This document provides an introduction to computer networks module. It begins by defining networks and listing the benefits of computer networks such as file sharing, sharing devices, sharing internet access, speed, cost, security, centralized software management, and electronic mail. It then identifies common network devices like hubs, network interface cards, routers, connectors, and modems. It also discusses different types of computer networks including local area networks (LAN), metropolitan area networks (MAN), and wide area networks (WAN). The document defines different network topologies such as star, ring, and bus networks. Finally, it covers current network technologies like Wi-Fi and Bluetooth. The overall goal of the module is for students to understand computer networks at a basic

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2. ICTL for Secondary School – Networks and The Internet Module
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MODULE 1
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Curriculum Development Centre
Ministry of Education

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1. Name of Module: Introduction to Networks
2. Learning Outcomes: Students should be able to:
a. define networks
b. list benefits of computer networks
c. identify the devices needed in computer networks
d. list types of computer networks
e. differentiate types of computer networks
f. state types of network topology (LAN, WAN, MAN)
g. explain current technology in computer networks
3. Knowledge and Skills
a. Network definitions
b. Benefits of sharing devices, data and information and internet access
c. Recognize devices for computer networks
d. List and differentiate the types of computer networks
e. List Types of network topology
f. Discuss and gather information on the current technology in computer
networks
4. Module Summary:
At the end of the module, students should be able to define networks, list the benefits
and the types of computer networks as well as network topology. They should be able to
identify the devices needed in computer networks and explain the current technology
used in computer networks.
This module contain 4 activities
Activity 1: Introduction to Networks
Activity 2: Type of Computer Networks
Activity 3: Network Topology
Activity 4: Current Technology in Computer Networks

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Activity 1: Introduction to Networks
a. Networks Definition
A network consists of two or more computers that are linked in order to share resources
(such as printers and CD-ROMs), exchange files, and allow electronic communications.
The computers on a network may be linked through cables, telephone lines, radio
waves, satellites or infrared light beams.
b. Benefits of Computer Networks
1. File Sharing - Network file sharing between computers gives you more flexibility
rather than using floppy drives or Zip drives. you can use the network to save
copies of your important data on a different computer, examples share photos,
music files and documents.
2. Sharing Devices. Sharing devices is another benefit in which a network exceeds
stand-alone computers. For example laser printers, fax machines, modems,
scanners and CD-ROM players, when these peripherals are added to a network,
they can be shared by many users.
3. Sharing Internet Access. In computer network, students can access the internet
simultaneously.
4. Speed. Using a network is faster way for sharing and transferring files. Without a
network, files are shared by copying them to floppy disk.
5. Cost. Networkable versions of many popular software programmes are available
at considerable savings compared to buying individual licensed copies. Its allows
easier upgrading of the program.
6. Security. Files and programmes on a network are more secure as the users do
not have to worry about illegal copying of programmes. Passwords can be
applied for specific directories to restrict access to unauthorized users.
7. Centralized Software Management. One of the greatest benefits of installing a
school network is the fact that all of the software can be loaded on one computer

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(the server). This saves time and energy when installing updates and tracking
files.
8. Electronic Mail. A network that provides the hardware necessary to install an e-
mail system. E-mail’s help in personal and professional communication for all
school personnel as it enables the spread of general information to the entire
school staff. Example, electronic mail on LAN (Local Area Network) enables
students to communicate with teachers and peers at their own school when
connected to the Internet, it enables users to communicate with others.
9. Flexible Access. School networks allow students to access their files from
computers throughout the school. Some schools provide public access to
students to begin an assignment in the computer lab and save then access the
file when they are at a cyber café or home.
c. Devices Needed in Computer Networks.
Hub
A central device that provides a common connection point
for nodes on a network.
Network Interface Card
A NIC (network interface card) is a piece of computer
hardware designed to allow computers to communicate
over a computer network.
Router
A device that forwards data packets along networks. A
router is connected to at least, two networks, commonly
two LANs or WANs or a LAN and its ISP’s network.
Connector
Short for Registered Jack-45, an eight-wire connector used
commonly to connect computers onto a local-area network

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(LAN), especially Ethernets. RJ-45 connectors look similar
to RJ-11 connectors used for connecting telephone
equipment.
Modem
Short for modulator-demodulator. A modem is a device or
program that enables a computer to transmit data over
telephone or cable lines. Computer information are stored
digitally, whereas information transmitted over telephone
lines are transmitted in a form of analogue waves. A
modem converts between these two forms.

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Activity 2: Types of Computer Networks:
a. Local Area Network (LAN)
Local Area Network are groups of computers and network devices connected together,
usually within the same building. The simplest form of LAN is to connect two computers
together.

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b. Metropolitan Area Network (MAN)
MAN is a network that interconnect users with computer resources in a geographic area
or region larger than that covered by a local area network (LAN) but smaller than the
area covered by wide area network (WAN)
c. Wide Area Network (WAN)
Wide Area Network is defined as a group of computers and network devices connected
across a large physical areas such as states or countries. Computers connected to a
Wide Area Network are often connected through the telephone system. They can also be
connected through leased lines or satellites. The largest WAN in existence is the
Internet.

