Download Chapter-4

Chapter 4
Telecommunications
and the Internet
Dr. Hassan Ismail
1
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
2
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
3
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
4
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
5
Voice Mail and Fax
•
Voice mail: Digitizes spoken message and
transmits it over a network
• Fax: Digitizes and transmits documents
over telephone lines
6
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
7
Common business applications
•
Distance learning: Education or training delivered
•
E-learning: Instruction delivered online using the
•
E-Commerce: buying or selling online online using
•
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
8
Network Topologies
• Star network
• Ring network
• Bus network
9
Bus Topology
10
Ring Topology
11
Star topology
12
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.
13
Evolution of Computer Networking
• Computer Networks: 1) Digitizing => 2) Modem
14
Evolution of Computer
Networking
• Centralized Computing: large centralized computer
called mainframe were used to process and store data
Mainframe
15
Evolution of Computer
Networking
Distributed Computing: multiple types of computers are networked
together to share information and services
16
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
17
Evolution of Computer
Networking
•Types of Networks
–
–
–
–
Private Branch Exchange (PBX)
Local Area Network (LAN)
Wide Area Network (WAN)
Personal Area Networks (PANs):
18
Evolution of Computer
Networking
• Types of Networks
– Private Branch Exchange (PBX):
• Central switching system
• Handle firm’s voice and digital communications
19
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)
20
Wide Area Networks (WANs)
•
Telecommunication network
•
Span large geographical distance
•
Consist of variety of cable, satellite, and
microwave technologies
•
Switched lines, dedicated lines
21
…WAN types
•
Global Networks: spans multiple countries
and may include several organizations
•
Enterprise Networks: WAN connecting
networks of single organization
•
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
22
Wide Area Networks (WANs)
• Telecommunication network
• Span large geographical distance
• Consist of variety of cable, satellite, and
microwave technologies
• Switched lines, dedicated lines
23
Personal Area Networks (PAN)
emerging technology uses wireless
communication to exchange data through
short-range radio communication for
short-distance (exp: Bluetooth)
24
The Internet
•How did the Internet Get Started?
– ARPANET
• U.S. Defense
• Advanced Research Projects Agency (ARPA)
– NSFNET
• National Science Foundation
25
The Internet
• Internet Technologies
– Packet-Switching Technology
– TCP/IP
• Transmission Control Protocol/Internet Protocol
• IP Datagram
– Connecting Independent Networks
• Routers
• Backbone Network
26
Packet switching
27
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
28
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.
29
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
30
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.
31
The Internet
• How Fast Is Your Connection?
–
–
–
–
–
–
–
Plain Old Telephone Service (POTS)
Integrated Services Digital Network (ISDN)
Digital Subsciber Line (DSL)
Cable Modems
Satellite Connections
T1 Lines
Asynchronous Transfer Mode (ATM)
32
The Internet
•Security in the Internet Age
– Encryption
– Firewalls
– Authentication
33
The Internet
• State of the Internet
• What are people doing on the Internet?
– E-mail
– What next for the Internet?
• Internet2
• Abilene network backbone
34
35
The Internet
• Internet Tools (see table in page 119)
–
–
–
–
–
–
–
E-mail
Telnet
File transfer
Listserv
Usenet
Archie
WAIS
– Gopher
– Voice over IP
36
World Wide Web
•
•
•
•
•
•
•
Web browser
Hypertext
Hyperlinks
Hypertext Markup Language (HTML)
Web servers
Hypertext Transfer Protocol (HTTP)
Uniform Resource Locator (URL)
37
World Wide Web
• World Wide Web Architecture
• World Wide Web Applications
–
–
–
–
Electronic brochure
Online ordering
Electronic marketplaces
Online customer service
38