APNIC guidelines for IPv6 allocation and assignment requests

APNIC Document identity

Title:APNIC guidelines for IPv6 allocation and assignment requests
Short title:ipv6-guidelines
Document ref:APNIC-114Version:011
Date of original publication:2 July 2004Date of this version:20 July 2023
Review scheduled:n/aObsoletes:apnic-114-v010
Status:ActiveComments:Implements prop-145

About this document

These guidelines are intended to complement the document IPv6 address allocation and assignment policy. These guidelines will be updated from time to time, in consultation with the
Asia Pacific and global Internet communities, to ensure they remain appropriate to the current addressing environment.

Table of contents

Section 1: Background
1.   Introduction
2.   Scope
3.   Additional guidance
4.   Goals of address space management
5.   Application of guidelines

Section 2: General guidelines
6.   Definitions
7.   Sparse Delegation Framework
7.1.    Avoiding Fragmentation
8.   Allocations to LIRs
8.1.   Initial allocation criteria
8.1.1.    A plan for 200 assignments
8.1.2.    Existing LIRs with IPv4 allocations from APNIC or an NIR
8.1.3.   Initial allocations larger than /32
8.1.4.   Expanding allocations received before August 2004
8.1.5.    Supporting documentation
8.2.   Subsequent allocation criteria
8.2.1.    Prior allocations to be used first
8.2.2.   Special circumstances
9.   Portable assignment criteria
9.1.   Initial assignments
9.1.1.  Multihoming assignment
9.1.2.  Internet Exchange assignment
9.1.3.  Critical Infrastructure assignment
9.1.4.  Provider Independent assignment
9.2.   Subsequent assignments
10.   Delegations by LIRs
10.1.   LIR assignments to end sites
10.1.1.   Second opinion request
10.1.2   Supporting documentation
10.2   Sub-allocations by LIRs
11.    Reverse DNS delegation
11.1.   Reverse DNS delegations in ip6.int and ip6.arpa
12.   Registration requirements
12.1.   Updating registration details
12.2.   Registering contact persons

Section 1: Background

1. Introduction

These guidelines are developed within the APNIC community and are consistent with the goals and policies applicable to IPv6 address space management. They are intended to assist organizations requesting IPv6 address space only. Nothing in these guidelines
should be considered to replace or modify any of the specific policies defined in other APNIC documents.


2. Scope

This document applies to the management of global unicast IPv6 public address space in the Asia Pacific region. This document does not apply to IPv4, multicast, or unique local IPv6 unicast addresses, or Autonomous System Numbers. It should be read in
conjunction with other APNIC documents, particularly  Part 3 of APNIC Internet Number Resource Policies.


3. Additional guidance

These guidelines are not intended to be exhaustive. Additional guidance and examples are available from the help information available for each APNIC request form and in FAQs and other information on the APNIC web site:


4. Goals of address space management

In this document, all reference to the goals of address space management refer to the goals described in the IPv6 address allocation and assignment policy, namely:

  • uniqueness;
  • registration;
  • aggregation;
  • conservation;
  • fairness; and
  • minimized overhead.


5. Application of guidelines

This document is primarily intended to guide ISPs when making assignments to their customers or requesting address space from APNIC. The issues discussed in this document reflect many of the considerations used by APNIC in evaluating requests for initial
allocations and subsequent allocations. It is intended that NIRs will either adopt these, or similar, guidelines for their own members.

Section 2: General guidelines

6. Definitions

Terms not defined in this document have the meaning given to them in the APNIC Definition Document and Policy Document.

7. Sparse Delegation Framework

APNIC delegates blocks of IPv6 address space to resource holders according to a “sparse delegation” algorithm. This delegation process is designed to maximize the growth potential for each delegation by maximizing the distance between them. The following
illustration shows the order in which a sequence of 16 delegations would be made in an available free pool using APNIC’s sparse delegation algorithm.  

Sparse Delegation Sequence

 1   |   |   |   |   |   |   |   2   |   |   |   |   |   |   |    
     |   |   |   3   |   |   |       |   |   |   4   |   |   |    
     |   5   |       |   6   |       |   7   |       |   8   |    
     9       10      11      12      13      14      15      16

  The sparse delegation algorithm used, selects the starting address for each new delegation by calculating the mid-point between the next two start addresses that are furthest apart in the free pool. The algorithm works from the beginning address
of the free pool to the end address before returning to the first available slot at the beginning of the pool. The effect is to successively sub-divide each remaining free block in two, the addresses after that point being used for the new delegation
and the preceding addresses being left available for subsequent delegation. In accordance with Section 5.1.2. of APNIC Internet Number Resource Policies, where possible,
subsequent delegations to the same resource holder are made from an adjacent address block by growing the delegation into the free space remaining, unless disaggregated ranges are requested for multiple discrete networks.  

