Sesuatu protokol itu adalah satu set
peraturan yang mentadbir talian komunikasi di antara beberapa buah komputer
yang terdapat pada suatu rangkaian. Peraturan-peraturan tersebut termasuklah
garis panduan yang merangkumi beberapa kriteria-kriteria sebuah rangkaian. Ini
termasuklah cara mengakses, topologi fizikal yang dibenarkan, jenis-jenis
perkabelan, dan kelajuan penghantaran data.
Contoh-contoh protokol yang paling
popular digunakan ialah:
1-Ethernet
2-Local Talk
3-Token Ring
4-FDDI
ETHERNET
Protokol Ethernet merupakan protokol yang paling digunakan dengan meluas.
Ethernet menggunakan cara kemasukan (access method) yang dikenali sebagai
CSMA/CD (Carrier Sense Multiple Access / Collision Detection). Ia merupakan
suatu sistem di mana setiap komputer menunggu arahan melalui kabel sebelum
menghantar mesej melalui rangkaian. Jika rangkaian didapati tidak sibuk,
barulah komputer tersebut menyampaikan maklumat atau mesejnya. Jika satu nod
lain terlebih dahulu telah menyiarkan mesejnya melalui kabel, komputer tersebut
akan menunggu dan akan mencuba sekali lagi apabila laluan membenarkan.Kadangkala
terdapat dua komputer yang kebetulan menghantar mesej pada waktu yang serentak.
Apabila kejadian ini berlaku maka akan terjadilah perlanggaran. Kedua-dua
komputer tersebut akan berundur buat sementara sebelum menghantar mesej semula.
Dengan sistem penghantaran yang sebegini, pelanggaran merupakan sesuatu yang
lumrah. Walau bagaimana pun, kelewatan yang terjadi akibat perlanggaran dan
penghantaran semula data itu tadi, adalah kecil dan biasanya tidak mempengaruhi
kepantasan penghantaran data di dalam rangkaian. Protokol Ethernet biasanya
digunakan untuk topologi linear bas, bintang atau pepohon. Data boleh dihantar
menggunakan kabel pasangan berpintal (twisted pair), kabel sipaksi (coaxial)
atau kabel fiber optik pada kepantasan 10 Mbps.
ETHERNET PANTAS (FAST ETHERNET)
Bagi mempertingkatkan penghantaran maklumat
yang lebih pantas, protokol Ethernet telah membangunkan suatu standard yang
menyokong dan membolehkan 100 Mbs. Inilah yang dikenali sebagai Ethernet
pantas.Ethernet pantas memerlukan penggunaan concentrator atau hab yang
berlainan dan lebih mahal kosnya serta rangkaian kad antaramuka (network
interface cards). Sebagai tambahan, kabel 5 pasangan berpintal (twisted pair)
ataupun kabel fiber optik jika perlu.
LOCAL TALK
Local Talk merupakan satu protokol
rangkaian yang dibangunkan oleh Apple Computer untuk Komputer Macintosh. Cara
yang digunakan oleh Local Talk dipanggil CSMA/CA (Carrier Sense Multiple Access
dengan Collision Avoidance). Ia hampir sama dengan CSMA/CD kecuali komputer
memberi isyarat terlebih dahulu sebelum data hendak dihantar. Adapter bagi
Local Talk dan kabel pasangan berpintal yang khas boleh digunakan untuk
menghubung satu siri komputer menggunakan port bersiri.Sistem operasi Macintosh
membenarkan sitem pengoperasian sesama pelanggan (peer-to-peer) tanpa perlu
perisian tambahan. Dengan penambahan versi fail pelayan dari perisian
AppleShare, sistem pelanggan-pelayan (client-server) bleh dilaksanakan. Protokol
Local Talk membenarkan topologi linear bas atau topologi pepohon dengan
menggunakan kabel pasangan berpintal. Satu kekurangan kecil bagi Local Talk
ialah dari segi kepantasan. Kepantasan bagi penghantaran maklumat bagi Local
Talk hanyalah 230 Kbps.
TOKEN RING
Protokol Token Ring telah dibangunkan oleh syarikat IBM pada pertengahan tahun
1980-an. Cara kemasukan (access method) menggunakan cara penghantaran maklumat
di dalam suatu bulatan. Di dalam Token Ring, beberapa komputer dihubungkan bagi
membolehkan isyarat berlegar di sepanjang talian rangkaian komputer tersebut.
Satu token elektronik bergerak mengelilingi bulatan dari satu komputer ke satu
komputer dan jika komputer tersebut tidak mempunyai informasi untuk dihantar,
ia akan bergerak melepasi komputer tersebut ke stesen kerja yang seterusnya.
Jika komputer tersebut hendak menghantar maklumat, ia akan mengisi data atau
maklumat kepada token yang datang kepadanya. Token tersebut kemudiannya
bergerak meneruskan perjalanannya sehingga ia sampai kepada komputer di mana
data atau maklumat tersebut hendak dihantar. Pada titik ini, data atau maklumat
tersebut akan diperolehi oleh komputer yang menerima. Protokol Gelang Token
mengkehendaki topologi Bintang Cecincin (star-wired ring) dengan penggunaan
kabel pasangan berpintal (twisted pair) atau kabel fiber optik. Ia berupaya
menjalankan operasi pada kepantasan 4 Mbps atau 16 Mpbs. Oleh kerana penggunaan
Ethernet yang semakin popular, persekitaran sekolah semakin kurang menggunakan
Gelang Token.
