About Internet

The Internet is the worldwide, publicly accessible network of
interconnected computer networks that transmit data by packet switching using
the standard Internet Protocol (IP). It is a "network of networks" that consists
of millions of smaller domestic, academic, business, and government networks,
which together carry various information and services, such as electronic mail,
online chat, file transfer, and the interlinked Web pages and other documents of
the World Wide Web.

Visualization of the various routes through a portion of the internet
Visualization of the various routes through a portion of the Internet

Terminology: Internet vs. World Wide Web

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 and other resources, linked by hyperlinks and URLs. The
World Wide Web is accessible via the Internet, as are many other services
including e-mail, file sharing, and others described below.

The best way to define and distinguish between these terms is with reference
to the Internet protocol suite. This collection of standards and protocols is
organized into layers such that each layer provides the foundation and the
services required by the layer above. In this conception, the term Internet
refers to computers and networks that communicate using IP (Internet protocol)
and TCP (Transmission Control Protocol). Once this networking structure is
established, then other protocols can run “on top.” These other protocols are
sometimes called services or applications. Hypertext Transfer Protocol (HTTP) is
the application layer protocol that links and provides access to the files,
documents and other resources of the World Wide Web.

Creation 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, or DARPA) 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 (SAGE) 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.

In 1950, Licklider moved from the Psycho-Acoustic Laboratory at Harvard
University to MIT, where he served on a committee that established Lincoln
Laboratory. He worked on the SAGE project. In 1957 he became a Vice President at
BBN, where he bought the first production PDP-1 computer and conducted the first
public demonstration of time-sharing.

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, one of the "eve" networks of today's
Internet. Following on from this, the British Post Office, Western Union
International and Tymnet collaborated to create the first international packet
switched network, referred to as the International Packet Switched Service (IPSS),
in 1978. This network grew from Europe and the US to cover Canada, Hong Kong and
Australia by 1981.

The first TCP/IP-wide area network was operational by January 1, 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 1985. Important, separate
networks that offered gateways into, then later merged with, 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 dial-up 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,
especially the international X.25 IPSS network, allowed for a great ease of
growth. Use of the term "Internet" to describe a single global TCP/IP network
originated around this time.

The network gained a public face in the 1990s. On August 6, 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.

An early popular web browser was ViolaWWW based upon HyperCard. It was
eventually replaced in popularity by the Mosaic web browser. In 1993 the
National Center for Supercomputing Applications at the University of Illinois
released version 1.0 of Mosaic, and by late 1994 there was growing public
interest in the previously academic/technical Internet. By 1996 the word
"Internet" was coming into common daily usage, frequently misused to refer 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

A rack of servers
A rack of servers

Aside from the complex physical connections that make up its infrastructure,
the Internet is facilitated by bi- or multi-lateral commercial contracts (e.g.,
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 March 10, 2007, 1.114 billion people use the Internet according to
Internet World Stats.

Internet protocols

In this context, there are three layers of 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 the way the commercial Internet providers connect via Internet
exchange points, research networks tend to interconnect into large subnetworks
such as:

These in turn are built around relatively smaller networks.

In network schematic diagrams, the Internet is often represented by a cloud
symbol, into and out of which network communications can pass.

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 (IP) 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, IP addresses, and protocol port
and parameter numbers.

On November 16, 2005, the World Summit on the Information Society, held in
Tunis, established the Internet Governance Forum (IGF) to discuss
Internet-related issues.

Language

The prevalent language for communication on the Internet is English. This may
be a result of 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.

After English (30% of Web visitors) the most-requested languages on the World
Wide Web are Chinese 14%, Japanese 8%, Spanish 8%, German 5%, and French 5%
(from Internet World Stats, updated January 11, 2007).

By continent, 36% of the world's Internet users are based in Asia, 29% in
Europe, and 21% in North America ([2]
updated January 11, 2007).

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 (incorrect display of
foreign language characters, 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 mobile Internet

The Internet can now be accessed virtually anywhere by numerous means. Mobile
phones, datacards, and cellular routers allow users to connect to the Internet
from anywhere there is a cellular network supporting that device's technology.

Common uses of the Internet

E-mail

The concept of sending electronic text messages between parties in a way
analogous to mailing letters or memos predates the creation of the Internet.
Even today it can be important to distinguish between Internet and internal
e-mail systems. Internet e-mail may travel and be stored unencrypted on many
other machines and networks out of both the sender's and the recipient's
control. During this time it is quite possible for the content to be read and
even tampered with by third parties, if anyone considers it important enough.
Purely internal or intranet mail systems, where the information never leaves the
corporate or organization's network and servers, is much more secure, although
in any organization there will be IT and other personnel whose job may involve
monitoring, or at least occasionally accessing, the email of other employees not
addressed to them. Web-based email (webmail) between parties on the same webmail
system may not actually 'go' anywhere—it merely sits on the one server and is
tagged in various ways so as to appear in one person's 'sent items' list and in
one or more others' 'in boxes' or other 'folders' when viewed.

E-mail attachments have greatly increased the usefulness of e-mail in many
ways. When a file is attached to an email, a text representation of the attached
data (which may itself be binary data) is actually appended to the e-mail text,
later to be reconstituted into a 'file' on the recipient's machine for their
use.

