Presentation about the Internet for 3 ESO

1. UNIT 1
COMMUNICATION
TECHNOLOGIES
TECHNOLOGIES, PROGRAMMING AND ROBOTICS
3 ESO

2. INDEX
• MOBILE PHONES
• RADIO
• SATELLITES AND POSITIONING SYSTEMS
• TELEVISION
• THE INTERNET
• NEGATIVE EFFECTS OF COMMUNICATION TECHNOLOGIES

3. 5. THE INTERNET

4. · The Internet is a global system that interconnects computer networks (private,
public, academic, business and government).
· These networks and their hardware can communicate between them thanks to
specific protocols (sets of rules, called TCP/IP). By following these rules, one
computer can (if it has permission) get data from another computer.
· Some internet processes happen
along cables, while others take place
wirelessly
• KEY CONCEPT
link

5. · Computer networks can be organized
according to their size:
1. PAN (Personal Area Network) 
by a person’s different devices that can
connect between them or to the Internet
or other networks.
2. LAN (Local Area Network)  A group
computers and peripheral devices
connected in a limited area (like a home,
school or an office). The objective of LAN
is to share resources like files,
peripherals, software licences or Internet
connection.
• TYPES OF NETWORKS

6. 2b. WLAN (Wireless Local Area Network)  LAN where the
interconnection between devices is achieved wirelessly.
3. MAN (Metropolitan Area Network)  A large computer
network which extends to a city or a large university campus
(up to 50km radio). Its purpose is to provide the link to the
Internet, typically along fiber optic cable connections.
4. WAN (Wide Area Network)  Formed by two or more
interconnected LAN, that share information and resources via
radio or telephone lines. It is mostly limited to companies or
organizations that have offices at different locations. It
over large geographic areas.
An intranet is a private network that a company uses to share
files and resources securely. It can be LAN or WAN.
• TYPES OF NETWORKS (II)

7. · A server is a computer designed to process requests and deliver data to another
computer. These processes can take place:
a) Over the Internet  For example, a web server where webpages can be
accessed by a client with a web browser. Other examples are online gaming
servers, chat servers, video streaming servers, email servers…These servers are
located in enormous high powered interconnected computers called server
clusters.
• SERVERS AND CLIENTS
b) Through a local network  For example,
a file server that stores data in a company’s
intranet or a print server that allows several
devices to print from one only printer.

8. · A client is a device or a pieces of software used to connect to the services offered by
a server.
· A web browser (Google, Safari, Opera, Mozilla, Microsoft Edge…) is a client program
through which we send an HTTP request to a web server. The web browser locates the
desired content in the www (World Wide Web) and displays it in the form of a web
page, video, image or audio.
• SERVERS AND CLIENTS (II)
Request for
data
Response (only
selected data)

9. · HTML (Hypertext Markup Language) is the computing language used in web
pages. A web browser is able to read HTML language and display it in an
understandable way.
• HTML, HTTP AND HTTPS
· HTTP stands for Hypertext Transfer Protocol. It is
the protocol that allows web browsers and servers to
communicate through requests and responses.
· HTTP communication can be easily intercepted.
HTTPS adds “Secure” to its title because the
connection between the browser and the server is
encrypted thus more secure.
Read this article if you are
interested in the benefits
and drawbacks of https.

10. • URL
· URL stands for Uniform Resource Locator and it’s what we call a web
address. It is a string of characters that form a reference to a resource
located in a server according to the HPPT/HTTPS protocols. The URL is
shown on most web browsers in an adress bar.
A typical URL might look like this:

11. • IP ADDRESS AND DNS
· An IP (Internet Protocol) address is a unique set of numbers that identify a
device (client or server) in a network.
· The DNS (Domain Name System) server translates domain names into IPs and
viceversa. This translation is not necessary if the website is stored in your devices’
cache from previous
visits.

12. • CACHE AND COOKIES
· The cache is a high speed very expensive piece
of memory that stores recently used data
temporarily. This way, next time the device
requests those data, it won’t need to go find it in
the main memory or in the Internet. The cache
speeds up the memory retrieval process. It’s
storage capacity is less than the hard drive’s.
· The cookies are small packets of information that are stored in your web browser’s
memory when you visit a website. They help the website keep track of your visits and
activity (for example, your shopping cart or your password). Normally, cookies are
not a risk for you computer, they can’t transmit viruses or malware. Anyway, some
advice:
https://us.norton.com/internetsecurity-privacy-what-are-cookies.html

13. Link to the
video
• HOW INFORMATION TRAVELS IN THE INTERNET

14. · Laws on data protection guarantee
that the personal data to provide to a
company through the www are
protected.
According to the European laws, these
data can be procesed, reused or given
to thirds, but they must always ask for
your agreement or consent.
Once you give your consent yo use
your data, you can contact the
company to withdraw your permission
and they must stop using your data
inmediately.
• LAWS IN THE INTERNET

15. · Laws of intelectual property protect creative works shared in the www so the
author has to give permission for anyone to reuse them. There are different types
of rights according to these laws:
a) Copyrights apply to writings, architecture, dance, photographs, videos, music,
drawings and films published online. Royalties are money you must pay to the
creator of something (music, photos…) to reuse it. There are ways to find
royalty free images with your web browser and specific search websites.
b) Trademark is the protection of comercial brands, names, logos and slogans.
• LAWS IN THE INTERNET