FIBER PENGAGIHAN DATA ANTARA MUKA (FDDI)
Fiber Pengagihan Data Antara Muka (Fiber
Distributed Data Interface – FDDI) merupakan satu protokol rangkaian
terutamanya untuk menghubungkan dua atau lebih rangkaian kawasan setempat, bagi
meliputi kawasan-kawasan yang jauh jaraknya. Cara kemasukkan (access method)
yang digunakan oleh FDDI turut melibatkan penghantaran token. FDDI menggunakan
topologi fizikal cecincin berkembar. Penghantaran biasanya terjadi pada salah
satu daripada token atau cecincin, namun begitu jika berlakunya kegagalan di
dalam rangkaian, sistem tersebut akan menggerakkan informasi secara automatik
menggunakan perjalanan rangkaian yang kedua seterusnya membentuk satu rangkaian
baru yang lengkap. Kelebihan yang ketara bagi penggunaan FDDI ialah kepantasan
di dalam penghantaran maklumat. Ia beroperasi menggunakan kabel fiber optik
pada 100 Mbps.
Internet ialah semua rangkaian komputer
di seluruh dunia yang disambungkan dengan rangkaian yang lebih kecil dan
bergerak lebih perlahan. Ia mempunyai amat banyak maklumat untuk dicapai oleh
sesiapa sahaja, dan ia menyediakan penghantaran maklumat serta-merta ke seluruh
dunia. Ini membolehkan manusia di seluruh dunia berkomunikasi di antara satu
sama lain dalam masa beberapa minit sahaja. Oleh sebab Internet semakin bertambah
popular, ia akan menjadi sebahagian daripada hidup anda. Pada mulanya, Internet
hanya terdapat di dalam sistem pendidikan, perbadanan, kerajaan atau agensi
lain, dan sangat mahal serta sukar untuk mendapatkan laluan ke Internet. Pada
masa ini, Internet boleh disambung melalui pelbagai kaedah menggunakan khidmat
komersil atau Penyedia Khidmat Internet (Internet Service Provider- ISP) yang
semakin bertambah bilangannya. Internet tidak lagi terhad kepada pakar teknikal
atau individu yang pandai komputer sahaja. Sesiapa sahaja yang ada laluan
komputer boleh menggunakan Internet sebelum dekad ini berakhir. Internet akan
terus berubah dan berevolusi.Teknologi baru akan terus muncul dan menyebabkan
sesetengah teknologi sekarang menjadi usang. Walaupun Internet berada pada
tahap perkembangan awal, inilah masanya untuk meneroka dan menjelajahi maklumat
yang begitu banyak yang didapati pada Internet. Pertumbuhan Internet yang pesat
telah mewujudkan cara baru untuk berkomunikasi. popularitinya dicerminkan oleh
pelbagai media yang kita gunakan pada hari ini.
Setiap hari, televisyen, radio dan media
cetak mewar-warkan rujukan URL, atau alamat lokasi Internet mereka pada
penghujung rancangan masing-masing. Banyak syarikat yang telah melabur masa dan
wang mereka pada Internet. Di antara komponen Internet yang penting ialah Web.
World Wide Web telah berkembang menjadi suatu cara baru berkomunikasi dengan
jutaan manusia. Di dalam tempoh antara bulan Julai 1995 hingga Januari 1996,
bilangan komputer yang tersambung secara langsung kepada rangkaian fizikal
Internet, yang juga dikenali sebagai hos, telah meningkat sekurang-kurangnya
70%. Pertumbuhan Internet yang mendadak boleh dikatakan akibat daripada
perkembangan penyemak seimbas (browser) Web bergrafik yang begitu pantas.
Komponen grafik Web telah mewujudkan suatu media baru kepada banyak syarikat
untuk mengiklankan produk mereka dan untuk berkomunikasi dengan pelanggan
mereka. Walaupun Web merupakan komponen Internet yang penting, namun begitu ada
juga bahagian-bahagian lain Internet yang dapat membawa anda kepada penemuan
yang menarik. Di antaranya ialah tapak Gopher dan FTP. Sistem pacuan menu tapak
Gopher mengandungi teks dan maklumat lain. Pelayan FTP juga membolehkan anda
memuat turun (download) fail teks dan juga fail audio serta video. Dengan
pelayan FTP, fail dari sistem yang jauh boleh dipindahkan ke komputer pengguna.
Mel elektronik, atau mel-e merupakan
satu lagi alat penting yang boleh digunakan. Mel-e menyediakan cara pantas
untuk berhubung dengan orang lain dalam jabatan yang sama mahupun di seluruh
dunia. Berbanding dengan kiriman surat melalui perkhidmatan pos yang mungkin
mengambil masa beberapa hari atau minggu, mesej mel-e dapat disampaikan di
dalam beberapa minit sahaja. Sama seperti mel-e, kumpulan berita merupakan satu
lagi cara berkomunikasi dengan orang lain. Kumpulan berita ialah forum
perbincangan dalam Usenet, tempat pengguna bertukar-tukar fikiran tentang tajuk
yang khusus. Menghantar mesej kepada kumpulan berita sama seperti menghantar
mesej kepada semua orang dalam suatu senarai mel yang besar. Kebanyakan alat
Internet ini dapat dimasuki melalui penyemak seimbas Web seperti Netscape
Navigator atau Internet Explorer. Tapak Web, Gopher dan FTP boleh menukar
malahan membina rangkaian yang terputus. Oleh kerana sifat Internet yang
sentiasa berkembang, pengalaman Internet pengguna akan berubah setiap kali
pengguna menggunakan penyemak seimbas Web.
