miércoles, 28 de septiembre de 2016

What is the internet? How does it work?

The Internet is the global system of interconnected computer networks that use the Internet protocol suite to link billions of devices worldwide.

The Internet has one very simple job: to move computerized information (known as data) from one place to another.
In this respect, the Internet works a bit like the postal service. Letters are simply passed from one place to another, no matter who they are from or what messages they contain. The job of the mail service is to move letters from place to place, not to worry about why people are writing letters in the first place; the same applies to the Internet.


A computer network or data network is a telecommunications network which allows computers to exchange data.

The Internet protocol suite is the computer networking model and set of communications protocols used on the Internet and similar computer networks.






We can see the Internet as a series of stages that range from when we type an address in a browser to when the web page appears on our screens. This whole process can take less tan a second.




1.  Users can connect to the internet if they have a contact with an Internet service provider (ISP) and pay a set fee. When we switch on a computer and connect to the Internet, our ISP (for example, Movistar, Jazztel, Ono, etc.) assings an address to our computer, called an IP address. Every computer is assigned a unique address on the Internet.





2.  A router is a device that let us connect to the Internet. Once connected, we open our browser and type the address of a page in it (URL). At this point, information starts to travel in the form of packets. The information sent out is the request or address of the web page that we want to visit and the information that is sent back is the content of the web page.

Each web page is also assigned an IP. This way, we can identify the origin and distintion of the flow of information.








3.   The next step in the information´s journey are the DNS. It would be very difficult to remember the IP address of every website that we could connect with. DNS servers simplify this task for us. DNS stands for domain name system and these servers assign a name to each IP address in the same way that a telephone directory assigns names to telephone numbers so that we do not have to remember them all.

For example, if we type the IP 64.233.189.104 in our browser, we are connected to the Google home page, which is the same as typing in "https://www.google.es"






4.   Our computer communicates with other computers following a common set of rules called a protocol.

  • The packets of information follow the TPC/IP protocol (transfer control protocol/Internet protocol).
  • Servers use the HTTP protocol (hypertext transfer protocol) to send and receive documents over the Internet.






5.   The DNS server sends the request to the server that hosts the web page we want to visit. The server sends us the information packets that make up the web page, which travel over the network along the quickest path that they can find.





6.   Finally, the packets reach our computer and are reassembled. The page is displayed in our browser.

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