Transcript Power Point Sides - Computer Science

Agenda
The Internet and the WWW

what’s the difference anyway?
History of The Internet
IP Addresses, URLs & Domain Names
READ Zeid: page 3-20
The Internet vs. World Wide Web
What EXACTLY is the difference between
the Internet and the World Wide Web?
Why is it important to know the difference?
The Internet
Computers can be connected in a variety of
different ways.

Ethernet, Token-ring, Wireless, Ports (Serial, Parallel,
USB). These are all communication subtrates.
Two or more connected computers form a
Network

The CS Dept. has its own Ethernet Network
Different types of networks can be connected

via bridges, gateways, etc.
The Internet
Two or more connected networks can be called an
inter-network

Inter-networks can obviously be connected
At some point in history, inter-networks became
connected across the entire USA

Eventually, inter-networks became connected across the
entire world
The entire world-wide collection of connected
networks became known as The Internet.
The Internet
Most experts in the “Network World” think of The
Internet as both
 The physical infrastructure (wires, routers,
hubs, switches, satellites, optical cables,
receivers, transmitters, etc.) that form the interconnections.
 And, the actual collection of computers (and
devices) that are “inter-connected.”
The World Wide Web (WWW)
Most experts think of The WWW as
 data that is accessible via a URL


(narrow definition)
All the data and services that are widely
available via The Internet

(general definition)
The World Wide Web (WWW)
Thus, The Internet is the physical hardware that
makes the connections possible and
The World Wide Web is the content and services
that are widely available over this massive
collection of connected computers.
Important Note:


Some companies use the Internet to share information,
but this information is only accessible through
proprietary protocols,
Since, it is NOT widely available, it is not really part of
the WWW.
The World Wide Web (WWW)
While the two terms are somewhat
synonymous to the non-expert,
You should be aware of the difference
between The Internet and the WWW
Internet
WWW
Internet Jargon
In the field of Network Communications
there are thousands of terms, most of which
are acronyms and are not found in standard
dictionaries.
The following website is good for
reference:
http://www.webopaedia.com
The World Wide Web (WWW)
Examples: Content & High-level Protocols
Content: WebPages


Hypertext Transfer Protocol (http)
URL (Universal Resource Locator)
Content: Data Files & Programs

File Transfer Protocol (ftp)
Content: Music & Videos

Gnutella Protocol
The World Wide Web (WWW)
More examples
Content: Email





SMTP (Simple Mail Transport Protocol)
IMAP (Internet Message Access Protocol)
POP (Post-Office Protocol)
DNS (Domain Name System)
MIME (Multipurpose Internet Mail Extensions)
Content: Peer to Peer messaging


AOL IM Protocol
MSN Messenger Protocol
The Internet
Examples: Hardware & Low-Level Protocols
Hardware



Computer, Ethernet card
Communication Substrate:
CAT-5 cable, fiber optic cable
Router, Hub, Switch, Bridge, Gateway
Low-Level Protocols/ Concepts


