ICTL ICTL

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 )

Figure 67. Right click and choose copy

Figure 78. Close the window.

copy

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 ).

Figure 1

2. Right click bill then click copy. Minimize the window.( Figure 2 )

Click here

Figure 2

3. Right click on Start Menu then, double click Explore . ( Figure 3 )

Figure 3

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.

Figure 7

8. Now bill file is displayed in the BAHAN folder.

Figure 8

paste