KEZAKO: Comment fonctionne Internet?

Summary

This script explains how the Internet functions as a network of networks, facilitating communication between computers worldwide. It details the process of data transmission, starting from a user's computer through various routers and the Internet backbone, which is a global infrastructure of high-speed connections maintained by telecommunication companies. The script also delves into the technology behind data encoding into light signals using lasers,调制频率, and the use of multiple frequencies and laser colors to increase data transmission rates. The summary highlights the complexity and the vast scale of the Internet's infrastructure, emphasizing the continuous need for expansion to meet growing demands.

Outlines

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🌐 Understanding the Internet's Infrastructure

This paragraph explains the fundamental concept of a computer network, which is a system that allows computers to communicate with each other. It emphasizes that networks can vary in size, from a few in a household to thousands in a university or corporation. The Internet is described as a network of networks, designed to connect these various networks and facilitate communication despite differences in 'languages'. The paragraph outlines the services provided by the Internet, such as email, web access, and instant messaging, and clarifies that all data transmission ultimately involves the movement of binary digits (0s and 1s). It also details the process of sending data internationally, which involves connecting to an Internet Service Provider (ISP) via physical mediums like copper wires, fiber, or wirelessly, and then through routers that determine the most efficient path for data to reach its destination. The Internet backbone, maintained by major telecommunication companies, is highlighted as a critical component of the Internet's infrastructure, consisting of vast computing centers linked by high-speed connections capable of handling the massive amounts of data transmitted monthly. The paragraph concludes with an explanation of how data is encoded into light signals for transmission via optical fibers, which are the primary medium for data transmission in the Internet backbone.

Transcripts

How does Internet work ?

Everything starts with the definition of a network

A computer network is a system

making computers communicate between them.

Thus, a network computer can send messages

to every other computer of its network.

Obviously, the messages are written in the computer language.

In other words,

it is composed of only two letters,

or rather two figures: bits of 0 and 1.

A network can link a various number of computers:

about 3 in a house,

thousands in a university or a big company.

There are millions of networks on Earth.

Internet has to link all those networks

and to ensure that they understand each other

in spite of sometimes different languages.

So Internet is a network of networks.

Internet provides a certain amount of services

such as electronic mail, web, instant messaging.

But in the end,

it always means transporting zeros and ones.

If you want to send data to the other side of the world,

you need to connect your computer

to your Internet access provider.

More precisely,

the computer will be connected via a copper wire,

a fibre or airwaves,

to a router of your Internet access provider.

This router is a computer

that will determine the shortest route

so that your data reach their destination.

Then, the router sends your data to one of the big networks

that constitutes the Internet spine

(the official name is Internet backbone),

that will transport it to the Internet access provider of the recipient.

The Internet backbone has been installed

by a dozen of big telecommunication companies.

It consists in huge computing centres

spread in the world

and linked by really high speed connections.

Those connections must be able to transport

the tens of billions of billions of bits

that pass through the Internet each month.

Their speed is in the order of a trillion,

(i.e. a thousand of billions)

of bits each second.

Data transmission lines of the Internet backbone

are optical fibres.

Today, several tens of millions of km of optical fibres,

laid down to the bottom of the ocean or buried in trenches,

transport zeros and ones of the Internet

everywhere in the world.

More specifically,

they transport the light of a laser

in which these data are encoded.

How do we do to encode zeros and ones into light?

The idea is simple.

First, we choose a rhythm for sending data.

For instance,

we choose to send a bit every millionth of second,

i.e. a rate of a million of bits per second,

or a megabit per second.

Then, we choose a code,

for instance, we turn off the laser for 0

and we turn it on for 1.

So the laser needs to be modulated

at a frequency of 1 megahertz.

In the end,

we just need to transform the light signal

into an electrical signal

(and we perfectly can),

and that's all there is to it!

Of course, for practical purposes,

the method used is a little more sophisticated

and frequencies of modulation much more higher.

To further increase the rate of only one fibre,

we can choose several frequencies of modulation,

and then, all we have to do is a selection.

We can even send laser beam of different colours,

this will allow an equivalent multiplication of the rate,

still in only one fibre.

Afterwards,

to respond to the increasing demand,

optical fibres have to be multiplied...

Production: Unisciel/ University of Lille 1 (SEMM)

Conception/Production: Maxime Beaugeois, Damien Deltombe and Daniel Hennequin

Editing/Special effects: Benoit Leleu

Music: Sébastien Ride, « Thunder Chacha » (SR Music)

Presentation: Maxime and Nina Beaugeois

Graphic design/Credits animation: Michaël Mensier.