The Internet is a global system of interconnected computer
networks that use the standard Internet protocol suite (often called TCP/IP,
although not all protocols use TCP) to serve billions of users worldwide. It is
a network of networks that consists of millions of private, public, academic,
business, and government networks, of local to global scope, that are linked by
a broad array of electronic, wireless and optical networking technologies. The
Internet carries an extensive range of information resources and services, such
as the inter-linked hypertext documents of the World Wide Web (WWW) and the
infrastructure to support email.
Most traditional communications media including telephone,
music, film, and television are reshaped or redefined by the Internet, giving
birth to new services such as Voice over Internet Protocol (VoIP) and Internet
Protocol Television (IPTV). Newspaper, book and other print publishing are
adapting to Web site technology, or are reshaped into blogging and web feeds.
The Internet has enabled or accelerated new forms of human interactions through
instant messaging, Internet forums, and social networking. Online shopping has
boomed both for major retail outlets and small artisans and traders.
Business-to-business and financial services on the Internet affect supply
chains across entire industries.
The origins of the Internet reach back to research of the
1960s, commissioned by the United States government in collaboration with
private commercial interests to build robust, fault-tolerant, and distributed
computer networks. The funding of a new U.S. backbone by the National Science
Foundation in the 1980s, as well as private funding for other commercial
backbones, led to worldwide participation in the development of new networking
technologies, and the merger of many networks. The commercialization of what
was by the 1990s an international network resulted in its popularization and
incorporation into virtually every aspect of modern human life. As of 2011,
more than 2.2 billion people — nearly a third of Earth's population — use the
services of the Internet.
The Internet has no centralized governance in either
technological implementation or policies for access and usage; each constituent
network sets its own standards. Only the overreaching definitions of the two
principal name spaces in the Internet, the Internet Protocol address space and
the Domain Name System, are directed by a maintainer organization, the Internet
Corporation for Assigned Names and Numbers (ICANN). The technical underpinning
and standardization of the core protocols (IPv4 and IPv6) is an activity of the
Internet Engineering Task Force (IETF), a non-profit organization of loosely
affiliated international participants that anyone may associate with by
contributing technical expertise.
Internet is a short form of the
technical term internetwork, the result of interconnecting computer networks
with special gateways or routers. The Internet is also often referred to as the
Net.
The term the Internet, when
referring to the entire global system of IP networks, has been treated as a
proper noun and written with an initial capital letter. In the media and
popular culture, a trend has also developed to regard it as a generic term or
common noun and thus write it as "the internet", without
capitalization. Some guides specify that the word should be capitalized as a
noun but not capitalized as an adjective.
The terms Internet and World Wide
Web are often used in everyday speech without much distinction. However, the
Internet and the World Wide Web are not one and the same. The Internet
establishes a global data communications system between computers. In contrast,
the Web is one of the services communicated via the Internet. It is a
collection of interconnected documents and other resources, linked by
hyperlinks and URLs.
History
Main articles: History of the
Internet and History of the World Wide Web
Professor Leonard Kleinrock with
the first ARPANET Interface Message Processors at UCLA.
Research into packet switching
started in the early 1960s and packet switched networks such as ARPANET, Mark I
at NPL in the UK, CYCLADES, Merit Network, Tymnet, and Telenet, were developed
in the late 1960s and early 1970s using a variety of protocols. The ARPANET in
particular led to the development of protocols for internetworking, where
multiple separate networks could be joined together into a network of networks.
The first two nodes of what would
become the ARPANET were interconnected between Leonard Kleinrock's Network
Measurement Center at the UCLA's School of Engineering and Applied Science and
Douglas Engelbart's NLS system at SRI International (SRI) in Menlo Park,
California, on 29 October 1969. The third site on the ARPANET was the
Culler-Fried Interactive Mathematics center at the University of California at
Santa Barbara, and the fourth was the University of Utah Graphics Department.
In an early sign of future growth, there were already fifteen sites connected
to the young ARPANET by the end of 1971. These early years were documented in
the 1972 film Computer Networks: The Heralds of Resource Sharing.
Early international
collaborations on ARPANET were sparse. For various political reasons, European
developers were concerned with developing the X.25 networks. Notable exceptions
were the Norwegian Seismic Array (NORSAR) in 1972, followed in 1973 by Sweden
with satellite links to the Tanum Earth Station and Peter Kirstein's research
group in the UK, initially at the Institute of Computer Science, London
University and later at University College London.
T3 NSFNET Backbone, c. 1992
In 1982, the Internet Protocol
Suite (TCP/IP) was standardized and the concept of a world-wide network of
fully interconnected TCP/IP networks called the Internet was introduced. Access
to the ARPANET was expanded in 1981 when the National Science Foundation (NSF)
developed the Computer Science Network (CSNET). In December 1974, RFC 675 – Specification
of Internet Transmission Control Program, by Vinton Cerf, Yogen Dalal, and Carl
Sunshine, used the term internet, as a shorthand for internetworking; later
RFCs repeat this use, so the word started out as an adjective rather than the
noun it is today.
