How does a Network work?
A computer network is similar to a post office system - only that the "mail" is transferred much faster. When a computer is logged onto a network with more than 2 users, be it a dial-up ISP(Internet Service Provider) or LAN(Local Area Network), it will be automatically assigned an Address. This usually looks like a string of numbers with 3 dots in the middle, (eg. 202.156.83.20). You may have more than one address if you are connected to both the Internet and your local LAN. You IP address (Internet Protocal), if on the Internet, may or may not be the same each time you log on. In every computer, there are also many ports, ranging from the number of 100 to that of more than 30000. Each port may be used for a certain operation/command in a program. No two programs may use a single port at one time together.
Now that the computer has been given an address, the computer
can be said to be already on the network. There are several types of connection
commands this computer can then begin to make connections.
They are:
1. Listen on a port.
2. Establish connection on a port and transfer data.
3. Contact a remote port.
4. Close a connection on a port.
There are two types of computers required a network connection: A Client, and a Server. The client refers to the computer that connects to the server, while the server can be said to be something like your telephone operator, as it accepts connections from one or more clients.
Different network applications and software handle data transfer between computers differently. A certain chat program, ICQ, for example, would make use of an live established connection to an ICQ mainserver whenever the user is online so that messages would be received and come through went sent by another user. A web browser, on the other hand, would only establish a connection to a server when the user wants to surf.
In case you may be wondering how is it is that sites may be named as www.something.com instead of an IP address, the answer is that http://www.something.com is really just a reference to an IP address(eg 202.156.83.20). There may be many different references to a certain IP address server on the internet. The browser finds the references from a large database named INTERNIC and then goes to the specified IP Address to download the webpage.
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