Fundamentals of Information Systems Fourth Edition

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Fundamentals of Information SystemsFourth Edition

• Chapter 4
• Telecommunications, the Internet, Intranets, and
  Extranets

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Why Learn About Telecommunications and Networks?

• Need to access data wherever it resides
• Fast, reliable communications
• Exchange messages
• Upload/download data and software
• Route business transactions
• Connect to remote databases
• Send output to printers

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An Overview of Telecommunications

• Telecommunications the electronic transmission
  of signals for communications
• Telecommunications medium anything that carries
  an electronic signal and interfaces between a
  sending device and a receiving device

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An Overview of Telecommunications (continued)
Figure 4.1 Elements of a Telecommunications
System
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Channel Bandwidth

• Telecommunications professionals consider the
  capacity of the communications path or channel
  when they recommend transmission media for a
  business
• Channel bandwidth the rate at which data is
  exchanged over a communication channel
• Usually measured in bits per second (bps)
• Broadband vs Narrowband

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Services

• Digital subscriber line (DSL)
  telecommunications service that delivers
  high-speed Internet access to homes and small
  businesses over the existing phone lines of the
  local telephone network
• Wireless telecommunications
• All major long distance carriers offer wireless
  telecommunications services that enable you to
  place phone calls or access the Internet

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Networks and Distributed Processing

• Computer network the communications media,
  devices, and software needed to connect two or
  more computer systems and/or devices
• Network nodes the computers and devices on the
  networks

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Network Types

• Personal area network (PAN)
• Bluetooth refers to the Danish king Harald
  Bluetooth Blaatand who unified Denmark and
  Norway. In the beginning of the Bluetooth
  wireless technology era, Bluetooth was aimed at
  unifying the telecom and computing industries.
• Local area network (LAN)

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Network Types (continued)
Figure 4.4 A Typical LAN
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Network Types (continued)

• Metropolitan area network (MAN)
• Wide area network (WAN)
• long distance phone calls internet access
• International networks
• laws regulating transborder data flow
• VoIP systems
• Mesh networking
• way to route communications among network nodes
  for continuous connections9

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Network Types (continued)
Figure 4.5 A Wide Area Network
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Distributed Processing

• Centralized processing all processing occurs in
  a single location or facility
• reduced cost
• improve security
• simplify backup and recovery
• Decentralized processing processing devices are
  placed at various remote locations
• suitable for companies with independent operating
  divisions

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Distributed Processing (continued)

• Distributed processing computers are placed at
  remote locations but connected to each other via
  a network
• data can be allocated to locations that can
  process it most efficiently
• minimizes consequences of a catastropic event
  (e.g. 9/11 or Katrina)

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Client/Server Systems

• Servers multiple computer platforms are
  dedicated to special functions, such as database
  management, printing, communications, and program
  execution.
• Clients Access the programs and data available
  from the servers.

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Client/Server Systems (continued)
Figure 4.8 Client/Server Connection
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Communications Software and Protocols

• Communications protocol a set of rules that
  govern the exchange of information over a
  communications channel.
• The channels are imperfect, but protocols insure
  communications are
• fast
• efficient
• error-free

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Communications Software

• Network operating system (NOS) systems software
  that controls the computer systems and devices on
  a network and allows them to communicate with
  each other
• Network-management software software that a
  manager uses on a networked desktop
• Monitors the use of individual computers and
  shared hardware (such as printers)
• Scans for viruses
• Update software and files
• Ensures compliance with software licenses

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Use and Functioning of the Internet

• Internet a collection of interconnected
  networks, all freely exchanging information with
  no single registration site

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Use and Functioningof the Internet (continued)

• Internet Protocol (IP) communication standard
  that enables traffic to be routed from one
  network to another as needed

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How the Internet Works

• The Internet transmits data from one computer
  (called a host) to another
• If the receiving computer is on a network to
  which the first computer is directly connected,
  it can send the message directly
• If the receiving computer is not on a network to
  which the sending computer is connected, the
  sending computer relays the message to another
  computer that can forward it

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How the Internet Works (continued)
Figure 4.11 Routing Messages over the Internet
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How the Internet Works (continued)

• Data is passed in chunks called packets
• Transmission Control Protocol (TCP) widely used
  transport-layer protocol that is used in
  combination with IP by most Internet applications
• Uniform Resource Locator (URL) an assigned
  address on the Internet for each computer
• Hypertext Transport Protocol (http) As the
  default protocol, it can often be omitted

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How the Internet Works (continued)

• Domain name includes an affiliation code
• An internationalized domain name (IDN) is an
  internet domain name that (potentially) contains
  non-ASCII characters.

