Introduction to the Internet and the World Wide Web - PowerPoint PPT Presentation

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Introduction to the Internet and the World Wide Web


Objectives Obtain an overview of the information and tools that are available on the Internet Learn what computer networks and internets ... Internet applications ... – PowerPoint PPT presentation

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Title: Introduction to the Internet and the World Wide Web

Introduction to the Internet and the World Wide
Tutorial 1
  • History, Structure, and Getting Connected

  • Obtain an overview of the information and tools
    that are available on the Internet
  • Learn what computer networks and internets are
    and how they work
  • Find out how the Internet and the World Wide Web
    began and grew
  • Compare different methods for connecting to the

Internet and World Wide WebAmazing Developments
  • The Internet is a large collection of computers
    all over the world connected to one another.
  • One of the most amazing technological
    developments of the 20th century.
  • The World Wide Web is a subset of computers on
    the Internet that has helped make Internet
    resources available to people who are not
    computer experts.

Internet and World Wide WebAmazing Developments
  • New Ways to Communicate
  • E-mail
  • Electronic discussions
  • Instant messaging
  • Information Resources and Software
  • Newspapers magazines
  • Government documents
  • Research reports books
  • Software download sites

Internet and World Wide WebAmazing Developments
  • Doing Business Online
  • Electronic storefronts
  • Coordinate worldwide operations
  • Recruit employees
  • Entertainment
  • Review restaurants, movies, theater, musical
    events and books.
  • Interactive games
  • Follow sports teams

  • Wont learn till later, but you should have
    antivirus software (and firewall) on your
  • Norton
  • McAfee
  • Etc.
  • May be provided by your ISP

Computer Networks
  • Network a collection of connected computers.
  • Network Interface Card (NIC) a card used to
    connect a computer to a network of other
  • Server computer that accepts requests and shares
    some or all of its resources with computers to
    which it is connected.

Client/Server Local Area Networks
  • Client computer connected to a server.
  • Network Operating System software that runs on a
  • Client/Server Networks one server computer
    sharing its resources with multiple client
  • Local Area Network (LAN) network of computers
    located close to each other.

Client/Server LAN
New Perspectives on the Internet, 5e Tutorial 1
Client/Server Local Area Networks
  • Node or network node each computer, printer, or
    other device connected to a network.
  • Minicomputer and mainframe computer larger, more
    expensive computers used by businesses and
    organizations to process large amounts of work.

Connecting Computers to a Network Types of
  • Twisted Pair oldest type, used by telephone
    companies, usually Category 1.
  • Coaxial Cable 20 times faster than Category 1,
    more expensive
  • Category 5 carries signals between 10 100
    times faster than coaxial cable, easy to
  • Fiber-optic cable most expensive, transmits
    pulsing beams of light through very thin strands
    of glass, fastest transmission rate.

Types of Cable
New Perspectives on the Internet, 5e Tutorial 1
Wireless Networks
  • Becoming more common as costs drop.
  • Old buildings -- expensive to install wiring.
  • Companies which use laptop computers.
  • Schools -- classrooms, libraries, and study
  • Homes.

Wide Area Networks
  • WAN a network of networks or an internet.
  • Internet a worldwide collection of
    interconnected networks owners have voluntarily
    agreed to share resources and network connections.

Connectivity Circuit Switching
  • Circuit switching
  • centrally controlled
  • single-connection method
  • used by most local telephone traffic today
  • Vulnerable to destruction of signal control point
    or any link in the single path that carries the

Connectivity Packet Switching
  • Packet-switching files and messages broken down
    into packets and labeled electronically with
    codes for their origin and destination.
  • Packets travel from computer to computer along
    the network until they reach their destination.
  • Routers determine the best way for a packet to
    move towards its destination.

Connectivity Packet Switching
  • Datagram packet with routing info.
  • Packet-switched networks more reliable
  • rely on multiple routers instead of central point
    of control.
  • each router can send individual packets along
    different paths if parts of the network are not

Origins of the Internet
  • DARPA (Defense Advanced Research Projects Agency)
    researchers connected first computer switches in
  • ARPANET grew over next three years to include
    over 20 computers. Grandpa of Internet.

Open Architecture Philosophy
  • Independent networks should not require any
    internal changes to be connected to the
  • Packets that do not arrive at their destinations
    must be retransmitted from their source network.
  • The router computers do not retain information
    about the packets they handle.
  • No global control will exist over the network.

