NPL network

Its original design, along with the innovations implemented in the ARPANET and the CYCLADES network, laid down the technical foundations of the modern Internet.

In 1965, Donald Davies, who was later appointed to head of the NPL Division of Computer Science, proposed a commercial national data network in the United Kingdom based on packet switching in Proposal for the Development of a National Communications Service for On-line Data Processing.

[1][2] The following year, he refined his ideas in Proposal for the Development of a National Communications Service for OnLine Data Processing.

[5] A written version of the proposal entitled A digital communications network for computers giving rapid response at remote terminals was presented by Roger Scantlebury at the Symposium on Operating Systems Principles in 1967.

[6][7][8][9] 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".

[10][11][12] The first theoretical foundation of packet switching was the work of Paul Baran, at RAND, in which data was transmitted in small chunks and routed independently by a method similar to store-and-forward techniques between intermediate networking nodes.

[16] 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.

Beginning in late 1966,[29] Davies' tasked Derek Barber, his deputy, to establish a team to build a local-area network to serve the needs of NPL and prove the feasibility of packet switching.

[34][35] The NPL team liaised with Honeywell in the adaptation of the DDP516 input/output controller,[29] and, the following year, the ARPANET chose the same computer to serve as Interface Message Processors (IMPs).

This work was carried out to investigate networks of a size capable of providing data communications facilities to most of the U.K.[7][28][53][54][55] Davies proposed an adaptive method of congestion control that he called isarithmic.

Davies, Scantlebury and Barber were active members of the International Network Working Group (INWG) formed in 1972.

[74][75][76] 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".

[81] The concepts of packet switching, high-speed routers, layered communication protocols, hierarchical computer networks, and the essence of the end-to-end principle that were researched and developed at the NPL became fundamental to data communication in modern computer networks including the Internet.

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