Chapter 1

Linking computers
By Giacomo Carlotta and Davide Lugli

Chapter 2

How the Internet was born
By Mattia Gualtieri, Erald Xholi, Andrea Arigliano and Morad Roufki

Chapter 3

The man who invented the web
By Filippo Marinelli, Marcello Masella, Giulio Mazzali and Leonardo Bosi

Chapter 4

How the Internet works
By Valeria Covalschi, Andrea Sciolti and Martina De Girolamo

Chapter 5

Web addresses (URL)
By Federico Caroli and Cristian Leonardi

Chapter 6

Connecting to the Internet
By Matteo Prampolini, Marcello Vaccari and Alessandro Tsulis

Chapter 7

Internet's Magna Charta
By Gabriele Gilioli, Yari Salsi and Lorenzo Bigi

Chapter 8

Open data
By Alessandro Saponaro, Davide Comastri and Rocco Meoli

Linking computers

Back to the beginning

How a network works

Since telephone lines are used as communication links between devices, each computer must be connected via a modem (modulator / demodulator) to access the network. The modem modulates the digital signal of a computer so that it can travel through the phone line. It also demodulates incoming signals from the phone line back into digital signals which can be read by the computer. Computers on a network must follow a protocol for the exchange of data. On the Internet, this is called “Transmission Control Protocol / Internet Protocol” (TCP/IP).

Separate LANs can be connected by bridges (if they use the same protocol) or by gateways (if they use different protocols), in order to form larger networks. Intra-nets are private networks that include Internet  features and are commonly used by large organizations to provide their users with certain facilities such as e-mail. Intra-nets are particularly useful because they grant organizations a better access, control and protection of their data.

Local Area Network

A LAN (Local Area Network) is a small network that interconnects a limited area such as a house or an office, whereas a WAN (Wide Area Network) links devices from a large area or even from all around the world. A LAN usually consists of servers, hosting files and services that other LAN users can access. The users can also share files and resources among each other. In a LAN, all the connected devices are called ‘nodes’, and they can be linked together in different ways, from linear to bus and star shaped.

A network is composed of different devices, each one with a different job:

Instead of using a server, clients can also exchange data directly between one another. This is called “peer-to-peer” (P2P) communication.

How the Internet was born

Back to the beginning

The Advanced Research Projects Agency Network was an early packet-switching network and the first network which implemented the TCP/IP protocol suite. ARPANET was designed for US military purposes during the Cold War in 1969, but paradoxically became one of the biggest civil projects in the world: a global network that connects all the devices on Earth.

The man who created the web

Back to the beginning

Tim Berners Lee

How the Internet works

Back to the beginning

First of all... What is it?

The Internet is a line and all the computers connected to this wire can communicate to each other.​
The heart of the Internet consists of powerful computers known as routers,  connected by high-speed links.
​ Routers are connected with smaller networks, composed of computers or peripheral devices such as printers and laptops.
​ Every computer has an IP address so that it can be unequivocally recognized.
The computers we use every day are not connected directly to the internet. For this reason, they are called "clients" and they are connected to the Web through an Internet Service Provider. 

Web addresses (URLs)

Back to the beginning

URL stands for “Universal Resource Locator” and is the web address you type into your browser to get a particular website.​
In order to find the website, the browser has to translate the URL into an IP address.​
Every URL has its own IP.​
When you search resources on the Internet, the browser sends the URL to the DNS server (Domain Name System) and receives the corresponding IP as a response.​

Connecting to the Internet

Back to the beginning

What you'll see in these slides

There are different ways to connect to the Internet:

Internet's Magna Charta

Back to the beginning

Tim's challenge

25 years ago, while working at CERN, Tim Berners-Lee got permission to pursue his side project that later became what we all know now as the World Wide Web.

Open Data

Back to the beginning

How did it all start?

After Tim Berners-Lee cried “Raw data now”, an open data movement was born.
It all started with Paul Clarke, who blogged a message with the data of bicycle accidents. Two days later the Times Online published a mashed-up map, made by this data, which showed riders the best path to follow.​