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d. Differences between Types of Computer Networks
Criteria LAN MAN WAN
Cost Low High Higher
Network Size Small Larger Largest
Speed Fastest Faster Fast
Transmission
Media Type
Twisted-Pair
Twisted-Pair and
Fibre-Optic
Fibre-Optic, radio
wave and satellite
Number of
computer
Smallest Large Largest
Activity 3: Types Of Network Topology :
a. Star Network
A star network is also known as star topology. A star network is designed with each node
(file server, workstations, and peripherals) connected directly to a central network hub.
The hub will control the flow of communication in the network. If one of the nodes fails,
the star network will still function as long as the hub is working.
Nodes
Star Network
b. Ring Network

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Ring network is also known as ring topology. A ring network consists of all computers
and other devices that are connected in a loop. In a ring network, each node connects
directly to the neighbouring nodes. If the device on a ring network fails, all the devices
before the failed device are unaffected but those after the failed device will not function.
Ring Network
c. Bus Network
A bus network is also known as a bus topology. A bus network consists of a single cable
to which all the computers and other devices are connected. It must have a common
backbone (the central cable) to connect all the devices. If one of the nodes fails, the bus
network will still function.
Bus Network
Activity 4: Current Technology in Computer Networks

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a. Wi-Fi
Official Wi-Fi logo
Wi-Fi (wireless fidelity) is a set of standards that refers to the Wireless Local Area
Network (WLAN) that applies IEEE 802.11 specification. Currently in
Some of the advantages of using Wi-Fi are as follows:
• Simplicity. You can connect computers anywhere in your home or school without
the use for wires. Computers connected to the network using radio signals and
computers can be up to 30 meters or so apart.
• Cost Wireless Networks are easy to set up and are inexpensive.
• Easy Access Wi-Fi supports 1
roaming by moving your computers from one
access point to another as you move around a 2
hot spot. Wi-Fi works like a two-
way radio communication.
A computer’s wireless adapter translates data into a radio signal and transmits it using
an 3
antenna. A wireless router receives the signal and 4
decodes it. It sends the
information to the internet using a physical, wired Ethernet connection.
To receive the signal, the router will receive data from the Internet, translating it into a
radio signal and sending it back to the wireless adapter.

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b. Bluetooth
Bluetooth logo Bluetooth Headset
Bluetooth is a network standard, specifically a protocol that defines how two Bluetooth
devices use short-range radio waves to transmit data. The data transfers between the
devices at a rate of up to 2 Mbps. To communicate with each other, Bluetooth devices
must be within 10 metres but can be extended to 100 metres with additional equipment.
A Bluetooth device contains a small chip that allows it to communicate with another
Bluetooth device. Examples of Bluetooth-enabled devices are desktop computers,
notebook computers, handheld computers, PDAs, smart phones, headset, microphones,
digital cameras, fax machines and printers.

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For computers and devices that are not Bluetooth-enabled, you can purchase a
Bluetooth wireless port adapter that will convert an existing USB port or serial port into a
Bluetooth port. For example, Windows XP has a built-in Bluetooth support that allows
users to easily configure Bluetooth communications.
Are Wi-Fi and Bluetooth competing technologies?
Bluetooth is designed for limited data transfer between two devices, one of which is
usually a mobile device (e.g. a notebook computer and a printer, a digital camera and a
desktop computer and between two PDAs). However Wi-Fi which supports data transfer
at faster rates allow users to network many computers and devices together wirelessly.
GLOSSARY
1
roaming – the ability to move from one coverage area to another without interruption
in service or lost in connectivity.
2
hot spot – a geographic area that is covered by a wireless network so that internet
access is made available to any device with a wireless card.
3
antenna – a component of a radio device that radiates radio waves from the source
and also receives signals from other transmitters.
4
decodes –the conversion of encoded data back to its original form.
ACKNOWLEDGEMENT
http://www.seniortechcenter.org/hardware_and_software/network_benefits.php
http://compnetworking.about.com/cs/wireless/f/whywirelesslan.htm
http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci214083,00.html
http://www.webopedia.com/TERM/W/wide_area_network_WAN.html
http://www.the-itleader.com/glossary/wireless-fidelity.html
http://www.bethamir.com/MAN.gif

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Title : Network
Module 1 Introduction to Network
Student’s Name : ______________________________________________
Class : _______________________________________________________
At the end of the lesson pupil have learn the following skills :
SKILLS
DON’T
KNOW
A LITTLE AVERAGE GOOD EXCELLENT
Define networks
List benefits of computer
networks
Identify the devices needed
in a computer Networks
List types of computer
networks
Differentiate types of
computer Networks
State types of network
topology
Explain current technology in
computer networks
Please tick ( √ ) one of the check box