Network and the Internet: Introduction to Computer

Basic knowledge for computer studies

1. Innovative Training Works Digital Literacy
Living OnlineLiving Online
Networks and the Internet

2. Living Online
Objectives
Identify network fundamentals
Identify the benefits and risks of network
computing
Identify the relationship between computer
networks, other communication networks, and
the Internet
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3. Living Online
Introduction
Today, millions of people are using the
Internet
Conduct business, do research, or read
the latest news
Download software and files, “shop” on-
line, play computer games, or look for
employment opportunities
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4. Living Online
Introduction
Number of users has been continuously
increasing to hundreds of millions over
the past few years
What really is the Internet? How does it
work? How did it start?
How can we benefit from the Internet?
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What is the Internet?
The Internet, or simply the Net, is a
collection of computer networks that link
millions of different computers around
the world.
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History of Internet

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Why Information Superhighway?
You can “travel” to
any of the millions of
computers that are
hooked up to the
Internet, computers
that might be
thousands of miles
away.
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How does Internet work?
Data travels by being relayed from one
computer on a network, to another
computer in another network until it
reaches its destination.
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What is a computer network?
A computer network is a group of
connected computers that exchange
information.
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What are Protocols?
Protocol is a standardized collection of
rules and conventions so that computers
can exchange information regardless of
their type or brand.
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Networks can be categorized:
By Scale
By Functional Relationship
By Topology
By Technology used
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Types of Networks (By Scale)
Local Area Network (LAN)
Metropolitan Area Network (MAN)
Wide Area Network (WAN)
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Local Area Network (LAN)
In LAN, computers are connected within
a local area, such as an office, a home,
or a school’s computer laboratory.
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Metropolitan Area Network (MAN)
MAN is a larger network than LAN. It
usually covers several offices, buildings
or schools, each with their own LAN but
connected to one another in the same
city or locale.
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Wide Area Network (WAN)
Computers in a WAN are much farther
apart, such as in two different cities. This
is used to connect Local Area Networks
together over vast distances.
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Networks (By Functional Relationship)
Peer-to-Peer
All computers in the network relatively have
the same function.
Client-Server
Specially designated computers called servers
are used for specialized tasks in serving the
needs of other user-computers (called clients)
on the network.
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16. Living Online
Networks (by Network Topology)
Topology refers to the layout or structure of
the network in relation with the flow of data.
The most common types of topologies are:
Star
Linear Bus
Ring
Hybrid
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Star Topology
The most commonly
applied topology.
Uses a central
device (hub) with
cables extending in
all directions.
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Linear Bus Topology
Uses one long cable (backbone) to which
computers and other devices are attached.
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Ring Topology
Consists of several computers joined
together to form a circle. Data moves
from one computer to the next in one
direction only.
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Hybrid Topology
Hybrid topology is a combination of
different types of topology used in a
network system to adapt to the different
design of floors or rooms in a building.
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What is Ethernet?
Ethernet is a computer network
technology used in a Local Area Network
(LAN). It is one of the most widely
implemented LAN standards.
A signal on the Ethernet cables reaches
every attached node in the network, a
correct destination “address” is important
to reach the intended recipient.
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22. Living Online
Network Interface Card
To connect to a network, the PC must
have a Network Interface Card (NIC).
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Internal PC NIC
(RJ45)
Wireless PC NIC
Internal PC NIC
(Coaxial)

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Connection/Cabling Options
Twisted Pair
Coaxial
Fiber Optics
Wireless
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Twisted Pair
This is one of the most widely used
communications media because it is
inexpensive and widely available.
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Unshielded Twisted Pair (UTP)UTP with RJ45 connectors

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Coaxial
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This is a cable with a center wire
surrounded with insulation; usually used
in cable TV.

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Fiber optics
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Instead of transmitting electrical
frequencies, a fiber optic cable transmits
pulsating beams of light. It is made up of
glass or plastic fibers.

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Wireless
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More and more people now use wireless
networking, also called Wi-Fi, to connect
their computers at home or in the office.

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The Hub
Hubs are used to connect PCs together
to form a network.
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The Switch
A switch works similar to a hub except
that user connected to the switch has
access to the full bandwidth.
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The Router
Routers examine the destination address
of the information and pass it on to the
appropriate segment(s) only.
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Benefits of Networking
Reduces costs (don’t have to buy printer
for each computer, etc.)
More productivity (don’t have to transfer
files by diskette, etc.)
Increases communication
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Disadvantages of Networking
Dependency
Security Risk
Loss of Autonomy or Privacy
Viruses
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Roles of Network Administrator
Managing the computer network
Making sure network is working properly
Responsible for network security
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Getting Connected to the Net
To connect your PC to the Internet, you
must have the following basic
requirements:
Internet Service Provider
Modem
Telephone Line
Internet Software (Web browser, e-mail, etc.
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35. Living Online
Types of Internet Connection
Narrowband
Dial-up
ISDN
Broadband
DSL
Cable
Dedicated Leased Line (such as T1)
Wireless (Wi-Fi)
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The Modem
Modem converts digital signals to analog
signals and vice-versa in a process
called modulation-demodulation.
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37. Living Online
Internet Service Providers
ISP is a company that provides you
connectivity to the Internet.
Infocom
ISP Bonanza
MozCom
Pacific Internet
Sky Internet, etc.
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Roles & Responsibilities of ISP

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Dial-up
The most common type of connection for
home users.
Considered the slowest but have the
reputation of being the most inexpensive.
Connection rates for dial-up modems
tend to fall at around 56 kbps.
You cannot use the telephone for the
Internet and phone calls for the same
time.
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Integrated Services Digital Network
ISDN is a type of digital telephone
connection that offers data transfer rates
of up to 128 kbps.
This can be a better than dial-up,
however ISDN connections are
considered still more or less outdated.
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Digital Subscriber Line (DSL)
Becoming widely available and can
provide an excellent connection.
Allows you to use the phone normally
while connected to the Internet.
DSL connections can be costlier than
dial-up.
DSL operates starting at 512 Kbps
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Cable
Offers very fast and reliable connections
with a fixed monthly fee.
It will not affect how you use your
telephone.
Offers data transfer rates of
approximately 1 mbps to 6 mbps.
Cable connections are not always
available in all areas.
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Dedicated Leased Line
Directly connects your computer to your
ISP’s network. Capable of transferring
data at 1, 544, 000 bits-per-second, such
as T1.
Upload and download speeds are the
same (symmetric)
Much more expensive than cable or DSL
connections.
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Wireless (Wi-Fi)
No cords or wires for as long as you are
in a WiFi “hotzone”.
Wireless broadband connections: Wi-Fi,
Satellite broadband, Wireless DSL, and
Wireless Digital Cable.
Connection speeds ranging from as little
as 256 Kbps to as much as 10+ Mbps.
You have to stay within a certain radius
to connect to a WiFi device.
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Roles and Responsibilities of ISP
Maintain connection
Customer Support
Technical Support
Security
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45. Living Online
How did it start?
In the 1960’s, there was a demand for
computer networks to help scientists and
researchers from widely dispersed
areas.
US Defense Department created
ARPANET (Advanced Research
Projects Agency Network) in 1969
ARPANET became the forerunner of
today’s Internet.
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46. Living Online
Internet Services
Electronic Mail (E-mail)
World Wide Web (Web)
Search & File Sharing (Google)
Instant Messaging (IM)
Internet Relay Chat (Chat, IRC)
Newsgroups
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