TCP/IP network access expanded
again in 1986 when NSFNET provided access to supercomputer sites in the United
States from research and education organizations, first at 56 kbit/s and later at
1.5 Mbit/s and 45 Mbit/s. Commercial internet service providers (ISPs) began to
emerge in the late 1980s and 1990s. The ARPANET was decommissioned in 1990. The
Internet was commercialized in 1995 when NSFNET was decommissioned, removing
the last restrictions on the use of the Internet to carry commercial traffic.
The Internet started a rapid expansion to Europe and Australia in the mid to
late 1980s and to Asia in the late 1980s and early 1990s.
This NeXT Computer was used by
Sir Tim Berners-Lee at CERN and became the world's first Web server.
Since the mid-1990s the Internet
has had a tremendous impact on culture and commerce, including the rise of near
instant communication by email, instant messaging, Voice over Internet Protocol
(VoIP) "phone calls", two-way interactive video calls, and the World
Wide Web with its discussion forums, blogs, social networking, and online
shopping sites. Increasing amounts of data are transmitted at higher and higher
speeds over fiber optic networks operating at 1-Gbit/s, 10-Gbit/s, or more. The
Internet continues to grow, driven by ever greater amounts of online
information and knowledge, commerce, entertainment and social networking.
During the late 1990s, it was
estimated that traffic on the public Internet grew by 100 percent per year,
while the mean annual growth in the number of Internet users was thought to be
between 20% and 50%. 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. As of 31 March 2011, the estimated total number of Internet
users was 2.095 billion (30.2% of world population). It is estimated that in
1993 the Internet carried only 1% of the information flowing through two-way
telecommunication, by 2000 this figure had grown to 51%, and by 2007 more than
97% of all telecommunicated information was carried over the Internet.
Technology
Protocols
Main article: Internet protocol
suite
The communications infrastructure
of the Internet consists of its hardware components and a system of software
layers that control various aspects of the architecture. While the hardware can
often be used to support other software systems, it is the design and the
rigorous standardization process of the software architecture that
characterizes the Internet and provides the foundation for its scalability and
success. The responsibility for the architectural design of the Internet
software systems has been delegated to the Internet Engineering Task Force
(IETF). The IETF conducts standard-setting work groups, open to any individual,
about the various aspects of Internet architecture. Resulting discussions and
final standards are published in a series of publications, each called a
Request for Comments (RFC), freely available on the IETF web site. The
principal methods of networking that enable the Internet are contained in
specially designated RFCs that constitute the Internet Standards. Other less
rigorous documents are simply informative, experimental, or historical, or
document the best current practices (BCP) when implementing Internet
technologies.
The Internet standards describe a
framework known as the Internet protocol suite. This is a model architecture
that divides methods into a layered system of protocols (RFC 1122, RFC 1123).
The layers correspond to the environment or scope in which their services
operate. At the top is the application layer, the space for the
application-specific networking methods used in software applications, e.g., a
web browser program. Below this top layer, the transport layer connects
applications on different hosts via the network (e.g., client–server model) with
appropriate data exchange methods. Underlying these layers are the core
networking technologies, consisting of two layers. The internet layer enables
computers to identify and locate each other via Internet Protocol (IP)
addresses, and allows them to connect to one-another via intermediate (transit)
networks. Last, at the bottom of the architecture, is a software layer, the
link layer, that provides connectivity between hosts on the same local network
link, such as a local area network (LAN) or a dial-up connection. The model,
also known as TCP/IP, is designed to be independent of the underlying hardware,
which the model therefore does not concern itself with in any detail. Other
models have been developed, such as the Open Systems Interconnection (OSI) model,
but they are not compatible in the details of description or implementation;
many similarities exist and the TCP/IP protocols are usually included in the
discussion of OSI networking.
The most prominent component of
the Internet model is the Internet Protocol (IP), which provides addressing
systems (IP addresses) for computers on the Internet. IP enables
internetworking and in essence establishes the Internet itself. IP Version 4
(IPv4) is the initial version used on the first generation of today's Internet
and is still in dominant use. It was designed to address up to ~4.3 billion
(109) Internet hosts. However, the explosive growth of the Internet has led to
IPv4 address exhaustion, which entered its final stage in 2011, when the global
address allocation pool was exhausted. A new protocol version, IPv6, was
developed in the mid-1990s, which provides vastly larger addressing
capabilities and more efficient routing of Internet traffic. IPv6 is currently
in growing deployment around the world, since Internet address registries
(RIRs) began to urge all resource managers to plan rapid adoption and
conversion.
IPv6 is not interoperable with
IPv4. In essence, it establishes a parallel version of the Internet not
directly accessible with IPv4 software. This means software upgrades or
translator facilities are necessary for networking devices that need to
communicate on both networks. Most modern computer operating systems already
support both versions of the Internet Protocol. Network infrastructures,
however, are still lagging in this development. Aside from the complex array of
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 defined by its
interconnections and routing policies.
Structure
The Internet structure and its
usage characteristics have been studied extensively. It has been determined
that both 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 GEANT, GLORIAD, Internet2, and
the UK's national research and education network JANET. These in turn are built
around smaller networks (see also the list of academic computer network
organizations).
