Unit1lesson2 lan 9th level: Computer Networks and Local Area Network

9th level Unit 1 : Computer Networks: the LAN AY 2011/2012

I- Computer Networks

I-1 – Presentation of a computer network: Task1: Observe carefully these figures and describe them.

Pioneer Preparatory

School of Sfax

9 Teacher: Mrs. IMEN TEKAYA BOUAZIZ

PIONEER PREPARATORY SCHOOL OF SFAX:

THE 9th LEVELLesson 2: INTRODUCING THE

LOCAL AREA NETWORK


* Terminals, and communication devices: iPad; iphone; smart phones; e-book; PSP;smart TV; …

**wires, cables, or a telecommunication system: are means of connection (physical links) through wires or wireless connection.

A network is a system of interconnected computers and peripherals (such as printers, scanners, network cards, modems, routers, work stations); it can consist of as few as two computers or millions of computers that are spread over a large geographical area connected (linked) by different types of physical links (for example, optical fiber cable, coaxial cable, telephone line, satellite transmission, radio waves, Wi-Fi, blue-tooth, infra red, etc.) allowing the movement (the transfer, the transmission) or the exchange of information between one center to the other; and the sharing of hardware and software resources.

So, Some of the primary reasons ( the purposes ) for networking PCs are as follows:

To provide services and Sharing files, Sharing printers and other devices in order to reduce the equipment costs, Enabling common administration and security, Supporting network applications such as Electronic mail or videoconferencing or groupware, etc, and Sharing Databases services.

Pioneer Preparatory School of Sfax


A computer network is a system of two or more ………………, terminals, and

communication devices* linked (……………..) by …………, cables, or a telecommunication

system** in order to …………….. software resources (data, files, programs, applications) or

hardware resources (printer or scanner, etc) and …………………….information. It allows

computers to ……………………. with each other. The purpose is to provide services and to

reduce distances and equipment costs.

Task 2: According to the last task, define a computer network.

Complete the following definition with words from this list: information, exchange, computers, connected, communicate, wires,

share

Observations


Task 3:

According to the previous task and pictures, what are the components of a

computer network?

A network computer is composed of:

.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I-2 – Types of computer networks:

A- Types of computer networks according to the geographic scale:

It depends on how much large is the area where it spans.

Task4: Fill in the blanks with the correct words.



Networks may be classif ied according to a wide variety of characterist ics such as:

Scale , the medium used to transport the data , Topology , Communication protocols used, Organizational scope, etc .


Local Area Networks (LAN) is a

network that is confined to a relatively

………….. area. It is generally limited to a

geographic area such as a lab, school, or

building.

The defining characteristics of LANs include their …………………… data transfer rates and their technology is generally less expensive.

WAN (…………….. Area Network)

spans a ……………….. physical distance.

A WAN is a geographically-dispersed

collection of ………… The data transfer

rate is quiet …..………. . The

……………......... is the largest WAN,

spanning the Earth. WANs are more

susceptible to errors due to the distances

data travels. They are more

sophisticated and complex than LANs.

Their technology is expensive.

Metropolitan Area Network or shortened

by MAN. A network in a city with high-speed

data transfer, which connects various locations such

as campuses, offices, government, and so on. MAN

network is a composite of several LANs Coverage

of this MAN among 10 to 50 km, MAN is the right

network to build a network between offices

in the city of factories / establishments and

headquarters are within its range.

There are other computer networks like: Campus Area Network (CAN),

Home Area Network (HAN), personal area Network (PAN)…

The Data Transfer Rate ( DTR ) is the speed at which data can be transmitted

between devices. It’s often expressed in




KB per second (KB/s) or MB/s. it depends on the distance, the quality of the line, and the

wire gauge.

Task 5: we want to make computers of the following company to communicate and to

exchange data between them. How to do it?

…………………………………………………..

…………………………………………………..

Evaluation1: Deduce the differences between a LAN and a WAN? Complete the

following table:

LAN WAN

Geographic area

Network cabling (means of connectivity)

Data Transfer Rate (DTR)

Evaluation2: Give examples of LAN and WAN networks?

LAN WAN

Wireless Networks

The Wireless LAN provides wireless network communication over short distances using Wi-Fi, radio waves or infrared signals.

