Internet-Draft Variable IID July 2024
Mishra, et al. Expires 24 January 2025 [Page]
Workgroup:
6MAN Working Group
Internet-Draft:
draft-mishra-6man-variable-iids-01
Updates:
RFC2464, RFC4291, RFC4861, RFC4862, RFC7136, RFC8273 (if approved)
Published:
Intended Status:
Standards Track
Expires:
Authors:
G. Mishra
Verizon Inc.
D. Shytyi
6WIND
A. Petrescu
CEA, LIST
N. Kottapalli
Ciena
D. Mudric
Ciena

SLAAC Prefixes with Variable Interface ID (IID)

Abstract

This draft proposes the use of a longer prefixes in PIO for SLAAC allowing a maximum prefix length of /80 with an IID of 48 bits. This would eliminate the race to the bottom concerns.

This implementation uses the RA/PIO bits to carry the variable IID to ensure backwards compatibility.

In the past, various IPv6 addressing models have been proposed based on a subnet hierarchy embedding a 64-bit prefix. The last remnant of IPv6 classful addressing is a inflexible interface identifier boundary at /64. This document proposes flexibility to the fixed position of that boundary for interface addressing.

Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at https://datatracker.ietf.org/drafts/current/.

Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."

This Internet-Draft will expire on 24 January 2025.

Table of Contents

1. Introduction

The Variable IID problem statement document [I-D.mishra-v6ops-variable-iids-problem-statement] goes into detail surrounding the problem we are trying to solve with this document. There are many reasons that have come up as to why the fixed boundary must be changed and the two leading issues are firstly parity between addressing mechanisms SLAAC, DHCPv6 and Static, and secondly that Access Networks (AN) Wireless Mobile Broadband (MBB) and Wireline Fixed Broadband (FBB) provisioning systems are fixed at /64 and cannot be changed and thus shorter prefixes as a solution is not possible. Thus the only solution is variable IID. It is recommended to read the problem statement document before this solutions space document.

The lowest common denominator method of configuration for IPv6 nodes is SLAAC [RFC4862], which is carefully designed to allow any prefix length and any interface identifier (IID) length, provided that they do not total more than 128 bits. Until now, specifications of "IPv6 over foo" mappings, starting with [RFC2464], have specified an IID length of 64 bits, consistent with the value specified by [RFC4291].

This document allows a router to announce an IID length other than 64 on a given link, and updates RFC [RFC4291], [RFC2464] (and numerous other "IPv6 over foo" documents TBD), and [RFC4862] accordingly. It extends [RFC4861] by defining a new "IID length" mechanism in RA messages.

This document proposes longer prefixes in PIO for SLAAC allowing a maximum prefix lenght of /80 and an IID for 48 bits. The recommendation would eliminate the race to the bottom. The implementaion for backwards compatibility leverages the use of 6 LSB bits of the 32 bit Reserved2 field in the PIO options header which today per RFC 4861 is initialized to 0 and is ignored by the receiver. Since the PIO Reserved2 field is initialized to 0 by the sender and is ignored by the receiver, it allows for backwards compatibility for Unmodified hosts.

2. Terminology

Terminolgoy used in defining the IPv6-Only Edge specification.

Modified Host: Supports this specification

Unmodified Host: Does not support this specification

3. Modified Procedures

The predefined IID length specified by [RFC4291], [RFC2464], etc. is used to configure the link-local IPv6 address of a node exactly as described in [RFC4862].

On a link where variable IID length is not supported, the predefined IID length will continue to be used to configure all other addresses using SLAAC.

On a link where variable IID length is supported, each modified router will include an "IID length" indication in every RA/PIO message with the A bit set. This will override the value defined in [RFC2464] (etc.) and in [RFC4291], for the prefix concerned.

In this variable IID specification it is recommended to put the IID length in the 6 LSB bits of the 32 Reserved2 field of the PIO for signaling to Modified hosts supporting variable IID that the prefix being advertised is not 64 bits.

00000000 would mean 64, i.e. no change and backwards compatible. Any other value would define an IID length in bits. Values less than 48 (00110000) are NOT RECOMMENDED. Values greater than 64 are impossible.