7.1. Avoiding Fragmentation

While the free space between sparse delegations is initially very large, the size of available blocks reduces as more sub-divisions occur. To minimize this effect, APNIC manages its central pool by making similar sized delegations from a number of
sub-pools, with large delegations made from one pool, small delegations made from another, and so on. In this way, the high frequency of smaller delegations will not cause sub-divisions of free space available to large address block holders, as they
are taken from different sub-pools. For more information about the resource ranges managed by APNIC see:



8. Allocations to LIRs

APNIC will allocate IPv6 address space to a network with global or local connectivity, provided the network meets the criteria stated in APNIC Internet Number Resource Policies.

The following networks are examples of the types of organizations that most commonly apply for an IPv6 allocation from APNIC.

This list is not intended to be exhaustive:
  • An organization providing IPv6 connectivity to the global Internet
  • An organization providing IPv6 connectivity to end sites.
  • An organization providing IPv6 access to shared facilities, storage, computing, or other services.
  • A large organization providing IPv6 connectivity to its own group or subsidiaries.

8.1. Initial allocation criteria

To qualify for an initial allocation of IPv6 address space, an organization must meet the criteria stated in section 9.2. of APNIC Internet Number Resource Policies. Under 4) in section 9.2.2,
an organization can choose from one of the two alternative criteria:

  1. Have a plan for making at least 200 assignments to other organizations within two years, OR
  2. Be an existing LIR with IPv4 allocations from APNIC, or from an NIR, which will make IPv6 assignments or sub-allocations to other organizations and announce the allocations in the inter-domain routing system within two years

These two alternative criteria are explained in sections 8.1.1. and 8.1.2. below.

8.1.1. A plan for 200 assignments

An organization must provide a plan to make at least 200 assignments within two years. However, APNIC regards the existence of the plan as a demonstration of the LIR’s readiness to commence IPv6 services and does not assess the feasibility of
the plan.

For example: An LIR with at least 200 customers currently using IPv4 address space can meet the initial allocation criteria of 200 assignments if it plans to provide them with IPv6 connectivity service within two years.

IPv4 sub-allocations made by an LIR to downstream ISPs can be used to justify the corresponding amount of /56 assignments.  

For example: If a CATV provider has 4,000 IP static connection customers in IPv4 and 5% of the customers (200 customers) are expected to subscribe to IPv6 services, then this provider will meet the initial allocation criteria of 200 assignments.
(A /56 can be assigned to end sites using either static or dynamic addressing).

If an LIR assigns a single static IP address in IPv4, the ISP can assign up to a /48 in IPv6. The LIR may also assign a smaller prefix in accordance with recommendations in RFC 6177.

8.1.2. LIRs with existing IPv4 allocations from APNIC or an NIR

To qualify under this criterion, an organization must:

  • Document an existing IPv4 allocation made to it by APNIC, or an NIR
  • Commit to making IPv6 assignments and/or sub-allocations
  • Agree to announce the IPv6 allocation in the routing table within two years

Note: Historical IP ranges do not meet the criteria of being “an existing IPv4 allocation from APNIC, or an NIR”. Historical IP ranges are defined in Section 2.5.2 of APNIC Internet Number Resource Policies.

8.1.3. Initial allocations larger than /32

LIRs can use existing IPv4 customers and IPv4 network infrastructure to justify an initial allocation larger than a /32 by providing documentation on the number of their existing IPv4 users as well as the extent of their IPv4 network infrastructure.
The HD ratio is used to determine the appropriate size of the IPv6 allocation based on IPv4 customer and infrastructure assignments. For more information, refer to Section 9.1 of the APNIC Internet Number Resource Policies.
LIRs are likely to be eligible for an initial allocation if they meet both of the following conditions:

  • They have received an IPv4 allocation as an LIR, or meet the criteria to receive an IPv4 allocation; and
  • They plan to transfer the existing IPv4 infrastructure or customers partly, or wholly, to IPv6 in two years.

LIRs are still requested to provide information on how many /56s they expect to assign within the first two years.