Or combined with :

Wired networksThe Wired LAN is a network using wires like cables to connect its components.




B- Types of computer networks according to the main types of LAN architectures:

C- Network topologies: Types of computer networks according to their topology in a LAN

Activity 6: Focus on these computer networks. What are the differences between them?

Observation: The difference between the three computer networks is in their ………….. : …………………………………………………………………………………………………

We talk about …………………………...

What means Network Topology ?

Activity 6: fill the blanks using these terms: nodes, the shape, Links, layout.

Activity 7: Try to search from the Internet the different kinds of network topologies.

There are many network topologies (used in LANs) such as:



http://en.wikipedia.org/wiki/Data_link


………. topology: All devices are

connected to a ………………., called the

……. Bus networks are relatively

inexpensive and easy to install for small

networks.

……… topology : All devices are

connected to one another in the shape

of a closed loop. Ring topologies are

relatively expensive and …………….., but

they offer …… data transfer rate and

can span ……… distances.

………….. topology : All devices are

connected to central equipment:

…………Star networks are relatively easy

to install and manage. All data must

pass through the hub.

Tree Topology: integrate multiple star topologies

together onto a bus. In its simplest form, only hub

devices connect directly to the tree bus and each hub

functions as the "root" of a tree of devices. This

bus/star hybrid approach supports future expandability

of the network much better than a bus (limited in the

number of devices due to the broadcast traffic it

generates) or a star (limited by the number of hub

connection points) alone.

Evaluation3: Enumerate the advantages and the disadvantages of each network

topology?

Bus topology Ring Star topology Tree Topology



Network Topology refers to ................................, or the ...................... of a computer network. It determines how different ........................ and ....................... (Computer, printer, modem…) are connected to each other in a network and how they communicate.

http://en.wikipedia.org/wiki/Computer_network

http://www.webopedia.com/TERM/T/data.html

http://www.webopedia.com/TERM/T/hub.html

http://www.webopedia.com/TERM/T/star_network.html

http://www.webopedia.com/TERM/T/ring_network.html

http://www.webopedia.com/TERM/T/network.html

http://www.webopedia.com/TERM/T/bus.html

http://www.webopedia.com/TERM/T/device.html


topology

Advantages

Disadvanta

ges

II- LAN devices:

Computers

Network card

(Ethernet card)

Cables (cable RJ45) : in the

case of a wired Network



Wireless Network cardWired Network card


Hub or switcher or router

Server (desktop computer)

Activity 8: Match each picture with its device’s description.

Device’s description Picture

a) LAN Card : a piece of computer

hardware to allow the attached

computer to communicate by network

using basic services of a LAN.

a+………

1)

b)Hub : A device which connects the

cables from computers and other

devices such as printers in a LAN.

b+………

2)

c)Router : A device that connects to

and receives data from outer networks

and sends data only to network nodes c+……….

a) How to set up a Local Network?

To configure each computer on the net, just follow the following steps:

go to Control Panel, double-click on "Network Connections", click the right mouse button on "Local Area Connection", choose properties, In the Windows LAN connection are displayed the various protocols installed. To

share files, play network games, use printer Each computer must be assigned an address called an IP address in order to

communicate. To do this you have to select the "Internet Protocol TCP / IP and click on “Properties”.=> The allocation of IP addresses can be automatically or be set manually, which is preferable for a small LAN.

Examples of IP address:

Computer N°: 1

IP Address: 192.168.0.1

Mask: 255.255.255.0



3)

http://en.wikipedia.org/wiki/Network_card


...

Computer N°: xxx

IP Address: 192.168.0.xxx

Mask: 255.255.255.0

Once the allocated IP address is done, simply close the window by clicking OK

(The DNS (domain name servers) will be left in automatic mode.

b) Note:

The IP address, also known as an «Internet Protocol» or simply an "IP

number", it identifies a particular computer connected to a network. The IP address is

a code made up of four sets of numbers from 0 to 255, separated by three dots. For

example "66.72.98.236" or "216.239.115.148"

IV- Using basic services of a LAN

Activity 9: You have a folder that contains text documents, images and sound files.