Many computer scientists describe
the Internet as a "prime example of a large-scale, highly engineered, yet
highly complex system". The Internet is 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. The principles of the routing and addressing methods for
traffic in the Internet reach back to their origins in the 1960s when the
eventual scale and popularity of the network could not be anticipated. Thus,
the possibility of developing alternative structures is investigated. The
Internet structure was found to be highly robust[33] to random failures and
very vulnerable to high degree attacks.
Governance
Main article: Internet governance
ICANN headquarters in Marina Del
Rey, California, United States
The Internet is a globally
distributed network comprising many voluntarily interconnected autonomous
networks. It operates without a central governing body. However, to maintain
interoperability, all technical and policy aspects of the underlying core
infrastructure and the principal name spaces are administered by the Internet
Corporation for Assigned Names and Numbers (ICANN), headquartered in Marina del
Rey, California. ICANN is the authority that coordinates the assignment of
unique identifiers for use on the Internet, including domain names, Internet
Protocol (IP) addresses, application port numbers in the transport protocols,
and many other parameters. Globally unified name spaces, in which names and
numbers are uniquely assigned, are essential for the global reach of the
Internet. ICANN is governed by an international board of directors drawn from across
the Internet technical, business, academic, and other non-commercial
communities. The government of the United States continues to have the primary
role in approving changes to the DNS root zone that lies at the heart of the
domain name system. ICANN's role in coordinating the assignment of unique
identifiers distinguishes it as perhaps the only central coordinating body on
the global Internet. On 16 November 2005, the World Summit on the Information
Society, held in Tunis, established the Internet Governance Forum (IGF) to
discuss Internet-related issues.
Modern uses
The Internet allows greater
flexibility in working hours and location, especially with the spread of
unmetered high-speed connections. The Internet can be accessed almost anywhere
by numerous means, including through mobile Internet devices. mobile phones,
datacards, handheld game consoles and cellular routers allow users to connect
to the Internet wirelessly. Within the limitations imposed by small screens and
other limited facilities of such pocket-sized devices, the services of the
Internet, including email and the web, may be available. Service providers may
restrict the services offered and mobile data charges may be significantly
higher than other access methods.
Educational material at all
levels from pre-school to post-doctoral is available from websites. Examples
range from CBeebies, through school and high-school revision guides, virtual
universities, to access to top-end scholarly literature through the likes of
Google Scholar. For distance education, help with homework and other
assignments, self-guided learning, whiling away spare time, or just looking up
more detail on an interesting fact, it has never been easier for people to
access educational information at any level from anywhere. The Internet in
general and the World Wide Web in particular are important enablers of both
formal and informal education.
The low cost and nearly
instantaneous sharing of ideas, knowledge, and skills has made collaborative
work dramatically easier, with the help of collaborative software. Not only can
a group cheaply communicate and share ideas but the wide reach of the Internet
allows such groups more easily to form. An example of this is the free software
movement, which has produced, among other things, Linux, Mozilla Firefox, and
OpenOffice.org. Internet chat, whether in the form of an IRC chat room or
channel, via an instant messaging system, or a social networking website,
allows colleagues to stay in touch in a very convenient way when working at
their computers during the day. Messages can be exchanged even more quickly and
conveniently than via email. These systems may allow files to be exchanged,
drawings and images to be shared, or voice and video contact between team
members.
Content management systems allow
collaborating teams to work on shared sets of documents simultaneously without
accidentally destroying each other's work. Business and project teams can share
calendars as well as documents and other information. Such collaboration occurs
in a wide variety of areas including scientific research, software development,
conference planning, political activism and creative writing. Social and
political collaboration is also becoming more widespread as both Internet
access and computer literacy spread.
The Internet allows computer
users to remotely access other computers and information stores easily,
wherever they may be. They may do this with or without computer security, i.e.
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 bookkeepers, in other remote locations, based
on information emailed 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 their desk, perhaps on the other side of the world on a
business trip or a holiday, can access their emails, access their data using
cloud computing, or open a remote desktop session into their office PC using a
secure Virtual Private Network (VPN) connection on the Internet. This can give
the worker complete access to all of their normal files and data, including
email and other applications, while away from the office. This concept has been
referred to among system administrators as the Virtual Private Nightmare,
because it extends the secure perimeter of a corporate network into remote
locations and its employees' homes.
Services
Information
Many people use the terms
Internet and World Wide Web, or just the Web, interchangeably, but the two
terms are not synonymous. The World Wide Web is a global set of documents,
images and other resources, logically interrelated by hyperlinks and referenced
with Uniform Resource Identifiers (URIs). URIs symbolically identify services,
servers, and other databases, and the documents and resources that they can
provide. Hypertext Transfer Protocol (HTTP) is the main access protocol of the
World Wide Web, but it is only one of the hundreds of communication protocols
used on the Internet. Web services also use HTTP to allow software systems to
communicate in order to share and exchange business logic and data.
