Group 1_Charisma : How does the internet work?

How did the Internet really get started? It all began with a satellite. In 1957 when the then Soviet Union launched Sputnik, the first man-made satellite, the cold war between the Russians and the Americans led to the then American President Dwight D. Eisenhower create the Advanced Research Projects Agency (ARPA) in 1958. ARPA's purpose was to give the United States a technological edge over other countries. It created a computer network which connected four computers running on four different operating systems. They called the network ARPANET. ARPANET laid the foundation for the present day internet.

Nobody owns the Internet. The Internet Society, a non-profit group established in 1992, monitors how we interact with the Internet.

Internet Protocol: IP Addresses:
Every machine on the Internet has a unique identifying number, called an IP Address. The IP stands for Internet Protocol, which is the language that computers use to communicate over the Internet. A protocol is the predefined way that someone who wants to use a service talks with that service. The "someone" could be a person, but more often it is a computer program like a Web browser.

A typical IP address looks like this:

216.27.61.137

To make it easier for us humans to remember, IP addresses are normally expressed in decimal format as a dotted decimal number like the one above. But computers communicate in binary form. The same IP address in binary looks like this:

11011000.00011011.00111101.10001001

All of these networks rely on Network Access Points or NAPs, backbones and routers to talk to each other.The Internet backbone is made up of many large networks which interconnect with each other. These large networks are known as Network Service Providers or NSPs. What is incredible about this process is that a message can leave one computer and travel halfway across the world through several different networks and arrive at another computer in a fraction of a second!

The routers determine where to send information from one computer to another. Routers are specialized computers that send your messages and those of every other Internet user speeding to their destinations along thousands of pathways. A router has two separate, but related, jobs:

* It ensures that information doesn't go where it's not needed. This is crucial for keeping large volumes of data from clogging the connections of "innocent bystanders."
* It makes sure that information does make it to the intended destination.

Protocol Stacks and Packets:
How does a computer with a unique IP address communicate with other computers connected to the Internet? An example should serve here: Let's say your IP address is 1.2.3.4 and you want to send a message to the computer 5.6.7.8. Obviously, the message must be transmitted over whatever kind of wire connects your computer to the Internet. Let's say you've dialed into your ISP(Internet Service Provider) from home and the message must be transmitted over the phone line. Therefore the message must be translated from alphabetic text into electronic signals, transmitted over the Internet, then translated back into alphabetic text. This is accomplished through the use of a protocol stack. Every computer needs one to communicate on the Internet and it is usually built into the computer's operating system (i.e. Windows, Unix, etc.). The protocol stack used on the Internet is referred to as the TCP(Transmission Control Protocol)/IP protocol stack because of the two major communication protocols used.
The ISP maintains a pool of modems for their dial-in customers. This is managed by some form of computer (usually a dedicated one) which controls data flow from the modem pool to a backbone or dedicated line router. This setup may be referred to as a port server, as it 'serves' access to the network. Billing and usage information is usually collected here as well.

After your packets traverse the phone network and your ISP's local equipment, they are routed onto the ISP's backbone or a backbone the ISP buys bandwidth from. From here the packets will usually journey through several routers and over several backbones, dedicated lines, and other networks until they find their destination, the computer with address 5.6.7.8. This is how the internet works.