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A Technical History of National Physical Laboratories (NPL) Network Architecture

About NPL Architecture: Donald Davies and his colleagues at the UK National Physical Laboratories independently developed the idea of packet switching, and developed a UK version of the ARPANET. In 1965 Donald Davies at the National Physical Lab (NPL) in Britain proposed a country wide packet communications network. He gave a talk on his proposal in 1966, and afterwards a person from the Ministry of Defence told him about Paul Baran's work for RAND being done independently. At the 1967 ACM Gatlinburg conference, Lawrence Roberts met Donald Davies and Roger Scantlebury from the NPL, who had published a paper at the conference called "A Digital Communications Network for Computers". They discovered that Leonard Kleinrock's work, Baran's work at RAND, and the work at NPL had been developed independently. It was almost like the idea was waiting to be developed. In 1970, Davies helped build a packet switched network called the Mark I to serve the NPL. The Mark I was replaced with an improved network called the Mark II in 1973, and remained in operation until 1986, but it never had the funding to develop on the scale of the ARPANET.


  • First group to adopt packet-switching
  • Davies was first coin term "packet"
  • First practical implementation of a local area network
  • Made several contributions to the technology of packet-switching
  • "Main catalyst" for the adoption of the new data communications network in the U.K.
  • Instrumental in passing on the knowledge of packet switching to the eventual ARPANET (Campbell Kelly 221-222,12)


Written by the THINK Protocols team, CS Dept, UT Austin
Please direct comments to Chris Edmondson-Yurkanan.

This document was last modified on Tuesday, 11-Jun-2002 10:18:03 CDT.