World Wide Web browser software,
such as Microsoft's Internet Explorer, Mozilla Firefox, Opera, Apple's Safari,
and Google Chrome, lets users navigate from one web page to another via
hyperlinks embedded in the documents. These documents may also contain any
combination of computer data, including graphics, sounds, text, video,
multimedia and interactive content that runs while the user is interacting with
the page. Client-side software can include animations, games, office
applications and scientific demonstrations. Through keyword-driven Internet
research using search engines like Yahoo! and Google, users worldwide have
easy, instant access to a vast and diverse amount of online information.
Compared to printed media, books, encyclopedias and traditional libraries, the
World Wide Web has enabled the decentralization of information on a large
scale.
The Web has also enabled
individuals and organizations to publish ideas and information to a potentially
large audience online at greatly reduced expense and time delay. Publishing a
web page, a blog, or building a website involves little initial cost and many
cost-free services are available. Publishing and maintaining large,
professional web sites with attractive, diverse and up-to-date information is
still a difficult and expensive proposition, however. Many individuals and some
companies and groups use web logs or blogs, which are largely used as easily
updatable online diaries. Some commercial organizations encourage staff to
communicate advice in 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. Collections of personal web pages
published by large service providers remain popular, and have become
increasingly sophisticated. Whereas operations such as Angelfire and GeoCities
have existed since the early days of the Web, newer offerings from, for
example, Facebook and Twitter currently have large followings. These operations
often brand themselves as social network services rather than simply as web
page hosts.
Advertising on popular web pages
can be lucrative, and e-commerce or the sale of products and services directly
via the Web continues to grow.
When the Web began in the 1990s,
a typical web page was stored in completed form on a web server, formatted in
HTML, ready to be sent to a user's browser in response to a request. Over time,
the process of creating and serving web pages has become more automated and
more dynamic. Websites are often created using content management or wiki
software with, initially, very little content. Contributors to these systems,
who may be paid staff, members of a club or other organization or members of
the public, fill underlying databases with content using editing pages designed
for that purpose, while casual visitors view and read this content in its final
HTML form. There may or may not be editorial, approval and security systems
built into the process of taking newly entered content and making it available
to the target visitors.
Communication
Email is an important
communications service available on the Internet. The concept of sending
electronic text messages between parties in a way analogous to mailing letters
or memos predates the creation of the Internet. Pictures, documents and other
files are sent as email attachments. Emails can be cc-ed to multiple email
addresses.
Internet telephony is another
common communications service made possible by the creation of the Internet.
VoIP stands for Voice-over-Internet Protocol, referring to the protocol that
underlies all Internet communication. The idea began in the early 1990s with
walkie-talkie-like voice applications for personal computers. 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 voice traffic, VoIP
can be free or cost much less than a traditional telephone call, especially
over long distances and especially for those with always-on Internet
connections such as cable or ADSL. VoIP is maturing into a competitive
alternative to traditional telephone service. Interoperability between
different providers has improved and the ability to call or receive a call from
a traditional telephone is available. Simple, inexpensive VoIP network adapters
are available that eliminate the need for a personal computer.
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 an emergency service,
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 phone equipment and the Internet access devices. VoIP has also
become increasingly popular for gaming applications, as a form of communication
between players. Popular VoIP clients for gaming include Ventrilo and Teamspeak.
Wii, PlayStation 3, and Xbox 360 also offer VoIP chat features.
Data transfer
File sharing is an example of
transferring large amounts of data across the Internet. A computer file can be
emailed 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 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 for access to the file. The price can be paid by the remote charging of
funds from, for example, a credit card whose details are also passed – usually
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 worldwide basis, are
changing the production, sale, and distribution of anything that can be reduced
to a computer file for transmission. This includes all manner of print
publications, software products, news, music, film, video, photography,
graphics and the other arts. This in turn has caused seismic shifts in each of
the existing industries that previously controlled the production and
distribution of these products.
Streaming media is the real-time
delivery of digital media for the immediate consumption or enjoyment by end
users. Many radio and television broadcasters provide Internet feeds of their
live audio and video productions. 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 available types of content is much wider, from
specialized technical webcasts to on-demand popular multimedia services.
Podcasting is a variation on this theme, where – usually audio – material is
downloaded and played back on a computer or shifted to a portable media 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
worldwide.
Digital media streaming increases
the demand for network bandwidth. For example, standard image quality needs 1
Mbit/s link speed for SD 480p, HD 720p quality requires 2.5 Mbit/s, and the
top-of-the-line HDX quality needs 4.5 Mbit/s for 1080p.
Webcams are a low-cost extension
of this phenomenon. While some webcams can give full-frame-rate video, the
picture either is usually small or updates slowly. Internet users can watch
animals around an African waterhole, ships in the Panama Canal, traffic at a
local roundabout or monitor their own premises, live and in real time. Video
chat rooms and video conferencing are also popular with many uses being found for
personal webcams, with and without two-way sound. YouTube was founded on 15
February 2005 and is now the leading website for free streaming video with a
vast number of users. It uses a flash-based web player to stream and show video
files. Registered users may upload an unlimited amount of video and build their
own personal profile. YouTube claims that its users watch hundreds of millions,
and upload hundreds of thousands of videos daily.
Access
Main article: Internet access
See also: Global Internet usage,
English on the Internet, and Unicode
Graph of Internet users per 100
inhabitants between 1997 and 2007 by International Telecommunication Union
The prevalent language for
communication on the Internet has been English. This may be a result of the origin
of the Internet, as well as the language's role as a lingua franca. Early
computer systems were limited to the characters in the American Standard Code
for Information Interchange (ASCII), a subset of the Latin alphabet.