TCP/IP (Transmission Control Protocol/Internet
Protocol)
Packet Switching
What is the Internet?
The largest network of networks in the world.
Uses TCP/IP protocols and packet switching .
Runs on any communication substrate.
http://som.csudh.edu/cis/lpress/history/arpamaps/
Brief History of the Internet
1968 - DARPA (Defense Advanced Research
Projects Agency) contracts with BBN (Bolt,
Beranek & Newman) to create ARPAnet
(Advanced Research Projects Agency)
1970 - First five nodes:
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UCLA
Stanford
UC Santa Barbara
U of Utah, and
BBN
Brief History of the Internet
1974 - TCP protocol invented by Vint Cerf
1984 – On January 1, the Internet with its
1000 hosts converts en masse to using
TCP/IP for its messaging
1968 is really the “birth” of the Internet
1984 is really the “high-school graduation”
of the Internet
ARPANET
is Born
1968
Hypertext
Invented
1965
Packet
Switching
Invented
1964
First Vast
Computer
Network
Envisioned
1962
1962
TCP/IP
Created
1972
Internet Named
TCP/IP Used
1984
WWW
Created
1989
Mosaic
Created
1993
Age of
eCommerce
Begins
1995
1995
We will prove that packet switching
works over a WAN.
Hypertext can be used to allow
rapid access to text data
Packet switching can be used to send
digitized data though computer networks
Great things can be done with
a vast world-wide network
We can do it cheaply by using
Digital circuits etched in silicon.
We do it reliably with “bits”,
sending and receiving data
We can access
information using
electronic computers
1945
1962
1968
Great efficiencies can be accomplished if we use
The Internet and the World Wide Web to conduct business.
The World Wide Web is easier to use if we have a browser that
To browser web pages, running in a graphical user interface context.
Computers connected via the Internet can be used
more easily if hypertext links are enabled using HTML
and URLs: it’s called World Wide Web
The ARPANET needs to convert to
a standard protocol and be renamed to
The Internet
We need a protocol for Efficient
and Reliable transmission of
Packets over a WAN: TCP/IP
Ideas from
1940s to 1968
1968
1995
Claude Shannon
The Father of Modern
Information Theory
Created the idea that all
information could be
represented using 1s and 0s.
Called these fundamental
units BITS.
Won a Nobel prize for his
master’s thesis in 1936
Source: http://www.research.att.com/~njas/doc/ces5.html
Vannevar Bush
Summary: Vannevar Bush
established the U.S.
military/university research
partnership that later
developed the ARPANET.
He also wrote the first
visionary description of the
potential use for information
technology, inspiring many
of the Internet's creators.
Source: Livinginternet.com
Paul Baran
Paul Baran developed the field of
packet switching networks
Worked for RAND organization
(first think tank)
Baran's architecture was well
designed to survive a nuclear
conflict, and helped to convince
the US Military that wide area
digital computer networks were a
promising technology.
Source: Livinginternet.com
Leonard Kleinrock
One of the pioneers of
digital network
communications
Helped build the early
ARPANET.
Vinton Cerf
Summary: Vinton Cerf is codesigner (with Bob Kahn) of
the TCP/IP networking
protocol.
Worked for DARPA, projects
include d


Source: Livinginternet.com
the Packet Radio Net (PRNET),
and
the Packet Satellite Network
(SATNET).
Tim Berners-Lee
The inventor of HTML.
Now works for Laboratory for
Computer Science (LCS)at the
Massachusetts Institute of
Technology (MIT).
Directs the W3 Consortium, an
open forum of companies and
organizations with the mission
to realize the full potential of
the Web.
Source: w3c.org
Internet Growth Trends
1977: 111 hosts on Internet
1981: 213 hosts
1983: 562 hosts
1984: 1,000 hosts
1986: 5,000 hosts
1987: 10,000 hosts
1989: 100,000 hosts
1992: 1,000,000 hosts
2001: 150 – 175 million hosts
2002: over 200 million hosts
By 2010, about 80% of the planet will be on the Internet
Important Milestones
September 2002
Netsizer.com – from Telcordia
Growth of Internet Hosts *
Sept. 1969 - Sept. 2002
250,000,000
Sept. 1, 2002
No. of Hosts
200,000,000
150,000,000
100,000,000
Dot-Com Bust Begins
50,000,000
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Time Period
Chart by William F. Slater, III
The Internet was not known as "The Internet" until January 1984, at which time
there were 1000 hosts that were all converted over to using TCP/IP.
Internet’s Growth
To get a market of 50 Million People
Participating:
Radio took 38 years
 TV took 13 years
 Once it was open to the General Public, The
Internet made it to the 50 million person
audience mark in just 4 years!
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URLs
Universal Resource Locator
www.cs.siena.edu
Human-readable WWW Address
IP Address
Numeric Internet Address
Part of the TCP/IP Protocol
URLs are translated into IP Addresses by
DNS Servers
DNS Domain Name System