The World Wide Web

Graphic representation of less than 0.0001% of the www, representing some of the hyperlinks
Graphic representation of less than 0.0001% of the WWW, representing some of the
hyperlinks

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 "Web
logs" 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.

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, but also provides security for the workers.

Collaboration

The low-cost and nearly instantaneous sharing of ideas, knowledge, and skills
has made collaborative work dramatically easier. Not only can a group cheaply
communicate and test, but the wide reach of the Internet allows such groups to
easily form in the first place, even among niche interests. An example of this
is the free software movement in software development which produced GNU and
Linux from scratch and has taken over development of Mozilla and OpenOffice.org
(formerly known as Netscape Communicator and StarOffice).

Internet 'chat', whether in the form of IRC 'chat rooms' or channels, or via
instant messaging systems allow colleagues to stay in touch in a very convenient
way when working at their computers during the day. Messages can be sent and
viewed even more quickly and conveniently than via e-mail. Extension to these
systems may allow files to be exchanged, 'whiteboard' drawings to be shared as
well as voice and video contact between team members.

Version control systems allow collaborating teams to work on shared sets of
documents without either accidentally overwriting each other's work or having
members wait until they get 'sent' documents to be able to add their thoughts
and changes.

File sharing

A computer file can be e-mailed to customers, colleagues and friends as an
attachment. It can be uploaded to a Web site 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 networks. 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 anything that 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
United States, 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 licenses. 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 television or radio receiver. The range of material is much wider,
from pornography to highly specialized 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.

Voice telephony (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.

VoIP has also become increasingly popular within the gaming world, as a form
of communication between players. Popular gaming VoIP clients include Ventrilo
and Teamspeak, and there are others available also.

Censorship

Some governments, such as those of Iran, the People's Republic of China and
Cuba, restrict what people in their countries can access on the Internet,
especially political and religious content. This is accomplished through
software that filters domains and content so that they may not be easily
accessed or obtained without elaborate circumvention.

In Norway, Finland and Sweden, major Internet service providers have
voluntarily (possibly to avoid such an arrangement being turned into law) agreed
to restrict access to sites listed by police. While this list of forbidden URLs
is only supposed to contain addresses of known child pornography sites, content
of the list is secret.

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.

Internet access

Common 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, Vienna, San Francisco, Philadelphia, Chicago,
Pittsburgh 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
phone networks, and fixed wireless services.

High-end mobile phones such as 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. An internet access provider and protocol
matrix differentiates the methods used to get online.

Leisure

The Internet has been a major source of leisure since before the World Wide
Web, with entertaining social experiments such as MUDs and 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. Over
6 million people use blogs or message boards as a means of communication and for
the sharing of ideas.

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. A song in the Broadway musical show Avenue
Q is titled "The Internet is for Porn" and refers to the popularity of this
aspect of the internet.

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 centralized 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.

The Internet has seen a growing amount of Internet operating systems, where
users can access their files, folders, and settings via the Internet. An example
of an opensource webos is Eyeos.

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].

Complex architecture

Many computer scientists see the Internet as a "prime example of a
large-scale, highly engineered, yet highly complex system".[2] 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. Further adding to the
complexity of the Internet is the ability of more than one computer to use the
Internet through only one node, thus creating the possibility for a very deep
and hierarchal based sub-network that can theoretically be extended infinitely
(disregarding the programmatic limitations of the IPv4 protocol).

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 more so than any
other advertising medium.

Examples of personalized marketing include online communities such as MySpace,
Friendster, Orkut, 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.

A very ineffective way of advertising on the Internet is through spamming an
email with advertisements. This is ineffective because, now, most email
providers offer protection against email spam. Most spam messages are sent
automatically to everybody in the email database of the company/person that is
spamming. This way of advertising is almost like using adware.

Adware is another ineffective way of advertising because most people simply
close a popup window when it shows up, not bothering to read it.

The name Internet

Internet is traditionally written with a capital first letter, as it
is a proper noun. 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.

Many newspapers, newswires, periodicals, and technical journals capitalize
the term (Internet). 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 in lower case
(internet). A significant number of publications use this form, including
The Economist, the Canadian Broadcasting Corporation, 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 and internet have had different
meanings, with internet being a contraction of internetwork or
internetworking and Internet referring to a matrix of networks using
TCP/IP (Transmission Control Protocol/Internet Protocol) according to the book
Where wizards stay up late. Under this distinction, the Internet is a particular
internet, but the reverse does not apply. The distinction was evident in many
RFCs, books, and articles from the 1980s and early 1990s (some of which, such as

RFC 1918, refer to "internets" in the plural), but has recently fallen into
disuseInstead, the term intranet is generally used for private networks.

Some people use the lower-case term as a medium (like radio or newspaper,
e.g. I've found it in internet), and capitalised (or first letter
capitalised) as the global network.

Significant Internet events

Malfunctions and attacks

References

Citations and notes


  1. ^

    "Toronto Hydro to Install Wireless Network in Downtown Toronto"    .
    Bloomberg.com. Retrieved 19-Mar-2006.

  2. ^
    Walter Willinger, Ramesh Govindan, Sugih Jamin, Vern Paxson, and Scott
    Shenker (2002).

    Scaling phenomena in the Internet    . In Proceedings of the National
    Academy of Sciences, 99    , suppl. 1, 2573 – 2580.

General

External links

General

Articles

History

Retrieved from "http://en.wikipedia.org/wiki/Internet"