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The Internet (also known simply as the Net) is
the worldwide, publicly accessible system of interconnected computer
networks that transmit data by packet switching using the standard
Internet Protocol (IP). It consists of millions of smaller domestic,
academic, business, and government networks, which together carry
various information and services, such as electronic mail, online chat,
and the interlinked Web pages and other documents of the World Wide Web.
Contrary to some common usage, the Internet and the World Wide Web are
not synonymous: the Internet is a collection of interconnected computer
networks, linked by copper wires, fiber-optic cables, wireless
connections etc.; the Web is a collection of interconnected documents,
linked by hyperlinks and URLs, and is accessible using the Internet. The
Internet also provides many other services including e-mail, file
sharing and others described below.
Contents 1 Creation of the Internet
2 Today's Internet
2.1 Internet protocols
2.2 Internet structure
2.3 ICANN
2.4 The World Wide Web
2.5 Remote access
2.6 Collaboration
2.7 File-sharing
2.8 Streaming media
2.9 VoIP
2.10 Language
2.11 Internet and the workplace
3 Censorship
4 Internet access
5 Leisure
6 A complex system
7 Marketing
8 Capitalization conventions
9 Significant Internet events
9.1 Malfunctions and attacks
10 See also
10.1 Major aspects and issues
10.2 Functions
10.3 Underlying infrastructure
10.4 Regulatory bodies
11 References
11.1 Citations and notes
11.2 General
12 External links
12.1 General
12.2 Articles
12.3 History Creation of the
Internet Main article: History of the Internet
The USSR's launch of Sputnik spurred the United States to create the
Advanced Research Projects Agency (ARPA, later known as the Defense
Advanced Research Projects Agency) in February 1958 to regain a
technological lead. ARPA created the Information Processing Technology
Office (IPTO) to further the research of the Semi Automatic Ground
Environment program, which had networked country-wide radar systems
together for the first time. J. C. R. Licklider was selected to head the
IPTO, and saw universal networking as a potential unifying human
revolution. Licklider recruited Lawrence Roberts to head a project to
implement a network, and Roberts based the technology on the work of
Paul Baran who had written an exhaustive study for the U.S. Air Force
that recommended packet switching (as opposed to Circuit switching) to
make a network highly robust and survivable. After much work, the first
node went live at UCLA on October 29, 1969 on what would be called the
ARPANET, the "eve" network of today's Internet.
The first TCP/IP wide area network was operational by 1 January 1983 ,
when the United States' National Science Foundation (NSF) constructed a
university network backbone that would later become the NSFNet. (This
date is held by some to be technically that of the birth of the
Internet.) It was then followed by the opening of the network to
commercial interests in 1995. Important separate networks that offered
gateways into, then later merged into the NSFNet include Usenet, Bitnet
and the various commercial and educational X.25 Compuserve and JANET.
Telenet (later called Sprintnet), was a large privately-funded national
computer network with free dialup access in cities throughout the U.S.
that had been in operation since the 1970s. This network eventually
merged with the others in the 1990s as the TCP/IP protocol became
increasingly popular. The ability of TCP/IP to work over these
pre-existing communication networks allowed for a great ease of growth.
Use of Internet as a phrase to describe a single global TCP/IP network
originated around this time.
The network gained a public face in the 1990s. In August 1991 CERN,
which straddles the border between France and Switzerland publicized the
new World Wide Web project, two years after Tim Berners-Lee had begun
creating HTML, HTTP and the first few web pages at CERN. In 1993 the
National Center for Supercomputing Applications at the University of
Illinois at Urbana-Champaign released the Mosaic web browser version
1.0, and by late 1994 there was growing public interest in the
previously academic/technical Internet. By 1996 the word "Internet" was
common public currency, but it referred almost entirely to the World
Wide Web.
Meanwhile, over the course of the decade, the Internet successfully
accommodated the majority of previously existing public computer
networks (although some networks such as FidoNet have remained
separate). This growth is often attributed to the lack of central
administration, which allows organic growth of the network, as well as
the non-proprietary open nature of the Internet protocols, which
encourages vendor interoperability and prevents any one company from
exerting too much control over the network.
Today's Internet Aside from the complex physical
connections that make up its infrastructure, the Internet is held
together by bi- or multi-lateral commercial contracts (for example
peering agreements) and by technical specifications or protocols that
describe how to exchange data over the network. Indeed, the Internet is
essentially defined by its interconnections and routing policies.
