What is IPv4 address?

The original internet addressing system is called 'Internet Protocol, Version 4' (IPv4), and it has numbered the computers of the Internet successfully for years. By employing 32-bits of recombined digits, IPv4 has a maximum of 4.3 billion possible addresses.

Now, while 4.3 billion addresses might seem plentiful, the Internet was going to exceed this number of devices by the end of 2012. Every computer, every cell phone, every iPad, every printer, every Playstation, and even soda machines require an IP address. There are not enough IPv4 addresses for all these devices!

Good news: a new internet addressing system is here, and it will fill our need for more computer addresses.

Internet Protocol version 6 (IPv6) is currently being rolled out across the globe, and its enlarged addressing system will fix the limitation of IPv4. You see, IPv6 uses 128 bits instead of 32 bits for its addresses, creating 3.4 x 10^38 possible addresses (that is a 'trillion-trillion-trillion'; undecillion' is an obscure term that describes this impossibly large number).

These trillions of new IPv6 addresses will meet the internet demand for the foreseeable future.

What is IPv4?

IPv4 (Internet Protocol Version 4) is the fourth revision of the Internet Protocol (IP) used to to identify devices on a network through an addressing system. The Internet Protocol is designed for use in interconnected systems of packet-switched computer communication networks (see RFC:791).

IPv4 is the most widely deployed Internet protocol used to connect devices to the Internet. IPv4 uses a 32-bit address scheme allowing for a total of 2^32 addresses (just over 4 billion addresses).  With the growth of the Internet it is expected that the number of unused IPv4 addresses will eventually run out because every device -- including computers, smartphones and game consoles -- that connects to the Internet requires an address.

Difference between IPv4 and IPv6 addresses

One of the differences between IPv4 and IPv6 is the appearance of the IP addresses. IPv4 uses four 1 byte decimal numbers, separated by a dot (i.e., while IPv6 uses hexadecimal numbers that are separated by colons (i.e. fe80::d4a8:6435:d2d8:d9f3b11).

  • IPv6 address consists of 128 bits, while an IPv4 address consists of only 32.
  • IPv6 has a lot more usable addresses compared to IPv4.
  • IPv6 is better suited to mobile networks than IPv4.
  • IPv6 addresses are represented in a hexadecimal, colon-separated notation(i.e. fe80::d4a8:6435:d2d8:d9f3b11), while IPv4 address use the dot-decimal notation (
  • IPv6 allows for bigger payloads than what is allowed in IPv4.

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