You have more than one computer at your home or office? It is fairly simple to network them–the ability for them to communicate with each other. Purchase a wireless router from Best Buy, have the right software, and you have created a network. Connect two networks together and you have an Internet– a computer network of computer networks.
The birth of the Internet can be traced back to the early 1970’s with a group of military installations, universities, and defense contractors, called the Defense Advanced Research Projects Agency (DARPA). In seeking ways to more easily share data, they created the physical structure that eventually would become the Internet.
The late 1970’s saw the rise of personal computers and a peripheral device called a MODEM that allowed two PCs to communicate over regular phone lines. At this time, long distance companies such as MCI were offering consumers discount long distance rates during late evening hours. PC owners placed bulletin board software on their machines, and late at night other PC owners could dial in, send and receive messages, read postings, and share files.
One of the first bulletin board systems was the Chicago Bulletin Board System (CBBS) that ran on a CP/M machine. One of the most popular configurations was the Apple Bulletin Board (ABBS) that ran on an Apple II and could handle six simultaineous calls. At the same time, a small company in Columbus Ohio leveraged it’s proximity to transcontinental telecommunication lines into the first on-line forum, accessible by phone lines, called Compuserve, which later became AOL On-line.
In 1989, a physicist at CERN in Geneva, Switzerland was looking for a way to more easily publish his data on the DARPA-NET. He developed a language called Hyper-Text Markup Language (HTML) and the World Wide Web was born.
The Internet closely parallels the telephone network and in many places the infrastructures are the same. The telephone system is a circuit switched system. From your handset, a twisted pair of copper wires runs to the local phone company’s switching equipment. A single physical circuit is created with switches between you and the called party.
The Internet is a packet switched system. When you connect to the Internet, you are a part of a single massive circuit. Your connection is assigned a unique address. Your computer creates many “chunks” or packets of data and then adds these packets to a continuous stream of data coursing through the system. Each packet has a destination address. The packet is electronicly switched through multiple connections to reach its destination.
The Internet is a highly de-centralized system. The transmission lines are often referred to as “pipes”, and just like pipes, have varying capacities for the amount of data(bandwidth) they can handle. The highest capacity pipe is the “backbone”, the largest is believed to be owned by GTE Sprint. The major Internet service Providers (ISP) and other major users connect to these backbones. Connections are serviced by devices called routers. They read the destination address in each packet and directs it to a connection closer to its eventual endpoint. If a router loses contact with its neighboring router, it devises another path to send the packets to their destination. This makes the Internet incredibly robust. It is almost impossible for the Internet to “go down”. More likely, your access to the Internet has broken.