet) which heralded the dawning of data services resulted in the GPO com- includes an address to tell the network a new age. missioning in July 1970 an experi- where the data is to be sent, error de- T mental, manual call-set-up, data net- tection to allow the receiver to confirm DATA COMMUNICATIONS 1 work that used operating at that the contents of the packet are cor- These early were large, 48,000bit/s (48kbit/s). rect and a source address to facilitate cumbersome and expensive machines However, computer communica- a reply. and inevitably a need arose for a com- tions is different to voice communi- Since each packet is self-contained, munication system that would allow cations not only in its form but also any number of them can be transmit- shared remote access to them. its nature. Whereas a voice call has a ted over the same physical network, An obvious candidate for such a clearly defined beginning and end with one after the other, with each poten- system was the national a reasonably continuous transfer of in- tially representing a totally different network but that had been designed formation in between, remote access and separate communication. In the and optimised for the transmission of to a computer is a much more sporadic USA these concepts were taken for- the human voice and not the digital bi- form of communication. Therefore ty- ward by the Advanced Research Proj- nary digits used by computers. Conse- ing up a telephone line continuously ect Agency (ARPA), which, under the quently, the Modulator/Demodulator between a user and computer is an un- guidance of Larry Roberts, developed or was designed to convert the necessary waste of resources because, its ARPAnet network for linking com- computer's data bits into that for much of the time, no data is being puters in North America. The first could be accepted and transmitted by sent. four computers were connected to the the . The Datel Mo- An alternative approach was need- ARPAnet in December 1969 and by dem No. 1A became available within ed and both at the Na- 1970 the network was extended inter- the UK in 1964 and was capable of tional Physical Laboratory (NPL) in nationally with a satellite link to the transmitting data at a rate of 200 bits the UK and Paul Baron at the RAND Goonhilly earth station in Cornwall per second (bit/s). Corporation in the USA were working and from there via undersea cable to By March 1969, the GPO reported on precisely that. In the mid-1960s the NORSAR seismic research facility that 3,334 modems were in use on its they both independently invented the in Kjeller, Norway. Meanwhile back

#% !!" !! 9ROXPH3DUW‡ #$%!&'()*+,!'-!#$%!.*/#.#(#%!'-!#%,%0'11(*.0+#.'*/!2)'-%//.'*+,/ in the UK, Donald Davies and his team built the NPL Network, which became operational in July 1971 as the world's first packet switching . Connecting the UK to ARPAnet was achieved on 25 July 1973 when, under the direction of Professor Peter Kirstein of University College , the first data packets were exchanged between University College London and the Information Sciences Institute in Cali- fornia. Whilst this connection used a satellite link operating at 9.6kbit/s, it was actually routed via Kjeller in Nor- The cloud has seen IT become a utility, accessed way where a new earth station had and used in exactly the same on-demand way as we been commissioned that removed the connect to the National Grid for electricity. necessity to use Goonhilly. On the 14 November 1973 the first full public demonstration of ARPAnet in the UK networks called X.75. published their Transmission Control was provided by Professor Kirstein The X.75-based International Protocol and Protocol (TCP/ when he delivered a lecture to the In- Packet Switch Stream (IPSS) Service IP) suite. On 1 January 1983, ARPA- stitution of Electrical Engineers. Also opened in 1978 with an international net adopted TCP/IP as its standard in 1973, was work- exchange located in London and links protocols and in 1991 the ARPAnet ing at PARC when he invented to data networks in the USA, Canada, morphed into the Internet. a local area packet-switched network Japan and into Europe via Euronet. On called . Standardised as IEEE 20 August 1981 the UK, X.25-based, HOME AND OFFICE 802.3 in 1983 and IEEE 802.11 (WiFi) Packet Switch Stream (PSS) service COMPUTING in 1999, Ethernet has become the was opened with switching exchanges These early data networks were used dominant local area network technol- designed using the TP4000 by companies for business processing ogy with a multi-billion dollar global processors and built by Plessey Con- applications and by the research com- market. trols (Poole). By 1983 customers were munity for remote access to mainframe The work on packet switching at offered a fully digital interface with the computing services. The concept of the NPL and ARPA naturally drew the launch by British using a network for information re- attention of the Post Office which, in (formerly Post Office Telecommunica- trieval purposes as we do today began 1977 establish its trial Experimental tions) of the KiloStream (64kbit/s) and to emerge with the launch of Packet Switching Service network. MegaStream (2Mbit/s) services. In services. Post Office Telecommuni- This network comprised three packet 1984 KiloStream was expanded to pro- cations launched the world's first pub- switching exchanges, designed us- vide International KiloStream facilitat- lic Viewdata service called in ing the 700E proces- ed by links provided through satellite March 1979. Customers were able to sor, located in London, Manchester earth stations at Goonhilly in Cornwall use their sets, linked via a (actually Dial House in Salford) and or Madley in Herefordshire. telephone, to access a central Informa- Glasgow with interconnecting links The development of X.25 was tion Retrieval Centre where data was running at 48kbit/s. Needless to say driven by the telecommunications organised into a series of information that at this time several other coun- companies (telcos) that were seeking pages. Prestel proved very successful tries were developing their own public to establish national public data net- with 80,000 user terminals connected data networks which created an in- works. However, telcos had a phi- by 1988 generating a total of 9.1 mil- centive to harmonise their respective losophy that the network service must lion accesses per week for pages of- designs towards a common network be inherently reliable which led to fered by 1,300 information providers. interface. Consequently, the Interna- the criticism that X.25 was inefficient One of the most popular services was tional Telegraph and Telephone Con- and too complex. A different school Prestel Travel and gateways offered sultative Committee, now the Inter- of thought in network design was access to a broader range of services national Telecommunications Union, emerging from the USA, not driven that included personal banking, train established Study Group VII for the by telcos but by computer scientists. timetables, stocks and shares trading, development of standards relating Their view was that the data network education and even a basic form of to data communications services. In did not need to be inherently reliable called Prestel Mailbox, which March 1976 it published its Orange providing that the computers using the was launched on 15 October 1984. books which included the specifica- service could detect and correct any Using the television as an access ter- tion of a standard for packet-switched packet errors that occurred in trans- minal for Prestel was logical because wide area networks called X.25 and mission. This work culminated in in the late 1970s domestic customers a standard for interconnecting such 1974 when Vinton Cerf and simply did not have a computer in

