Cambridge Ring (computer network)
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The Cambridge Ring was an experimental
local area network A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building. By contrast, a wide area network (WAN) not only covers a large ...
architecture developed at the Computer Laboratory, University of Cambridge starting in 1974 and continuing into the 1980s. It was a
ring network A ring network is a network topology in which each node connects to exactly two other nodes, forming a single continuous pathway for signals through each node – a ring. Data travels from node to node, with each node along the way handling eve ...
with a theoretical limit of 255
node In general, a node is a localized swelling (a " knot") or a point of intersection (a vertex). Node may refer to: In mathematics * Vertex (graph theory), a vertex in a mathematical graph * Vertex (geometry), a point where two or more curves, line ...
s (though such a large number would have badly affected performance), around which cycled a fixed number of packets. Free packets would be "loaded" with data by a machine wishing to send, marked as received by the destination machine, and "unloaded" on return to the sender; thus in principle, there could be as many simultaneous senders as packets. The network ran over twin
twisted-pair Twisted pair cabling is a type of wiring used for communications in which two conductors of a single circuit are twisted together for the purposes of improving electromagnetic compatibility. Compared to a single conductor or an untwisted ba ...
cabling (plus a fibre-optic section). There are strong similarities between the Cambridge Ring and an earlier ring network developed at
Bell Labs Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mul ...
based on a design by John R. Pierce. That network used T1 lines at bit rate of 1.544 MHz and accommodating 522 bit messages (data plus address). People associated with the project include
Andy Hopper Sir Andrew Hopper (born 1953) is a British-Polish Computer Technologist and entrepreneur. He is treasurer and vice-president of the Royal Society, Professor of Computer Technology, former Head of the University of Cambridge Department of Compu ...
, David Wheeler,
Maurice Wilkes Sir Maurice Vincent Wilkes (26 June 1913 – 29 November 2010) was a British computer scientist who designed and helped build the Electronic Delay Storage Automatic Calculator (EDSAC), one of the earliest stored program computers, and who i ...
, and
Roger Needham Roger Michael Needham (9 February 1935 – 1 March 2003) was a British computer scientist. Early life and education Needham was born in Birmingham, England, the only child of Phyllis Mary, ''née'' Baker (''c''.1904–1976) and Leonard Wil ...
. In 2002, the Computer Laboratory launched a graduate society called the Cambridge Computer Lab Ring named after the Cambridge Ring.


See also

* Cambridge Distributed Computing System * Internet in the United Kingdom § History *
JANET Janet may refer to: Names * Janet (given name) * Janet (French singer) (1939–2011) Surname * Charles Janet (1849–1932), French engineer, inventor and biologist, known for the Left Step periodic table * Jules Janet (1861–1945), French psych ...
* NPL network *
Packet switching In telecommunications, packet switching is a method of grouping data into '' packets'' that are transmitted over a digital network. Packets are made of a header and a payload. Data in the header is used by networking hardware to direct the p ...
*
Token Ring Token Ring network IBM hermaphroditic connector with locking clip. Screen contacts are prominently visible, gold-plated signal contacts less so. Token Ring is a computer networking technology used to build local area networks. It was introduc ...
* University of London Computer Centre


References


External links


Cambridge Ring Hardware





Cambridge Computer Lab Ring
* 1974 introductions Experimental computer networks History of computing in the United Kingdom Local area networks Network topology University of Cambridge Computer Laboratory {{compu-network-stub