The Internet

Who invented the Internet?

In 1990 Tim Berners-Lee worked out how to send

information as web pages, with pictures and text. This became

what we now call the World Wide Web

In the USA Vinton Cerf and Bob Khan invented the rules that allow the

Internet to work properly in 1973.They are known as ‘The Fathers of the

Internet’!

In 1968 Paul Baran and others in the USA and Donald Davies in the

UK invented a way to break information up and send it over a

computer network

In 1961 Leonard Kleinrock created the initial idea of the ARPANET, the precursor to the Internet in his first paper entitled "Information Flow in

Large Communication Nets"

In 1971 Ray Tomlinson

sent the first email message

In 1983 Jon Postel and Paul Mockapetris invented the way we name computers

– the DNS system

Who is in charge of the Internet?

ICANNGlobally organises names and

Internet address

Smaller ISPsInternet Service Providers

Own and sell access to network, cables, (e.g. BT, Sky, O2 etc)

GovernmentsCan control and censor content on World Wide Web in their country

The Internet Society

Develops policy, education etc

The Internet Engineering Task Force

Supports the technical development of the Internet

Backbone ISPsOwn most of the main cables and

infrastructure

Domain registrarse.g Nominet

Buys Internet addresses from ICANN and sell them to users

Network access

Policy and structure

Internet address ‘map’

Content

W3CWorld Wide Web Consortium

Global group looking after the Web policies and development

EveryoneAnyone with access

can make a webpage

Nobody? Everybody?

What does the Internet look like?

How is the Internet connected?

Undersea cables connect the Internet across the world…

Internet Hubs around the world connect everything together, and route internet traffic along the fastest cable route…

Overhead telephone lines and cables carry internet data…

Underground cable carries internet data under our feet…

Originally the wires were made of copper, with a

plastic coating to protect them

Now the wires are made of thin glass strands, and are called optical cables

Wireless masts can send internet data through the air for short distances to create a WiFi hotspot…

The Wi-Fi antennae, or masts have a transmitter

that sends out Wi-Fi radio signals that can be used by laptops, phones

etc.

Wireless Internet (WiFi) uses radio waves that are transmitted from masts or antenna to create a

WiFi hot spot.

Wi-Fi in our homes homes…

The wireless hub send out Wi-Fi signals that

we can connect our laptop, computer, iPad or phone to, and use

the Internet.

We use a wireless router or hub to give us wireless connections at home.

This means we don’t have to connect our devices directly to the internet

with a cable or lead.

The router or hub is connected to the

rest of the Internet via the telephone

socket or cable TV socket

Because the satellite dish is so far away it takes a few seconds for the information to be transferred. This

means satellite Internet is not used as much as other types of connection

Why don’t we use satellites?

Satellites also have much smaller bandwidth than fibre cables, which means they can transmit much less data per

second

Satellites are expensive to make and to launch into

space

They ARE very useful for rural communities and places that cable

can’t reach easily

Where are things on the Internet stored?

These racks hold computers called servers. They have lots

of hard drive memory

Lots of these racks together is called a server farm

The web page content (text and images,

sounds and video) is saved onto a hard

drive memory

Data centres are used to store lots of

information for websites like

Facebook and Hotmail

How does the Internet get into my home?

How do you find things on the Internet?

Searching within a website…

Searching the World Wide Web with a search engine

https://www.google.com/insidesearch/howsearchworks/crawling-indexing.html

What is Google?

We can think of the Internet Network

like a library building – it is the

structure that holds all the information

on the web…

The World Wide Web is a bit like all the books

inside the library…

A website is like an information book on a

particular subject…

A individual web page is like a page inside an

information book…

…and Google is like the Librarian who knows all the

books in the library, and can find the one you need…

Useful Web Links

BBC Webwisehttp://www.bbc.co.uk/webwise/guides/what-is-the-internet

A Packet’s Tale – There and Back Againhttp://vimeo.com/52585365http://www.worldsciencefestival.com/2012/06/there_and_back_again_a_packets_tale/

Junior ICT Companionhttp://www.parkfieldict.co.uk/ictcompanion/files/dc/internetcontents.html

What is the Internet?http://www.primaryresources.co.uk/online/internet.swf

LGfL – History of Computing http://www.hoc.lgfl.net

How does Google Search work?https://www.google.com/insidesearch/howsearchworks/crawling-indexing.html

Tim Berners-Lee Answers to FAQshttp://www.w3.org/People/Berners-Lee/Kids.html#Where