Networks

Lesson 1

1

Starter

Find the hidden words in the grid and then

write a definition next to each describing

what you think that term means.

2

3

Objective of the lessonUnderstand what a network is and describe 3 network

topologies.

• All of you will:– Be able to describe what a network is and identify at least one

network topology.• Most of you will:

– Describe the advantages and disadvantages of 2 different network topologies.

• Some of you will:– Describe the advantages and disadvantages of 3 different network

topologies and explain how data flow on a network may be disrupted.

4

• Everybody should complete Tasks 1 and 2 and write your answers on the sheet.

• Some of you may also want to get the extra marks by completing the extension activity.

• This homework is due in next lesson.

• Make sure you have written your homework clearly in your planner.

Homework

What is a network?• A network is two or more computers linked

together so that they can communicate with each other.

• They could be connected in several different ways:– Cables– Wireless– Satellites

Why use a network?• Networks are used so that:

– People can communicate with each other.

– They can store their files centrally.

– They can share software.– They can share peripherals

(such as printers).– They can easily update the

system.• Work stations and

peripherals on a network as referred to as “Nodes”.

Work station

Server

Peripheral

Nodes

Networks

Networks can have quite

complicated layouts as one

network can be connected to

another network.

Network topologies• “Topology” is the word used to describe the

shape of a network.• There are three main topologies:

Ring

Bus

Star

Ring topology• The Ring topology is the

simplest and uses the least amount of cabling so it is also the cheapest.

• All the data travels around the ring in one direction and passes through all the workstations on the network.

• If a connection is lost, the whole network stops working.

Bus topology• The Bus topology uses a central cable which all nodes

are connected to.• The data travels along the central cable.• If one connecter is broken the rest of the network

still works but if the central cableis broken thenthe whole networkstops working.

Star topology• The star topology is the most

robust type of network. • The network is controlled by a

central “Server” which controls how the data moves around the system.

• If one cable is broken the rest of the network can still work without any delay.

• The network will only stop working if the central server stops working.

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What is a server?• A server is a powerful computer which holds

the operating system software to run the network.

• It allows people to:– Log onto the system.– Keep files centrally.– Send print jobs to the printer.– Control internet access and email on the network.

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Group activity• Your teacher will split you into teams.• You will each have a set of “Network Cards”.

You will have to arrange them onto the piece of paper and draw in where the cables are to show the following types of network:– Bus– Star– Ring

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Logging onto the network• When you connect to the network you need

to tell the server who you are. • What two things do you need to input when

you log onto the system?– User ID– Password

• Why do you think you need these two items?

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Suitable passwords• Passwords should be kept secret so that only you

know your own password.• Rules for a good password:– Make sure it is not too easy to guess (your name or

“password”).– Make sure you use a mixture of letters, numbers and

even symbols.– Make sure you use a mixture of upper and lower case

letters.– Make sure you do not tell anybody else your password.

16

Cloud computing• Use the internet to find

out what is meant by the term “cloud computing”.

• Write a paragraph to describe what it is and the advantages and disadvantages of using cloud computing.

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Answer the following questions:1. What is a network?2. Why do people use networks?3. Name the three topologies.4. Which topology uses the least amount of cabling?5. Which topology is the most secure?6. What tasks does a server do?7. What is meant by the term cloud computing?8. What are the advantages and disadvantages of using

cloud computing?

How much do you remember?