Transcript chap4_presentation_sumana

“TELECOMMUNICATIONS
AND THE INTERNET”
BY
SUMANA SHARMA
TELECOMMUNICATION IN
ORGANIZATIONS!
The whole world is within
your reach!
SIMPLIFYING THE JARGON!
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Telecommunications refers to the
transmission of information
(voice,data,pictures,video,sound)
from one point to another over a
network.
Bandwidth is the data carrying
capacity of the network. Greater the
bandwidth,faster is the speed of data
transmission!
INTERPERSONAL
COMMUNICATION APPLICATIONS
 e Mail or Electronic mail
 Internet relay chat or instant
messaging
 Newsgroups
 Mailing lists
 Fax
 Voice mail
 Video conferencing
BUSINESS COMMUNICATION
APPLICATIONS
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e Commerce or Electronic commerce
Electronic data interchange(EDI)
Telecommuting
Electronic funds transfer
Distance learning
Telemedicine
COMPONENTS OF A COMPUTER
NETWORK
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Sender or a Transmitter
Receiver
Transmission media
Protocols or rules
TYPES OF COMMUNICATION
REAL TIME
Instant messaging, video conferencing
 NON REAL TIME
E mail, voice mail.
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HOW DO COMPUTERS
COMMUNICATE WITH EACH
OTHER?
Computers talk in Binary Language.
 They use different combinations of
the digits 0 and 1 to express all that
they want to say!
 If we wish to communicate with a
computer we would need to translate!
 The process of translation is called
“digitization”

COMPUTING – HOW COMPUTERS
PERFORM TASKS?
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Centralized computing
Distributed computing
Collaborative computing
TYPES OF COMPUTER
NETWORKS
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PRIVATE BRANCH EXCHANGE OR
PBX
While at work, majority of the
telephone calls made by employees
are for intra-company
communication!
It is feasible for medium to large
businesses to have their own
telephone exchange.
LOCAL AREA NETWORK
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A group of computers and other
devices in a relatively limited area
(such as a single building) that are
connected by a communications link
enables every device to interact with
any other device on the network
CAMPUS AREA NETWORK
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An interconnection of local-area
networks within a limited
geographical space, such as a
school campus or a military base.
WIDE AREA NETWORK (WAN)
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A system of interconnected
computers encompassing a large
geographic range, including cities,
states, or countries
METROPOLITAN AREA NETWORK
A data communications network that
 covers an area larger than a campus
area network and smaller than a wide
area network,
 interconnects two or more LANs, and
 usually covers an entire metropolitan
area, such as a large city and its
suburbs.
PERSONAL AREA NETWORK
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Network in which all devices are
distributed locally around an
individual person (range is from 10100m).
These different devices are capable
of communicating with each other!
GLOBAL AREA NETWORK
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An international network that spans
all departments, offices, and
subsidiaries of the corporation.
ENTERPRISE NETWORK
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A term coined by IBM to describe a
private network, linking sites within a
company.
VALUE ADDED NETWORK
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This is is a privately owned, or
proprietary network.
A company that acts as a
clearinghouse for electronic
transactions between trading
partners
INTERNET
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INTERNET IS NOTHING BUT A
NETWORK OF NETWORKS!!
Born when DoD started a project
called Advanced Research Projects
Agency Network (ARPANET)
Goal was to develop a decentralized
system that could withstand an
enemy attack.
UCLA, SRI, UCSB, and Utah were the
first four nodes.
INTERNET RELIES ON PACKET
SWITCHING TECHNOLOGIES
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A huge amount of data can be split
into smaller chunks and then sent
across the transmission medium.
At the receiving end all the chunks
are put together to retrieve the
original data.
Very efficient technology that makes
best use of available bandwidth!
HOW DO NETWORKS TALK TO
EACH OTHER?
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Using TCP/IP (Transmission control
protocol/Internet protocol).
TCP deals with breaking a large
piece of data into manageable
chunks. These tiny packets of data
are called datagrams.
IP deals with attaching an address
label over them so that that they can
reach the desired destination.
ROUTERS- A MEANS OF
CONNECTING TWO NETWORKS
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High speed device capable of
relaying data from one network to
another.
