This is Lesson 1 on Computing Systems & Networks – the Internet, taken from teachcomputing.org.
Today, you are going to….
- learn about the internet as a network of networks
- demonstrate how information is shared across the internet
- discuss why a network needs protecting
1.
The internet is a worldwide system of interconnected computer networks, that communicate with each other.
Sometimes the internet is simply called the net.
2.
What is a network?
A computer network is a set of computers sharing resources
3.
Messages are sent from one computer to another in a network.
The computers in a network are connected with a switch.
Imagine your table is a network.
All the computers will get a message to pass to the switch, who will then pass the message to the computer it is meant for.
4.
Messages can also be send from one network to another network.
The networks are connected to each other with a router. (Routers enable messages to be passed between networks via switches.)
A message follows a certain path, to go from one network to another network :
- it goes from one computer
- to that network’s switch
- to a router
- to the switch of the other network
- to the receiving computer
5.
It is a worldwide system of computer networks.
It is a network of… networks!
All across the world, networks on the internet are joined by physical cables.
6.
It is important to keep a network safe.
Let’s look at network security.
A firewall is a network security device that monitors traffic to or from your network. It allows or blocks requests, based on a set of security rules.
There are different reasons why it may not be a good idea to pass on a message. For example:
- Some information is private
- Some information is not relevant to others
- Some information can be harmful (e.g. a computer virus)
Let’s pretend some of you are ‘routers’. The routers have built in “firewalls”. These accept a message, or block it…
Would you allow the following messages to enter your network, or would you reject some of the messages?
Alternatively, do this task also as a roleplay, with some students being “routers” and others “computers”. The “computers” draw messages out of a hat, and take it to the “routers”, who either allow or block the messages.
7.
- A network is two or more computers that are linked in order to share information.
- A device, called a switch, sends information between computers.
- The internet is a network of networks.
- A device, called a router, connects two or more networks.
- It is important to protect networks from information that is private or harmful.
- A firewall is a device that monitors traffic to or from your network. It allows or blocks traffic based on security rules.
This is the original lesson source:
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