After English (27%), the most
requested languages on the World Wide Web are Chinese (23%), Spanish (8%),
Japanese (5%), Portuguese and German (4% each), Arabic, French and Russian (3%
each), and Korean (2%). By region, 42% of the world's Internet users are based
in Asia, 24% in Europe, 14% in North America, 10% in Latin America and the
Caribbean taken together, 6% in Africa, 3% in the Middle East and 1% in
Australia/Oceania. The Internet's technologies have developed enough in recent
years, especially in the use of Unicode, that good facilities are available for
development and communication in the world's widely used languages. However,
some glitches such as mojibake (incorrect display of some languages'
characters) still remain.
Common methods of Internet access
in homes include dial-up, landline broadband (over coaxial cable, fiber optic
or copper wires), Wi-Fi, satellite and 3G/4G technology 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. These terminals are widely accessed for various
usage like ticket booking, bank deposit, online payment etc. 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 would-be
users need 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. A whole campus or park, or
even an entire city can be enabled. Grassroots efforts have led to wireless
community networks. Commercial Wi-Fi services covering large city areas are in
place in London, Vienna, Toronto, San Francisco, Philadelphia, Chicago and
Pittsburgh. The Internet can then be accessed from such places as a park bench.
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 in general 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.
An Internet blackout or outage
can be caused by local signaling interruptions. Disruptions of submarine
communications cables may cause blackouts or slowdowns to large areas, such as
in the 2008 submarine cable disruption. Internet blackouts affecting almost
entire countries can be achieved by governments as a form of Internet
censorship, as in the blockage of the Internet in Egypt, whereby approximately
93% of networks were without access in 2011 in an attempt to stop mobilization
for anti-government protests.
In an American study in 2005, the
percentage of men using the Internet was very slightly ahead of the percentage
of women, although this difference reversed in those under 30. Men logged on
more often, spent more time online, and were more likely to be broadband users,
whereas women tended to make more use of opportunities to communicate (such as
email). Men were more likely to use the Internet to pay bills, participate in
auctions, and for recreation such as downloading music and videos. Men and women
were equally likely to use the Internet for shopping and banking. More recent
studies indicate that in 2008, women significantly outnumbered men on most
social networking sites, such as Facebook and Myspace, although the ratios varied
with age. In addition, women watched more streaming content, whereas men
downloaded more. In terms of blogs, men were more likely to blog in the first
place; among those who blog, men were more likely to have a professional blog,
whereas women were more likely to have a personal blog.
Overall Internet usage has seen
tremendous growth. From 2000 to 2009, the number of Internet users globally
rose from 394 million to 1.858 billion. By 2010, 22 percent of the world's
population had access to computers with 1 billion Google searches every day,
300 million Internet users reading blogs, and 2 billion videos viewed daily on
YouTube.
Social impact
Main article: Sociology of the
Internet
The Internet has enabled entirely
new forms of social interaction, activities, and organizing, thanks to its
basic features such as widespread usability and access. Social networking
websites such as Facebook, Twitter and MySpace have created new ways to
socialize and interact. Users of these sites are able to add a wide variety of
information to pages, to pursue common interests, and to connect with others.
It is also possible to find existing acquaintances, to allow communication
among existing groups of people. Sites like LinkedIn foster commercial and
business connections. YouTube and Flickr specialize in users' videos and
photographs.
In the first decade of the 21st
century, the first generation is raised with widespread availability of
Internet connectivity, bringing consequences and concerns in areas such as
personal privacy and identity, and distribution of copyrighted materials. These
"digital natives" face a variety of challenges that were not present
for prior generations.
The Internet has achieved new
relevance as a political tool, leading to Internet censorship by some states.
The presidential campaign of Howard Dean in 2004 in the United States was
notable for its success in soliciting donation via the Internet. Many political
groups use the Internet to achieve a new method of organizing in order to carry
out their mission, having given rise to Internet activism, most notably
practiced by rebels in the Arab Spring. Some governments, such as those of
Iran, North Korea, Burma, the People's Republic of China, and Saudi Arabia,
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, Denmark, 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 authorities. While this list of forbidden URLs is supposed to contain
addresses of only known child pornography sites, the content of the list is secret.
Many countries, including the United States, have enacted laws against the
possession or distribution of certain material, such as child pornography, via
the Internet, but do not mandate filtering software. There are many free and
commercially available software programs, called content-control software, with
which a user can choose to block offensive websites on individual computers or
networks, in order to limit a child's access to pornographic materials or
depiction of violence.
The Internet has been a major
outlet for leisure activity since its inception, with entertaining social
experiments such as MUDs and MOOs being conducted on university servers, and
humor-related Usenet groups receiving much 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 taken advantage of the World Wide Web,
and often provide a significant source of advertising revenue for other
websites. Although many governments have attempted to restrict both industries'
use of the Internet, in general this has failed to stop their widespread
popularity.