Open Architecture Philosophy
  • Protocol Rules for formatting, ordering, and
    error-checking data sent across a network.
  • New set of protocols developed in 1970 by Vincent
    Cerf and Robert Kahn
  • Transmission Control Protocol
  • Internet Protocol
  • (TCP/IP)

Open Architecture Philosophy
  • TCP rules used by computers on a network to
    establish and break connections.
  • IP rules for routing of individual data packets.
  • TCP/IP used today in LANs and on the Internet.
  • Vincent Cerf considered to be the father of the
    Internet by many.

Birth of E-MailA New Use for Networks
  • Ray Tomlinson, an ARPANET researcher, wrote a
    program that could send and receive messages over
    the network in 1972.
  • E-mail was born and rapidly became widely used in
    the computer research community.
  • ARPANET continued to develop faster and more
    effective network technologies.
  • Began sending packets by satellite in 1976.

More New Uses for Networks Emerge
  • File Transfer Protocol (FTP) - transfer files
    between computers.
  • Telnet - users log in to their computer accounts
    from remote sites.
  • Mailing lists (LISTSERV), information posting
    areas (Usenet), and adventure games among new
    applications appearing on the ARPANET.

Commercial Interest Increases
  • National Science Foundation (NSF) prohibited
    commercial network traffic on its networks.
  • Larger firms built TCP/IP-based WANs that used
    leased telephone lines to connect field offices
    to corporate headquarters.
  • NSF permitted commercial access. Initially there
    was resentment but business invested much money,
    speed increased and costs fell.

Commercial Interest Increases
  • Intranet LANs or WANs that use TCP/IP protocol
    but do not connect to sites outside the firm.
  • Extranet an intranet that allows selected
    outside parties to connect.
  • ARPANET grew from 4 computers in 1969 to over
    300,000 by 1990.

Growth of the Internet
  • Formal definition of Internet was adopted in 1995
    by the Federal Networking Council (FNC).

From Research Project to Information
Growth in number of Internet hosts
New Perspectives on the Internet, 5e Tutorial 1
Growth of the Internet
  • Number of hosts connected to Internet includes
    only computers directly connected to the
  • Internet traffic now carries more files that
    contain graphics, sound, and video, so Internet
    files have become larger.

New Structure for the Internet
  • Organized around four network access points
    (NAPs), operated by four different
    tele-communications companies.
  • The four companies and their successors sell
    access to the Internet through their NAPs to
    organizations and businesses.
  • The NSFnet still exists for government and
    research use.

New Structure for the Internet
  • More than 180 million connected host computers
    and more than 700 million worldwide Internet
  • TCP/IP numbering system that identifies users on
    the Internet is running short of numbers.
  • IP version 4 provides a maximum of about 4
    billion addresses.
  • IP version 6 approved in 1997 by the IETF allows
    existing users to continue accessing the Internet
    while new system is being implemented.

New Structure for the Internet
  • The Internet has become one of the most amazing
    technological and social accomplishments of the
  • Computers linked to this interconnected network
    are located in almost every country of the world.
  • Billions of dollars change hands every year over
    the Internet.

World Wide Web
  • World Wide Web a way of thinking about
    information storage and retrieval. Can view
    multimedia documents (text, graphics, audio, and
  • Web software that runs on some of the computers
    connected to each other through the Internet.
  • In 1990, Tim Berners-Lee of CERN developed the
    World Wide Web.
  • HTTP Protocol that transfers Web pages.

  • Hypertext Markup Language (HTML) a language that
    includes a set of codes (or tags) attached to
  • Hypertext Server a computer that stores files
    written in HTML other computers connect to it
    and read files.
  • Hypertext Link (hyperlink) points to another
    location in the same or another HTML document.

  • Web Browser software that lets users read HTML
    documents and move from one HTML document to
    another through hypertext link tags in each
  • HTML is a subset of Standard Generalized Markup
    Language (SGML) which has been used for many
    years to manage large document-filing systems.

  • GUI (graphical user interface) a way of
    presenting program output using pictures, icons,
    and other graphical elements.
  • e.g. CoreFTP vs. command line
  • Much easier to learn and use
  • Point and click

Hypertext and Graphical UserInterfaces Come to
the Internet
  • Mosaic first GUI program to read HTML and use
    HTML documents hyperlinks to navigate from page
    to page on computers anywhere on the Internet.

Commercializationof the Internet
  • Businesses quickly recognized profit-making
    potential offered by a world-wide network of
    easy-to-use computers.
  • The Netscape Navigator Web browser was an instant
  • Internet Explorer Web browser entered the market
    soon after Netscapes success became apparent.