You want to give a copy of this folder to your friends. Propose solutions to do it.

The local network is built to facilitate sharing hardware and

software resources:

Sharing documentsPioneer

Preparatory School of Sfax



Sharing Printer Sharing messages Sharing screen

4.1- Sharing documents

Task 9: Page39: how to share a folder in a LAN?

Select the folder or the file to share Click the right mouse button Choose the command “Sharing and Security” On the tab “Sharing” check the option “ share

this folder on the network” Click on ok to confirm your action

4.2- Sharing Peripherals (Printer)

Task 10: Each pupil wants to print his formatted text. Unfortunately, the laboratory is

equipped with one printer. Give a suitable solution to your friends.




To share a printer installed in a computer

included in a local area network, you have

to follow these steps

1. Select the Printer that you want to share

2. Right click it and choose the printer properties command,

3. Choose the option Sharing tab

4. Active the radio button Share this printer

5. and propose a name

6. Validate with ok.




4.3- Sending and receiving messages

Task 11: Do you remember the role of the following program? In which kind of

network can use it?




Task 12: Can you send and receive a

message via a local computer network?

Solution: ……………………………………

…………………………………………………

…………………………………………………

Task 13: Launch <Pop Messenger> and send “hello” to your friend.

To send a message to my friend using

PopMessenger, I have to:




4.4- Sharing screen

Task 14: During your project, you have to prepare a PowerPoint presentation. Propose a

method that allows you to show your screen to one of your friends



Question:

Observe this illustration and fined other

operations that we can do with Pop

Messenger.

With Pop Messenger, we can:

………………………………………………………………………………

…………………………………………………………………………

…………………………..


V- How to protect a LAN?

Task 16: What you need to protect your computer from cyber viruses?

Exercises

Task 1: Complete the definition of computer network with the following words:

Computers / Data transfer rate/ high/ connected/ small/ wide



In this chapter, I learned…

There exist two kinds of networks: Local Area Network LAN and Wide Area

Network WAN.

A computer network permits to share hardware and software Resources and ensure communication between computers.

A computer network decrease costs and reduce distances.


A local network is a set of ……………., equipments and communications devices…………..

together in a ………… physical area (Society, Administration,…) via specific rules

(protocol for communication).

The ………………….. …..of a local network is often …………..

Task 2:

Create a new folder named “Course” under Local Disk C:\, and then share it.

Task 3:

Present 3 advantages of a computer network.

1. …………………………………………………………………………………………….2. …………………………………………………………………………………………….3. …………………………………………………………………………………………….

Task 4: Send to your friends the definition of a local network as a message (text or

vocal) through the local messaging software.

Task 5: Complete the definition of computer network with the following words:

Telecommunication / of communication / linked / exchange / computer

A …………………. network is a collection of terminals, computers and ……………………..

systems. These entities are ……………..and connected together through physical lines

named lines …………………… in order to transport and to ……………… data.

Task 6: Create a poster that you will stick in the proximity of your computer. It will be

destined to all students who want to use the computer network in order to accede to

your files. This poster must contain at least 3 advice and 3 obligations for using the

content of your hard disk which is shared to others.

Evaluation

Evaluation 1: Tick the correct answer




If you have less than 7 correct answers, you must see again this chapter!



To establish the connection of a LAN, you must have a network card and wires. What do you need to establish a WAN connection?

Some mobiles have the Bluetooth option. Can you explain this kind of data transmission? Do you know some others?

Questions True False I don’t

know

The Internet is a local network.

Data are exchanged in a local network with a high

DTR.

We cannot share the printers in a local network.

In a local network, we can share folders.

We cannot neither send nor receive messages in a

LAN.

The use of a LAN is very expensive.

It’s possible to share the hard disk in a local network.

The term DTR means the data capacity of network.

The distance hasn’t any effect on a DTR of a network.

We can only send and receive messages in a local

network.

When I use a computer of a local network, I can

accede to all connected computers and change

configurations, move files and folders as I like and

block the access to certain applications.

Unit1lesson2 lan 9th level: Computer Networks and Local Area Network

Technology

network computer

types of computer networks

network cards

network applicationssuch

local area networks

geographic area

level unit

imen tekaya bouaziz