Exmaple of valid IID Length value: "00111011" /69 with 59 bit IID

(Note: Reserved1 is not available - see [RFC8425].)

When a modified node receives an "IID length" less than 64, it will use that value instead of the default for all unicast address autoconfiguration under that prefix, except link-local.

4. Operational Considerations

- Unmodified hosts and unmodified routers: no change, all use 64-bit IIDs.

- Modified hosts and unmodified routers: no change, all use 64-bit IIDs.

- Modified routers and unmodified hosts: no change, all use 64-bit IIDs.

- Modified hosts and modified routers: configure to use longer prefixes and shorter IIDs if desired.

Mixure of Modifiled and Unmodified hosts router on a link is not recommmended.

5. Security Considerations

The administrator should be aware to maintain 64 bit interface identifier for privacy when connected directly to the internet so that entropy for optimal heuristics are maintained for security.

Variable length interface identifier shorter than 64 bits should be used within networks where there there are out-of-band guarantees that the hosts are trusted (e.g. corporate intranets and private networks).

6. IANA Considerations

IANA Request for RA PIO registry for RESERVE2

7. Contributors

Brian Carpenter.

8. Acknowledgements

9. References

9.1. Normative References

[I-D.bourbaki-6man-classless-ipv6]
Bourbaki, N., "IPv6 is Classless", Work in Progress, Internet-Draft, draft-bourbaki-6man-classless-ipv6-10, , <https://datatracker.ietf.org/doc/html/draft-bourbaki-6man-classless-ipv6-10>.
[I-D.ietf-6lo-6lobac]
Lynn, K., Martocci, J., Neilson, C., and S. Donaldson, "Transmission of IPv6 over Master-Slave/Token-Passing (MS/TP) Networks", Work in Progress, Internet-Draft, draft-ietf-6lo-6lobac-08, , <https://datatracker.ietf.org/doc/html/draft-ietf-6lo-6lobac-08>.
[I-D.ietf-6lowpan-btle]
Nieminen, J., Savolainen, T., Isomaki, M., Patil, B., Shelby, Z., and C. Gomez, "Transmission of IPv6 Packets over BLUETOOTH Low Energy", Work in Progress, Internet-Draft, draft-ietf-6lowpan-btle-12, , <https://datatracker.ietf.org/doc/html/draft-ietf-6lowpan-btle-12>.
[I-D.mishra-v6ops-variable-iids-problem-statement]
Mishra, G., Shytyi, D., Petrescu, A., Kottapalli, N., and D. Mudric, "SLAAC Prefixes with Variable Interface ID (IID) Problem Statement", Work in Progress, Internet-Draft, draft-mishra-v6ops-variable-iids-problem-statement-01, , <https://datatracker.ietf.org/api/v1/doc/document/draft-mishra-v6ops-variable-iids-problem-statement/>.
Templin, F., "Asymmetric Extended Route Optimization (AERO)", Work in Progress, Internet-Draft, draft-templin-aerolink-82, , <https://datatracker.ietf.org/doc/html/draft-templin-aerolink-82>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
[RFC2450]
Hinden, R., "Proposed TLA and NLA Assignment Rule", RFC 2450, DOI 10.17487/RFC2450, , <https://www.rfc-editor.org/info/rfc2450>.
[RFC2464]
Crawford, M., "Transmission of IPv6 Packets over Ethernet Networks", RFC 2464, DOI 10.17487/RFC2464, , <https://www.rfc-editor.org/info/rfc2464>.
[RFC2467]
Crawford, M., "Transmission of IPv6 Packets over FDDI Networks", RFC 2467, DOI 10.17487/RFC2467, , <https://www.rfc-editor.org/info/rfc2467>.
