1. Unit 1.5 - Network Topologies, protocols and layers Lesson 1

2. Big picture
Most computers and devices are connected together via networks. This opens up new opportunities and advantages.
What are the advantages?

3. Learning Objectives
Students will be able to identify a Star and Mesh Topology
Students will be able to compare Advantages and Disadvantages of Wi-Fi and Ethernet
Understand and explain what encryption is and why it is required

4. What is a Network?
A computer network is a number of computers linked together to allow them to share resources. Networked computers can share hardware, software and data.
BBC Bitesize

5. Engagement Activity
Networks are all around you, in school, at home in businesses and hospitals.
Think about what these networks look like
Draw a diagram to represent one of these networks. Include the parts, devices and wires
Be ready to explain your diagram

6. Key Words
Topology
Mesh Network
Star Network
WiFi
Encryption
Ethernet

7. Activity 1 You will be given some string and cups.
Create a Mesh Network
Create a Star Network
Think about and discuss the features of each.

8. Activity 1 - Answer

9. Activity 1 - Answer

10. Content A Mesh Network is …. A Star Network …..
Where some or all of the workstations or other devices are connected directly to each of other. Most are usually connected to the node that they exchange the most data with. 
A Star Network …..
In a star network, each device is connected by an individual cable directly to the server. Star networks are usually the layout of choice in schools and offices because they tend to be the most reliable of the topologies.

11. Activity 2
You will be given a selection of cards that show the advantages and disadvantage's of Wired and Wireless networks (Ethernet and WiFi)
Sort the into groups
Compare you answers with other students.

12. Activity 2 - Answer

13. WiFi WiFi is Wireless Frequency
- radio waves are used to transmit data packets without the need for wires.
This method is slower and more vulnerable to attack but it removes the need for cabling and networks
This means that it can be set up in remote locations such as in vehicles, in parks or on planes etc.

14. WiFi Frequency and Channels

15. Encryption
Encryption is a method of scrambling data with a key code which makes no sense.
On an open or public WiFi network anyone can join and sniff out packets of data from other users.
Therefore encryption is used. If intercepted the data will have no meaning
In order to read the data the user is required to decrypt the data using the key.

16. Content
When you are using a secure site for example your bank, or purchasing on Amazon, encryption applied to keep your details safe:
The encryption method used is called 'SSL' (Secure Socket Layer).
A tiny padlock appears in your browser window, usally on the left hand side of the address bar and the website address starts with

17. Twitter example

18. Consider Twitter Twitter users a HTTPS when you log in, why?
Why does the data need to be encrypted?
What could happen if it was not encrypted?

19. Encryption video

20. Encryption task

21. Encryption task

22. Key Words Recap Topology Mesh Network Star Network WiFi Encryption
Ethernet

23. Plenary Answer some questions from the exam papers on the topics
Create a short animation or film on Network security.
Stretch yourself!
Code an encryption program using a programming language of your choice.

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