The InternetIllustrated Introductory, Fourth Edition

1
The InternetIllustrated Introductory, Fourth
Edition

• Unit A
• Understanding Internet Basics

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U n i t O b j e c t i v e s

• Explore uses for the Internet
• Understand networks
• Understand network connectors
• Learn the origins of the Internet

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U n i t O b j e c t i v e s

• Understand the growth of the Internet
• Understand how the World Wide Web works
• Connect to the Internet
• Evaluate Internet service options

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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.

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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

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Explore Uses for the Internet

• The Internet is used for
• obtaining information
• communicating
• buying and selling goods and services
• downloading software
• accessing multimedia
• playing online games

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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

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Explore Uses for the Internet

• Three types of electronic discussion groups
• mailing lists
• newsgroups
• blogs

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Explore Uses for the Internet
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Understand Networks

• A network is two or more computers connected to
  each other.
• A computer becomes part of a network by
  connecting to a nearby computer or to the
  Internet.
• Networks allow computers to share resources.

• Internetthe worldwide connection of
  interconnected networks
• internetany interconnected network

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Computer Networks

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

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Client/Server Local Area Networks

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

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Understand Networks

• A client/server LAN

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Understand Network Connectors

• Computers are connected using
• twisted-pair cables - telephone wires
• coaxial cables 20 faster than twisted pair
• fiber-optic cables transmit signal using
  coaxial cable
• wireless connections popular increase
  productive - effectiveness

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Connecting Computers to a Network Types of
Cable

• 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
  install.
• Fiber-optic cable most expensive, transmits
  pulsing beams of light through very thin strands
  of glass, fastest transmission rate.

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Types of Cable
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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.

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Connecting Computers to a Network Wireless
Networks

• Becoming more common as costs continue to drop.
• Welcome in organizations that occupy old
  buildings.
• Popular with companies whose employees use laptop
  computers.
• Used by schools in classrooms, libraries, and
  study lounges.
• Used in homes.

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Wireless Home Network
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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.

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Origins of the Internet

• DARPA researchers connected first computer
  switches in 1969.
• ARPANET grew over next three years to include
  over 20 computers.
• Computers communicated to other computers on the
  network by using Network Control Protocol (NCP).
• Protocol collection of rules for formatting,
  ordering, and error-checking data sent across a
  network.

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Learn the Origins of the Internet

• 1960s
• The DOD created DARPA to examine ways to connect
  its computers to one another and to weapons
  installations all over the world.
• DARPA created the first network, ARPANET, in
  1969.
• ARPANET was four computers networked together.

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Origins of the Internet

• Early 1960s by the U.S. Department of Defense
  (DOD).
• Major research project authorized as a part of
  national security.
• Explored ways to connect large mainframe
  computers and weapons installations distributed
  all over the world.
• Defense Advanced Research Projects Agency (DARPA)
  charged with the task

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Learn the Origins of the Internet

• Connectivity
• Circuit switching centrally controlled single
  connection method used for telephone traffic
• Packet switching files are broken down to
  packets that travel computer to computer

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Learn the Origins of the Internet
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Learn the Origins of the Internet

• Open architecture

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Connectivity Circuit Switchingvs Packet
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
  signal.

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Connectivity Circuit Switchingvs 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.

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Connectivity Circuit Switchingvs Packet
Switching

• Routers use routing algorithms programs to
  determine best path for packets.
• 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
  operating.

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Open Architecture Philosophy

• Four Key Points
• Independent networks should not require any
  internal changes to be connected to the
  Internet.
• 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.

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Open Architecture Philosophy

• New set of protocols developed in 1970 by Vincent
  Cerf and Robert Kahn
• Transmission Control Protocol
• Internet Protocol
• (TCP/IP)
• TCP rules used by computers on a network to
  establish and break connections.
• IP rules for routing of individual data packets.

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Open Architecture Philosophy

• TCP/IP used today in LANs and on the Internet.
• Term Internet first used in a 1974 article about
  the TCP protocol written by Cerf and Kahn.
• Vincent Cerf considered to be the father of the
  Internet by many.

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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.

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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.

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Commercial Interest Increases

• National Science Foundation (NSF) prohibited
  commercial network traffic on networks it
  funded.
• Businesses use commercial e-mail services.
• Larger firms built TCP/IP-based WANs use leased
  telephone lines to connect field offices to
  corporate headquarters.
• NSF permitted two commercial e-mail services, MCI
  Mail and CompuServe, to establish limited
  connections to the Internet in 1989.