[RFC2470]
Crawford, M., Narten, T., and S. Thomas, "Transmission of IPv6 Packets over Token Ring Networks", RFC 2470, DOI 10.17487/RFC2470, , <https://www.rfc-editor.org/info/rfc2470>.
[RFC2492]
Armitage, G., Schulter, P., and M. Jork, "IPv6 over ATM Networks", RFC 2492, DOI 10.17487/RFC2492, , <https://www.rfc-editor.org/info/rfc2492>.
[RFC2497]
Souvatzis, I., "Transmission of IPv6 Packets over ARCnet Networks", RFC 2497, DOI 10.17487/RFC2497, , <https://www.rfc-editor.org/info/rfc2497>.
[RFC2526]
Johnson, D. and S. Deering, "Reserved IPv6 Subnet Anycast Addresses", RFC 2526, DOI 10.17487/RFC2526, , <https://www.rfc-editor.org/info/rfc2526>.
[RFC2529]
Carpenter, B. and C. Jung, "Transmission of IPv6 over IPv4 Domains without Explicit Tunnels", RFC 2529, DOI 10.17487/RFC2529, , <https://www.rfc-editor.org/info/rfc2529>.
[RFC2590]
Conta, A., Malis, A., and M. Mueller, "Transmission of IPv6 Packets over Frame Relay Networks Specification", RFC 2590, DOI 10.17487/RFC2590, , <https://www.rfc-editor.org/info/rfc2590>.
[RFC2710]
Deering, S., Fenner, W., and B. Haberman, "Multicast Listener Discovery (MLD) for IPv6", RFC 2710, DOI 10.17487/RFC2710, , <https://www.rfc-editor.org/info/rfc2710>.
[RFC3056]
Carpenter, B. and K. Moore, "Connection of IPv6 Domains via IPv4 Clouds", RFC 3056, DOI 10.17487/RFC3056, , <https://www.rfc-editor.org/info/rfc3056>.
[RFC3146]
Fujisawa, K. and A. Onoe, "Transmission of IPv6 Packets over IEEE 1394 Networks", RFC 3146, DOI 10.17487/RFC3146, , <https://www.rfc-editor.org/info/rfc3146>.
[RFC3177]
IAB and IESG, "IAB/IESG Recommendations on IPv6 Address Allocations to Sites", RFC 3177, DOI 10.17487/RFC3177, , <https://www.rfc-editor.org/info/rfc3177>.
[RFC3306]
Haberman, B. and D. Thaler, "Unicast-Prefix-based IPv6 Multicast Addresses", RFC 3306, DOI 10.17487/RFC3306, , <https://www.rfc-editor.org/info/rfc3306>.
[RFC3315]
Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins, C., and M. Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, , <https://www.rfc-editor.org/info/rfc3315>.
[RFC3513]
Hinden, R. and S. Deering, "Internet Protocol Version 6 (IPv6) Addressing Architecture", RFC 3513, DOI 10.17487/RFC3513, , <https://www.rfc-editor.org/info/rfc3513>.
[RFC3587]
Hinden, R., Deering, S., and E. Nordmark, "IPv6 Global Unicast Address Format", RFC 3587, DOI 10.17487/RFC3587, , <https://www.rfc-editor.org/info/rfc3587>.
[RFC3590]
Haberman, B., "Source Address Selection for the Multicast Listener Discovery (MLD) Protocol", RFC 3590, DOI 10.17487/RFC3590, , <https://www.rfc-editor.org/info/rfc3590>.
[RFC3627]
Savola, P., "Use of /127 Prefix Length Between Routers Considered Harmful", RFC 3627, DOI 10.17487/RFC3627, , <https://www.rfc-editor.org/info/rfc3627>.
[RFC3756]
Nikander, P., Ed., Kempf, J., and E. Nordmark, "IPv6 Neighbor Discovery (ND) Trust Models and Threats", RFC 3756, DOI 10.17487/RFC3756, , <https://www.rfc-editor.org/info/rfc3756>.
[RFC3775]
Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in IPv6", RFC 3775, DOI 10.17487/RFC3775, , <https://www.rfc-editor.org/info/rfc3775>.
[RFC3810]
