[sig-policy] prop-080: Removal of IPv4 prefix exchange policy

  • To: Policy SIG <sig-policy at apnic dot net>
  • Subject: [sig-policy] prop-080: Removal of IPv4 prefix exchange policy
  • From: Randy Bush <randy at psg dot com>
  • Date: Fri, 29 Jan 2010 03:04:54 -0500
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  • User-agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/22.3 Mule/5.0 (SAKAKI)
      The proposal, 'Removal of IPv4 prefix exchange policy', has been sent to
      the Policy SIG for review. It will be presented at the Policy SIG at
      APNIC 29 in Kuala Lumpur, 1-5 March 2010.
      We invite you to review and comment on the proposal on the mailing list
      before the meeting.
      The comment period on the mailing list before an APNIC meeting is an
      important part of the policy development process. We encourage you to
      express your views on the proposal:
            - Do you support or oppose this proposal?
            - Does this proposal solve a problem you are experiencing? If
              so, tell the community about your situation.
            - Do you see any disadvantages in this proposal?
            - Is there anything in the proposal that is not clear?
            - What changes could be made to this proposal to make it more
      Information about this and other policy proposals is available from:
      Randy, Ching-Heng, and Terence
      prop-080-v001: Removal of IPv4 prefix exchange policy
      Authors:   Guangliang Pan <gpan at apnic dot net>
      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:
      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",
              Section 7, "Historical prefix exchange policy" in "Policies for
              historical Internet resources in the APNIC Whois Database",