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NETWORKSNETWORKS
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
(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
(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.
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.
(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.
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-PairTwisted-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.
Star Network
Nodes
(b) Ring Network
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
(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 1roaming by moving your computers from one access
point to another as you move around a 2hot 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 3antenna. A wireless router receives the signal and 4decodes 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.
(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.
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.
SHARE DOCUMENTSHARE DOCUMENT
Activity 1 : Sharing a folder on the network
Notes:This activity is only to show how to allow users to share a folder on the network.
1. Click Start then, click My Documents.
Figure 12. Right click the folder that you want to share then click Sharing and Security.
Figure 2
Click here
Click here
3. The Properties dialog box appears, tick Share this folder on the network and allow network users to change my files. Then click OK.
Figure 34. Now you can see the difference between shared and unshared drive.
Unshared Shared
Figure 4
Tick here
Activity 2 : Receiving documents through LAN
Notes:
a. To achieve this activity, more than one computer in the network must be active at the same time.
b. This activity can be done only if the person who will receive/transfer file or document enabled his/her folder sharing first.
c. The example shown in this activity is different from your computer interface. You may use any suitable file or folder.
1. Right click on Start Menu, then click My Network Places as shown in Figure 1.
Figure 1
2. Double click on My Network Places as shown in Figure 2.
Figure 2
3. Click Microsoft Window Network then click workgroup to see entire computer. ( Figure 3 )
Figure 3
4. The following steps show how to copy a document from the computer named PC1. ( Figure 4 )
Figure 4
Double click here
5. Double click PC1. Then click BAHAN. ( Figure 5 )
Figure 5
6. Click document named Activity 1. ( Figure 6 )
9. The following step will show how to paste the copied file into your own folder.
10.Click on Start Menu, then click My Documents as shown in Figure 8.
Figure 8
11.Double click My Document. Right click folder TUGASAN then click open.
Figure 9
12.Right click anywhere in the folder, click Paste. ( Figure 10 )
Figure 10
13.Now you can see the document Activity 1 in the designated folder (Figure 11).
Figure 11
Activity 3 : Transferring documents through LAN
Notes:
a. More than one computer in the network must be active at the same time to achieve this activity.
b. This activity can be done only if the person who will receive/transfer file or document enabled his/her folder sharing first.
c. The example shown in this activity is different from your computer interface. You may use any suitable file or folder.
1. Right click on Start Menu then, click My Documents ( Figure 1 ).
4. Click My Network Places . ( Figure 4 )
Figure 4
5. Double click folder BAHAN on PC1 (pc1). ( Figure 5 )
Click here
Figure 5
6. All the content inside folder BAHAN will be displayed. ( Figure 6 )
Figure 6
7. Right click anywhere in BAHAN folder, then click paste.