SC ICT CertificationLevel 1

SC ICT CertificationLevel 1

09 What Is The Internet?

By Ross Parker

The Internet• wikipedia.org: “The Internet is a global

system of interconnected computer networks that interchange data by packet switching using the standardized Internet Protocol Suite (TCP/IP). It is a ‘network of networks’...”

The Internet is not IM, The Internet is not P2P, The Internet is not Chat, The Internet is not Email,

The Internet is not The Web:

The Internet is simply a communications channel!

The Internet facilitates these applications

Visualise It!

Partial map of the Internet based on the January 15, 2005 data found on opte.org. Each line is drawn between two nodes, representing two IP addresses. The length of the lines are indicative of the delay between those two nodes. Lines are colour-coded as follows: * Dark blue: net, ca, us * Green: com, org * Red: mil, gov, edu * Yellow: jp, cn, tw, au, de * Magenta: uk, it, pl, fr * Gold: br, kr, nl * White: unknown Source: Matt Britt, Wikimedia Commons

Simplify It!

PC PC

PrinterPC

Switch &

Firewall

The InternetWhy a cloud?

LAN

Switch &

Firewall

LAN

Server

1945Vannevar Bush

publishes paper on Memex machine

1957USSR launches

Sputnik

1958USA forms

ARPA

1960J.C.R. Licklider publishes "Man-

Computer Symbiosis"

1961Leonard Kleinrock

publishes “Information Flow in Large

Communication Nets"

1966 Larry Roberts publishes "Towards a Cooperative Network of Time-Shared

Computers"

1969ARPAnet

commissioned by USA DoD: 4 nodes

1971ARPAnet: 15

nodes w/ 23 hosts

1973ARPAnet extends to

England and Norway

1973 Vint Cerf and Bob

Kahn propose “internetwork”

1976Queen Elizabeth II sends an email

1979 USENET

established

1982 TCP/IP

established

1983IP-capable UNIX

workstations available

1984DNS Introduced1,000+ hosts

1986Internet

Engineering Task Force (IETF) born

1988 Internet Relay Chat (IRC) developed by

Jarkko Oikarinen

1989100,000+

hosts

1991World-Wide Web

(WWW) released by CERN; Tim Berners-Lee

19921,000,000+

hosts

1993 Mosaic breaks! WWW grows at

341,634% per annum

1995 Commercial

access via dial-up

1997 Browser wars

199940,000,000+

hosts

2005350,000,000+

hosts

History of the Internet

Theory

Development

Growth

Explosion!

Important Strands• Move from single machines to networked

machines– WAN first, then LAN

• Move from isolated networks to internetworks• Move from academic to commercial use• Move from organisational to personal use• Growth in range and richness of applications

Astounding GrowthCan you imagine a bridge that can handle this growth in traffic? This is robust engineering. And it was a largely open process…

Licensing• All original work used here is licensed under the Creative Commons Attribution-Share

Alike 3.0 Unported license. For more details please look at http://creativecommons.org/licenses/by-sa/3.0/.

• This license has been chosen to permit a high degree of sharing, whilst protecting the author’s control as to how the content is used.

• Please respect this license and use accordingly!• Recycled and borrowed works from other sources are used under appropriate

licenses, which are not affected by this license. The original source is always given. • All original work created by Ross Parker (Sha Tin College, English Schools

Foundation, Hong Kong), except where specified.