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The address of a particular computer on
the internet, used to identify it uniquely for communications purposes.
Every computer that sends or receives information on the internet must have
an Ip address, expressed as a 32-bit number, which is attached
to every message that is sent. Thus the recipient of any message has a
return address to which it can reply if necessary. This is especially
important on the web, where a server must know exactly where to send back a
requested page.
According to the current version of the ip
protocol, version 4, the number itself is arranged in four groups of up
to three numbers and has two parts: one identifies the network on which a
machine resides and the other is for the machine itself. Each group is
represented by a number between o and 255, giving numbers like
170.224.17.153. These numbers are translated into the alphabetic names
associated with them (in the above example,
www.economist.com) by a name
server.
Although a huge quantity of individual addresses are
supported by this system, many numbers are reserved for special
purposes and are not available for use by companies or individuals. The
incredible growth of the internet has rapidly depleted the available
numbers, especially those designated for use with small networks (known as
class c addresses). Enter Ip version 6, already implemented in some
operating systems, which will use 128-bit numbers. This new system,
sometimes known as Ipng (for "new generation"), theoretically enables
340,282,366,920, 938,463,463,374,607,431,768,211,456 possible addresses;
that is, 665,570,793,348,866,943,898,599 for each square metre of the Earth.
This should be enough for even the most information-hungry economy. |