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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.
• Internet Engineering Task Force (IETF) a
  self-organized group that makes technical
  contributions to the engineering of the Internet
  and its technologies.
• ARPANET grew from 4 computers in 1969 to over
  300,000 by 1990.

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Growth of the Internet

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

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From Research Project to Information
Infrastructure
Growth in number of Internet hosts
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Growth of the Internet

• Number of hosts connected to Internet includes
  only computers directly connected to the
  Internet.
• Internet traffic now carries more files that
  contain graphics, sound, and video, so Internet
  files have become larger.

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Understand the Growth of the Internet

• 1980s
• Firms used PCs to construct intranets.
• Businesses used commercial e-mail services to
  communicate with firms outside their intranets.
• Larger firms built TCP/IP-based WANs and leased
  telephone lines to connect their intranets.
• In 1989, the NSF permitted MCI Mail and
  CompuServe to allow their subscribers to exchange
  e-mails with members of the academic and research
  communities who were connected to the Internet.

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Understand the Growth of the Internet

• 1990s
• In 1991, the NSF began implementing plans to
  privatize much of the Internet via Internet
  hosts.
• In 1995, the FNC adopted the formal definition of
  Internet.

It is interesting to note that a formal
definition of the term Internet was not created
until 1995.
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Understand the Growth of the Internet
FNCs definition of the Internet
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Understand the Growth of the Internet
By 2005, the number of Internet hosts had grown
to over 300 million.
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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.

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New Structure for the Internet

• More than 180 million connected host computers
  and more than 700 million worldwide Internet
  users.
• 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.

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New Structure for the Internet

• The Internet has become one of the most amazing
  technological and social accomplishments of the
  century.
• 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.

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World Wide Web

• World Wide Web a way of thinking about
  information storage and retrieval.
• Web software that runs on some of the computers
  connected to each other through the Internet.
• Two important innovations played key roles
• hypertext
• graphical user interfaces (GUIs)

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Origins of Hypertext

• 1945 Vannevar Bush speculated engineers would
  build a machine that would store a persons
  books, and research results on microfilm.
  Mechanical aids would help retrieve.
• 1960 Ted Nelson described similar system where
  text on one page links to text on other pages. He
  called it hypertext.
• 1960s Douglas Engelbart created first
  experimental hypertext system on one of the large
  computers.

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Hypertext and Graphical UserInterfaces Come to
the Internet

• Hypertext Markup Language (HTML) a language that
  includes a set of tags attached to text.
• 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.

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Hypertext and Graphical UserInterfaces Come to
the Internet

• Web Browser software that lets users read HTML
  documents and move from one HTML document to
  another through hypertext link tags in each
  file.
• HTML subset of Standard Generalized Markup
  Language
• SGML has been used by organizations 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.

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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.

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The Web and 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
  success.
• Internet Explorer Web browser entered the market
  soon after Netscapes success became apparent.

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Growth of the World Wide Web
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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.

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Hierarchy of Internet Service Providers
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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.

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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.

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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
  Mbps.
• T1 or T3 connections often used by businesses
  and large organizations much more expensive than
  POTS or ISDN connections.

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Connection Bandwidth

• Internet 2 operated by group of research
  universities and the NSF has backbone bandwidths
  greater than 10 Gbps.
• Cable connection increasingly available in the
  U.S. can deliver up to 10 Mbps to an individual
  user.
• 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.

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Connecting Through YourSchool or Employer

• Many universities and community colleges offer
  Internet access to their students, faculty
  members, and other employees.
• Your employer might offer you a connection to the
  Internet through the computer you use in your
  job.
• 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
  benefits

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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
  customers.
• Quality of service may deteriorate significantly
  over time if ISP adds many new customers without
  expanding bandwidth.

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Connecting Through a DSL Provider

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

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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 can provide very fast downloads
  to your computer from the Internet (up to 170
  times faster than a telephone line connection).
• Greatest disadvantage for most people is that
  cable connection is not available in all areas.

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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.

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Summary

• 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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Clues to Use

• The transfer protocol is the set of rules that
  computers use to move files from one computer to
  another on an internet.
• HTTP is the most common transfer protocol used on
  the Internet.
• File transfer protocol (FTP) and the Telnet
  protocol are also still used.

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Clues to Use

• No one knows how many users are on the Internet.
• The Internet has no central management or
  coordination.
• Routing computers do not maintain records of the
  data packets they handle.
• It is estimated that
• at least 300 million host computers are connected
  to the Internet
• and more than 700 million people worldwide use
  it.

