Chapter 4 Telecommunications, the Internet, Intranets, and Extranets

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

• Overview of Telecommunications and the Networks
• Use and Functioning of the Internet
• Internet and Telecommunication Services
• The World Wide Web
• Intranets and Extranets
• Net Issues

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Overview of Telecommunications and the
NetworksTelecommunications Defined

• Telecommunications the electronic transmission
  of signals from one point to another.
• Data
• Voice

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Overview of Telecommunications and the
NetworksElements of a Telecommunications System
Transmission Medium
Digital
Analog
Digital
Sending Computer
Receiving Computer
Telecommunications Device
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Overview of Telecommunications and the
NetworksMedia Types
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Overview of Telecommunications and the Networks
Common Telecommunications Devices
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Overview of Telecommunications and the
NetworksCarriers and Services

• Common carriers long distance telephone
  companies
• Switched lines communications line that uses
  switching equipment to allow one transmission
  device to be connected to other transmission
  devices.
• Digital subscriber lines (DSL) communication
  line that uses existing phone wires going into
  todays homes and businesses to provide speeds up
  to 500Kbps at a cost of 20 or more per month.

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Overview of Telecommunications and the Networks
Line and Service Types
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Overview of Telecommunications and the Networks
Upstream and Downstream

• This term should not be confused with downlink.
• In telecommunications generally, a transmission
  from an information server toward an end user is
  referred to as downstream and a transmission
  toward the server is referred to as upstream. In
  some transmission technologies, such as Digital
  Subscriber Line (DSL), the rates of data transfer
  upstream and downstream are not the same. In DSL,
  downstream data rates are higher since the kind
  of information that needs to get to the user
  (including still and video images and sound)
  requires a higher data rate. User responses back
  to the computer on the upstream path can be
  smaller since they are usually text-only.
• In a Token Ring network, a computer station is
  downstream from any station through which the
  token on the ring has already passed.
• In CATV, a downstream channel is one used to
  transmit signals from the headend to the user. An
  upstream channel is one in another frequency band
  that is used to send signals from the user back
  to the headend.
• www.whatis.com

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Overview of Telecommunications and the Networks
Networks and Distributed Processing

• Computer network - communications media, devices,
  and software needed to connect two or more
  computer systems.
• Centralized processing - processing occurs in a
  single location or facility.
• Decentralized processing - processing devices are
  placed at various locations.
• Distributed processing - computers are placed at
  remote locations but are connected to each other
  via telecommunications devices.

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Overview of Telecommunications and the Networks
Terminal-to-Host, File Server, and Client/Server

• Terminal to host application and database
  reside on one computer and user interfaces via a
  dumb terminal.
• File server architecture where application and
  database reside on one host computer
• Client/server architecture in which multiple
  computer platforms are dedicated to special
  functions such as database management, printing,
  communications, and program execution

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Overview of Telecommunications and the Networks
Common Communications Protocols
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Use and Functioning of the Internet Routing
Messages Over the Internet
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Use and Functioning of the Internet U.S.
Top-Level Domain Affiliations
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Use and Functioning of the Internet Three Ways
to Access the Internet
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Internet and Telecommunications Services Summary
of Internet Services

• E-mail
• Instant messaging
• Telnet
• FTP
• Chat rooms
• Internet phones
• Internet video conferencing
• Content streaming

• Shopping on the Web
• Web auctions
• Music, radio, and video on the Internet
• Electronic data interchange
• Public network and specialized services
• Distance learning

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Net Issues Cryptography
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Terminology

• Backbone one of the Internets high-speed,
  long-distance communications networks
• Communications protocol - rules and standards
  that make communications possible
• Communications software - provides error checking
  and message formatting, detects problems,
  maintains logs, and data security.
• Cookie text file that an Internet company can
  place on the hard drive of a computer system to
  track the Web movements of its users
• Cryptography process of converting a message
  into a secret code and changing the encoded
  message back to regular text.
• Digital Signature encryption technique used to
  verify the identify of a message sender for the
  processing of online financial transactions
• Encryption conversion of a message into a
  secret code
• Extranet - a network that links selected
  resources of the intranet of a company with its
  customers, suppliers, or other business partners
• Firewall - a device that sits between your
  internal network and the outside Internet
• Home page cover page for a Web site that has
  titles, graphics, and text.
• Hypermedia tools that connect the data on Web
  pages, allowing users to access topics in
  whatever order they wish
• Hypertext markup language (HTML) standard page
  description language for Web pages
• Internet - transmits data from one computer
  (called a host) to another.
• Internet Protocol (IP) communication standard
  that enables traffic to be routed from one
  network to another.
• Intranet an internal corporate network built
  using Internet and WWW standards and products
• Networks - used to share hardware, programs, and
  databases across the organization.
• Network management software - a manager can
  monitor the use of individual computers and
  shared hardware
• Network operating system - controls the computer
  systems and devices on a network and allows them
  to communicate with each other
• Virtual private network - a secure connection
  between two points across the Internet