Policy Proposal 2002-3: Micro-Assignments for Multihomed Networks - Previous Version [Archived]

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This policy proposal was amended and reposted to PPML on 11/18/2003. Click here to view the amended proposal.

Proposal:

If an end-user is not multi-homed, the minimum justified block of IP address space assigned by ARIN is a /20. If assignments smaller than /20 are needed, end-users should contact their upstream provider.

If an end-user is multi-homed, and has an ARIN assigned ASN, the minimum justified block of IP address space assigned by ARIN is a /22. Such assignment will be made from a reserve block for this purpose. If multi-homed assignments smaller than a /22 are needed, end users should contact their upstream provider.

Discussion:

It has further been argued that should this policy (or something following from it) be endorsed at the meeting, then an assessment should be made of the impact of this policy’s implementation by number of requests and route table impact for 2 consecutive 6 month periods. If the impact is not believed to be problematic, then a proposal should be made to lower the minimum to /23 with the same assessment. Given no problems for /23 then a proposal for /24 as a minimum would be made.

Also, an assessment of the number of allocations that are still multihomed after 12 months should be made to determine whether there is any change in status of these end nets.

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Amended text as posted to PPML on 3/21/2003:

Proposal:

If an end-user is not multi-homed, the minimum block of IP address space assigned by ARIN is a /20. If assignments smaller than /20 are needed, end-users should contact their upstream provider.

If an end-user is multi-homed, and has an ARIN assigned ASN, the minimum block of IP address space assigned by ARIN is a /22. If assignments smaller than a /22 are needed, end users should contact their upstream provider.

Problem Summary:

Many end-user organizations are choosing to multi-home for reliability reasons. At the same time, many are using technologies such as NAT, or load balancers that reduce the need for external IP space. These groups are forced today to take one of two actions:

Use IP space from one of their upstreams on both connections. This can lead to load balancing issues, and also makes the end-user more dependent on the ISP who assigned the space. The ISP’s business problems, for instance could force downtime and/or renumbering.
“Waste” address space (often by not using the technologies that conserve it) in order to qualify for a /20 under the current policy.

In order to allow people to both conserve address space, and reap the benefits of multi-homing the minimum size assignment for those who do multi-home should be made smaller.

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Original text as posted to PPML on September 22, 2002:

Proposal:

ARIN’s current minimum assignment size is a /20. The following is proposed to enable multihomed networks to obtain their IPv4 address space directly from ARIN:

Multihomed networks not meeting ARIN’s current allocation guidelines may receive a properly justified /21-/24 sized network provided they have no other ARIN assigned space, and return all non-portable address space within 3 months of receiving their allocation. No justification (other than being multihomed, having no other allocations, and returning all other non-portable space) is required for a /24.