Transcript The Internet

Lecture 10
The Internet
Internet and Society
• Medium making fundamental changes in
the nature of communications,
entertainment, and commerce
– business communication between suppliers, coworkers, and customers
– email between friends and family
– personal services: banking, shopping, travel
reservations, research
Network of Networks
• A connection of multiple networks
• Networks communication with each other
over a suite of standardized protocols
– TCP/IP sends data broken up into “envelopes”
or packets over the Internet
• Traffic sent in gigabit speeds over lines
connected with routers and switches
Network of Networks
• High-speed lines are the backbone of the
Internet
• WWW makes it possible to navigate from
resource to resource on the Internet by
clicking on highlighted text or graphics
• Multimedia, hypermedia way to view
information
Connections to the Internet
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T-1
T-3
ISDN
Cable TV facilities
Internet Service Providers (ISPs)
DSL
Twisted pair
History Internet
• 1969: started by the Department of Defence
– ARPANET
– to enable scientists at Universities to share
research information from distant locations
– originally designed to develop at network
secure enough to withstand a nuclear attack
First Use of Internet
• Based on packet switching
• Packet switching breaks up the data to be
transferred so that multiple computers can
share the same data line
• Separate data line not necessary for
transmitting
• In case of attack, as one computer goes
down another can be used
1984
• More sites added to the ARPANET, term
Internet started to be used
• ARPANET shut down, Internet left intact
• 500 computers on the Internet
– 1987: oversight of the Internet transferred from
the Department of Defense to the National
Science Foundation
Expansion of Users
• Computer hobbyist groups rally around
Internet
– newsgroups formed around special interest
groups such as: cooking, technology and
lifestyles
• sexually oriented groups
• religious groups
1990
• Until this time Internet completely text
based
• No graphics, pictures, or colors
• All tasks done without point-and-click
assistance of a browser, instead had to learn
commands like
– get mail
– “j” for next message, etc.
WWW
• World Wide Web browser developed in
1989
• Is a graphics based vehicle to link users to
source of information
• Users click on graphics or text to be
transferred to another site
• 1993: Mosaic browser developed at U of
Illinois
Bulletin Board Systems
• Used independently from the Internet
• Allowed people with modems to read information
and post information on a PC
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to post bugs in software
downloading engineering designs
information on specifications for requests for proposals
to chat and exchange ideas on specific topics
replaced by WWW
Who Runs the Internet?
• Internet Society
• Internet Assigned Numbers Authority
• Internet Corporation for Assigned Names and
Numbers
• Internet Engineering Task Force
• Network Solutions Inc.
• IOPS.ORG
• WWW consortium
Who Owns the Internet?
• No one organization owns the Internet
• World wide arrangement of interconnected
networks
• Network service providers: ATT, Cable &
Wireless, Sprint, UUNET, GTE,
MCIWorldCom carry Internet traffic
Who Owns the Internet?
