Reclaiming Unused IPv4 Address Space

The 2018 APNIC Survey showed that not all organisations are ready to deploy IPv6. While APNIC supports IPv6 deployment, it must continue to support access to IPv4 address space. 57% of survey participants said APNIC should reclaim or recover unused address space in response to IPv4 exhaustion.

APNIC began this work in 2019 by defining unused IPv4 address space as 'a /24 or more of a delegated prefix that is no longer needed by its registered holder'. To assess whether a prefix is still needed, APNIC agreed to contact Members whose IPv4 delegations have a /24 or more that does not appear in the global routing system.

At APNIC 49 in 2020, APNIC Chief Scientist Geoff Huston presented an analysis of routing and addressing in the Internet. He showed that the global pool of allocated but unadvertised IPv4 address space was then about 50 /8s, and growing slowly.

In July 2019, APNIC staff analysed the pool of unadvertised IPv4 delegations and grouped them by the policy that applies to each. The unadvertised space could be handled as follows:

APNIC planned to complete this work by the end of 2020 and to share progress with the community through the APNIC Blog and at APNIC 50.

(Source: APNIC Blog)