The amount of IPv4 space is just about used up. That means IPv4 addresses are scarce resources. Scarcity can limit the future expansion of the Internet. Those who wish to connect to the world, but do not have a global IP address, cannot do so. This is especially true in the developing world, with less IPv4 space available. A transition to IP version 6 (IPv6) removes this scarcity and balances the IP addresses allocated to each continent.
Countries and continents which have historically not had large access to Internet infrastructure have received fewer IPv4 addresses than countries where the global Internet was rapidly adopted. IPv4 addresses have been allocated based on how many IPs were used in each region. If a continent used most of its IP addresses, it will likely get new IP blocks. This means that developed countries connected to the Internet early and in larger numbers have more IPv4 addresses to use, reuse and reallocate. If the world were to stay with IPv4, the lack of IP addresses allocated to the developing world would create a bottleneck and barrier to developing Internet technologies in those countries.
IP address space is distributed by the Internet Assigned Numbers Authority (IANA). The IANA distributed blocks of IPs (usually a /8) to a Regional Internet Registry (RIR), which then distributed to Internet Service Providers and others. RIRs are:
Current IPv4 IP Address allocation:
As you can see, the USA and Canada alone take up almost half the IPv4 allocation of the whole world, while Africa and Latin America have small slivers of IP space. IPv6 is a whole new ball game. First off, the sheer size of IPv6 address space is so gigantic that most of it has not been allocated at all and is still reserved.
Current IPv6 Allocation for the World
The small slices are all the world’s IPv6 allocation so far.
Each RIR has been assigned a /12 along with a few /23s and other blocks. There has been little need to request more space than these /12s, and because of this, IPv6 RIR allocation is fairly evenly distributed at the moment. As IPv6 usage grows, this may slowly change.
Still, because IPv6 addresses will not become scarce resources, developing countries do not have to worry about not being able to receive the IP addresses they desire as their demand grows. The adoption of IPv6 ensures more equal opportunities to develop the Internet. Current IPv6 allocation, excluding reserved address space, looks like this:
IPv6 Allocation Excluding Reserved Addresses
Finally, to put things into size perspective, all the IPv4 address space is 2^32 = 4,294,967,296 IP addresses. Every IPv6 RIR has been assigned more than a /12. A single /12 has 2^52 = 4,503,599,627,370,496 /64s! Each /64 contains 2^64 IP addresses. Comparing 2^32 and 2^52 visual is meaningless, the IPv4 number doesn’t even render:
Download our Subnet Cheat Sheet for all the essential information you need to quickly perform subnet calculations in your head.If you want to learn more about networking and get the Cisco CCNA certification, we highly recommend the Cisco CCNA Gold Bootcamp as your CCNA training course. The CCNA is by far the most in-demand networking certification by employers, and the Gold Bootcamp is the highest rated Cisco course online. It has an average rating of 4.8 from over 30,000 public reviews: