«Contents 1. Introduction 1.1. Overview 2. Definitions 2.1. Internet Registry (IR) 2.2. Regional Internet Registry (RIR) 2.3. National Internet ...»
IPv6 Address Allocation and Assignment
APNIC, ARIN, RIPE NCC
Document ID: ripe-450
Date: February 2009
Obsoletes: ripe-388, ripe-412,, ripe-421
This document defines registry policies for the assignment and allocation of globally unique IPv6
addresses to Internet Service Providers (ISPs) and other organisations. It was developed through
joint discussions among the APNIC, ARIN and RIPE communities.
2.1. Internet Registry (IR)
2.2. Regional Internet Registry (RIR)
2.3. National Internet Registry (NIR)
2.4. Local Internet Registry (LIR)
2.9. End Site
3. Goals of IPv6 address space management
3.7. Minimised Overhead
3.8. Conflict of goals
4. IPv6 Policy Principles
4.1. Address space not to be considered property
4.2. Routability not guaranteed
4.3. Minimum Allocation
4.4. Consideration of IPv4 Infrastructure
5. Policies for allocations and assignments
5.1. Initial allocation 5.1.1. Initial allocation criteria 5.1.2. Initial allocation size
5.2. Subsequent allocation 5.2.1. Subsequent allocation criteria 5.2.2. Applied HD-Ratio 5.2.3. Subsequent Allocation Size
5.3. LIR-to-ISP allocation
5.4. Assignment 5.4.1. Assignment address space size 5.4.2. Assignments shorter than a /48 to a single End Site 5.4.3. Assignment to operator's infrastructure
5.6. Reverse lookup
5.7. Existing IPv6 address space holders
6. Assignments for Internet Experiments
6.1. Defining the experiment
6.3. Non-commercial basis
6.4. Period of the temporary resource registration
6.6. Making the request
7. Assignments for Anycasting TLD Nameservers
9. Appendix A: HD-Ratio
10. Appendix B: Background information
10.2. Why a joint policy
10.3. The size of IPv6's address space
1.1. Overview This document describes policies for the allocation and assignment of globally unique Internet Protocol version 6 (IPv6) address space.
[RFC 4291] designates 2000::/3 to be global unicast address space that the Internet Assigned Numbers Authority (IANA) may allocate to the RIRs. In accordance with [RFC 4291], IANA allocated initial ranges of global unicast IPv6 address space from the 2000::/3 address block to the RIRs. This document concerns the initial and subsequent allocations of the 2000::/3 unicast address space, for which RIRs formulate allocation and assignment policies. All bits to the left of /64 are in scope.
This policy is subject to future review and potential revision, subject to continuing experience in the administration of IPv6.
2. Definitions [Note: some of these definitions will be replaced by definitions from other RIR documents in order to be more consistent.] The following terms and their definitions are of particular importance to the understanding of the goals, environment and policies described in this document.
Responsibility for management of IPv6 address spaces is distributed globally in accordance with the hierarchical structure shown below.
2.1. Internet Registry (IR) An Internet Registry is an organisation that is responsible for distributing IP address space to its members or customers and for registering those distributions. IRs are classified according to their primary function and territorial scope within the hierarchical structure depicted in the figure above.
2.2. Regional Internet Registry (RIR) Regional Internet Registries are established and authorised by respective regional communities and recognised by the IANA to serve and represent large geographical regions. The primary role of RIRs is to manage and distribute public Internet address space within their respective regions.
2.3. National Internet Registry (NIR) A National Internet Registry primarily allocates address space to its members or constituents, which are generally LIRs organised at a national level. NIRs exist mostly in the Asia Pacific region.
2.4. Local Internet Registry (LIR) A Local Internet Registry is an IR that primarily assigns address space to the users of the network services that it provides. LIRs are generally ISPs whose customers are primarily End Users and possibly other ISPs.
2.5. Allocate To “allocate” means to distribute address space to IRs for the purpose of subsequent distribution by them.
2.6. Assign To “assign” means to delegate address space to an ISP or End User for specific use within the Internet infrastructure they operate. Assignments must only be made for specific purposes documented by specific organisations and are not to be sub-assigned to other parties.
2.7. Utilisation The actual usage of addresses within each assignment may be low when compared to IPv4 assignments. In IPv6, "utilisation" is only measured in terms of the bits to the left of the efficiency measurement unit (/56). In other words, "utilisation" effectively refers to the assignment of network prefixes to End Sites and not the number of addresses assigned within individual End Site assignments.
Throughout this document, the term "utilisation" refers to the assignment of network prefixes to End Sites and not the number of addresses assigned within individual subnets within those End Sites.
2.8. HD-Ratio The HD-Ratio is a way of measuring the efficiency of address assignment [RFC 3194 ]. It is an
adaptation of the H-Ratio originally defined in [RFC1715 ] and is expressed as follows:
Log (number of allocated objects) HD = ---------------------------------------------Log (maximum number of allocatable objects) where (in the case of this document) the objects are IPv6 site addresses assigned from an IPv6 prefix of a given size.
2.9. End Site An End Site is defined as an End User (subscriber) who has a business or legal relationship (same
or associated entities) with a service provider that involves:
that service provider assigning address space to the End User that service provider providing transit service for the End User to other sites that service provider carrying the End User's traffic that service provider advertising an aggregate prefix route that contains the End User's assignment
3. Goals of IPv6 address space management
3.1. Goals IPv6 address space is a public resource that must be managed in a prudent manner with regards to the long-term interests of the Internet. Responsible address space management involves balancing a set of sometimes competing goals. The following are the goals relevant to IPv6 address policy.