Vida, R., Ed. and L. Costa, Ed., "Multicast Listener Discovery Version 2 (MLDv2) for IPv6", RFC 3810, DOI 10.17487/RFC3810, , <https://www.rfc-editor.org/info/rfc3810>.
[RFC3956]
Savola, P. and B. Haberman, "Embedding the Rendezvous Point (RP) Address in an IPv6 Multicast Address", RFC 3956, DOI 10.17487/RFC3956, , <https://www.rfc-editor.org/info/rfc3956>.
[RFC3972]
Aura, T., "Cryptographically Generated Addresses (CGA)", RFC 3972, DOI 10.17487/RFC3972, , <https://www.rfc-editor.org/info/rfc3972>.
[RFC4039]
Park, S., Kim, P., and B. Volz, "Rapid Commit Option for the Dynamic Host Configuration Protocol version 4 (DHCPv4)", RFC 4039, DOI 10.17487/RFC4039, , <https://www.rfc-editor.org/info/rfc4039>.
[RFC4086]
Eastlake 3rd, D., Schiller, J., and S. Crocker, "Randomness Requirements for Security", BCP 106, RFC 4086, DOI 10.17487/RFC4086, , <https://www.rfc-editor.org/info/rfc4086>.
[RFC4193]
Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast Addresses", RFC 4193, DOI 10.17487/RFC4193, , <https://www.rfc-editor.org/info/rfc4193>.
[RFC4213]
Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms for IPv6 Hosts and Routers", RFC 4213, DOI 10.17487/RFC4213, , <https://www.rfc-editor.org/info/rfc4213>.
[RFC4291]
Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture", RFC 4291, DOI 10.17487/RFC4291, , <https://www.rfc-editor.org/info/rfc4291>.
[RFC4338]
DeSanti, C., Carlson, C., and R. Nixon, "Transmission of IPv6, IPv4, and Address Resolution Protocol (ARP) Packets over Fibre Channel", RFC 4338, DOI 10.17487/RFC4338, , <https://www.rfc-editor.org/info/rfc4338>.
[RFC4380]
Huitema, C., "Teredo: Tunneling IPv6 over UDP through Network Address Translations (NATs)", RFC 4380, DOI 10.17487/RFC4380, , <https://www.rfc-editor.org/info/rfc4380>.
[RFC4429]
Moore, N., "Optimistic Duplicate Address Detection (DAD) for IPv6", RFC 4429, DOI 10.17487/RFC4429, , <https://www.rfc-editor.org/info/rfc4429>.
[RFC4548]
Gray, E., Rutemiller, J., and G. Swallow, "Internet Code Point (ICP) Assignments for NSAP Addresses", RFC 4548, DOI 10.17487/RFC4548, , <https://www.rfc-editor.org/info/rfc4548>.
[RFC4692]
Huston, G., "Considerations on the IPv6 Host Density Metric", RFC 4692, DOI 10.17487/RFC4692, , <https://www.rfc-editor.org/info/rfc4692>.
[RFC4861]
Narten, T., Nordmark, E., Simpson, W., and H. Soliman, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, DOI 10.17487/RFC4861, , <https://www.rfc-editor.org/info/rfc4861>.
[RFC4862]
Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless Address Autoconfiguration", RFC 4862, DOI 10.17487/RFC4862, , <https://www.rfc-editor.org/info/rfc4862>.
[RFC4887]
Thubert, P., Wakikawa, R., and V. Devarapalli, "Network Mobility Home Network Models", RFC 4887, DOI 10.17487/RFC4887, , <https://www.rfc-editor.org/info/rfc4887>.
[RFC4941]
Narten, T., Draves, R., and S. Krishnan, "Privacy Extensions for Stateless Address Autoconfiguration in IPv6", RFC 4941, DOI 10.17487/RFC4941, , <https://www.rfc-editor.org/info/rfc4941>.
[RFC4944]
Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, "Transmission of IPv6 Packets over IEEE 802.15.4 Networks", RFC 4944, DOI 10.17487/RFC4944, , <https://www.rfc-editor.org/info/rfc4944>.
[RFC5072]
