1. 1.4 Wired and Wireless Networks
In this unit you will cover…

2. 3. The Internet LOs To define and explain the internet
To absolutely definitely know the difference between Internet and WWW
To explain the purpose of DNS
To explain the purpose of hosting
To explain the cloud

3. The Internet

4. The Internet - What is the internet? - Where does the internet live?
- Who controls the internet?

5. The Internet The internet does not live in one place
The internet is not controlled by any one person or country
The internet is not Google
Let’s go back in time…

6. A History Lesson
The year is 1969 and the United States Army has started to use computers to do super important army stuff
They’ve got networks at each base, already allowing them to share resources within each base
America is a pretty big place though, with bases all over the country, they wanted a way to link them all…
Thus, the internet was born!

8. A History Lesson So what were they doing?
They were connecting networks together
We already know of this concept as a WAN
This was the first instance of connecting multiple networks together

9. The Internet
The idea of connecting networks together grew and spread globally, now people were able to communicate all over the world using computers.
Here’s the all important definition that you absolutely need to remember:
The internet is a global computer network made up of interconnected networks.

10. WWWWWWWWWW So, what’s the world wide web if it’s not the internet?
The internet was great for beardy academic types; using it to share academic data but it wasn’t of much use to the everyday person
An everyday person

11. World Wide Web
Just such a beardy academic person was Tim Berners-Lee, a British scientist working at CERN in Switzerland.
In 1989 he decided that there should be a better, consistent and friendlier way to share information on the internet.
Tim (Sir Tim now)’s invention was the web page.
Specifically, he invented http, html and the web browser

12. HTML The web remains mostly the same today
Web pages are made of HTML code
HyperText Markup Language
HTML is a set of instructions in the form of tags that a web browser understands
The tags instruct the browser exactly how the page should appear
HTML is a standard – you should know what a standard is by now!

13. HTML Look at this demonstration of HTML…
Now write down a definition for HTML

14. HTTP A protocol was created to control the transfer of web pages
HTTP – HyperText Transfer Protocol
A computer requests a web page from a web server
The web server sends the web page to the client computer
This is all done using IP Addresses, which we’re all experts on now…

15. DNS
If websites are requested using IP addresses, how come you don’t have to type an IP address in every time you want Google or Netflix?
You only have to look at phone numbers to realise how rubbish this would be – how many phone numbers can you remember at one time?

16. TASK - DNS What websites do these IP addresses belong to?
Now the other way around! (use
IP Address
Website

17. DNS
Instead of normal people like you and I having to remember all of the IP addresses, we created giant phone books on the internet
This is called DNS – Domain Name Service
The pretty, friendly Domain Name (e.g. or is a lie!
It’s just there to help us, it’s not actually where the website lives

18. DNS
When your computer requests a website (e.g., it must find out the IP address that actually lives at
The request hits a DNS Server, the DNS Server looks through its list for “google.com”, if it finds it, it’ll give the IP address back to your computer
If it doesn’t know it, it’ll ask another DNS server

19. Not found. Try over there
Request
Request:
Sends HTML to client address
Client
Request:
Response:
Not found. Try over there
DNS Server
DNS Server

20. DNS
Hopefully now you should be able to write down a good definition for what DNS is
AND
Bullet point the separate steps that happen when your computer requests a web page

21. Hosting
Even though the internet doesn’t live in one specific place, our websites still have to live somewhere!
They are stored on web servers
A web server is a server that can communicate using HTTP, receiving requests from and sending HTML to clients
These web servers host websites

22. Hosting Any computer can be a web server with the correct software
People often pay for web hosting in data centres – the servers there are maintained by other people and the user is guaranteed a quality of service
Data centres can also offer a more reliable internet connection with the appropriate bandwidth and speed to support high internet traffic
Data centres may also offer additional security from web attacks

23. Amazon even put a datacentre in a lorry
Hosting
A typical datacentre
Amazon even put a datacentre in a lorry

24. The Cloud
With all of these massive and powerful datacentres, a phenomena has started to take over the world…. The cloud!
In simplest terms; the cloud is where services and data are stored and provided remotely over the internet
Examples of cloud that you use daily (probably) are: Office 365, iCloud, Google Drive, Spotify, Apple Music, Sky Q
They’re all services that rely entirely on an internet connection

25. The Cloud NEGATIVE POSITIVE Some people love the cloud and some don’t…
“I don’t know where my stuff is!”
“I can access my files from anywhere!”
“What if my internet goes down?”
“It’s more reliable than storing it myself”
“What if I lose my password?”
“I can do more with my data in the cloud”
“What if somebody gets into my account?”
“I don’t need to spend as much on storage”