As of January 2006, over 1 billion people use the Internet according to
Internet World Stats.
Internet protocols In this context, there are three
layers of protocols:
At the lowest level is IP, which defines the datagrams or packets that
carry blocks of data from one node to another. The vast majority of
today's Internet uses version four of the IP protocol (i.e. IPv4), and
although IPv6 is standardised, it exists only as "islands" of
connectivity, and there are many ISPs who don't have any IPv6
connectivity at all.[1]
Next comes TCP and UDP - the protocols by which one host sends data to
another. The former makes a virtual 'connection', which gives some level
of guarantee of reliability. The latter is a best-effort,
connection-less transport, in which data packets that are lost in
transit will not be re-sent.
On top comes the application protocol. This defines the specific
messages and data formats sent and understood by the applications
running at each end of the communication.
Unlike older communications systems, the Internet protocol suite was
deliberately designed to be independent of the underlying physical
medium. Any communications network, wired or wireless, that can carry
two-way digital data can carry Internet traffic. Thus, Internet packets
flow through wired networks like copper wire, coaxial cable, and fibre
optic, and through wireless networks like Wi-Fi. Together, all these
networks, sharing the same protocols, form the Internet.
The Internet protocols originate from discussions within the Internet
Engineering Task Force (IETF) and its working groups, which are open to
public participation and review. These committees produce documents that
are known as Request for Comments documents (RFCs). Some RFCs are raised
to the status of Internet Standard by the IETF process.
Some of the most-used application protocols in the Internet protocol
suite are DNS, POP3, IMAP, SMTP, HTTP, HTTPS and FTP. There are many
other important ones; see the lists provided in these articles.
All services on the Internet make use of defined application protocols.
Of these, e-mail and the World Wide Web are among the most well known,
and other services are built upon these, such as mailing lists and
blogs. There are many others that are necessary 'behind the scenes' and
yet others that serve specialised requirements.
Some application protocols were not created out of the IETF process, but
initially as part of proprietary commercial or private experimental
systems. They became much more widely used and have now become de facto
or actual standards in their own right. Examples of these include IRC
chat rooms, and various instant messaging and peer-to-peer file sharing
protocols. Internet structure
There have been many analyses of the Internet and its structure. For
example, it has been determined that the Internet IP routing structure
and hypertext links of the World Wide Web are examples of scale-free
networks.
Similar to how the commercial Internet providers connect via Internet
exchange points, research networks tend to interconnect into large
subnetworks such as:
GEANT
GLORIAD
Internet2
JANET (the UK's Joint Academic Network aka UKERNA)
These in turn are built around relatively smaller networks. See also the
list of academic computer network organizations
In network schematic diagrams, the Internet is often represented by a
cloud symbol, into and out of which network communications can pass.
ICANN Main article: ICANN
The Internet Corporation for Assigned Names and Numbers (ICANN) is the
authority that coordinates the assignment of unique identifiers on the
Internet, including domain names, Internet protocol addresses, and
protocol port and parameter numbers. A globally unified namespace (i.e.,
a system of names in which there is one and only one holder of each
name) is essential for the Internet to function. ICANN is headquartered
in Marina del Rey, California, but is overseen by an international board
of directors drawn from across the Internet technical, business,
academic, and non-commercial communities. The US government continues to
have the primary role in approving changes to the root zone file that
lies at the heart of the domain name system. Because the Internet is a
distributed network comprising many voluntarily interconnected networks,
the Internet, as such, has no governing body. ICANN's role in
coordinating the assignment of unique identifiers distinguishes it as
perhaps the only central coordinating body on the global Internet, but
the scope of its authority extends only to the Internet's systems of
domain names, Internet protocol addresses, and protocol port and
parameter numbers.
On Nov. 16, 2005, the World Summit on the Information Society, held in
Tunis, established the Internet Governance Forum (IGF) to discuss
Internet-related issues.
Graphic representation of a very small part of the WWW, representing
some of the hyperlinks[edit]
The World Wide Web
Main article: World Wide Web
Through keyword-driven Internet research using search engines like
Google, millions worldwide have easy, instant access to a vast and
diverse amount of online information. Compared to encyclopedias and
traditional libraries, the World Wide Web has enabled a sudden and
extreme decentralization of information and data.
