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IP Addressing

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IP Addressing

Internet Protocol (IP) addresses are unique numeric identifiers that are needed by every device that connects to the Internet. The are a shared common resource that must be managed carefully to ensure the continued growth and stability of the Internet. Most of the Internet is currently addressed with IP version 4 (IPv4) addresses. IPv6 addresses are also in use, but not yet to the same extent. IPv6 is a more recent protocol, offering a much larger address pool than IPv4. However, IPv6 is not intended as a direct replacement for IPv4. Rather, the two address protocols are able to be used together across the Internet.

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Concepts and questions

How are IP addresses managed and distributed?

IP addresses are managed by the Internet Assigned Numbers Authority (IANA), which has overall responsibility for the IP address pool, and by the Regional Internet Registries (RIRs) to which IANA distributes large blocks of addresses.

The RIRs manage, distribute, and publicly register IP address (and related Internet number resources, such as Autonomous System Numbers and reverse DNS delegations) within their respective regions. They do this according to policies which are developed within their respective regional communities, through open and bottom-up processes. There are currently five RIRs:

  • AfriNIC, serving the African region
  • APNIC, serving the Asia Pacific region
  • ARIN, serving North Americaand several Caribbean and North Atlantic islands
  • LACNIC, serving Latin America and the Caribbean, and
  • RIPE NCC, serving Europe, the Middle East, and parts of Central Asia

The five RIRs together also form the Number Resource Organization (NRO), which carries out joint activities of the RIRs, including joint technical projects, liaison activities, and policy co-ordination. The following links provide more background on IP address management:

How are IPv6 addresses allocated? Shouldn't addresses be allocated on a geographical basis to ensure that distribution is equitable?

Both IPv4 and IPv6 addresses are allocated to those who show that they need addresses for their networks. For technical reasons the allocation of IP addresses has to follow the topology of the network and not geography or national borders. The Internet cannot work otherwise. Therefore, the addresses are allocated for use in specific networks, as they are required. The RIRs do this within community-developed policies that are designed to ensure that distribution is fair and equitable.

In the early days of the Internet, the method for distributing IP addresses was less formal, which did lead to some organisations receiving disproportionately large address ranges. However, the RIRs were formed to provide a better way of distributing addresses. They have been successful at developing fair and equitable distribution policies. They have also helped to provide stability of the address pool and routing tables throughout a long period of rapid growth.

What happens when IPv4 addresses run out?

Although the pool of available IPv4 addresses is diminishing, the technical community does not expect IPv4 operation will end in the near term. Even if there are no more IPv4 addresses available, the existing IPv4 networks will continue to function. In fact, IPv6 and IPv4 are expected to co-exist for many years to come.

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