Transcript Chapter-4

Chapter 4
Telecommunications
and the Internet
Dr. Hassan Ismail
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Chapter 4 Objectives
• Understand the role of
telecommunications in organizations
• Understand the evolution of computer
networks
• Understand the Internet and how it works
• Understand basic Internet services
• Understand the use of the World Wide
Web
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The Role of Telecommunications
and Networks in Organizations
• Definitions
– Telecommunications – the transmission of all forms of
information, including digital data, voice, fax, sound,
and video, from one location to another over some type
of network
– Network – a group of computers and associated
peripheral devices connected by a communication
channel capable of sharing information and other
resources (e.g., like a printer) between users
– Bandwidth – the carrying capacity of
telecommunications networks
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The Role of Telecommunications
and Networks in Organizations
• Interpersonal Communication Applications
– E-mail and Groupware
– Voice mail & Facsimile (fax)
– Teleconferencing, Data conferencing and
Videoconferencing
– Common business applications:
• Distance learning,
• E-learning
• E-commerce
• E-business
• Telemedicine
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Electronic Mail and Groupware
• E-mail: Eliminates telephone tag and costly
long-distance telephone charges
• Groupware: Enables work groups at
different locations to participate in
discussion forums and work on shared
documents and projects
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Voice Mail and Fax
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Voice mail: Digitizes spoken message and
transmits it over a network
• Fax: Digitizes and transmits documents
over telephone lines
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Teleconferencing, data conferencing,
and videoconferencing
• Teleconferencing: Ability to confer with a
group of people simultaneously
• Data conferencing: Two or more users
can edit and modify data files
simultaneously
• Videoconferencing: Participants are able
to see each other over video screens
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Common business applications
•
Distance learning: Education or training delivered
•
E-learning: Instruction delivered online using the
•
E-Commerce: buying or selling online online using
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E-business: use the internet technology to support
business.
•
Telemedicine: exchange of medical information from
one location to another via a computer network.
over a distance to individuals in one or more locations
Internet or private networks
the Internet or private networks
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Network Topologies
• Star network
• Ring network
• Bus network
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Bus Topology
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Ring Topology
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Star topology
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Evolution of Computer
Networking
• Sharing Information
– Senders and receivers that have something to
share
– Transmission media: cable to send the
message
– Rules or protocols: dictating communication
between senders and receivers.
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Evolution of Computer Networking
• Computer Networks: 1) Digitizing => 2) Modem
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Evolution of Computer
Networking
• Centralized Computing: large centralized computer
called mainframe were used to process and store data
Mainframe
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Evolution of Computer
Networking
Distributed Computing: multiple types of computers are networked
together to share information and services
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Evolution of Computer
Networking
Collaborative Computing:
two or more networked computers are used to
accomplish a common processing task.
(1)
(2)
(3)
1. Requests record to change
3. Returns changed record
2. Returns requested record
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Evolution of Computer
Networking
•Types of Networks
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Private Branch Exchange (PBX)
Local Area Network (LAN)
Wide Area Network (WAN)
Personal Area Networks (PANs):
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Evolution of Computer
Networking
• Types of Networks
– Private Branch Exchange (PBX):
• Central switching system
• Handle firm’s voice and digital communications
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Evolution of Computer
Networking
Local Area Network (LAN):
– Telecommunication network
– Require its own dedicated channels
– Encompass a limited distance
– Gateway, router, Network Operating System (NOS)
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Wide Area Networks (WANs)
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Telecommunication network
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Span large geographical distance
•
Consist of variety of cable, satellite, and
microwave technologies
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Switched lines, dedicated lines
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…WAN types
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Global Networks: spans multiple countries
and may include several organizations
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Enterprise Networks: WAN connecting
networks of single organization
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Value-Added Networks (VANs): private,
third-party managed networks (lease
communication lines rather than investing in
dedicated network equipment).
•
Metropolitan Area Networks (MANs):
network for city-wide area
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Wide Area Networks (WANs)
• Telecommunication network
• Span large geographical distance
• Consist of variety of cable, satellite, and
microwave technologies
• Switched lines, dedicated lines
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Personal Area Networks (PAN)
emerging technology uses wireless
communication to exchange data through
short-range radio communication for
short-distance (exp: Bluetooth)
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The Internet
•How did the Internet Get Started?
– ARPANET
• U.S. Defense
• Advanced Research Projects Agency (ARPA)
– NSFNET
• National Science Foundation
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The Internet
• Internet Technologies
– Packet-Switching Technology
– TCP/IP
• Transmission Control Protocol/Internet Protocol
• IP Datagram
– Connecting Independent Networks
• Routers
• Backbone Network
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Packet switching
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The Internet
• Web Domain Names and Addresses
– Uniform Resource Locator (URL)
– Common domain extensions
• .edu .org .mil .com .net
• .ca .th .no (country codes)
– IP Addresses
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The Internet
• Who Manages the Internet?
– Domain Name System (DNS) – a system used to
associate Internet host names with their Internet
IP addresses
– The Internet Registry – provides central
maintenance of the DNS root database, used to
associated Internet hostnames with their IP
addresses.
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The Internet
• Who Manages the Internet?
– Internet Corporation for Assigned Names and
Numbers (ICANN) – a non-profit corporation
manages IP addresses, domain names, and root server
system management
– InterNIC Registration Service – assigns Internet
addresses
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The Internet
• How Do You connect to the Internet?
– Internet Service Providers (ISPs): which will give
you username and password to access to the
internet.
– Network Access Points (NAPs): within which ISPs
can connect to one another.
– Internet backbone: which is the collection of main
network connections and telecommunications
lines comprising the Internet.
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The Internet
• How Fast Is Your Connection?
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Plain Old Telephone Service (POTS)
Integrated Services Digital Network (ISDN)
Digital Subsciber Line (DSL)
Cable Modems
Satellite Connections
T1 Lines
Asynchronous Transfer Mode (ATM)
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The Internet
•Security in the Internet Age
– Encryption
– Firewalls
– Authentication
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The Internet
• State of the Internet
• What are people doing on the Internet?
– E-mail
– What next for the Internet?
• Internet2
• Abilene network backbone
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The Internet
• Internet Tools (see table in page 119)
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E-mail
Telnet
File transfer
Listserv
Usenet
Archie
WAIS
– Gopher
– Voice over IP
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World Wide Web
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Web browser
Hypertext
Hyperlinks
Hypertext Markup Language (HTML)
Web servers
Hypertext Transfer Protocol (HTTP)
Uniform Resource Locator (URL)
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World Wide Web
• World Wide Web Architecture
• World Wide Web Applications
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Electronic brochure
Online ordering
Electronic marketplaces
Online customer service
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