8.1.4. Expanding allocations received before August 2004

Organizations that received an initial allocation of IPv6 can take advantage of the August 2004 policy permitting initial allocations larger than /32. To expand the initial allocation size without needing to meet subsequent allocation criteria,
the LIR must have received its initial allocation before 16 August 2004 and must meet the initial allocation criteria described in Section 9.2 of the “APNIC Internet Number Resource Policies“.
For more information, see: prop-021: Expansion of the initial allocation space for existing IPv6 address space holders.

8.1.5. Supporting documentation

The APNIC IPv6 Allocation Request Form gives LIRs the opportunity to include additional documentation to support the request for an initial IPv6 allocation.

Examples of the types of information an LIR can include in the “Additional information” section of the form to support the request are:
  • network diagrams
  • approximate deployment dates
  • a brief description of IPv6 deployment method (use of IPv6 tunneling, dual stack, etc.)
  • service plans (web hosting, access service, etc.)
  • network equipment information to demonstrate that the LIR has a plan to implement IPv6-ready infrastructure; and
  • IPv4 infrastructure and/or customer information if the LIR chooses the option of using existing IPv4 infrastructure to justify the request (see Section 8.1.2.).

  When requesting an initial allocation from APNIC, network equipment information such as the vendor and model name of an LIR’s equipment, is not mandatory; however, if an LIR requests a large pool of address space for CATV or ADSL operations, APNIC
may ask for information on the network’s equipment.

8.2. Subsequent allocation criteria

8.2.1. Prior allocations to be used first

An LIR is not eligible to receive subsequent allocations until its current assignments reach a HD ratio of 0.94 based on /56 assignments.

8.2.2. Special circumstances

An LIR may request an exception to the HD 0.94 rule when:

  • It has a demonstrated need for an assignment that is larger than the amount of remaining space,
  • It is announcing its existing IPv6 allocation and can demonstrate a need or requirement to build discrete networks,
  • It requires the additional allocation for technical reasons such as for IPv4 to IPv6 transitional technologies, or
  • It can demonstrate other reasons accepted by APNIC as valid circumstance, or in accord with applicable policies.


9. Portable assignment criteria

Organizations with a previously delegated IPv4 assignment from APNIC are eligible for an appropriately sized IPv6 block under Section 9.2.1 of the “APNIC Internet Number Resource Policies“. Organizations
are also able to demonstrate a need for direct assignment of IPv6 address blocks under the following conditions.

  • Multihoming assignment
  • Internet Exchange assignment
  • Critical Infrastructure assignment
  • Provider Independent assignment

9.1. Initial assignments

APNIC will allocate a minimum of a /48 to organizations that meet the following criteria.

9.1.1.  Multihoming assignment
  1. To be eligible for an IPv6 assignment under this policy, an organization needs to be, or plan to be, receiving fulltime connectivity from more than one ISP, and
  2. have one or more of its routing prefixes announced by at least two ISPs.
9.1.2  Internet Exchange assignment
  1. An Internet Exchange Point (IX or IXP) is a layer 1 and layer 2 network structure that interconnects three or more Autonomous Systems (AS) for the purpose of Internet traffic interchange.
  2. Addresses delegated under this policy must be used exclusively to connect participant devices to the Exchange Point.
9.1.3.  Critical Infrastructure assignment
  1. Critical infrastructure assignments are available only to the actual operators of network infrastructure that perform the functions described in the policy.
  2. Examples of Critical Infrastructure networks are listed at 5.9.3 of the IPv6 address allocation and assignment policy.
  3. The maximum assignment made under these terms is /32 per operator.
9.1.4  Provider Independent assignment

Direct assignment of IPv6 addresses is possible where an organization can demonstrate other reasons accepted by APNIC as valid circumstance, or in accord with applicable policies. For example, organizations that can demonstrate;

  1. the network is statically addressed and of a size or complexity that make renumbering operationally impractical, together with evidence that dynamic or multiple addressing options are either not available from the relevant ISP or are unsuitable;
  2. that any future renumbering of the relevant network could potentially interfere with services of a critical medical or civic nature, or
  3. other reasons accepted by APNIC as valid circumstance, or in accord with applicable policies.

Note: A larger address block may be assigned according to demonstrated need. Only one IPv6 address block is to be assigned to an organization upon an initial request; subnets of this block may be assigned by the organization to its different sites if needed.  

9.2. Subsequent assignments

Eligibility for subsequent Provider Independent assignments under Section of the “APNIC Internet Number Resource Policies” is subject to the following conditions:

  • An address block larger than /48 may be assigned if;
    1. the network address plan demonstrates that the need is above a /48 0.94 HD-ratio, or
    2. the network plan is for multiple discrete networks. That is, the organization can demonstrate a need or requirement to build discrete networks, and
    3. the organization can demonstrate its use of the previous assignment generated the minimum possible number of global routing announcements and the maximum aggregation of that block, and
    4. how the subsequent assignment would be managed to minimize the growth of the global IPv6 routing table.


