Lesson: Computer Networks and Protocols

Lesson: Computer
Networks and Protocols

Year 7 – Digital Technologies

How many devices are connected to the internet?

2

Starter activity

In this lesson, you will:

●Define what a computer network is and explain how data is transmitted between
computers across networks

●Define ‘protocol’ and provide examples of non-networking protocols

Lesson: Computer Networks and Protocols

3

Objectives

These are all forms of communication. Can you match the name with the image and the year
in which they were first used?

Telegram

Historic communication methods

4

Activity 1

Email

Carrier pigeon

Telephone

Semaphore

1961

1876

1837

1167

1791

Carrier pigeon

Semaphore

Answers

5

Activity 1

Telegram

Telephone

Email

1961

1876

1837

1167

1791

A computer network is when two or more
computers are connected together to allow
them to communicate.

This brings many benefits, which will be
covered later on.

What is a computer network?

6

Activity 2

What common daily activities do you think
use computer networks?

Think, pair, share

Using computer networks

7

Activity 2

Morning: music playing via a Bluetooth
speaker, asking Alexa for the weather
forecast, controlling your central heating via
an app on your phone

Daytime: logging on to a PC for a
Computing lesson, accessing files stored on
the school network, printing to the library
printer, researching a topic on the internet

How many common daily activities do you think use computer
networks?

8

Evening: Using social media, playing games
online

Activity 2

Key milestones

9

Activity 3

1999

Mini computers: Nokia

introduced a mobile phone that
could connect to the internet.

1989

World Wide Web:

Tim Berners-Lee invented the

WWW.

1974–1977

The first personal computers:
IBM and Apple were a couple of

the brands releasing PCs.

1969

The internet: The first internet

was called the ARPANET. Only a

few people had access to it

initially.

Question
revisited:
How many
devices are
now connected
to the internet?

Guidance:
There are just
under 8 billion
people on the
planet.

Think, pair, share

1950–1970

Mainframe computers:

Mainframe computers grew in
popularity. These were large

and expensive.

Imagine that you needed to send a message
from Australia to the UK but no computer
networks exist.

●What methods would you use?

●What information would you need?

●Would anyone be involved in relaying
the message?

Think, pair, share

A message to the UK (part 1)

10

Activity 4

Imagine that you needed to send a message
from Australia to the UK and computer
networksdo exist.

●What methods would you use?

●What information would you need?

●Would anyone be involved in relaying
the message?

Think, pair, share

A message to the UK (part 2)

11

Activity 4

An answer to the first scenario (no computer networks) might have been to write and
post a letter.

How is a letter sent from Australia to the UK? What steps are involved between putting
the letter in the postbox and it arriving at the destination?

(Hands up)

Message transmission: letters

12

Activity 4

Just as a letter does not go directly from the sender to the recipient, the email does not travel
from a sender’s machine through a cable or “into the cloud” directly to the recipient’s machine.

The message is passed on to many mail servers along the way, who help get the message to its
destination.

Message transmission: email

13

Activity 4

All methods of communication need rules
in place in order to pass on the message
successfully. These sets of rules are called
protocols.

What protocol exists for meeting someone
new?

Is this the same in all countries?

Protocols

14

Activity 5

Australia:

●Smile, and say ‘Hello’

●Shake right hands (shaking left hands
is considered disrespectful in many
countries)

Protocols

15

Question:

In which cultures do people use the below
protocols to greet each other?

●Bowing

●Rubbing noses

●Sticking your tongue out

Activity 5

Question: In which cultures do people use the
below protocols to greet each other?

Answer:

●Bowing: Japan

●Rubbing noses: Inuit

●Sticking your tongue out: Tibetan

Protocols

16

It is important that both parties involved in
communication know the rules. This is the
same with computer network protocols.

Activity 5

Climbers often attach to a rope for safety
via a belay clip.

The length of this rope is controlled by a
person called the belayer.

The belayer is responsible for the climber’s
safety.

Climber and belayer protocol

17

A series of commands exist in order for the
climber and belayer to communicate during
the climb.

Can you order them correctly so that the
climber can ascend safely?

Activity 6

Belay: To fix a rope around an object

to secure it

Commands to order

18

Activity 6

Command

Person

Meaning

Belay On

Belayer

The rope is secured and slack taken up so it is tight.

Climbing

Climber

I wish to climb.

Off Belay

Climber

I wish to be detached from the rope. The climber only says this command when it is safe to
do so at their destination.

Belay Off

Belayer

The belay rope has been disconnected.

Climb On

Belayer

I am happy for you to climb.

Slack

Climber

I need some slack rope in order to climb up.

On Belay?

Climber

Is the rope secured?

Answers

19

Activity 6

Command

Person

Meaning

Order number
(1 to 7)

On Belay?

Climber

Is the rope secured?

1

Belay On

Belayer

The rope is secured and slack taken up so it is
tight.

2

Climbing

Climber

I wish to climb.

3

Climb On

Belayer

I am happy for you to climb.

4

Slack

Climber

I need some slack rope in order to climb up.

5

Off Belay

Climber

I wish to be detached from the rope. The
climber only says this command when it is safe
to do so at their destination.

6

Belay Off

Belayer

The belay rope has been disconnected.

7

What rules (protocols) exist for an email
address?

An ‘@’ symbol must be used.

The email address must be unique.

Computer protocols: email and web address protocols

20

What parts of this web address show rules
(protocols) being used?

https://playford.sa.edu.au/

All website addresses start with ‘http:// or
https://’ followed by domain name
‘playford.sa.edu.au’

All website addresses are unique.

They use dots to separate each part of the
address.

Activity 7

Would you like to revise your answer in the light of the lesson?

How many devices are connected to the internet?

21

Plenary

Answer: Over 27 billion

22

Plenary

Answer:
There are currently just under 8 billion people on the
planet. In 2019, the number of connected devices on
the internet reached 27 billion! A projected 75 billion
will be online by 2025 (statista.com).

In this lesson, you…

Defined what a computer network is and
explained how data is transmitted between
computers across networks.

Defined a protocol and looked at examples
of non-networking protocols.

Next lesson

23

Next lesson, you will…

Look at the hardware necessary for
connecting devices to networks.

Summary