Internet Protocol
From Simple English Wikipedia, the free encyclopedia
The Internet Protocol is a set of rules for processing packets of information sent between computers on the Internet. Each computer that uses the Internet Protocol has at least one IP address which is like a telephone number for talking to that computer.
This set of rules is like a language, but in Computer science they call it protocol. A board of engineers has defined some of those protocols, which sit on top of each other ( thats called layered architecture). On top of the Internet protocol there is the Transport Control Protocol and the User Datagram Protocol (and some others). Below it, there are protocols of the Network layer, like Ethernet.
At the moment there are two versions of the Internet Protocol. One is called IP Version 4 (IPv4), the other one is called IP Version 6 (IPv6).
[edit] IP address
An IP address is a number given to each computer on the internet. It is like a postal address or telephone number, but for the computer. Internet protocol (IP) defines how communication from one address to another work.
Some computers have the same IP address for a very long time. These IP addresses are called "static IP addresses". Some computers change their IP from time to time. These IP addresses are called "dynamic IP addresses".
[edit] IP Version 4
With IPv4, each address consists of four octets. An octet is a number, that is coded on 8 bits. There are 256 different such numbers. They go from 0 to 255. To make an IP address, one takes 4 such numbers. To translate between an IP address and the name of the computer, a system called Domain Name System is used. It can translate between the number and the IP Address.
With IPv4, some adresses are special, for example 127.0.0.1 (which maps to 'localhost'). This is the local computer. In general, 0 stands for the network, and 255 stats for all hosts on that network (called broadcast address). Computers that are on the same network share 3 of the 4 numbers. A computer can be one more than one network. It can also have several names.
[edit] IP Version 6
Unfortunately, 4 octets are not enough to cover the demand for IP Addresses. There are special IP Version 4 addresses everyone can use. IP Version 6 uses 16 octets (128 bits). So instead of 4 numbers there are now 16 numbers. Also IPv6 addresses are usually written as hexadecimal numbers (8 hexadecimal numbers). They are separated by colons (:). Zeros can be left out.
Only very few people use IPv6 now. The country of Japan changed to IPv6.
