Kip Becker, Ph.D.

Boston University

Introduction to the World Wide Web

GOGLOBAL@BU.EDU

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

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