10. Delegations by LIRs

10.1. LIR assignments to end sites

An LIR can assign a /64 to /48 to an end site customer network based on their requirements. The following guidelines may be useful:

  • /64 where it is known that only one subnet is required.
  • /56 for small sites where it is expected only a few subnets will be required within the next two years. Subscribers can receive a /56 when connecting through on-demand or always-on connections such as small office and home office enterprises.
  • /48 for larger sites, or if an end site is expected to grow into a large network.

An LIR must submit a second opinion request to APNIC if it plans to assign more than a /48 to a single end site (see Section 10.1.2 below).

10.1.1. Second opinion request

Currently, the global Internet community considers a /48 assignment to be sufficient address space for an end site. Therefore, when an end site requires an assignment larger than /48, or it requires additional /48 assignments after the initial
assignment, the LIR must first submit a second opinion request.

10.1.2. Supporting documentation

The APNIC Second Opinion Request Form gives LIRs the opportunity to include additional documentation to support the request for an assignment to an end site that is larger than a /48. Examples of the types of information an LIR can include in
the Additional information section of the form to support the request are:

  • Network diagram of an end site
  • Network equipment information
  • Full details to justify multiple /48 assignments to an end site (for example, the number of clients (PCs or other network equipment), or other information which justify multiple /48 assignments)

10.2. Sub-allocations by LIRs

LIRs do not need to submit a second opinion request before making sub-allocations to downstream ISPs (please see Section 8.2 above). However, APNIC encourages LIRs to contact APNIC hostmasters for advice if LIRs are unsure how much address space
to sub-allocate.


11. Reverse DNS delegation

LIRs should maintain reverse DNS delegations for their customers’ networks. If a network is not specifically associated with an LIR then the reverse DNS delegation should be maintained by APNIC. In both IPv4 and IPv6 networks, it is the LIR’s responsibility
to delegate or to maintain PTR records for its customers’ networks. The size of a reverse DNS delegation by an LIR to an end site will usually be a /48, which is the recommended minimum assignment to an end site specified in RFC 6177. However, it is possible
to delegate a prefix longer than /48. Some organizations may delegate such a prefix in their internal network.  

11.1. Reverse DNS delegations in ip6.int and ip6.arpa

As specified in RFC 3596, reverse DNS delegations in the ip6.int tree have been deprecated, and APNIC has now removed all ip6.int reverse delegations from the APNIC Whois Database. For more information, see: Reverse DNS delegations resource guide



12. Registration requirements

LIRs are responsible for promptly and accurately registering their allocations, sub-allocations, and assignments in the APNIC Whois Database, as follows:

  • All allocations and sub-allocations must be registered.
  • Assignments for networks equal to or larger than /48 must be registered.
  • Registration of assignments smaller than /48 is optional and may be registered at the discretion of the LIR and the network administrator.

When an LIR makes a sub-allocation to a downstream ISP, the LIR is responsible for ensuring that assignments from the sub-allocated range are registered in the database; however, the LIR may delegate the responsibility to the downstream ISP. If an LIR
registers an assignment smaller than a /48, it will be counted as a utilized /48 when assessing existing address utilization for future IPv6 allocation requests.

Note: Privacy of customer assignments (prop-007-v001) was implemented in 2004. APNIC policy no longer requires the registration of assignments and sub-allocations to be publicly available. The registration of customer assignments is still required, but will be ‘hidden’ by default.

12.1. Updating registration details

LIRs must update the APNIC Whois Database when any of the registration information changes. This is the responsibility of the LIR concerned, but may be formally delegated to the end user as a condition of the original assignment.

12.2. Registering contact persons

Administrative and technical contact persons must be registered. In addition, it is mandatory to register an Incident Report Team (IRT) object for each allocation and assignment record in the APNIC Whois Database. The registered administrative contact
(admin-c) must be someone who is physically located at the site of the network, subject to the following exceptions:

  • For residential networks or users, the network’s technical contact may be registered as admin-c.
  • For networks in exceptional circumstances that make it impractical to maintain an on-site administrative contact, an off-site person may be registered as the admin-c.
  • The technical contact (tech-c) need not be physically located at the site of the network, but must be a person who is responsible for the day-to-day operation of the network.