Growth of the World Wide Web
New Perspectives on the Internet, 5e Tutorial 1
Connection Options
  • NAPs (network access points) offer connections to
    large organizations and businesses.
  • Those businesses provide Internet access to other
    business and individuals as ISPs.
  • Internet service providers (ISPs) provide
    customers with software to connect to the ISP,
    browse the Web, send and receive e-mail messages,
    and perform other Internet-related functions.

Hierarchy of Internet Service Providers
New Perspectives on the Internet, 5e Tutorial 1
Connection Bandwidth
  • Bandwidth amount of data that can travel through
    a communications circuit in one second.
  • Bandwidth depends on the type of connection ISP
    has to the Internet and the kind of connection
    you have to the ISP.
  • Available bandwidth for any type network
    connection between two points is limited to
    narrowest bandwidth that exists in any part of
    the network.

Connection Bandwidth
  • Bandwidth measured in bits per second (bps).
  • When you extend your network beyond a local area,
    the speed of the connection depends on type of
    connection used.
  • POTS (or plain old telephone service) is one way
    to connect computers or networks over longer
    distances. 28-56 kbps

Connection Bandwidth
  • Digital Subscriber Line (DSL) higher grade of
    service offered by some telephone companies.
  • Integrated Services Digital Network (ISDN) first
    technology developed using a DSL protocol offers
    bandwidths up to 256 Kbps.
  • Asymmetric Digital Subscriber Line (ADSL) offers
    transmission speeds ranging from 16 Kbps to 9
  • T1 or T3 connections often used by businesses
    and large organizations much more expensive than
    POTS or ISDN connections.

Connection Bandwidth
  • Cable connection increasingly available in the
    U.S. can deliver up to 10 Mbps to an individual
  • Satellite connection appealing to users in
    remote areas can download at a bandwidth of
    approximately 400 Kbps.
  • Fixed-point wireless connections offered by
    some companies
  • technology similar to wireless LANs
  • limited and more expensive.

  • Internet 2 operated by group of research
    universities and the NSF has backbone bandwidths
    greater than 10 Gbps.
  • Develop new technologies that will be rapidly
    deployed to expand the Internet.

  • Internet2 is a consortium being led by 207
    universities working in partnership with industry
    and government to develop and deploy advanced
    network applications and technologies,
    accelerating the creation of tomorrow's Internet.
    Internet2 is recreating the partnership among
    academia, industry and government that fostered
    todays Internet in its infancy.
  • The primary goals of Internet2 are to
  • Create a leading edge network capability for the
    national research community
  • Enable revolutionary Internet applications
  • Ensure the rapid transfer of new network services
    and applications to the broader Internet

Connecting Through YourSchool or Employer
  • Many universities and employers offer Internet
    access to their students, faculty members, and
  • Most schools and employers have an acceptable use
    policy (AUP) that specifies the conditions under
    which you can use their Internet connections.
  • possibly least expensive option
  • should carefully consider if limitations placed
    on use of the Internet are greater than the

Connecting Through anInternet Service Provider
  • Reliable connectivity at a reasonable price.
  • Terms of AUPs usually less restrictive.
  • Offer modem connections to individuals and higher
    speed connections to businesses. May also offer
    DSL connections to individual and business
  • Quality of service may deteriorate significantly
    over time if ISP adds many new customers without
    expanding bandwidth.

Connecting Through a DSL Provider
  • Connections increasingly available in the U.S.
    and a few other countries.
  • Significantly faster connection that dial-up
  • Speeds and subscription rates similar to cable
  • Sometimes long delays in installation and repair

Connecting Through YourCable Television Company
  • Cable modem converts digital signals into
    radio-frequency analog signals similar to
    television transmission signals.
  • Signals travel over the same lines that carry
    cable television signals.
  • Cable connection is up to 170 times faster than a
    telephone line connection.
  • Cable connection is not available in all areas.

Connecting by Satellite
  • Satellite Internet connections may be only option
    available in rural areas.
  • Speeds and monthly fees similar to those of cable
    and DSL providers.
  • Installation fee usually considerably higher
    because the dish must be installed and aimed at
    the satellite.

  • The Internet and the Web began in the military
    and research communities.
  • The Internet and the Web have become an important
    worldwide infrastructure.
  • The Internet and the Web support many resources
    through one of the most powerful communication
    tools the world has ever known.
  • There are a number of options for connecting your
    computer and the computers of businesses and
    other organizations to the Internet.
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