________________________________________________________________________ prop-080-v001: Removal of IPv4 prefix exchange policy ________________________________________________________________________ Authors: Guangliang Pan Version: 1 Date: 29 January 2010 1. Introduction ---------------- This is a proposal to remove the policy that currently permits resource holders to return three or more noncontiguous IPv4 address blocks and have the prefixes replaced with a single, larger, contiguous block. 2. Summary of current problem ------------------------------ Current APNIC policy[1] permits organizations to exchange three or more IPv4 prefixes and receive a single portable CIDR range of equal length or one bit shorter. Such exchanges may be requested without the requirement to document the efficiency of existing assignments and the usage rates. At the time this policy was introduced, it served a good purpose: it aimed to encourage return of noncontiguous small historical blocks to help reduce the size of the global routing table. However, as the remaining unallocated IPv4 addresses continue to be depleted, it will become increasingly difficult for APNIC to fulfil requests made under this prefix exchange policy. 3. Situation in other RIRs --------------------------- ARIN has two policies related to exchanging noncontiguous prefixes. For more information, see section 4.6, "Amnesty and Aggregation Requests" and section 4.7, "Aggregation Requests" in the ARIN Number Resource Policy Manual at: https://www.arin.net/policy/nrpm.html AfriNIC, LACNIC and RIPE have no similar prefix exchange policies. 4. Details of the proposal --------------------------- It is proposed that APNIC remove the policy that enables networks to exchange noncontiguous address blocks in exchange for a single, aggregated range. 5. Advantages and disadvantages of the proposal ------------------------------------------------ 5.1 Advantages - It removes a policy responsibility that APNIC will not able to fulfil during the IPv4 exhaustion period. - It prevents organizations taking advantage of the exchange policy to obtain more IPv4 addresses from APNIC by rounding up to the next bit without justification of the need. This is of particular concern as the remaining unallocated IPv4 pool becomes smaller. 5.2 Disadvantages - It prevents organizations willing to renumber and aggregate address blocks from being able to do so. However, given the fragmentation of the global routing table for other reasons during the IPv4 address exhaustion period, this is a minor disadvantage, that will have very little adverse impact on the size of the global routing table. 6. Effect on APNIC members --------------------------- This proposal will prevent APNIC members from exchanging noncontiguous prefixes for a single prefix. However, as noted in the "Disadvantages" section above, this inability to aggregate routes is not likely to have a significant impact on the size of the global routing table during the IPv4 address exhaustion period. 7. Effect on NIRs ------------------ NIR members will also be prevented from exchanging noncontiguous prefixes for a single prefix. 8. References --------------- [1] See: Section 11.4, "Renumbering to promote aggregation" in "Policies for IPv4 address space management in the Asia Pacific region", http://www.apnic.net/policy/add-manage-policy Section 7, "Historical prefix exchange policy" in "Policies for historical Internet resources in the APNIC Whois Database", http://www.apnic.net/policy/historical-resource-policies