Varada, S., Ed., Haskins, D., and E. Allen, "IP Version 6 over PPP", RFC 5072, DOI 10.17487/RFC5072, , <https://www.rfc-editor.org/info/rfc5072>.
[RFC5121]
Patil, B., Xia, F., Sarikaya, B., Choi, JH., and S. Madanapalli, "Transmission of IPv6 via the IPv6 Convergence Sublayer over IEEE 802.16 Networks", RFC 5121, DOI 10.17487/RFC5121, , <https://www.rfc-editor.org/info/rfc5121>.
[RFC5214]
Templin, F., Gleeson, T., and D. Thaler, "Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)", RFC 5214, DOI 10.17487/RFC5214, , <https://www.rfc-editor.org/info/rfc5214>.
[RFC5375]
Van de Velde, G., Popoviciu, C., Chown, T., Bonness, O., and C. Hahn, "IPv6 Unicast Address Assignment Considerations", RFC 5375, DOI 10.17487/RFC5375, , <https://www.rfc-editor.org/info/rfc5375>.
[RFC5453]
Krishnan, S., "Reserved IPv6 Interface Identifiers", RFC 5453, DOI 10.17487/RFC5453, , <https://www.rfc-editor.org/info/rfc5453>.
[RFC5533]
Nordmark, E. and M. Bagnulo, "Shim6: Level 3 Multihoming Shim Protocol for IPv6", RFC 5533, DOI 10.17487/RFC5533, , <https://www.rfc-editor.org/info/rfc5533>.
[RFC5535]
Bagnulo, M., "Hash-Based Addresses (HBA)", RFC 5535, DOI 10.17487/RFC5535, , <https://www.rfc-editor.org/info/rfc5535>.
[RFC5692]
Jeon, H., Jeong, S., and M. Riegel, "Transmission of IP over Ethernet over IEEE 802.16 Networks", RFC 5692, DOI 10.17487/RFC5692, , <https://www.rfc-editor.org/info/rfc5692>.
[RFC5942]
Singh, H., Beebee, W., and E. Nordmark, "IPv6 Subnet Model: The Relationship between Links and Subnet Prefixes", RFC 5942, DOI 10.17487/RFC5942, , <https://www.rfc-editor.org/info/rfc5942>.
[RFC5969]
Townsley, W. and O. Troan, "IPv6 Rapid Deployment on IPv4 Infrastructures (6rd) -- Protocol Specification", RFC 5969, DOI 10.17487/RFC5969, , <https://www.rfc-editor.org/info/rfc5969>.
[RFC6052]
Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X. Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052, DOI 10.17487/RFC6052, , <https://www.rfc-editor.org/info/rfc6052>.
[RFC6126]
Chroboczek, J., "The Babel Routing Protocol", RFC 6126, DOI 10.17487/RFC6126, , <https://www.rfc-editor.org/info/rfc6126>.
[RFC6146]
Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful NAT64: Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers", RFC 6146, DOI 10.17487/RFC6146, , <https://www.rfc-editor.org/info/rfc6146>.
[RFC6164]
Kohno, M., Nitzan, B., Bush, R., Matsuzaki, Y., Colitti, L., and T. Narten, "Using 127-Bit IPv6 Prefixes on Inter-Router Links", RFC 6164, DOI 10.17487/RFC6164, , <https://www.rfc-editor.org/info/rfc6164>.
[RFC6177]
Narten, T., Huston, G., and L. Roberts, "IPv6 Address Assignment to End Sites", BCP 157, RFC 6177, DOI 10.17487/RFC6177, , <https://www.rfc-editor.org/info/rfc6177>.
[RFC6296]
Wasserman, M. and F. Baker, "IPv6-to-IPv6 Network Prefix Translation", RFC 6296, DOI 10.17487/RFC6296, , <https://www.rfc-editor.org/info/rfc6296>.
[RFC6437]
Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme, "IPv6 Flow Label Specification", RFC 6437, DOI 10.17487/RFC6437, , <https://www.rfc-editor.org/info/rfc6437>.
[RFC6583]
Gashinsky, I., Jaeggli, J., and W. Kumari, "Operational Neighbor Discovery Problems", RFC 6583, DOI 10.17487/RFC6583, , <https://www.rfc-editor.org/info/rfc6583>.
[RFC6741]
Atkinson, RJ. and SN. Bhatti, "Identifier-Locator Network Protocol (ILNP) Engineering Considerations", RFC 6741, DOI 10.17487/RFC6741, , <https://www.rfc-editor.org/info/rfc6741>.
[RFC6877]
Mawatari, M., Kawashima, M., and C. Byrne, "464XLAT: Combination of Stateful and Stateless Translation", RFC 6877, DOI 10.17487/RFC6877, , <https://www.rfc-editor.org/info/rfc6877>.
[RFC7084]
Singh, H., Beebee, W., Donley, C., and B. Stark, "Basic Requirements for IPv6 Customer Edge Routers", RFC 7084, DOI 10.17487/RFC7084, , <https://www.rfc-editor.org/info/rfc7084>.
[RFC7094]
McPherson, D., Oran, D., Thaler, D., and E. Osterweil, "Architectural Considerations of IP Anycast", RFC 7094, DOI 10.17487/RFC7094, , <https://www.rfc-editor.org/info/rfc7094>.
[RFC7217]
Gont, F., "A Method for Generating Semantically Opaque Interface Identifiers with IPv6 Stateless Address Autoconfiguration (SLAAC)", RFC 7217, DOI 10.17487/RFC7217, , <https://www.rfc-editor.org/info/rfc7217>.
[RFC7278]
Byrne, C., Drown, D., and A. Vizdal, "Extending an IPv6 /64 Prefix from a Third Generation Partnership Project (3GPP) Mobile Interface to a LAN Link", RFC 7278, DOI 10.17487/RFC7278, , <https://www.rfc-editor.org/info/rfc7278>.
[RFC7296]
Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. Kivinen, "Internet Key Exchange Protocol Version 2 (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, , <https://www.rfc-editor.org/info/rfc7296>.
[RFC7368]
Chown, T., Ed., Arkko, J., Brandt, A., Troan, O., and J. Weil, "IPv6 Home Networking Architecture Principles", RFC 7368, DOI 10.17487/RFC7368, , <https://www.rfc-editor.org/info/rfc7368>.
[RFC7421]
Carpenter, B., Ed., Chown, T., Gont, F., Jiang, S., Petrescu, A., and A. Yourtchenko, "Analysis of the 64-bit Boundary in IPv6 Addressing", RFC 7421, DOI 10.17487/RFC7421, , <https://www.rfc-editor.org/info/rfc7421>.
[RFC7788]
Stenberg, M., Barth, S., and P. Pfister, "Home Networking Control Protocol", RFC 7788, DOI 10.17487/RFC7788, , <https://www.rfc-editor.org/info/rfc7788>.
[RFC8064]
Gont, F., Cooper, A., Thaler, D., and W. Liu, "Recommendation on Stable IPv6 Interface Identifiers", RFC 8064, DOI 10.17487/RFC8064, , <https://www.rfc-editor.org/info/rfc8064>.
[RFC8084]
Fairhurst, G., "Network Transport Circuit Breakers", BCP 208, RFC 8084, DOI 10.17487/RFC8084, , <https://www.rfc-editor.org/info/rfc8084>.
[RFC8156]
Mrugalski, T. and K. Kinnear, "DHCPv6 Failover Protocol", RFC 8156, DOI 10.17487/RFC8156, , <https://www.rfc-editor.org/info/rfc8156>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
[RFC8425]
Troan, O., "IANA Considerations for IPv6 Neighbor Discovery Prefix Information Option Flags", RFC 8425, DOI 10.17487/RFC8425, , <https://www.rfc-editor.org/info/rfc8425>.

9.2. Informative References

[RFC8273]
Brzozowski, J. and G. Van de Velde, "Unique IPv6 Prefix per Host", RFC 8273, DOI 10.17487/RFC8273, , <https://www.rfc-editor.org/info/rfc8273>.

Authors' Addresses

Gyan Mishra
Verizon Inc.
Dmytro Shytyi
6WIND
Paris
France
Alexandre Petrescu
CEA, LIST
CEA Saclay
91190 Gif-sur-Yvette
France
Phone: +33169089223
Naveen Kottapalli
Ciena
300 Concord Road
Billerica, MA 01821
United States of America
Dusan Mudric
Ciena
Canada