Many individuals and some companies and groups have adopted the use of
'weblogs' or blogs, which are largely used as easily-updatable online
diaries. Some commercial organizations encourage staff to fill them with
advice on their areas of specialization in the hope that visitors will
be impressed by the expert knowledge and free information, and be
attracted to the corporation as a result. One example of this practice
is Microsoft, whose product developers publish their personal blogs in
order to pique the public's interest in their work.
For more information on the distinction between the World Wide Web and
the Internet itself — as in everyday use the two are sometimes confused
— see Dark internet where this is discussed in more detail.
Remote access The Internet allows computer users to
connect to other computers and information stores easily, wherever they
may be across the world. They may do this with or without the use of
security, authentication and encryption technologies, depending on the
requirements.
This is encouraging new ways of working from home, collaboration and
information sharing in many industries. An accountant sitting at home
can audit the books of a company based in another country, on a server
situated in a third country that is remotely maintained by IT
specialists in a fourth. These accounts could have been created by
home-working book-keepers, in other remote locations, based on
information e-mailed to them from offices all over the world. Some of
these things were possible before the widespread use of the Internet,
but the cost of private, leased lines would have made many of them
infeasible in practice.
An office worker away from his desk, perhaps the other side of the world
on a business trip or a holiday, can open a remote desktop session into
his normal office PC using a secure Virtual Private Network (VPN)
connection via the Internet. This gives him complete access to all his
normal files and data, including e-mail and other applications, while he
is away.
This concept is also referred to by some network security people as the
Virtual Private Nightmare, because it extends the secure perimeter of a
corporate network into its employees' homes; this has been the source of
some notable security breaches.
Collaboration This low-cost and nearly instantaneous
sharing of ideas, knowledge and skills has revolutionized some, and
given rise to whole new, areas of human activity. One example of this is
the collaborative development and distribution of Free/Libre/Open-Source
Software (FLOSS) such as Linux, Mozilla and OpenOffice.org. See
Collaborative software.
File-sharing Main article: File sharing
A computer file can be e-mailed to customers, colleagues and friends as
an attachment. It can be uploaded to a website or FTP server for easy
download by others. It can be put into a "shared location" or onto a
file server for instant use by colleagues. The load of bulk downloads to
many users can be eased by the use of "mirror" servers or peer-to-peer
networking.
In any of these cases, access to the file may be controlled by user
authentication; the transit of the file over the Internet may be
obscured by encryption and money may change hands before or after access
to the file is given. The price can be paid by the remote charging of
funds from, for example a credit card whose details are also passed -
hopefully fully encrypted - across the Internet. The origin and
authenticity of the file received may be checked by digital signatures
or by MD5 or other message digests.
These simple features of the Internet, over a world-wide basis, are
changing the basis for the production, sale and distribution of many
types of product, wherever they can be reduced to a computer file for
transmission. This includes all manner of office documents,
publications, software products, music, photography, video, animations,
graphics and the other arts. This in turn is causing seismic shifts in
each of the existing industry associations, such as the RIAA and MPAA in
the USA, that previously controlled the production and distribution of
these products in that country.
Streaming media Many existing radio and television
broadcasters provide Internet 'feeds' of their live audio and video
streams (for example, the BBC). They may also allow time-shift viewing
or listening such as Preview, Classic Clips and Listen Again features.
These providers have been joined by a range of pure Internet
'broadcasters' who never had on-air licences. This means that an
Internet-connected device, such as a computer or something more
specific, can be used to access on-line media in much the same way as
was previously possible only with a TV or radio receiver. The range of
material is much wider, from pornography to highly specialised technical
web-casts. Podcasting is a variation on this theme, where—usually
audio—material is first downloaded in full and then may be played back
on a computer or shifted to a digital audio player to be listened to on
the move. These techniques using simple equipment allow anybody, with
little censorship or licensing control, to broadcast audio-visual
material on a worldwide basis.
Webcams can be seen as an even lower-budget extension of this
phenomenon. While some webcams can give full frame rate video, the
picture is usually either small or updates slowly. Internet users can
watch animals around an African waterhole, ships in the Panama Canal,
the traffic at a local roundabout or their own premises, live and in
real time. Video chat rooms, video conferencing, and remote controllable
webcams are also popular. Many uses can be found for personal webcams in
and around the home, with and without two-way sound.
