High Quality Content by WIKIPEDIA articles! IPv4 address exhaustion is the depletion of the pool of unallocated Internet Protocol Version 4 (IPv4) addresses. The IP address space is managed by the Internet Assigned Numbers Authority (IANA) globally, and by five regional Internet registries (RIR) responsible in their designated territories for assignment to end users and local Internet registries, such as Internet service providers. With IANA`s exhaustion on 31 January 2011, and the RIR APNIC`s exhaustion on 15 April 2011, some parts of the world have already exhausted their IPv4 allocations, and the remaining RIRs are expected to deplete their pools within a few years.