Chapter 2 The Internet and World Wide Web

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Chapter 2The Internet and World Wide Web
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History of the Internet
p. 48
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The Internet

• How has the Internet grown?

p. 48
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Control of the Internet (W3C)

• World Wide Web Consortium (W3C)

• public, cooperative, and independent network
• set standards and guidelines

p. 49
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The Internet

• What are some services found on the Internet?

p. 48 Fig. 2-1
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Connecting to the Internet

• High-speed connection

• Slow-speed technology

• Dial-up accessmodem in your computer uses a
  standard telephone line to connect to the
  Internet

Digital subscriber line (DSL), cable telephone
Internet services (CATV), cable modem provide
connections using regular copper telephone lines
Connection is always onwhenever the computer
is running
Connection must be established each time you log
on. Slow but inexpensive
p. 49
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Accessing the Internet

• Providers

• ISP, regional or national
• ATT, Earthlink
• OSP (AOL and MSN, for example)
• Provides expanded features like instant messaging
• Wireless Internet Service Provider (WISP)
• Verizon Wireless

p. 50
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Connecting to the Internet Backbone
Step 5. Regional ISP uses leased lines to send
data to a national ISP
Step 1. Request data from a server on Internet
Step 3. Data travels through telephone lines to a
local ISP
Step 4. Data passes through routers
Step 6. National ISP routes data across the
country
Step 2. Modem converts digital signals to analog
signals
Step 8. Server sends data back to you
Step 7. National ISP passes data to local ISP
p. 50 Fig. 2-2
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How the Internet Works

• Internet addressingIP address

• Number that uniquely identifies each computer or
  device connected to Internet

p. 51 Figs. 2-3 2-4
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The World Wide Web
What is the World Wide Web (WWW)?service of the
Internet
p. 52
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The World Wide Web

• What is a Web browser?

• Program that allows you to view Web pages

p. 52
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The World Wide Web

• What is a URL?

• Unique address for a Web page
• A web server delivers the Web page to your
  computer

p. 54 Fig. 2-6
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The World Wide Web

• What is a hyperlink (link)?

• Built-in connection to another related Web page
  location

• Item found elsewhere on same Web page
• Different Web page at same Web site
• Web page at a different Web site

p. 54
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The World Wide Web

• What is a search engine?

• Program used to find Web sites and Web pages by
  entering words or phrases called search text

p. 55 Fig. 2-8
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SearchingHow it works

• special software robots, called spiders build
  lists of the words found on Web sites.
• Web crawling
• starting points are lists of heavily used servers
  and very popular pages.
• indexing the words on its pages and following
  every link found within the site.
• spidering system quickly begins to travel,
  spreading out across the most widely used
  portions of the Web.

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Google

• began as an academic search engine.
• uses multiple spiders, usually three at one time.
  Each spider could keep about 300 connections to
  Web pages open at a time. At its peak
  performance, using four spiders, their system
  could crawl over 100 pages per second, generating
  around 600 kilobytes of data each second.
• When the Google spider looked at an HTML page, it
  took note of two things
• The words within the page
• Where the words were found

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The World Wide Web

• What are the basic types of Web sites?

p. 57 Fig. 2-10
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The World Wide Web

• What is streaming audio?

• Transfers data in a continuous and even flow
• Enables you to listen to the sound as it
  downloads to your computer
• Radio stations use streaming audio to broadcast
  over the Web

p. 61
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The World Wide Web

• What is video?

• Consists of full-motion images with soundplayed
  back at various speeds
• MPEG (Moving Pictures Experts Group) is popular
  video compressionstandard

p. 61
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The World Wide Web

• What is virtual reality (VR)?

• Use of computers to simulate real or imagined
  environment
• Appears as a three dimensional (3-D) space
• Used for games and many practical applications

p. 62
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The World Wide Web

• What are plug-ins?

• Programs that extend the capability of a
  browser
• You can download many plug-ins at nocost from
  variousWeb sites

p. 62 Fig. 2-14
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The World Wide Web

• What is e-commerce?

• Short for electronic commerce
• Business transaction that occurs over the
  Internet

Business to consumer (B2C)Sale of goods to
general public
Consumer to consumer (C2C)One consumer sells
directly to another
Business to business (B2B)Business providing
goods andservices to other businesses
p. 62 Fig. 2-15
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Other Internet Services

• What is FTP?

• File Transfer ProtocolInternet standard that
  allows you to upload and download files with
  other computers on the Internet

p. 66
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Other Internet Services

• What are newsgroups and message boards?

• Newsgroup

• Online area where users discuss a particular
  subject

• Message board

• Type of discussion group

• Many Web sites use message boards because they
  are easier to use

p. 67 Fig. 2-19
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Other Internet Services

• What is a mailing list (list serve)?

• Group of e-mail addresses given a single name
• When a message is sent to the mailing list,
  everyone on the list receives the message
• To add your name to a mailing list you must
  subscribe to it to remove your name you must
  unsubscribe

p. 67
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Other Internet Services

• What is a chat?

• Real-time typed conversation that takes place on
  a computer

• Chat room is location on server that permits
  users to discuss topics of interest

p. 68 Fig. 2-20
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Other Internet Services

• What is instant messaging (IM)?

• A real-time Internet communications service that
  notifies you when one or more people are online
  and allows you to exchange messages or files

p. 69 Fig. 2-21
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Internet 2

• developed by a consortium of universities and
  technology companies in 1996 to provide vast
  improvements in connection speeds. The goal of
  the project has always been to stay three to four
  years ahead of what is commercially available
  through the public Internet.
• Provides data at 10gbps (gigabits per second)
• More than 227 universities, libraries, public
  schools and research institutions are connected
  to Internet2. The network connects to more than
  57 international high-capacity networks.
• Peer-to-peer applications, high-definition
  videoconferencing, remote manipulation of lab
  equipment, and distributed computing are all
  applications that are enabled by Internet2.

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Example of Internet 2 Use

• Internet2 nodes are connected to the Abilene
  national backbone through regional fiber networks
  with almost unlimited bandwidth capacity.
• Musical Webcasts over the Internet can transfer
  up to 250 megabytes of data per second over
  Internet2. This is more than 4,000 times the rate
  of a standard dial-up modem and more than 800
  times that of a cable modem.