1. Unit 1.4 Wired and Wireless Networks Lesson 3

2. Big Picture
We use the internet on a daily basis, but do we realise what is involved in this?
What is operating the background for us to do this?

3. Learning Objectives
Understand the internet is a worldwide collection of computers
Understand the role of DNS as part of the internet
Understand what is meant by hosting
Understand what is meant by the cloud
Understand what is meant by a virtual network
Understand why virtual networks are used

4. Engagement Activity
Do you use a virtual network? Do they know what one is?
Why are virtual networks important and how can they add a new level of security to keeping your personal data safe?

5. Key Words
Internet
DNS
Hosting
The cloud
Virtual network
VPN

6. The Internet
Worldwide collection of computer networks that are connected together (Inter-networking)
They operate on protocols such as TCP/IP

7. DNS Server
When accessing a webpage we use a URL to access the page e.g.
http tells the computer to use the hypertext transfer protocol which puts the packets together to be used in a web browser
www tells us that this is a webpage and that it is located on the world wide web
ocr.org.uk is the domain name

8. DNS Server
When you type that URL into the web browser the computer will query a DNS Server (Domain Name Server)
The DNS has a list of all domain names and their associated IP addresses.
All packets are transmitted as IP addresses – therefore to access the server that holds the OCR website – we would need to know the IP address.
This is the role of the DNS server

9. DNS Server
Without a DNS server the user would have to type in IP addresses to access a webpage:
E.g
Imagine remembering your favourite web pages now?

10. Hosting
In order to let other people see your web site, it will be placed on a web server. This is known as hosting.
You would select a suitable domain name e.g. myInterestingNetworkingSite.co.uk
You would need to register the domain name with a domain registrar – they would ensure that the domain name is unique and not already registered
Each registered domain name would have an associated IP address – this would then be registered on a DNS

11. The Cloud The cloud is a network of servers
Some servers will run applications
Some servers will store data
The benefits of the cloud is that you can
increase storage e.g. from mobile phones
Access files from anywhere in the world
Collaborate with others from around the world

12. Activity 1
Let’s watch two videos that explain what a virtual private network is.
What is virtual network in general? What can they be used for?
Let’s construct a mind map on the board to represent the abilities of a virtual network.

13. Virtual Networks
Within a LAN (Local Area Network) it is possible to break the network into virtual networks to allow one group of devices to not “see” another group of devices on the network. E.g. Administrators and school users.
They share the same network hardware and cabling but software determines what the different virtual networks can access and see/use
Easier to maintain a network and also leads to a flexible network setup
Machines can be added and removed from a virtual network without having to re-wire.

14. Activity 2 Peer teach Your groups will be assigned a topic
You need to research your topic and create a 5 minute lesson to teach your peers about what you have learnt

15. Plenary You have four definitions in front of you
Write your name on each definition
Place the correct definition in the correct box as you leave

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