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Kip Becker, Ph.D.
Boston University
Introduction to the World Wide Web
HTTP:// WWW.BU.EDU/GOGLOBAL
Large is no longer scary
Consumers Rule
Information cost low
Information Available
Compete in real time rather than in “cycle time”
Operate in a world characterized by low barriers to entry, near-zero variable costs of operation and shifting competition
WHAT ARE SOME NEW
ECONOMYCONCEPTS
ALL ABOUT - ANYWHERE –ANYTIME
“THE EVERYTHING NET”
Productivity in Goods and Services 1960 - 94
(Annual Index of output per Person – Hour, 1960=100)
Ratio Scale
100
120
140
160
180
200
220
240
260
280
300
1960
1964
1967
1969
1972
1977
1980
1983
1986
1990
Commercial Goods Sector
Commercial Services Sector
Will the internet increase service productivity ?
1974
WHAT YOU ARE LOOKING AT IS THE
WORLD WIDE WEB AS IT WAS IN
EARLY STATES. IT IS PRIVATE AND , AS
YOU CAN SEE, VERY SMALL
BUT THIS IS NOT THE BEGINNING
SO LET’S EXPLORE THE HISTORY OF
THIS AMAZING INVENTION
THE INTERNET
SO LET ME PROVIDE YOU WITH A VERY
BRIEF HISTORY
• Internet’s beginnings traced to memos written in 1962 MIT’s Joseph Carl Robnett Licklider outlining the galactic networking concept
• Great advances made in network technology 1960s WERE NEEDED TO GET IDEAS MOVING
•HAD TO FIND WAYS To connect computers &permit transfer of information locally,
•organizations installed •Local Area Networks. • then connected LANs to WANs
•BUT ---- •LAN technology were limited in functions
1. A global networked environment is
known as the
2. A counterpart within organizations,
is called a:
3. An extends intranets so
that they can be accessed by
business partners.
EARLY CONNECTIONS
Internet
Intranet
extranet
•To allow computers and networks separated by larger distance to communicate
•GOVERNMENT GOT INTERESTED AND FUNDED
ARPA (Advanced Research Projects Agency)
TO DEVELOP a Wide Area Network (WAN) the ARPANET WHY CARE? WHY INVENT WEB ?)
TO ANSWER THAT QUESTION WE HAVE TO GO BACK AND ASK
•What was going on in 50s 60s? great communist threat ! •Production moved around auto plants, manufacturing whole idea was “one bomb” BUT INFORMATION NOT SAFE ! BANKING INFO, TAXES, SOCIAL SECURITY, CITENSHIP LOTS OF UNFORMATION GOVERNENT FUNDS ARPANET FOR GOVERNMENT USE
1989–1991: Web “invented” - Tim Berners-Lee at
CERN 1993CERN e World Wide Web was free for everyone to use and develop, no fees 1993: Marc Andreesen /Others at NCSA create Mosaic, Web browser with GUI that runs on Windows, Macintosh, or Unix
1994: Andreessen, Jim Clark Netscape; first commercial Web browser, Netscape Navigator
August 1995: Microsoft introduces Internet Explorer, its version of Web browser
Lets take a look at some of the early players
1988: First major malicious internet-based
attack
major Internet worms"The Morris Worm",
it was written by Robert Tappan Morris
major interruptions large parts of Internet
1995: Commercialization of the internet
considered year web became
commercialized. First, SSL (Secure
Sockets Layer) encryption Netscape, safer
to conduct financial transactions (like
credit card payments) online. first sale on
"Echo Bay" was made that year. Echo Bay
later became eBay. Amazon.com also
started in 1995, No profit 2001
THE WEB PROGRESSES
1995, Federal Networking Council (FNC) "Internet" refers to the global information system
(i) logically linked together by globally unique
address space based on Internet Protocol (IP)
(ii) able support communications using the
Transmission Control Protocol/Internet Protocol
(TCP/IP)
(iii) uses or makes accessible high level
services layered on the communications and
related infrastructure described herein.
CONNECTIONS:
NETWORK OF NETWORKS
ISPs
– INTERNET SERVICE PROVIDERS
NAPs
– NETWORK ACCESS POINTS/ PACIFIC BELL NAP IN SANFRANCISCO & AMERITEC NAP CHICAGO
NSPs
– “BACKBONE” NETWORK SERVICE PROVIDERS\ MCI, PSINET ETC.
NAP NAP
ISP YOU
NSP - BACKBONE
message
sent on
HERE IS THE “OPEN
ACCESS” DEBATE
HARD/SOFT WARE Characteristics allow shared
access of data
1. Unique identification each computer network of millions of computers - thousands networks..
Important each computer be uniquely identified
Internet Protocol(IP) address. 198.108.95.145
2. Human-friendly addressing ↑ Domain Name System(DNS) gave address recognizable letters &
words instead of IP address. http://www.bu.edu/GoGlobal
3. Packet Switching Remedy delays associated unequally sized data transfers, instead of
transferring files in their entirety, whole files broken into data packets
before transferred over network
4. Routing Dedicated, special-purpose computers which serve as an intermediary
between networks. Route packets efficiently through networks and are
building blocks of the internet. Packets used TCP software insures
safe delivery of packets
ONE of MOST IMPORTANT PROTOCOLS
TCP/IP Solves the global internetworking problem
• Transmission Control Protocol (TCP)
– Ensures that 2 computers can communicate with one another in a reliable fashion
Prevents loss of data ckecs packets Eliminates duplicate
• Internet Protocol (IP)
• packets are labeled with the addresses of the sending and receiving computers
Sends confirmation received /not Retransmitted Error-free communication
Packet Switching
Slices digital messages into packets
Sends packets along different communication paths as they become available
Reassembles packets once they arrive at destination
Uses routers – Special purpose computers that interconnect the computer networks that make
up the Internet and route packets
– Routing algorithms ensure packets take the best available path toward their destination
Less expensive, wasteful than circuit-switching
Packet Switching Figure 3.3, Page 132
Slide 3-19