VITTA Networking CD - network types

networking curriculum
support CD for senior
secondary studies

Topics
. Home
. Networking History
. Why network?
. OSI model
. Connecting up
. Protocols
. Technology
. Network types
. Topologies
. Issues
. Design factors
. Economic effects
. www links
. Site map

networking > network types > the internet

The Internet

The Internet is a global network of interconnected WANs. It allows any LAN user to communicate with a user on any other LAN. It uses a mesh topology, giving near-perfect reliability if any component in the Internet fails. It relies on everyone using the same protocols such as TCP/IP, FTP, SMTP and HTTP so they can communicate regardless of what type of computer they are using.

The Internet was first developed by the American military during the Cold War in the 1960s. Fearful that the USSR could knock out US military communications during a nuclear war, the RAND corporation was asked to work out how postnuclear America could maintain a command-and-control network, linked from city to city, state to state, base to base even if most of its structure had been bombed back to the stone age

They realised that any centrally controlled network would be an obvious and immediate target for an enemy missile, so control of the network would have to be distributed. They also knew that if a single city or communication line were destroyed, they would need to be able to bypass it and send the messages another way.

RAND mulled over these problems in deep military secrecy, and in 1964 Paul Baran proposed a daring concept for a new network:

It would have no central authority: all the nodes in the network would be equal in status to all other nodes, each node with its own authority to originate, pass, and receive messages.
There would be numerous interconnections between nodes so if one channel or site were bombed, messages could simply take another path from A to B and bypass the melted crater that had been a city or military base.
- It would be designed from the beginning to operate while in tatters.
The network would be assumed to be unreliable at all times.
Network communications would be divided into packets, each packet separately addressed, and each packet would wind its way through the network on an individual basis. The particular route that the packet took would be unimportant. Only final results would count. Basically, the packet would be tossed like a hot potato from node to node to node, more or less in the direction of its destination, until it ended up in the proper place. If big pieces of the network had been blown away, that simply wouldn't matter; the packets would still continue on their way, bouncing across the country by whatever nodes happened to survive.

While RAND, MIT and UCLA worked on such a failsafe networking concept, the National Physical Laboratory in Great Britain set up the first test network on these principles in 1968. Shortly afterward, the Pentagon's Advanced Research Projects Agency (ARPA) started a larger, more ambitious project in the USA.

ARPA installed the first node of their super-network in Autumn 1969 at UCLA. By December 1969, there were four nodes in the network, which was named ARPANET.

The four computers could transfer data on dedicated high-speed transmission lines and scientists and researchers could share one another's computer facilities by long-distance. By 1971 there were fifteen nodes in ARPANET; by 1972, there were thirty-seven.

By its second year of operation, ARPANET's users had warped the computer-sharing network into a high-speed electronic post- office. Instead of long-distance military communications, the main traffic on ARPANET was scientific research, news and personal messages. Researchers were using ARPANET to collaborate on projects, to trade notes on work, and to gossip.

E-mail was invented by Ray Tomlinson in 1972. The telnet protocol, enabling logging on to a remote computer, was introduced in 1972. The FTP protocol, enabling file transfers between Internet nodes, was published in 1973. The Unix to Unix Copy Protocol (UUCP) was invented in 1978 at Bell Labs. Usenet (newsgroups) was started in 1979 based on UUCP, providing a means of exchanging information throughout the world.

ARPANET grew exponentially as more and more universities and organisations and their libraries connected. It soon became so large that information was becoming harder to find. The first effort to index the Internet was created in 1989 when McGill University in Montreal created an archiver for ftp sites, which they named Archie. This software would periodically reach out to all known openly available ftp sites, list their files, and build a searchable index of the software.

Throughout the '70s, ARPA's network grew; its decentralized structure and standardised communication protocols making expansion easy. ARPANET could accommodate many different kinds of very different computers.

At that time, ARPA's standard communication protocol was NCP, Network Control Protocol, but it was superseded by a higher-level, more sophisticated standard known as TCP/IP (first proposed by Bob Kahn). TCP, or "Transmission Control Protocol," converts messages into streams of packets at the source, and then reassembles them back into messages at the destination. IP, or "Internet Protocol," handles the addressing, seeing to it those packets are routed across multiple nodes and even across multiple networks with multiple standards (e.g. Ethernet networks.)

By 1977, TCP/IP was being used by other networks to link to ARPANET, and in 1983 the military segment of the tightly controlled ARPANET broke off and became MILNET.

As the '70s and '80s advanced and many more people discovered personal computers, it was fairly easy to link these computers to the growing network-of-networks. As the use of TCP/IP became more common, entire networks joined ARPANET using the freely available TCP/IP software. It was difficult to stop people from barging in and linking up, and in fact, nobody wanted to stop them from joining this branching complex of networks, which came to be known as the "Internet."

At first, ARPANET was a curiosity enjoyed by early computer hackers and researchers. Then other government and commercial organisations realised that computer networking had become an utter necessity.

In 1984 the National Science Foundation’s Office of Advanced Scientific Computing (NSFNET) made huge technical progress linking newer, faster, supercomputers through thicker, faster links. Other government agencies joined in: NASA, the National Institutes of Health, and the Department of Energy.

The growing Internet started to take its familiar structure. Foreign computers started being identified by their geographical locations, such as ".au" and ".uk" (the Americans have no geographical identifier). Domains were also grouped by six basic types: gov (government sites), mil (military), edu (educational), com (commercial), org (non-profit organisations) and net (gateway sites between networks).

ARPANET formally expired in 1989, a happy victim of its own overwhelming success, and became the internet.

Now, hundreds of millions of everyday people use this gigantic mother-of-all-computer-networks.

By 1995, the US government gave up pretending that the Internet was its baby. The National Science Foundation ended its sponsorship of the Internet backbone, and all traffic relied on commercial networks. AOL, Prodigy, and CompuServe came online. The Internet's pace of growth in the early 1990s was ferocious - growing at a rate of twenty percent a month

ARPA's network, designed to assure control of a ravaged society after a nuclear holocaust, has been overthrown by its mutant child the Internet, which is anarchic and thoroughly out of the control of any government. The Internet is run and controlled by the people who are currently using it. The only rules are those made by its users, such as ‘netiquette’, which defines network etiquette.

In 1989 Tim Berners-Lee proposed a new protocol for information distribution. This protocol, which became the World Wide Web in 1991, was based on hypertext--a system of embedding links in text to link to other text.

It was boosted in 1993 by the graphical browser Mosaic created by Marc Andreessen, who later started Netscape Corp.

In 1994, Tim Berners-Lee and others formed the World Wide Web Consortium (W3C) to promote and develop standards for the fledgling World Wide Web, named by Tim Berners-Lee, who also invented HTTP, the web protocol.

Since then, the web and email have been built into all computer operating systems and have become a daily way of life for most people and organisations around the world.

worksheets
. history
. why network
. osi model
. connecting
. protocols
. technology
. topologies (tla)
. issues
. network types
. design
. economics
. economics (cs)
- solutions -

quizzes
. why network
. osi model
. connecting
. protocols
. technology
. topology
. issues
. network types
. design
. economics

networking curriculumsupport CD for seniorsecondary studies

networking > network types > the internet

The Internet

networking curriculum
support CD for senior
secondary studies