What is the Internet?

In essence the Internet is a term used to describe thousands of computers, spanning over 65 countries. Some people may liken this to a single entity, but this is not true. The Internet is transitory, ever changing, reshaping and remolding itself. Ordinarily a collection of thousands of computers world wide might not attract so much attention. However people are using this new medium in ways that simply was not possible a mere five years ago.

Here is a short list of things the Internet has been used for in the last few years.

Two Chinese students in Beijing alert the world to a dying girl mysterious illness, thanks to the Internet. Doctors from around the world help the Chinese doctors diagnose and save her life.

A man in New York, yearning for a fresh start explores the possibilities of living in Santa Cruz, without leaving his home.

A boy in Canada learning how to use computers becomes a cyber pen-pal with a girl in Japan.

From war torn Bosnia appeals for food and medical supplies issue forth via email and newsgroups.

A man in Iowa locates a lost family member, now living in Brazil.

A Judge calls the Internet "The single most important advancement to freedom of speech since the writing of the Declaration of Independence"

A college student sent email to his/her parents asking for more money, corresponds via email with his/her professors and works on a project, collecting data from questionnaires sent out via email.

Just how were all these things made possible? The Internet. The single largest telecommunications system ever conceived by humankind.

There are four basic building blocks to the Internet, Hosts, Routers and Clients and Connections. Hosts and Clients are explained later in the chapter, but for now, be content to know that unless you have very special circumstances, in most cases your computer falls under the "Client" category. Data is sent from your computer in the form of a "packet". You can liken a packet to be similar to an envelope, it surrounds your data and contains both a return and destination address. Your computer handles the packets for you, it's all done in the background, without your knowledge.

A Router is a special device. Basically routers sit at key points on the Internet and act like traffic cops at an intersection of hundreds of streets. The Router basically reads the destination address on the packets being sent by your computer and then forwards the packet to the appropriate destination. In some cases your data will travel through several routers before reaching its ultimate destination.

Fig 1.1 Sample Internet Connections

Connections. This is a catch all term describing how you can connect from one point to another point. As an end user, your only concern is that the connection is good, but for a network engineer, this can mean several different types of technologies, including;

Dial Up Phone Lines
Fiber Optics
ISDN
Frame Relay
Satellite Links

Fortunately, for this author and you, we do not need to know anything about the connection other than it exists.

Complex, and unbelievably intricate, the Internet is so vast most governments are still struggling to figure out how to integrate it into their lives. But how did it all start?