Internet Protocol (IP) addresses are the unique numeric identifiers assigned to every computer or device that is connected to the Internet. So while we use domain names, for example, www.nashirnet.net, to identify NashirNet website, the computers themselves don’t actually talk to the domain name, they talk to the unique number associated with that domain name.
That number is the IP address.
The original Internet Protocol, IPv4, was developed in the early 1980s and served the global Internet community for more than three decades. IPv4 had a capacity of just over four billion IP addresses, which was enough for the experiment that the Internet started as in the 1980s. But IPv4 is a finite space, and after years of rapid Internet expansion, the pool of available unallocated addresses for IPv4 has been fully allocated to Internet services providers (ISPs) and users.
IPv4 look like this:
192.0.2.53
IPv6, is the next generation of the Internet protocol that has a massively bigger address space than IPv4. Compared to IPv4’s 32-bit address space of four billion addresses, IPv6 has a 128-bit address space, which is 340 decillion addresses.
IPv6 addresses are written in hexadecimal, which can fit more information into fewer digits. Colons separate the segments of IPv6 addresses instead of dots; for example, 2001:0db8::53. In fact, when you see two colons side by side in an IPv6 address, you know that all the segments between them contain only zeros. You would have to expand the example address to 2001:0db8:0000:0000:0000:0000:0000:0053 without those colons.
There are more than seven billion people on the planet, and many of those people want to have more than one device that has network connectivity, and because of the huge increase in the number of users and devices associated with the Internet, along with the limited number of IPv4, it has started to show the problem of lack of adequate addresses to cover this increase.
The Internet Engineering Task Force (IETF) has started since the beginning of the nineties on developing a new version of Internet protocol to avoid this problem, promulgating what is known as version sixth of Internet Protocol (IPv6) which provides a very large number of addresses (approximately 340 trillion trillion trillion addresses) that can cover the expansion of the Internet and its growth for decades.
in addition IPv6 has more additional features compared with the fourth edition.
IP addresses are distributed in a hierarchical system. As the Internet Assigned Numbers Authority (IANA) functions operator, ICANN allocates IP addresses to the five Regional Internet Registries (RIRs) around the world, and the RIRs then allocate smaller IP address blocks to ISPs and other network operators.
From there, the ISPs and other Internet operators assign the addresses to the individual Internet connections used by most computer users.
ICANN’s Board of Directors ratified the policy governing the allocation of IPv6 address space to RIRs in September 2006.
The key policy elements are:
A /12 is a block 1,048,576 times the size of the minimum allocation made by RIRs to ISPs and other network operators. Some ISPs run very large networks and receive blocks thousands of times larger than the minimum, but a /12 allows for at least tens of thousands of allocations to organizations running networks before the block is fully allocated.
To give you a sense of how many IP addresses are in a /12 block: All five RIRs were allocated a /12 of IPv6 address space in 2006. As of the end of 2010, none of them had requested additional address space.
For more information about IP address please use the following links: