Computer network
A system of interconnected hosts communicating via protocols and hardware.
A computer network is a group of communicating computers and peripherals known as hosts, which exchange data via communication protocols facilitated by networking hardware. Hosts are identified by network addresses, and may also have hostnames mapped to addresses using a hosts file or a name server such as Domain Name Service. The physical medium includes wired media like copper cables and optical fibers, as well as wireless radio-frequency media. The arrangement of hosts and hardware is known as the network topology.
The origins of computer networking trace to 1940, when George Stibitz connected a terminal to a distant calculator, demonstrating remote computing. In the late 1950s, the U.S. military built a networked radar system using the first commercial modem, which transmitted data over telephone lines at 110 bits per second. During the 1960s, Paul Baran and Donald Davies independently invented packet switching, a method for routing data blocks across a distributed network; Davies’ design included high-speed routers and communication protocols, while Baran’s work focused on adaptive routing. Their ideas were implemented in the NPL network in the United Kingdom. Concurrently, time-sharing systems were pioneered by Christopher Strachey and John McCarthy, enabling multiple users to share a computer. In the Soviet Union, Anatoly Kitov proposed a network of computing centers for economic and military control, but his plan was rejected.
The ARPANET, inspired by J. C. R. Licklider’s concept of an “Intergalactic Computer Network,” began in 1969, connecting four university nodes via circuits. Its routing and software were developed by a team at Bolt Beranek & Newman. Leonard Kleinrock’s mathematical modeling of packet-switched networks and later work on hierarchical routing underpinned its development. In 1973, Peter Kirstein connected the ARPANET to British academic networks, creating the first international heterogeneous network. That same year, Robert Metcalfe and David Boggs described Ethernet, a local area networking system inspired by the ALOHAnet packet radio network. The French CYCLADES network, directed by Louis Pouzin, was the first to make hosts responsible for reliable data delivery. In 1974, Vint Cerf and Bob Kahn published a seminal paper on internetworking, and later that year the first Transmission Control Protocol specification was written, coi
- first_known_network
- 1940
- first_network_creator
- George Stibitz
- key_early_concept
- packet switching
- key_early_inventors
- Paul Baran and Donald Davies
- common_modern_example
- global Internet
Lore & Background
A computer network is a collection of interconnected hosts—computers and peripherals—that exchange data using communication protocols, facilitated by networking hardware. Each host is identified by a unique network address, which hardware uses to locate it; hosts may also have human-readable hostnames, mapped to addresses via a hosts file or a name server like the Domain Name System. The physical medium for data transmission includes wired media such as copper cables and optical fibers, as well as wireless radio-frequency media. The arrangement of hosts and hardware within a network is called its topology. The first known computer network was demonstrated in 1940, when George Stibitz connected a teletype terminal at Dartmouth College to his Complex Number Calculator at Bell Labs in New York, marking the first remote use of a computing machine. In the late 1950s, a network of computers was built for the U.S. military’s SAGE radar system, using the first commercial modem (the Bell 101) to transmit digital data over telephone lines at 110 bits per second. During the 1960s, Paul Baran and Donald Davies independently invented packet switching; Davies’ hierarchical network design introduced high-speed routers and the end-to-end principle, implemented in the NPL local area network in 1968–69. Today, nearly all computers connect to networks, from the global Internet to embedded networks in electronic devices, enabling services like the World Wide Web, digital media, email, and instant messaging.
Reader's Guide
Computer networks underpin nearly all modern digital communication, from the global Internet to embedded networks in electronic devices. Networks support applications such as the World Wide Web, digital video and audio, storage servers, printers, and email. Many applications have only limited functionality unless connected to a network. A computer network consists of communicating computers and peripherals, called hosts, which exchange data using communication protocols facilitated by networking hardware. Each host is identified by a network address, enabling hardware to locate it; hosts may also have memorable hostnames, mapped to addresses via a hosts file or a name server like the Domain Name Service. Information travels over physical media, including wired copper cables, optical fibers, and wireless radio-frequency links. The arrangement of hosts and hardware defines the network topology. The first computer network appeared in 1940, when George Stibitz linked a terminal at Dartmouth to his Complex Number Calculator at Bell Labs in New York. Today, nearly all computers connect to a network, whether the global Internet or embedded networks in modern electronics. The concept of packet switching, independently invented by Paul Baran and Donald Davies during the 1960s, was seminal for data communication between computers. Davies’ hierarchical design included high-speed routers and communication protocols, while Baran’s work addressed adaptive routing of message blocks across a distributed network. The ARPANET, beginning in 1969, connected the first four nodes using circuits between universities, with routing and flow control designed by Bob Kahn and the IMP team. Ethernet, a local area networking system, was created at Xerox PARC by Robert Metcalfe and David Boggs, inspired by the packet radio ALOHAnet. The French CYCLADES network was the first to make hosts responsible for reliable data delivery rather than the network itself. In 1974, Vint Cerf and Bob Kahn published a seminal paper on internetworking, and the first Transmission Control Protocol specification coined the term Internet.
Did You Know?
- The first computer network was created in 1940 by George Stibitz, connecting a terminal at Dartmouth to his Complex Number Calculator at Bell Labs.
- Paul Baran and Donald Davies independently invented packet switching in the 1960s.
Frequently Asked Questions
What is a computer network?
A computer network is a collection of interconnected devices—called hosts—that exchange data using standardized communication protocols and supporting hardware. These hosts can be linked through physical media such as copper cables, optical fibers, or wireless radio-frequency signals.
Who is credited with creating the first computer network?
George Stibitz is recognized as the creator of the first known network, dating back to 1940. His pioneering work laid the groundwork for the interconnected systems that would later define modern computing.
What is packet switching and who developed the concept?
Packet switching is the foundational idea of breaking data into small, independently routed packets that are reassembled at the destination. The concept was independently developed by Paul Baran and Donald Davies during the early era of networking research.
How do hosts on a network identify and locate each other?
Each host is assigned a unique network address, and human-readable hostnames can be mapped to those addresses through a local hosts file or a name server such as DNS. This addressing system is what allows devices to find and communicate with one another across the network.
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