!9ROXPH3DUW‡ !! "!! #& THE INTERNET AND ACCESS way beyond the means of a domestic TO THE INTERNET customer. This led Cliff Stanford to The next important advance came in propose a new form of business that March 1989 when Sir Tim Berners- would act as the intermediary be- Lee published his now iconic paper tween the domestic user and the Inter- entitled, "Information Management: A net. He bought access to Proposal" [1], in which he proposed the Internet and then charged custom- an integration of hypertext with the ers a monthly subscription for which Internet to create what he termed the they could have dial-up access via his WorldWideWeb. Information coded company to the Internet. Demon In- as hypertext could be transmitted over ternet therefore became the UK's first the Internet using the hypertext trans- Internet Service Provider when it was By 1970 the network was extended fer protocol (http) and displayed on launched on 1 June 1992. internationally with a satellite link a computer using dedicated browser From the mid- onwards there to the Goonhilly earth station in software. Tim Berners-Lee created was a rapid growth in the number of Cornwall. his first web browser in November Internet users worldwide driven by the 1990 and the soft- expansion of available web content, their homes. This was of course set to ware was released onto the Internet improving modem technology, the change because of the invention of the in August 1991 thus transforming it declining price of owning a personal microprocessor, which now fuelled a from an obscure network into a valu- computer and easier-to-use graphical revolution in home computing. able source of information to which browser interfaces. On 29 January 1980, Sir Clive Sin- millions wanted access. By December A growing user community natu- clair launched the UK's first sub-£100 1992 there were 26 known web serv- rally drove the evolution of the web , the ZX80, which was ers on the Internet but within a year itself with websites becoming more followed on 5 March 1981 with the that number had increased to 200. To- sophisticated and multimedia rich. ZX81 and then on 23 April 1982 with day the total number of web servers is The move from Web 1.0 to Web 2.0 what became Britain's best selling probably unknown but in June 2008 saw the emergence of interaction and computer, the ZX Spectrum. Google reported that it had detected collaboration epitomised by the social Priced at between £125 and £175 over one trillion unique active web networking revolution and now Web the Spectrum became the computer page addresses. 3.0 is creating the intelligent web and of choice for teenagers keen on play- For the domestic customer, con- the Internet of Things concepts. How- ing games or becoming budding com- necting their computer to the outside ever, such developments could not puter programmers. The BBC Micro, world took on a new urgency. Unfor- have been realised had new access designed and built by Acorn Comput- tunately, because domestic technology not been created to replace ers was launched in December 1981 were permanently wired, early slow- the V.90 modem. and was rapidly adopted within UK speed modems had to use an acoustic On 22 March 1988 researchers schools and supported by learning coupler into which was plugged the working at Bell Communications Re- materials produced by the BBC. Con- handset of a conventional telephone. search, Inc (Bellcore) in the USA filed necting a home computer to the out- An important step that overcame a patent for Asymmetric Digital Sub- side world in the 1980s was of limited this limitation occurred on 19 No- scriber Line (ADSL). This technology but growing interest because of the vember 1981 when BT introduced its exploited the higher frequency car- success of services such as Prestel's plug and socket interface for the home rying capacity of the local loop cop- which allowed people to which meant that modems could now per cables to transmit computer data play online games, to download soft- have a direct electrical connection to above the voice band thus allowing ware, to post messages, to send and the telephone line. In 1988, ITU Rec- for a theoretical maximum download receive email and to publish pages in ommendations V.21 and V.23 extend- speed of 24Mbit/s with ADSL2+. BT a gallery area. Inevitably, this early ed modem speed to 1200bit/s. This launched its ADSL service in June 2000 and highly influential period in the de- was followed in 1991 with the V.32bis and an ADSL 2+ service in 2006. A velopment of the home computer was Recommendations which increased competitor local access technology is characterised by a range of incompat- speeds to 14.4kbit/s and then, on 25 the cable network that ible machines, the predominant use September 1998, modems reached was installed within the UK follow- of which was playing games. That their pinnacle of development with the ing the Cable and Act, changed when IBM launched its Per- release of the V.90 Recommendation 1984. Companies that were awarded sonal Computer on 12 August 1981. which offered a maximum download cable TV licences built new networks Originally intended for the profession- speed of 56kbit/s and a maximum up- based on a combination of optical fi- al market, this standardised hardware load speed of 33.6kbit/s. bre and coaxial copper cables, which design with its MS-DOS operating sys- Connecting a home computer to gave them an early technological ad- tem provided by Microsoft spawned a a modem and a telephone line was vantage over BT for the provision of series of compatible derivatives that nevertheless still only solving half the high speed . For ex- started to become affordable for the task because connection to the Inter- ample Nynex CableComms began a home user. net required a leased line and this was trial of technology on