• Network providers own the high-speed lines
• Tier 1 providers own nationwide networks
• Tier 1 providers lease fiber lines from
carriers such as ATT and connect their own
switches and routers the leased lines
• transfer data between locations called
“peering” sites
Peering
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A way to exchange data between networks
Also called a network access point
First funded by the NSF
Now set up privately by: GTE
Internetworking, MCI WorldCom, Sprint,
etc
• “Meeting places” to exchange data
Internet Services
• FTP: file transfer protocol
– to log onto a computer at another site to retrieve
copies of text files
• SMTP: simple mail transfer protocol
• Archie: developed to simplify FTP by
enabling searches
• Gopher: precursor to web browsers, more
menu driven than Archie
Telnet
• Service for creating an interactive session
with a computer on a different network
• Lets users log onto another computer
located on the Internet as if they are a local
terminal
• Telnet pilot.msu.edu
Linking and Graphics
• Way to make using and navigating the
Internet easier
• Not a separate part of the Internet
• Graphical way to use the Internet
• Provides links to information using text and
graphic images embedded in documents to
move from one site to another
• Commands no longer necessary
WWW
• Created in 1989 by Tim Berners-Lee at
CERN
• European Lab for Particle Physics
• Basic concepts:
– any type of client should be able to find
information worldwide without needing to
know a particular computer language using any
type of terminal
HTML
• Hypertext markup language came out in
1991
• tool used to create Web documents
• authoring software that controls the look of
a web page
• all commands start and end with <> signs
• now software available to do this for you
XML
• Extensible Markup Language
• Web language used to create standard
“labels” or fields within Internet pages
• Allows for exchanges between different
computer applications and organizations
– search for “part #”, when data base stores it
under “part number”
VXML
• Voice Extensible Markup Language used
for speed recognition
• Standard way to access the Web via voice
commands
• ATT, Lucent and Motorola
– goal to be able to hear for example traffic
updates or stock quotes by dialing up the
Internet from a phone
Home Pages
• Default first page that users see when
visiting a Web site
• Document created using HTML
• Web pages are connected with hypertext
links, which are highlighted pieces of text
that transfer surfers to another site or page
Hosting
• The computer or server at which documents or
databases for Web pages are located
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Corporations
Internet Service Providers
Hosting companies
Universities
• Making documents available on Web is called
“publishing” to the Web
Hosting
• Requires:
– providing telephone connections to the Internet
– security to keep hackers out
• CSP: commerce service provider
• ISP: internet service provider (AOL)
– portal sites: Lycos, Yahoo also provide hosting
Browsers
• Graphical interface between users and Web
• Provide the graphics capability associated
with the Web
• Allows users to go directly to any home
page by typing in the address or bookmark
– Mosaic first browser (U of I and CERN)
– Netscape Navigator by Netscape
– Internet Explorer by Microsoft
E-Mail
• Invented by Ray Tomlinson, engineer at
BBN in Cambridge, Massachusetts, 1972
• Based on service that is part of the suite of
protocols called TCP/IP
– SMTP
– specifies addressing conventions
• mail to multiple users, how to carbon copy
• user name and their computer (@)
E-mail
• First used within organizations within
buildings
• Progressed to:
– LANs
– commercial electronic mail services offered
independent of Internet
– now widely available from various sources
E-mail Attachments
• ASCII text exchange not sufficient,
businesses needed to exchange:
– spreadsheets
– brochures
– Powerpoint and Word documents
• MIME developed as standard for sending
attachments
Internet2
• Introduced to develop new networking
protocols and technologies
• Fiber optic network connecting 130
universities
• Based on high-speed IP protocols
• Future of it not yet clear, need of it not yet
clear
Privacy on the Web
• Loss of privacy while on-line major concern
of net users
– tracking what sites you may have visited
– personal information placed on the web
– sites that collect email addresses without a
users knowledge, which are marketed later
– email read by non-recipients
Cookies
• Originally designed to benefit users
• Online organizations which require user ID
and passwords could store this
information in the form of a cookie so that
repeat visitors to a site could avoid having
to fill out form information on each visit
• http://www.cookiecentral.com/ccstory/index
.html
Cookies
• Now used by advertisers and marketing
groups to track and target user habits on the
web
• Cookies can be matched to the profile of a
user's interests and browsing habits
• Also used to keep track of how many times
a user has been shown a banner at any web
site
Internet Addresses
• Availability is running out and disputes are
arising concerning who has the power to
give address out
• URL: uniform resource locator
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based on TCP/IP protocols, IP address
bit or octets in address
left of @ user name to the right domain name
domain name = computer address
Internet Address
• To the right of the organizational name
description of the type of organization using
the address, this is a top level domain
• Countries outside US use geographical toplevel domain nameS
– Netherlands = NE
– Belgium = BE
– Bolivia = BO
Domain Names
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.com = commercial business
.org = non-profit organizations
.net = networks
.edu = educational institutions
.gov = governmental bodies
.mil = the military