Getting Internet Number Resources

How are Internet Number Resources Distributed?

The Internet Assigned Numbers Authority (IANA) distributes large blocks of Internet number resources (IPv4, IPv6, ASNs) to the five Regional Internet Registries (RIRs): AFRINIC, APNIC, ARIN, LACNIC, and the RIPE NCC. The RIRs then allocate smaller blocks to organizations within their defined regions.

How Do I Get Internet Number Resources?

You should first check with the RIR in your region. (See the map to find the RIR for your country.) Each RIR community develops its own regional distribution policies. RIR policies generally set minimum criteria for networks that need Internet number resources. If your network does not meet those criteria, you should approach an upstream provider, also known as a Local Internet Registry (LIR) or Internet Service Provider (ISP). If your network does meet the criteria, you can get resources directly from the RIR. Some regions also have National Internet Registries (NIRs) that work with the RIR to provide resources in their countries.


Regional Internet Registries map

The Internet community develops technical and operational policies that determine how RIRs manage and administer Internet number resources. For a basic overview of regional policies, see the RIR Comparative Policy Overview. See the Policies section for more information on regional and global policy development.

About Internet Number Resources

What are Internet Number Resources?

Internet number resources include Internet Protocol (IP) address space (both IPv4 and IPv6) and Autonomous System Numbers (ASNs). An IP address is a numeric identifier that includes information about how to reach a network location through the Internet routing system. Every device directly connected to the Internet must have an IP address. Every IP address must be unique for devices to connect to the Internet and to each other. An Autonomous System (AS) is a group of IP networks that use a single and clearly defined routing policy. ASNs are globally unique numbers used to identify these groups of networks. ASNs allow an autonomous system to exchange routing information with neighbouring autonomous systems.

What are IPv4 and IPv6?

There are two versions of Internet Protocol in use: IP version 4 (IPv4) and IP version 6 (IPv6). IPv4 was the first version to be widely used, and still accounts for most of today’s Internet traffic. The total size of the IPv4 address pool will not support the growing numbers of Internet devices. IPv6 provides far more addresses than IPv4. IPv6 is deployed in networks all over the globe and is supported by modern operating systems. The main deployment model for IPv6 is “dual stacking,” where operators support both IPv4 and IPv6 in their networks. The two protocols both operate across the Internet and most users will never be aware of which address protocol is responsible for delivering their e-mails or downloading their web pages. Although the IPv6 protocol is different to IPv4, the most important difference between the two is the size of the address pool. Each IPv4 address consists of 32 bits and addresses are often formatted into a dotted decimal notation such as Each byte is a number between 0 and 255. An IPv6 address consists of 128 bits, usually written as eight groups of four hexadecimal characters, such as 2001:DB8::/32. A double colon (::) may replace sets of consecutive zeros.

IP version IPv4 IPv6
Deployed 1981 1999
Address Size 32-bit number 128-bit number
Address Format Dotted Decimal Notation: Hexadecimal Notation: 2001:0DB8:0234:AB00: 0123:4567:8901:ABCD
Number of Addresses 232 = 4,294,967,296 2128 = 340,282,366,920,938,463,463,374,607,431,768,211,456
Examples of Prefix Notation 10/8 (a “/8” block = 1/256th of total IPv4 address space = 224 = 16,777,216 addresses) 2001:0DB8:0234::/48 2600:0000::/12

Like IP addresses, Autonomous System (AS) numbers are important Internet number resources. As the Internet has expanded over time, the original pool of available AS numbers has dwindled, and they are now running out.

As a result, engineers have adjusted the AS number specification from two bytes to four bytes. This means that the pool of AS numbers has grown from around 65,000 to over 4 billion.

Network managers and ICT vendors need to be aware of these changes and act now to ensure their networks and products are compatible with the new AS numbers.