VoIP VoIP stands for Voice over IP, where IP refers to
the Internet Protocol that underlies all Internet communication. This
phenomenon began as an optional two-way voice extension to some of the
Instant Messaging systems that took off around the year 2000. In recent
years many VoIP systems have become as easy to use and as convenient as
a normal telephone. The benefit is that, as the Internet carries the
actual voice traffic, VoIP can be free or cost much less than a normal
telephone call, especially over long distances and especially for those
with always-on ADSL or DSL Internet connections.
Thus VoIP is maturing into a viable alternative to traditional
telephones. Interoperability between different providers has improved
and the ability to call or receive a call from a traditional telephone
is available. Simple inexpensive VoIP modems are now available that
eliminate the need for a PC.
Voice quality can still vary from call to call but is often equal to and
can even exceed that of traditional calls.
Remaining problems for VoIP include emergency telephone number dialing
and reliability. Currently a few VoIP providers provide some 911 dialing
but it is not universally available. Traditional phones are line powered
and operate during a power failure, VoIP does not do so without a backup
power source for the electronics.
Most VoIP providers offer unlimited national calling but the direction
in VoIP is clearly toward global coverage with unlimited minutes for a
low monthly fee. Language
Main article: English on the Internet
The most prevalent language for communication on the Internet is
English. This may be due to the Internet's origins, as well as English's
role as the lingua franca. It may also be related to the poor capability
of early computers to handle characters other than those in the basic
Latin alphabet.
Further information: Unicode
After English (32% of web visitors) the most-requested languages on the
world wide web are Chinese 13%, Japanese 8%, Spanish 7%, German 6% and
French 4% (from Internet World Stats, updated November 30, 2005).
By continent, 34% of the world's Internet users are based in Asia, 29%
in Europe, and 23% in North America ([2] updated November 21, 2005).
The Internet's technologies have developed enough in recent years that
good facilities are available for development and communication in most
widely used languages. However, some glitches such as mojibake (also
known as krakozyabry) still remain.
Internet and the workplace The Internet is allowing
greater flexibility in working hours and location, especially with the
spread of unmetered high-speed connections and Web applications.
The Internet has given employees a forum from which to voice their
opinions about their jobs, employers and co-workers, creating a massive
amount of information and data on work that is currently being collected
by the Worklifewizard.org project run by Harvard Law School's Labor &
Worklife Program. Censorship
Main article: Internet censorship
Some governments, such as in Iran and China restrict what people in
their countries can access on the Internet, especially political and
religious content, through software that filters domains and content, so
they may be easily accessed or obtained without elaborate circumvention.
Many countries have enacted laws making the possession or distribution
of certain material, such as child pornography, illegal, but do not use
filtering software.
There are many free and commercially available software programs with
which a user can choose to block offensive Web sites on individual
computers or networks, such as to limit a child's access to pornography
or violence. See Content-control software.
Internet access Main article: Internet access
Internet public access point.Wikibooks has more about this subject:
Online linux connectCommon methods of home access include dial-up,
landline broadband (over coaxial cable, fibre optic or copper wires),
Wi-Fi, satellite and cell phones.
Public places to use the Internet include libraries and Internet cafes,
where computers with Internet connections are available. There are also
Internet access points in many public places such as airport halls and
coffee shops, in some cases just for brief use while standing. Various
terms are used, such as "public Internet kiosk", "public access
terminal", and "Web payphone". Many hotels now also have public
terminals, though these are usually fee based.
Wi-Fi provides wireless access to computer networks, and therefore can
do so to the Internet itself. Hotspots providing such access include
Wi-Fi-cafes, where a would-be user needs to bring their own
wireless-enabled devices such as a laptop or PDA. These services may be
free to all, free to customers only, or fee-based. A hotspot need not be
limited to a confined location. The whole campus or park, or even the
entire city can be enabled. Grassroots efforts have led to wireless
community networks. Commercial WiFi services covering large city areas
are in place in London, San Francisco, Philadelphia, Chicago, and other
cities, including Toronto by the end of 2006. The Internet can then be
accessed from such places as a park bench.[1]
Apart from Wi-Fi, there have been experiments with proprietary mobile
wireless networks like Ricochet, various high-speed data services over
cellular or mobile phone networks, and fixed wireless services.
High end mobile phones such as Symbian smartphones generally come with
internet access through the phone network. Web browsers such as Opera
are available on these advanced handsets, which can also run a wide
variety of other Internet software. More mobile phones have internet
access than PCs, though this is not as widely used.
Leisure The Internet has been a major source of leisure
since before the World Wide Web, with entertaining social experiments
such as MOOs being conducted on university servers, and humor-related
Usenet groups receiving much of the main traffic. Today, many Internet
forums have sections devoted to games and funny videos; short cartoons
in the form of Flash movies are also popular.
The pornography and gambling industries have both taken full advantage
of the World Wide Web, and often provide a significant source of
advertising revenue for other Web sites. Although many governments have
attempted to put restrictions on both industries' use of the Internet,
this has generally failed to stop their widespread popularity.
One main area of leisure on the Internet is multiplayer gaming. This
form of leisure creates communities, bringing people of all ages and
origins to enjoy the fast-paced world of multiplayer games. These range
from MMORPG to first-person shooters, from role-playing games to online
gambling. This has revolutionized the way many people interact and spend
their free time on the Internet.
While online gaming has been around since the 1970s, modern modes of
online gaming began with services such as GameSpy and MPlayer, which
players of games would typically subscribe to. Non-subscribers were
limited to certain types of gameplay or certain games.
Many use the Internet to access and download music, movies and other
works for their enjoyment and relaxation. As discussed above, there are
paid and unpaid sources for all of these, using centralised servers and
distributed, peer-to-peer technologies. Discretion is needed as some of
these sources take more care over the original artists' rights and over
copyright laws than others.
Many use the World Wide Web to access news, weather and sports reports,
to plan and book holidays and to find out more about their random ideas
and casual interests.
People use chat, messaging and email to make and stay in touch with
friends worldwide, sometimes in the same way as some previously had pen
pals. Social networking web sites like Friends Reunited and many others
like them also put and keep people in contact for their enjoyment.
Cyberslacking has become a serious drain on corporate resources; the
average UK employee spends 57 minutes a day surfing the web at work,
according to a study by Peninsula Business Services[3].
A complex system Many computer scientists see the
Internet as a "prime example of a large-scale, highly engineered, yet
highly complex system" (Willinger, et al). The Internet is extremely
heterogeneous. (For instance, data transfer rates and physical
characteristics of connections vary widely.) The Internet exhibits
"emergent phenomena" that depend on its large-scale organization. For
example, data transfer rates exhibit temporal self-similarity.
Marketing The Internet has also become a large market for
companies; some of the biggest companies today have grown by taking
advantage of the efficient nature of low-cost advertising and commerce
through the Internet; also known as e-commerce. It is the fastest way to
spread information to a vast amount of people simultaneously. The
Internet has also subsequently revolutionized shopping—for example; a
person can order a CD online and receive it in the mail within a couple
of days, or download it directly in some cases. The Internet has also
greatly facilitated personalized marketing which allows a company to
market a product to a specific person or a specific group of people
moreso than any other advertising medium.
Examples of personalized marketing include online communities such as
Myspace, Friendster, and others which thousands of Internet users join
to advertise themselves and make friends online. Many of these users are
young teens and adolescents ranging from 13 to 25 years old. In turn,
when they advertise themselves they advertise interests and hobbies,
which online marketing companies can use as information as to what those
users will purchase online, and advertise their own companies' products
to those users.
Capitalization conventions Internet is traditionally
written with a capital first letter. The Internet Society, the Internet
Engineering Task Force, the Internet Corporation for Assigned Names and
Numbers, the World Wide Web Consortium, and several other
Internet-related organizations use this convention in their
publications.
Various newspapers, newswires, periodicals, and technical journals
capitalize the term. Examples include the New York Times, the Associated
Press, Time, The Times of India, Hindustan Times and Communications of
the ACM.
Others assert that the first letter should be written small (internet).
A significant number of publications use this form, including The
Economist, the Financial Times, The Guardian, The Times, and The Sydney
Morning Herald. As of 2005, many publications using internet appear to
be located outside of North America — although one U.S. news source,
Wired News, has adopted the lower case spelling.
Historically, internet was considered by the technical community to be a
contraction of internetwork or internetworking, while "Internet" simply
referred to the largest such internet. The distinction was evident in
many RFCs, books, and articles from the 1980s and early 1990s. As there
are no longer any other significant internetworks, the distinction has
fallen out of use. |