3.2. Uniqueness Every assignment and/or allocation of address space must guarantee uniqueness worldwide. This is an absolute requirement for ensuring that every public host on the Internet can be uniquely identified.
3.3. Registration Internet address space must be registered in a registry database accessible to appropriate members of the Internet community. This is necessary to ensure the uniqueness of each Internet address and to provide reference information for Internet troubleshooting at all levels, ranging from all RIRs and IRs to End Users.
The goal of registration should be applied within the context of reasonable privacy considerations and applicable laws.
3.4. Aggregation Wherever possible, address space should be distributed in a hierarchical manner, according to the topology of network infrastructure. This is necessary to permit the aggregation of routing information by ISPs and to limit the expansion of Internet routing tables.
This goal is particularly important in IPv6 addressing, where the size of the total address pool creates significant implications for both internal and external routing.
IPv6 address policies should seek to avoid fragmentation of address ranges.
Further, RIRs should apply practices that maximise the potential for subsequent allocations to be made contiguous with past allocations currently held. However, there can be no guarantee of contiguous allocation.
3.5. Conservation Although IPv6 provides an extremely large pool of address space, address policies should avoid unnecessarily wasteful practices. Requests for address space should be supported by appropriate documentation and stockpiling of unused addresses should be avoided.
3.6. Fairness All policies and practices relating to the use of public address space should apply fairly and equitably to all existing and potential members of the Internet community, regardless of their location, nationality, size, or any other factor.
3.7. Minimised overhead It is desirable to minimise the overhead associated with obtaining address space. Overhead includes the need to go back to RIRs for additional space too frequently, the overhead associated with managing address space that grows through a number of small successive incremental expansions rather than through fewer, but larger, expansions.
3.8. Conflict of goals The goals described above will often conflict with each other, or with the needs of individual IRs or End Users. All IRs evaluating requests for allocations and assignments must make judgments, seeking to balance the needs of the applicant with the needs of the Internet community as a whole.
In IPv6 address policy, the goal of aggregation is considered to be the most important.
4. IPv6 Policy Principles To address the goals described in the previous section, the policies in this document discuss and follow the basic principles described below.
4.1. Address space not to be considered property It is contrary to the goals of this document and is not in the interests of the Internet community as a whole for address space to be considered freehold property.
The policies in this document are based upon the understanding that globally unique IPv6 unicast address space is licensed for use rather than owned. Specifically, IP addresses will be allocated and assigned on a license basis, with licenses subject to renewal on a periodic basis. The granting of a license is subject to specific conditions applied at the start or renewal of the license.
RIRs will generally renew licenses automatically, provided requesting organisations are making a “good faith” effort at meeting the criteria under which they qualified for or were granted an allocation or assignment. However, in those cases where a requesting organisation is not using the address space as intended, or is showing bad faith in following through on the associated obligation, RIRs reserve the right to not renew the license.Note that when a license is renewed, the new license will be evaluated under and governed by the applicable IPv6 address policies in place at the time of renewal, which may differ from the policy in place at the time of the original allocation or assignment.
4.2. Routability not guaranteed There is no guarantee that any address allocation or assignment will be globally routable.
However, RIRs must apply procedures that reduce the possibility of fragmented address space which may lead to a loss of routability.
4.3. Minimum allocation RIRs will apply a minimum size for IPv6 allocations to facilitate prefix-based filtering.
The minimum allocation size for IPv6 address space is /32.
4.4. Consideration of IPv4 infrastructure Where an existing IPv4 service provider requests IPv6 space for eventual transition of existing services to IPv6, the number of present IPv4 customers may be used to justify a larger request than would be justified if based solely on the IPv6 infrastructure.
5. Policies for Allocations and Assignments
5.1. Initial allocation 5.1.1. Initial allocation criteria
To qualify for an initial allocation of IPv6 address space, an organisation must:
a) be an LIR;
b) advertise the allocation that they will receive as a single prefix if the prefix is to be used on the Internet;
c) have a plan for making sub-allocations to other organisations and/or End Site assignments within two years.
5.1.2. Initial allocation size Organisations that meet the initial allocation criteria are eligible to receive a minimum allocation of /32.
Organisations may qualify for an initial allocation greater than /32 by submitting documentation that reasonably justifies the request. If so, the allocation size will be based on the number of existing users and the extent of the organisation's infrastructure.
5.2. Subsequent allocation Organisations that hold an existing IPv6 allocation may receive a subsequent allocation in accordance with the following policies.
5.2.1. Subsequent allocation criteria Subsequent allocation will be provided when an organisation (i.e. ISP/LIR) satisfies the evaluation threshold of past address utilisation in terms of the number of sites in units of /56 assignments. The HD-Ratio [RFC 3194] is used to determine the utilisation thresholds that justify the allocation of additional address as described below.
5.2.2. Applied HD-Ratio The HD-Ratio value of 0.94 is adopted as indicating an acceptable address utilisation for justifying the allocation of additional address space. Appendix A provides a table showing the number of assignments that are necessary to achieve an acceptable utilisation value for a given address block size.
5.2.3. Subsequent allocation size When an organisation has achieved an acceptable utilisation for its allocated address space, it is immediately eligible to obtain an additional allocation that results in a doubling of the address space allocated to it. Where possible, the allocation will be made from an adjacent address block, meaning that its existing allocation is extended by one bit to the left.
If an organisation needs more address space, it must provide documentation justifying its requirements for a two-year period. The allocation made will be based on this requirement.