DIFFERENCE BETWEEN
INTERNET AND THE WORLD WIDE
WEB OR WWW
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Internet is a network of networks
while the world wide web is a
collection of documents(web pages)
that are held on and sent through the
internet
IP ADDRESSES AND DOMAIN
NAMES
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The internet is a massive computer
network comprising of millions of
computers.
Each computer has a unique address
associated with it.
This is called an IP address. For
example: 212.14.56.39 is an IP
address.
This Numeric address can be
mapped to a name (web address) for
ease of remembering.
DOMAIN NAME OR URL
(UNIFORM RESOURCE LOCATOR)
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Domain name is an alias for the
“difficult to remember” IP address.
Example : www.vcu.edu
Web
Domain
name
Educational
institutions
ROLE OF ICANN IN MANAGING IP
TO DOMAIN NAME MAPPING
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ICANN (Internet corporation for
assigned names and numbers)
manages the exhaustive database
consisting of domain names and
their corresponding IP addresses
and vice versa.
WORLD WIDE WEB
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A web browser provides an easy-touse interface for accessing the
information on the World Wide Web.
Hypertext documents contains
information and hyperlinks.
Hyperlinks are links to other related
documents.
http://www.vcu.edu/
Web pages are written in HTML
(Hyper text mark up language)
INTERNET IS NOBODY’S PRIVATE
PROPERTY!
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Nobody owns the internet!
Many non-profit organizations help in
maintaining it though!
Examples:
ISOC (Internet society)
ICANN (Internet society for assigned
names and numbers)
IAB (Internet architecture board)
DIFFERENT WAYS OF
ACCESSING THE INTERNET
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Individuals usually connect to the
Internet using either:
Dial Up
DSL or Digital subscriber line
ISDN or Integrated services digital
network
Cable modems
Satellite connections
DIAL UP
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Uses normal telephone line to
establish a connection.
Maximum speed of 56 Kbps can be
achieved.
DIGITAL SUBSCRIBER LINE
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Uses normal telephone line to
achieve extremely high data rates.
Two popular variations are :
ADSL or Asymmetric DSL
Downstream speed of 1.5 Mbps to 9
Mbps
Upstream speed of 16 to 640 Kbps
SDSL or Symmetric DSL
Downstream and upstream speeds of
3 Mbps
CABLE MODEMS
 Utilizes coaxial cable to access the
internet.
 Requires a cable modem to be
installed.
 Data rates of upto 2 Mbps can be
achieved.
SATELLITE CONNECTIONS
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Utilizes geostationary satellites to
access the internet.
Propagation delay is a major concern
HOW BUSINESSES OR OTHER
ORGANIZATIONS ACCESS THE
INTERNET
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Using Leased lines.
Using ATM or Asynchronous transfer
mode networks
LEASED LINE
A leased line is a dedicated phone
line to your telephone exchange.
 It has two popular variants:
 T1 = 24 telephone lines
Data rates of upto 1.5 Mbps
 T3= 672 telephone lines
 Data rates of upto 45 Mbps
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ATM
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Based on packet switching.
Fixed packet size of 53 bytes.
Data rates of upto 2.2 Gbps can be
achieved.
SECURITY – THE MILLION
DOLLAR QUESTION!
Authentication
Log in with your password
 Firewalls
Shield information from hackers or
unauthorized users!
 Encryption
The sender turns on the lock.Only the
receiver has the key
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POPULAR INTERNET TOOLS
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e mail: Used for transmitting and
receiving messages.
Telnet: An Internet protocol that
allows a user at a remote terminal to
login to other computer systems on
the Internet
FTP or File transfer protocol:A way of
transferring files over the Internet
from one computer to another.
Internet tools - continued
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Usenet: Collection of newsgroups
across the internet.
Mailing lists: Allows group of people
with a common interest to send
messages to each other.
Archie: Juggle through FTP sites to
see if they have the information you
are looking for!
Internet tools - continued
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Gopher: Was the means of accessing
information(plain text) on the internet,
before the world wide web was born!
VoIP or Voice over IP: A technology for
transmitting ordinary telephone calls over
the Internet using packet-linked routes
WAIS or Wide area Information server:
distributed information retrieval system on
the Internet used to retrieve documents
using keywords searching defined
databases.