#' !!" !! 9ROXPH3DUW‡ #$%!&'()*+,!'-!#$%!.*/#.#(#%!'-!#%,%0'11(*.0+#.'*/!2)'-%//.'*+,/ its Manchester network in 1996 that with its the began its Similarly the national telco-operated offered customers a download speed transformation into a pocket comput- networks are being refined and re- of 10Mbit/s and an upload speed of er. An early example was the Nokia modelled as packet-switched-only 768kbit/s. Through numerous merg- 9000 Communicator released in 1996 Next Generation Networks in which a ers, these companies were consolidat- that offered a handset that could be single infrastructure delivers all of our ed as in February 2007. opened to reveal a full computer key- services. Our thirst for speed is relentless, board, large screen and a set of stan- driving the need to replace the local dard office applications. FINALLY, THE CLOUD loop copper by fibre. Providing fi- In 1997, Nokia released the 7110 Perhaps surprisingly, as early as 1962, bre to every home in the country is which was the first mobile to allow Joseph Carl Robnett Licklider put for- currently prohibitively expensive but access to the web via a Ap- ward a vision of an intergalactic com- installing fibre from the exchange plication Protocol browser. It was Er- puter network. In many ways the building to the street cabinet is practi- icsson's R380 released in 2000 that is original ARPAnet and now the web are cal and this is the basis for the cur- now regarded as the first true smart- physical realisations of this vision but rent roll-out of super-fast phone which combined the function- it was not until 1999 that salesforce. services. ality of a mobile phone, personal or- com pioneered the concept of deliver- A new larger street cabinet needs ganiser, Wireless Application Protocol ing enterprise applications through a to be installed alongside the existing browser, email and SMS messaging. website. This was then followed in one to house the digital subscriber Then in 2007 Steve Jobs an- 2002 by Amazon Web Services that line access which is nounced that Apple was entering offered a suite of web-based services linked back to the equipment in the the mobile phone market. Apple's for storage and computation. These exchange building via a dedicated fi- iPhone has been a truly disruptive have subsequently been added to by bre. Hence, this fibre-to-the-cabinet technology that redefined the design Amazon's Elastic Compute Cloud and solution reduces the length of copper and functionality of the smart-phone. Google Apps that allow organisations in the data path and has the poten- A move from 2G to 2.5G (General to their applications within the tial to increase local loop download Packet Service) networks pro- web. speeds to 80Mbit/s. By the summer vided users with increased data carry- Today, the cloud is seen as some of 2012, was reporting that ing capacity by Internet access universal entity that can be accessed it has achieved 10 million homes with over a separate packet switched ser- as easily from home as it can on the its fibre-to-the-cabinet roll-out. vice. This was further enhanced with move. A UK Internet user will typical- the move to , and now service ly spend 90 minutes per week access- MOBILE COMPUTING eliminates circuit-switched voice to ing social networking sites and email In parallel with the technical advances provide a high speed mobile network () and over 50% of those users that brought the web into our homes that is completely packet-switched. will go online via their (Office for National Statistics). Un- FOOTNOTES derpinning all of this is the pioneering work and engineering achievement 1 A series of articles by Phil Kelly, “Computer Communications – the early that first brought us packet switching days 1966 – 1986”, were published in The Journal of the Institute of and which now has developed that Telecommunications Professionals, Vol 4 pt 4, Dec 2010, Vol 5 Pt 1, Mar technology to turn the cloud from a 2011 and Vol 5 Pt 2, Jun 2011 mere symbol into a global business that is expected to be worth $241 bil- lion by 2020. ABBREVIATIONS References ADSL Asymmetric ARPA Advanced Research Project Agency 1. Berners-Lee, T. Information NPL National Physical Laboratory Management: A Proposal. CERN, Mar 1989, May 1990.

ABOUT THE AUTHOR

Nigel Linge is Professor of Telecommunications at the University of Salford where he is responsible for teaching computer networking technologies at both undergraduate and postgraduate level and undertaking research into communication protocols, location- based services and the application of networks to energy monitoring. In addition, he has an active interest in the preservation and promotion of telecommunications heritage. He is a member of the ITP, Fellow of the IET and BCS, a CEng and CITP. NIGEL LINGE NIGEL

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