This document provides an overview of computer networks and the internet. It describes communication systems, elements of a network like servers and network interface cards, and different types of network connections. The document defines what the internet is and explains internet domains and common top-level domains. It also outlines several popular internet services including blogs, wikis, email, virtual communities, forums, chats, and methods for finding information online. Differences between webmail and POP email are summarized at the end.

1. Internet
Paula Serrano
Anna Sanchez
Maria Sánchez

2. Contents
* Comunication systems
* Computer networks
* Functions of a network
* Elements of a network
* Internet networks
* What is internet?
* Internet domains
* Internet services
* Blogs and wiki pages
* Electronic mail or email
* Virtual communities and social networks
* Other internet services
* More sevices…
* Finding information
* Differences between web mail and POP mail.

3. systems
*Interlocutors: are the people who use the networked computers. They
are called network users.
*Messages: are the files on the network that we can access: Written
documents, videos, music, drawings, programs…
*Means: The instruments used by the interlocutors to send and receive
massages.
*Code: The system of signs - a language, smoke signals or tom-tom drums
- that the interlocutors share and use to create their messages.

4. Computer networks
A network is two or more computers connected to one another that can
share documents, files, printers, etc.

5. network
If some computers are connected into a network:
* You can send and receive information from one computer to another
and from one house to another.
* You can also send to your teacher a piece of work done on the
computer.

6. network
A network basically consists of the following elements:
1.- The server and the terminals
2.- A network interface card for each network computer. This transmits
and receives the information to and from the rest of the computers.
3.- A transmission means: the cables that are connect the computers. If
the network is wireless, cables are unnecessary.
4.- An element that controls and distributes informationa among the
computers. This elements can be hub (concentrador) or a switch
(conmutador)
5.- The necessary programs to transmit the infirmation from one
computer to another.

7. networks
An interconnected network or a network of
networks is two or more networks connected
together to form a system.
For connect several networks, we have to use
the same codes (protocols) on each network.

8. What is internet?
The internet is a huge network of networks, interconnected worldwide.
For go to the Internet you need to use a server. (Google Chrome,
Internet Explorer…). Each server is identified by a domain name.

9. Internet domains
Web addresses normally end in a dot followed by two or three letters;
for example:
*www.iescanet.cat
*www.redcross.org
*www.educacion.es
*www.losacrodes.com
The letters after ‘www.’ in web addresses represent the domain name.
A domine name is the server name plus the generic top-level domain (.org,
.es, .com…) separeted by a dot (.). This indicate the location
organisation or field that this website belongs to.

10. Internet services
* Web pages (hypertext)
These are enriched text documents with many format options. They are
divided into frames and can included images and other multimedia
elements (sound or video files).
The difference between web pages and conventional documents is that
web pages include links to different parts of the document or web
sites.
We need a browser for send and recive documents.

11. Blogs and wiki pages
*Blogs: This are pages that are periodically updated. They contain
articles from one or several authors. The most recent entry appears
first on the page. Readers can write comments about the article.
Each blog has rules of use an a topic.
*Wiki pages:These pages can be created and modified by different
users from their browser. Anyone can participate in creating and
editing the information.
The most well-known wiki is Wikipedia.

12. email
This service enables us to send and recieve messages that can contain
either text alone or text with multimedia elements (sound, video,
photo…).
There are two options for using this:
* Go onto a web page that offers this servise (Gmail, Yahoo Mail,
Hotmail…).
* Use a program that manages email, such as Outlook Express (windows),
Mozilla Thunderbird, Evolution (Linux), Mail (for Macintosh
computers)...

13. Virtual communities and social
networks
A virtual community is a group of people who communicate and have a
relationship in a virtual space, like the Internet, instead of a physical
space.
Social networks have envolved from virtual communities. They are online
communities where people from all over the world are in contact for a
particular reason .

14. services
*Debate and news forums. Network users can exchange information and
opinions through these services.
*Chats and videoconferences. A text conversation between two or more
users is called a chat. A videoconference is a conversation usiing voice
as well as live video transmission.
*IP telephony, is another technology, that enables two or more people
talkover the network. Is like a telephone conversation but it’s done over
the interent.

15. More services...
*Instant messaging. This service enables us to communicate in real time
with another user connected to the Internet anywhere in the world.
(Like a chat but between to people).
*P2P networks. These are tools for massive interchange of video, music,
text files. It’s a programm where one ‘gives’ the file and an other ‘takes’
it.
*File transfer. This is used to send large files from one computer to
another quickly and efficiently.

16. Finding information
A search engine is a web page resource that has a database of contents
of web pages throughout the Internet, worldwide.
We can find information in:
* Dictionaries
* Wikipedia
* Portals
* ect…

17. Differences between web mail and
POP mail
*Web mail: For consult your own mail you need to connect to the
Internet from any computer. The files of the mail always stay in the
Internet. You have the option of download it but it stay in the web mail.
*POP mail: For consult your own mail you need to enter with a specific
computer. The files of the mail download automatically and they are
saved in the computer memory.