Transcript internet - UTRGV Faculty Web

The Internet
TexPREP Summer Camp
Computer Science
The Internet
Internet: is a global network of networks.
On top of it we can get different types of
services such as: WWW, e-mail, FTP, VoIP,
Chat, online games, etc.
One of its main advantages is that we can
connect networks of different types. Another
is that it spans over the whole world.
The Internet
bc.theambitious.com
History
It became operative in 1969 as ARPANET and
after some changes it was named the Internet.
It was developed for military purposes but today
it is a public, cooperative, and independent
network.
Although it is not controlled by anybody in particular
there are organizations, like World Wide Web
Consortium (W3C), that set standards so it can
continue growing in an organized way.
How it works
Every computer has a unique id (IP address) that
identifies it.
Information is broken into small packets that are
sent through any available path between the
sending device and the receiving device
following the TCP/IP protocols.
Once the packets arrive at the receiver, they are
put together in order to form the original
message.
Access
We typically access the Internet through an ISP
(Internet Service Provider).
They provide us different ways to access the Internet,
some of them are:
• Dial-up (56 Kbps)
Modem
• DSL (384 Kbps – 6 Mbps)
• Cable (1.5 Mbps – 6 Mbps)
• Cellular phone (3G: ~6 Mbps)
• Satellite (500 Kbps)
• Fixed wireless (70 Mbps)
Internet
Services
The Internet allows us to have access to
different types of services: WWW, email, FTP,
etc.
Most of them are based on the Client/Server
model. This means we need to access the
corresponding server in order to get the
service. For example, to see a web page we
need to access a web server; to send an email
we need to access an email server; and so on.
WWW
WWW stands for World Wide Web. It is a collection of
web sites located around the world.
A web site is a collection of web pages.
A web page is a multimedia document (text, graphics,
video, sound, hyperlinks, etc.)
To access a web page we need to use a web browser.
Each web page has unique id called URL (Uniform
Resource Locator). They can be accessed by
specifying a domain name or its corresponding IP
address.
WWW (continued)
It is possible to extend the capabilities of a web
browser by installing plug-ins on our
computer.
With them we can:
• Play videos or music (Windows Media Player,
RealPlayer, QuickTime, etc,)
• View pdf files (Adobe Acrobat Reader)
• View animations (Flash Player)
e-mail
This service allows us to send and receive messages.
We can include attachments in our messages.
Incoming servers
POP (Post Office Protocol)
IMAP (Internet Message Access Protocol)
Web based
Outgoing server: SMTP (Simple Mail Transfer Protocol)
Netiquette
Set of rules that suggest acceptable behaviors users
should follow while on the Internet.
A few examples:
Provide a meaningful subject
Explain attachments
Use uppercase and lowercase letters
Be careful what you send
Be polite
Use the Bcc function for group mailings
Don’t send replies to all recipients
Malware
Short for malicious software. These are programs that
can affect your computer system in different ways
(destroy information, spy, make your computer
vulnerable, control your computer, etc.).
It includes viruses, worms, trojan horses, and spyware.
You should install utilities on your computer that can seek
and destroy the malicious programs they find on your
computer or prevent them from infecting your system.
Examples of these utilities are anti-virus, anti-spyware,
anti-trojan, and firewall software.