What is the Internet?

What is the Internet?

Strictly speaking, the Internet is a communications protocol, a language which computers use to

talk to each other, called TCP/IP. This language is designed to enable computers to exchange

data reliably and efficiently, though not necessarily quickly.

More generally, the term is used to signify the network of computers connected using TCP/IP: the

connecting wires and the equipment used to route the information (the network infrastructure),

and the computers themselves.

Even more generally, the Internet is often used to indicate the community of users and computers

collectively. Though a very broad definition, this is perhaps the most useful and interesting —

the Internet is really an information-based society.

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Protocols created by the community

The TCP/IP and related protocols that are used across the Internet are designed and agreed upon

by the users and administrators of the individual parts of the Internet: anyone can contribute to

the growth and direction of the Internet, though you do need to know a fair amount of technical

detail to get involved. In this way, the Internet is not so much controlled by an organisation, as

encouraged in a certain direction by its members. It's a kind of open, contributory democracy.

Sometimes, companies will try to force the net to go the way they want, but usually there's enough

resistance from the mass of contributors to only go that way if the idea or direction is good for

the 'net as a whole.

The influence each person has on the direction of the Internet is usually related to their technical

knowledge and reputation, with widely respected techies holding the most power. It's perhaps

more of a technocracy than a traditional democracy.

Protocols serving information to a community

The Internet, as a “network of networks”, consists of many computers, called servers or
hosts, which are linked by communication lines. The administrators of these hosts may make
information or software stored on them publically available, so that others can view, download
or use the data. At the last count (Jul 2007), there were an estimated 489 million hosts [http://
www.isc.org/index.pl?/ops/ds/] connected to the Internet.

Figure 1.1. Growth in number of Internet hosts

However, most Internet-connected computers act only as clients ; they access the data stored
on other servers, but don't store or share any information themselvesi. It's hard to estimate
how many client computers there are in cyberspace, because many connect dynamically or
are hidden behind firewalls, but a conservative estimate (according to Nielsen//Netratings
[http://www.nielsen-netratings.com]) would be more than 800 million, possibly much higher.
According to Internet World Stats [http://www.internetworldstats.com/], nearly 1.5 billion
people have some form of Internet access.
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Dynamic and permanent connections

Clients may be permanently connected (often known as “always-on”), or may connect
dynamically when needed.
Permanent connections are most commonly made through a local area network (LAN) or a
digital subscriber line (DSL or ADSL ), and give instant 24/7 access.
A temporary, dynamic connection such as that provided by a modem link needs to be connected
each time the Internet is used, which can cause a delay. Modem links also tend to be slower than
dedicated digital links, because they use normal voice telephone lines which are not designed
to carry digital signals.
DSL connections also carry a digital signal across wiring designed for analogue signals, but do
so by overlaying a very high frequency signal (well beyond human hearing) onto the normal
connection. This means that not only can the same line carry voice and data simultaneously, but
that for short distances, a much higher bandwidth can be carried.
Dedicated wiring for Internet traffic is most commonly found in companies and other
organisations, where a LAN is used to connect clients and hosts together. Usually, this forms
an enclosed network which connects to the outside world through a single point, which can be
controlled and protected against intrusion and viruses. Connection to this type of network is
normally instantaneous and 'always-on'
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