Country (.au, .ca, .mn) Educational (.edu) Organizations (.org) Business (.com) Government (.gov) Military (.mil)
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Internet Service Providers

• Internet service provider (ISP) any company that
  provides individuals or organizations with access
  to the Internet
• Most charge a monthly fee
• Many ISPs and online services offer broadband
  Internet access through digital subscriber lines
  (DSLs), cable, or satellite transmission

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The World Wide Web

• The Web, WWW, or W3
• A menu-based system that uses the client/server
  model
• Organizes Internet resources throughout the world
  into a series of menu pages, or screens, that
  appear on your computer
• Hypermedia tools that connect the data on Web
  pages, allowing users to access topics in
  whatever order they want

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The World Wide Web (continued)

• Hypertext Markup Language (HTML) the standard
  page description language for Web pages
• HTML tags codes that let the Web browser know
  how to format text - as a heading, as a list, or
  as body text - and whether images, sound, and
  other elements should be inserted

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The World Wide Web (continued)
Figure 4.13 Sample Hypertext Markup Language
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Web Browsers

• Web browser software that creates a unique,
  hypermedia-based menu on a computer screen,
  providing a graphical interface to the Web
• The menu consists of graphics, titles, and text
  with hypertext links
• Popular Web browsers Microsoft Internet
  Explorer, Netscape Navigator, Mozilla Firefox,
  Apple Computers Safari

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Search Engines and Web Research

• Search engine Web search tool
• Examples Yahoo.com, Google.com
• Most search engines are free
• Searches can use words, such as AND and OR to
  refine the search
• Google Basics
• http//www.google.com/intl/en/help/basics.html
• Google Advanced Operators
• http//www.google.com/intl/en/help/refinesearch.ht
  ml

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Search Engines and Web Research (continued)

• Meta-search engine submits keywords to several
  individual search engines and returns results
  from all these search engines
• http//www.dogpile.com/

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Search Engines and Web Research (continued)
Table 4.10 Popular Search Engines
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Web Programming Languages

• Java
• An object-oriented programming language from Sun
  Microsystems based on C
• Allows small programs (applets) to be embedded
  within an HTML document

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Internet and Web Applications E-Mail, Instant
Messaging, and Push Technology

• E-mail is no longer limited to simple text
  messages
• Sound and images can be embedded in messages
• Files that contain text documents, spreadsheets,
  graphs, or executable programs can be attached
• Instant messaging allows two or more individuals
  to communicate online using the Internet
• Push technology (send information automatically
  to a user rather than on request)

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Internet Phone and Videoconferencing Services

• Internet phone service enables you to communicate
  with others around the world
• Relatively inexpensive
• Useful for international calls
• Ability to keep your phone number when you move
  to another location
• Internet videoconferencing
• Supports both voice and visual communications

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Shopping on the Web

• Shopping on the Web for books, clothes, cars,
  medications, and even medical advice can be
  convenient, easy, and cost effective
• http//www.webmd.com/
• Bot software tool that searches the Web for
  information, products, or prices
• http//www.pricegrabber.com/

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Web Auctions

• Web auction Internet site that matches buyers
  and sellers
• eBay is one of the most popular auction sites
• Traditional companies are starting their own
  auction sites

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Music, Radio, Video, and TV on the Internet

• Music, radio, and video are hot growth areas on
  the Internet
• Audio and video programs can be played on the
  Internet, or files can be downloaded for later
  use

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Intranets and Extranets

• Intranet
• Internal corporate network built using Internet
  and World Wide Web standards and products
• Used by employees to have ready access to
  corporate information
• Reduces need for paper

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Intranets and Extranets (continued)

• Extranet
• A network based on Web technologies that links
  selected resources of a companys intranet with
  its customers, suppliers, or other business
  partners
• Virtual Private Network (VPN) secure connection
  between two points across the Internet

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