The Internet and the Web

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The Internet and the Web

• Lecture 10

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Overview

• The Internet and the World Wide Web provide means
  for global communication, information retrieval,
  commerce and entertainment
• The Internet is a highway that moves ideas and
  information
• Were travelling through cyberspace, the space of
  electronic movement of ideas and information

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Overview

• The Internet was born as the ARPANET in 1969
• In 1992, the World Wide Web was born

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What Was the Victorian Internet

• The Telegraph invented in the 1840s.
• Signals sent over wires that were established
  over vast distances
• Morse Code was dots and dashes, or short signals
  and long signals
• The electronic signal standard of /- 15 v. is
  still used in network interface cards today.

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What is the Internet?

• A network of networks, joining many government,
  university and private computers together and
  providing an infrastructure for the use of
  E-mail, bulletin boards, file archives, hypertext
  documents, databases and other computational
  resources.

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What is the Internet?

• The vast collection of computer networks which
  form and act as a single huge network for
  transport of data and messages across distances
  which can be anywhere from the same office to
  anywhere in the world.

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A brief history

• 1968 - DARPA (Defense Advanced Research Projects
  Agency) contracts with BBN (Bolt, Beranek
  Newman) to create ARPAnet
• 1970 - First five nodes
• UCLA
• Stanford
• UC Santa Barbara
• U of Utah, and
• BBN

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The creation of the Internet

• The creation of the Internet solved the following
  challenges
• Basically inventing digital networking as we know
  it
• Survivability of an infrastructure to send /
  receive high-speed electronic messages
• Reliability of computer messaging

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Internet growth trends
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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

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Internet growth trends

• 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

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By September 2002 the Internet reached two
important milestones

• gt 200,000,000 IP Hosts

gt 840,000,000 Users
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Internet Applications

• The most common Internet applications are
• communicating,
• shopping,
• researching and
• entertainment.

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Internet Applications

• Communicating - sending e-mail and discussion
  group participation
• Shopping - one of the fastest growing
  applications
• Researching - using virtual libraries
• Entertainment - music, movies, reading and games

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Web Library
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Access

• Providers give access to the Internet.
• Internet connections are either direct, SLIP and
  PPP, or by terminal connection.
• Protocols are rules for exchanging information
  between computers.

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Providers

• Providers - already connected to the Internet,
  provide a pathway for other users
• Colleges and universities
• Internet service providers (ISP) - offering
  access for a fee ATT, Mindspring, etc.
• Online services provider - provide numerous other
  services and content in addition to Internet
  access AOL the biggest

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Connections

• Direct or dedicated - full time direct link, very
  fast access
• SLIP and PPP
• Serial line Internet protocol (SLIP)
• Point-to-point protocol (PPP)
• Users become part of a giant client/server
  network
• Reliable access at lower cost than dedicated
  arrangement

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TCP/IP

• Stands for transmission control protocol/Internet
  protocol
• Messages broken into packets
• Packets may take different routes over the
  network to reach the same destination
• At destination, packets are reassembled

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E-Mail

• By far the most common Internet activity
• With Internet access and an e-mail program, one
  can reach anybody in the world similarly equipped
• Basic elements
• Header - subject, address and attachments
• Message
• Signature

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E-mail
Microsoft Outlook Express e-mail client
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E-Mail Addresses

• Internet uses the domain name system (DNS), which
  gives names and numbers to people and computers
• Address has three parts
• Domain code - geographical location or
  organizational identification
• Domain name - references a specific organization
• User name - identifies unique user or computer in
  the domain

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Internet Address
dcoats_at_usc.edu
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Common Internet Domain Codes
com Commercial
org Other organizations
gov Government
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Discussion Groups

• Mailing lists
• Newsgroups
• Chat groups

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Discussion Groups

• Mailing lists
• Members send messages to the list address
• Message then copied and automatically sent to all
  members
• Persons must subscribe to participate some
  decide they want to unsubscribe

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Discussion Groups

• Newsgroups
• Most popular discussion group
• Located on a special network called UseNet
• Chat groups
• Allow live communication in real time
• Communication by typed messages

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Discussion Groups

• Terms
• Reading communications before contributing is
  called lurking
• Helps potential participants understand the
  culture of the group

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Discussion Group Terms
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Electronic Commerce

• Electronic commerce is buying and selling over
  the Internet. Web storefronts offer goods and
  services. Electronic payment options include
  check, credit card and electronic cash.

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Web storefront
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Internet Services

• Telnet runs programs on remote computers.
• FTP transfers files.
• Gopher provides menus for available resources.
• The Web provides a multimedia interface to
  available resources.

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Internet Services

• Telnet - to connect to another computer and run
  programs on it
• FTP - file transfer protocol, an Internet service
  for file transfer
• Downloading - transmitting files from the host to
  client
• Uploading - transmitting files from the client to
  host

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Internet Services

• Gopher - menu based information retrieval system
• The Web
• The Internet is the physical network
• The Web is the multimedia interface, with
  information arranged in pages

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Browsers

• Browsers connect to Web sites using URL addresses.

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Browsers

• Software packages that allow users to navigate
  the Web, and read the multimedia formatted pages
• Locations of these pages or sites are called
  uniform resource locator or URL

protocol
http//www.eatright.org
domain name
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(No Transcript)
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Web Pages

• Browsers interpret HTML documents to display Web
  pages.

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Web Pages

• After browser makes contact, document is sent to
  users computer
• Document usually coded in HTML or hypertext
  markup language

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Web Pages

• The browser interprets the HTML and the result is
  a displayed page
• A dominant characteristic of most pages is the
  hyperlinks, which allow users to quickly connect
  to other pages or Web sites

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Web Pages

• Applets - special programs written in the Java
  programming language
• Quick to download
• Easy for browsers to interpret
• Used for animations, graphics display,
  interactivity

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Search Tools

• Indexes are organized by categories.
• Search engines are organized like a database.

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Search Tools

• Finding the right information on the Web can be
  frustrating and time-consuming, the solution
  search tools
• Indexes - like directories, organized by category
  and subcategory

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Yahoo index
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Search Tools

• Search engines - or Web crawlers or Web spiders
• Information organized in a database
• Key word or words used to access addresses for
  related information
• Database kept current by automated programs that
  travel the Web and collect information
• Some popular programs HotBot, Google,
  WebCrawler and Alta Vista

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HotBot search engine
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Plug-ins

• Automatically work with your browser for
  functionality some examples include
• Macromedias Shockwave for dynamic animations
• Apples Quicktime for viewing video files
• Silicon Graphics Cosmos for 3-D graphics and
  virtual reality

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Organizational Internets Intranets and Extranets

• Intranets are private networks within an
  organization.
• Extranets are private networks connecting
  organizations.
• Firewalls use proxy servers to provide security.

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Intranets

• Private networks within an organization
• Like the Web outside, browsers, web pages and web
  sites are employed
• Prime objective is information availability and
  flow for company employees only

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Extranets

• Private networks connecting two or more
  organizations
• Increases efficiency and reduces costs by
  facilitating information flow between firms that
  do a lot of business with each other

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Firewalls

• Information security is very important
• Firewalls are designed to control access to the
  company network from the outside
• Key component is the proxy server, which acts as
  a gatekeeper