Waht the Internet is

Often people tend to identify the Internet with the Web (also called WWW, that actually stands for "World Wide Web"). As a matter of fact though, the Web is only one part of the Internet. Among the other main services the Internet provides are:
e-mail, newsgroups, mailing lists, intranets, newsgroups, telecommunications services, privately owned networks, IRC (chat services), instant messaging, etc.

The WWW however is definitely the most trafficked part of the Internet. It is made up of millions of webpages that use the HTTP protocol, a system based on hypertext, whose most widely used formatting language is HTML.

To put it very simply, the Internet is an improvement of the traditional telephone network. The old telephone cables used to have a very narrow band, enough to carry the 50-60 bits necessary for a typical phone call. With modern optic fibers the amount of bits has been multiplied by 100,000 times. With so much "room" available, the remaining space has been filled up with digital data, the very substance of the Internet. As a result, now telephone lines carry more data than voice.

The Internet as we know it today is a world-wide system of computer networks where users, at any one computer (called client) connected to the net, can get information from a number of servers that host the information or data requested.

Physically, the Internet uses a portion of the total resources of the currently existing public telecommunications networks. Technically, what makes the Internet so special is its use of a set of protocols called TCP/IP, also used for intranets and extranets.

*** Do you want to see an interesting demostration of how Internet connections work? Look up this website, where you can actually trace your requests from Italy to any website: it will tell you how long it takes to reach your target and also the route followed, plus a map of the actual route.

*** Click on the images below to see an example of the European backbones

These and other very interesting Internet maps can be found at www.cybergeography.org

Did you know that the space available on the Internet is going to be filled up? The fact is that the Internet, as it is conceived now, can only host 4.2 billion domains (let's say websites): this is because each domain is identified by a 32-digit binary code which can hold only 4.2 possible different combinations.
Only a few hundred million domains are still available, till scientists do not come up with a solution, which, however, is not so simple to implement.

More in detail we can say that the general architecture of the net is based on nodes - the smallest unit of the whole system - which are single computers that are part of a single network and host digital information and data. They are the servers where, for example, are kept the webpages people look for when surfing in the Internet.
The nodes are connected by routing systems to smaller networks, which are connected to other larger networks and then back to the computer.

So, what practically happens is that the Internet user connects to a ISP (Internet Service Provider) which connects to another ISP and so on till the node where the data requested are hosted.

However, not all networks and connections are the same: there exist a hierarchy in the system. For example, IAPs (Internet Access Provider) manage small portions of traffic; instead ITPs (Internet Transit Provider) take care of handling very large volumes of traffic, these are better known as backbones, the real superhighways where billions of bytes travel from one part of the world to another.

When ISPs connect to each other, there is a system of routers that automatically direct the traffic on the best possible route for the packets so that they get to their destination. Throughout the globe there are a number of NAPs (Network Access Point): their task is to manage the various national backbones, i.e. the part of the route followed by the packets when they travel long distances. Of course the connection speed varies according to whether the data travel on backbones or smaller routes.