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Understand How the World Wide Web Works

• The Web and the Internet are not the same
  thing.
• The Internet is the entire system of networked
  computers.
• The World Wide Web is a method used to access
  information contained on a subset of those
  networked computers.
• You connect to the Internet, and then use the
  World Wide Web to access information.

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Connect to the Internet

• To connect to the Internet, individuals and
  businesses must set up an account with an
  Internet Service Provider (ISP).
• ISPs provide access to a NAP.

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Connect to the Internet
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Connect to the Internet

• Types of connections to the Internet
• telephone service connection (POTS or plain old
  telephone service)
• T1 and T3 line connections
• Digital Subscriber Line (DSL)
• cable
• satellite
• wireless

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Connect to the Internet

• Modem
• Short for modulator-demodulator
• Converts signals between a computer (uses digital
  signals) and a twisted-pair or coaxial cable
  transmission line (uses analog signals)
• Modulationconverting a digital signal to an
  analog signal
• Demodulationconverting that analog signal back
  into digital form
• Cable modem
• required for a cable connection through a cable
  television company
• DSL modem
• required for a DSL connection

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Connect to the Internet

• To connect a device to the Internet without
  cables, you need a wireless network interface
  card (WLAN card) or a Wi-Fi compatible device.
• You also must be within range of a wireless
  access point that is connected to the Internet.

Some public locations provide wireless access
points for free or for a small fee.
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Evaluate Internet Service Options

• Ways of connecting to the Internet
• school or employer connection
• telephone line connection
• cable connection
• satellite connection
• hot spots

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Evaluate Internet Service Options

• Select an ISP
• What is the monthly base fee and how many hours
  of Internet service are included?
• What is the hourly rate for time used over the
  monthly base amount?
• Is the telephone access number local or long
  distance?
• Which specific Internet services are included?
• What software is included?
• What user-support services are available?

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Internet Basics Include

• Exploring uses for the Internet
• Understanding networks
• Understanding network connectors
• Learning the origins of the Internet
• Clues to use Transfer protocol

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Internet Basics Include (cont.)

• Understanding the growth of the Internet
• Clues to use Number of Internet users
• Understanding how the World Wide Web works
• Connecting to the Internet
• Evaluating Internet service options

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Terms to Use

• Internet
• a collection of computers all over the world that
  are connected to one another
• World Wide Web
• a subset of the Internet
• Web pages
• documents formatted to be viewed on the Web
• Web site
• a collection of related Web pages stored on a
  computer

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Terms to Use

• E-mail
• electronic messages transferred between two or
  more computers
• Instant messages (IM)
• messages exchanged over the Internet in real time

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Terms to Use

• Server
• any computer that accepts requests from other
  computers connected to it and shares its
  resources with those connected computers
• Client
• a computer connected to a server
• Client/server network
• a network consisting of one server and multiple
  clients
• LAN
• a network of computers that are physically close
  to each other
• WAN
• a network of LANs

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Terms to Use

• Network operating system
• the software that runs on the server and
  coordinates the flow of information among its
  various clients
• Network interface card (NIC)
• a removable circuit board used to connect a
  computer to a network by attaching a cable from
  the NIC to the server or to another client

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Terms to Use

• Packet switching
• a method of sending information that breaks down
  files and messages into data packets
• TCP/IP
• Transmission Control Protocol (TCP) includes
  rules that computers on a network use to
  establish and break connections
• Internet Protocol (IP) includes rules for routing
  individual data packets
• Open architecture philosophy
• each network connected to the Internet can use
  its own protocols and data-transmission methods
  internally
• Network access points (NAPs)
• physical locations where networks connect to the
  Internet

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Terms to Use

• Intranets
• LANs or WANs that use the TCP/IP protocol but do
  not connect to sites outside the firm
• Internet hosts
• computers that connect a LAN or a WAN to the
  Internet

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Terms to Use

• Hypertext Markup Language (HTML)
• a computer language that marks text with a set of
  tags, or codes, that define the structure and
  behavior of a Web page
• Web server
• a computer that stores files written in HTML and
  lets other computers connect to it and read those
  files
• Web browser
• software that reads HTML documents and moves from
  one HTML document to another
• Links
• text, graphics, or other Web page elements that
  connect to additional data on the Web site you
  are currently exploring or on a Web site halfway
  around the world