]> Dataplane.org

Chicago IL 60605 United States of America +1 312 493-0305 jtk@dataplane.org https://dataplane.org/jtk/

Operations and Management Internet Engineering Task Force IPv6 ASN addressing This document describes a method and policy for ASN prefix-based addressing for IPv6.

Introduction This document defines an address allocation system (called "APbA") whereby an Autonomous System (AS) number is embedded as sub-prefix bits of an IPv6 address, resulting in approximately 1.1 quintillion addresses per AS. Advantages of this mechanism include the ability to get allocate AS-specific and unique address space without an allocation protocol or registration process. This system also makes it easy to determine an association between AS and address, which is useful for debugging and auditing purposes. This mechanism draws inspiration from . Unlike that earlier specification however, this system applies specifically to unicast addressing, supports 32-bit ASNs, and provides significantly more addresses per AS. Some administrative challenges identified by remain and questions about the integration into modern technology such as are addressed later in this document.

Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.

Address Space An IPv6 address with the prefix [IANA-assigned 16-bit prefix] indicates that the adress is a APbA address. The embedded AS follows as a sub-prefix. A 16-bit AS is left-padded with 0s. The remaining 96-bit suffix bits are locally significant and defined by the corresponding AS.

APbA address format

Example Consider, for example AS 64496. Written in hex, we get an IPv6 prefix of 3fff:0:fbf0::/32.

Private, Reserved, Special Use, and Unallocated ASNs AS numbers may be reserved for private or special use. They may also be unallocated. These AS designations MUST be maintained when mapped to APbA addresses, which may render these addresses unavailable or inappropriate for public use.

Registry Considerations Internet registries SHOULD provide service functions and support for APdA addresses.

IANA Considerations This memo requests a 16-bit IPv6 address prefix assignment from IANA.

Security Considerations APdA addresses SHOULD have corresponding ROAs if externally and publicly routed on the Internet. Network operators MAY reject APdA route announcments otherwise.

References Normative References Informative References

Acknowledgements The following individuals provided an array of feedback to help improve this document: Roland Dobbins. Any remaining errors or imperfections are the sole responsbility of the document authors.