Internet Protocol (IP) address is a unique number which identifies the devices that are connected to the Internet. Each device has a unique IP address.
IPv4 is a 32-bit address which defines both network and host address. It is capable of providing four billion unique addresses which are not enough for all the devices in use.
A new version IPv6 has been invented to offer a limitless number of unique address which is capable of providing for about trillions of devices. It is a 128-bit address which has eight sets of four hexadecimal digits and each block is separated by a colon(:).