Internet ( slaidid ) (0)

Internet
Andra Oja
What is Internet?
The Internet is a global system of interconnected
computer networks that use the standard Internet
Protocol Suite (TCP/IP) 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.
History of the Internet
1957:The United States Department of Defense
formed a small agency called ARPA (Advanced
Research Projects Agency) to develop military
science and technology.
1961-1965:The Massachusetts Institute of
Technology (MIT) started to research sharing
information in small, phone-linked networks.
ARPA is one of their main sponsors.
1966: The first ARPANET plan is unveiled by
Larry Roberts of MIT. Packet switching
technology is getting off the ground, and small
university networks are beginning to be
developed.
# 1969:The Department of Defense commissions
the fledgling ARPAnet for network research. The
first official network nodes were UCLA, Standford
Research Institute,UCSB, and the University of
Utah. The first node to node message was sent
from UCLA to SRI.
# 1971: more nodes join the network, bringing the
total to 15. These new nodes include Harvard and
NASA.
# 1973: ARPAnet goes global when the the
University College of London and Norway's Royal
Radar Establishment join up.
1974: Network intercommunication is becoming
more sophisticated; data is now transmitted more
quickly and efficiently with the design of TCP
(Transmission Control Program).
1976: Unix is developed at AT and T; Queen
Elizabeth sends out her first email message.
1979: USENET, the mother of all networked
discussion groups, is developed.
1982: Internet technology protocols are
developed, commonly known as TCP/IP
(Transmission Control Protocol and Internet
Protocol).
1984: Number of hosts is now up to 1000, with
more being added every day.
1985: The first registered domain is
Symbolics.com.
1987: Number of hosts breaks the 10,000 mark.
1988: First large-scale Internet worm affects
thousands of Internet hosts.
1991: Tim Berners-Lee develops the World Wide
Web.
1993: The World Wide Web's annual growth is
now at a staggering 341,634%.
1994: ARPAnet celebrates 25th anniversary.
1995-1997: RealAudio introduces Internet
streaming technology, dial-up systems emerge
(America Online, Compuserve),
1998-present:The Internet continues to
experience staggering growth. More people use
the Internet to get connected to others, find
information, conduct business, and share
information than ever before in history.
1998-present:The Internet continues to
experience staggering growth. More people use
the Internet to get connected to others, find
information, conduct business, and share
information than ever before in history.
Internet protocols
The Internet Protocol (IP) is the principal
communications protocol used for relaying
datagrams (packets) across an internetwork using
the Internet Protocol Suite. Responsible for
routing packets across network boundaries, it is
the primary protocol that establishes the Internet.
IP is the primary protocol in the Internet Layer of
the Internet Protocol Suite and has the task of
delivering datagrams from the source host to the
destination host solely based on their addresses.
For this purpose, IP defines addressing methods
and structures for datagram encapsulation.
The structure of the Internet
The Internet is basically a hierarchy that allows
any Internet connected device in one geographic
location, talk to another Internet connected device
in another geographic location. The way that the
information is transmitted varies greatly, and in
some countries, wireless ham radios are even
used to transmit email. Keep in mind that the word
"connected" is used very loosely here.
The Open Systems
Interconnection (OSI) Model
The seven open systems interconnection layers
(OSI) are a staple of most networking textbooks.
The idea is that a network will work on many
different levels, or "layers" each of which will
perform a supporting function for the next layer.
OSI Model
Internet packets, or Internet
datagrams
An Internet protocol packet, or datagram, is a
morcel of information that is sent out on the net.
For example if you send an email to someone,
then your computer will break that email message
down into small peices and "encapsulate" them
into packets with some destination address. This
encapsulation means that your message, or more
likely a small part of your message, will be put
inside of an Internet packet.
IPV4 datagram
Governance
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.
Communication
Electronic mail, or 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.
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.