One main area of leisure activity
on the Internet is multiplayer gaming. This form of recreation creates
communities, where people of all ages and origins enjoy the fast-paced world of
multiplayer games. These range from MMORPG to first-person shooters, from
role-playing video games to online gambling. While online gaming has been
around since the 1970s, modern modes of online gaming began with subscription
services such as GameSpy and MPlayer. Non-subscribers were limited to certain
types of game play or certain games. Many people use the Internet to access and
download music, movies and other works for their enjoyment and relaxation. Free
and fee-based services exist for all of these activities, using centralized
servers and distributed peer-to-peer technologies. Some of these sources
exercise more care with respect to the original artists' copyrights than
others.
Many people use the World Wide
Web to access news, weather and sports reports, to plan and book vacations and
to find out more about their 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. The Internet has seen a growing number of Web
desktops, where users can access their files and settings via the Internet.
Cyberslacking can become a drain
on corporate resources; the average UK employee spent 57 minutes a day surfing the
Web while at work, according to a 2003 study by Peninsula Business Services.
Internet addiction disorder is excessive computer use that interferes with
daily life. Psychologist Nicolas Carr believe that Internet use has other
effects on individuals, for instance improving skills of scan-reading and
interfering with the deep thinking that leads to true creativity.
Internet usage has been correlated
to users' loneliness. Lonely people tend to use the Internet as an outlet for
their feelings and to share their stories with others, such as in the "I
am lonely will anyone speak to me" thread.
Cybersectarianism is a new
organizational form which involves: "highly dispersed small groups of
practitioners that may remain largely anonymous within the larger social
context and operate in relative secrecy, while still linked remotely to a
larger network of believers who share a set of practices and texts, and often a
common devotion to a particular leader. Overseas supporters provide funding and
support; domestic practitioners distribute tracts, participate in acts of
resistance, and share information on the internal situation with outsiders.
Collectively, members and practitioners of such sects construct viable virtual
communities of faith, exchanging personal testimonies and engaging in
collective study via email, on-line chat rooms and web-based message
boards."
Internet and political
revolutions
The New York Times suggested that
social media websites such as Facebook and Twitter helped people organise the
political revolutions in Egypt where it helped certain classes of protesters
organise protests, communicate grievances, and disseminate information.
The potential of the Internet as
a civic tool of communicative power was thoroughly explored by Simon R. B.
Berdal in his thesis of 2004:
“As the globally evolving Internet provides ever new
access points to virtual discourse forums, it also promotes new civic relations
and associations within which communicative power may flow and accumulate. Thus,
traditionally ... national-embedded peripheries get entangled into greater,
international peripheries, with stronger combined powers... The Internet, as a
consequence, changes the topology of the "centre-periphery" model, by
stimulating conventional peripheries to interlink into
"super-periphery" structures, which enclose and "besiege"
several centres at once.”
Berdal, therefore, extends the
Habermasian notion of the Public sphere to the Internet, and underlines the
inherent global and civic nature that intervowen Internet technologies provide.
To limit the growing civic potential of the Internet, Berdal also notes how
"self-protective measures" are put in place by those threatened by
it:
“If we consider China’s attempts to filter
"unsuitable material" from the Internet, most of us would agree that
this resembles a self-protective measure by the system against the growing
civic potentials of the Internet. Nevertheless, both types represent
limitations to "peripheral capacities". Thus, the Chinese government
tries to prevent communicative power to build up and unleash (as the 1989
Tiananmen Square uprising suggests, the government may find it wise to install
"upstream measures"). Even though limited, the Internet is proving to
be an empowering tool also to the Chinese periphery: Analysts believe that
Internet petitions have influenced policy implementation in favour of the
public’s online-articulated will ...”
Internet and philanthropy
The spread of low-cost internet
access in developing countries has opened up new possibilities for peer-to-peer
charities, which allow individuals to contribute small amounts to charitable
projects for other individuals. Websites such as Donors Choose and Global
Giving now allow small-scale donors to direct funds to individual projects of
their choice.
A popular twist on internet-based
philanthropy is the use of peer-to-peer lending for charitable purposes. Kiva
pioneered this concept in 2005, offering the first web-based service to publish
individual loan profiles for funding. Kiva raises funds for local intermediary
microfinance organizations which post stories and updates on behalf of the
borrowers. Lenders can contribute as little as $25 to loans of their choice,
and receive their money back as borrowers repay. Kiva falls short of being a
pure peer-to-peer charity, in that loans are disbursed before being funded by
lenders and borrowers do not communicate with lenders themselves.
However, the recent spread of
cheap internet access in developing countries has made genuine international
person-to-person philanthropy increasingly feasible. In 2009 the US-based
nonprofit Zidisha tapped into this trend to offer the first person-to-person
microfinance platform to link lenders and borrowers across international
borders without intermediaries. Inspired by interactive websites such as
Facebook and eBay, Zidisha facilitates direct dialogue and microlending
transactions between individual web users worldwide and computer-literate,
low-income entrepreneurs in developing countries. Zidisha members can fund loans
for as little as a dollar, which the borrowers then use to develop business
activities that improve their families' incomes while repaying loans to the
members with interest. Zidisha borrowers access the internet via public
cybercafes, donated laptops in village schools, and even smart phones, then
create their own profile pages through which they share photos and information
about themselves and their businesses. As they repay their loans, borrowers
continue to share updates and dialogue with lenders via their profile pages.
This direct web-based connection allows Zidisha members themselves to take on
many of the communication and recording tasks traditionally performed by local
organizations, bypassing geographic barriers and dramatically reducing the cost
of microfinance services to the entrepreneurs.