Network Working Group F. L. Templin, Ed. Internet-Draft Boeing Research & Technology Updates: rfc3879, rfc4291 (if approved) 22 May 2024 Intended status: Standards Track Expires: 23 November 2024 IPv6 MANET Local Addresses (MLAs) draft-templin-6man-mla-02 Abstract Mobile Ad-hoc NETworks (MANETs) present an interesting challenge for IPv6 addressing due to the indeterminant neighborhood properties of MANET interfaces. MANET routers must assign an IPv6 address to each MANET interface that is both unique and routable within the MANET but must not be forwarded to other networks. MANET routers must be able to assign self-generated addresses when there is no infrastructure present on the link that can delegate topology-relative IPv6 addresses or prefixes. This document therefore specifies a means for MANET routers to generate and assign MANET Local Addresses (MLAs). 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 23 November 2024. Copyright Notice Copyright (c) 2024 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/ license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights Templin Expires 23 November 2024 [Page 1] Internet-Draft IPv6 MLAs May 2024 and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. IPv6 MANET Local Addresses (MLAs) . . . . . . . . . . . . . . 3 3. Assigning IPv6 MLAs to an Interface . . . . . . . . . . . . . 4 4. Reclaiming fec0::/10 . . . . . . . . . . . . . . . . . . . . 4 5. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 5 6. Implementation Status . . . . . . . . . . . . . . . . . . . . 5 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 8. Security Considerations . . . . . . . . . . . . . . . . . . . 5 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 10.1. Normative References . . . . . . . . . . . . . . . . . . 6 10.2. Informative References . . . . . . . . . . . . . . . . . 6 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 7 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction When two or more IPv6 [RFC8200] nodes come together within a common local operating region (e.g., during the formation of a Mobile Ad-hoc Network (MANET)), they must be able to assign unique MANET-local addresses and exchange IPv6 packets even if there is no operator infrastructure present. The key feature of these MANET-local IPv6 addresses is that they must be assured unique so that there is no chance of conflicting with an address assigned by another node. There is no requirement that the addresses have topologically-oriented prefixes, since the (newly- formed) local network may not (yet) connect to any other Internetworking topologies. The MANET-local IPv6 addresses could then be used for continuous local-scoped communications and/or to bootstrap the assignment of topologically-oriented addresses under the IPv6 multi-addressing architecture [RFC4291]. This document proposes a new unique local unicast address space known as MANET Local Addresses (MLAs). MLAs use the formerly-deprecated IPv6 site-local prefix fec0::10 according to the address generation procedures specified in this document. Templin Expires 23 November 2024 [Page 2] Internet-Draft IPv6 MLAs May 2024 2. IPv6 MANET Local Addresses (MLAs) The IPv6 addressing architecture specified in [RFC4291] and [RFC4193] defines the supported IPv6 unicast/multicast/anycast address forms with various scopes including link-local, site-local, unique-local and global. Unique-local and global-scoped unicast addresses are typically assigned through Stateless Address AutoConfiguration (SLAAC) [RFC4862] and/or the Dynamic Host Configuration Protocol for IPv6 (DHCPv6) [RFC8415], but these services require the presence of IPv6 network infrastructure which may not be immediately available in spontaneously-formed MANETs or other isolated local networks. A new IPv6 address type known as the DRIP Entity Tag (DET) (or, Hierarchical Host Identity Tag (HHIT)) [RFC9374] provides a well- structured address format with exceptional uniqueness properties. A portion of the address includes the node's self-generated Overlay Routable Cryptographic Hash IDentifier (ORCHID) while the remainder of the address includes a well-formed IPv6 prefix plus bits corresponding to an attestation service that supports address proof- of-ownership. Verification of the attestation aspect of the address requires access to network infrastructure, but this may not always be available. MANET interfaces have the interesting property that a MANET router R will often need to forward packets between MANET nodes A and B even though R uses the same interface in the inbound and outbound directions. Since nodes A and B may not be able to communicate directly even though both can communicate directly with R, the link connectivity property is intransitive and the IPv6 Neighbor Discovery (ND) Redirect service cannot be used. Conversely, R may need to forward packets between nodes A and B via different MANET interfaces within a single MANET that includes multiple partitions. Due to these degenerate link properties, the use of IPv6 Link Local Addresses (LLAs) is also out of scope. This document therefore introduces a new fully-self-generated IPv6 unicast address format known as the MANET Local Address (MLA) that can be used either instead of or in addition to a DET/HHIT and/or other IPv6 unicast address types (noting again that a single interface may have multiple IPv6 addresses [RFC4291]). The address uses the formerly-deprecated Site-Local IPv6 Address prefix fec0::10 according to the modified format shown in Figure 1: | 11 bits | 53 bits | 64 bits | +----------+-+-----------------------+----------------------------+ |1111111011|L| subnet ID | interface ID | +----------+-+-----------------------+----------------------------+ Templin Expires 23 November 2024 [Page 3] Internet-Draft IPv6 MLAs May 2024 Figure 1: IPv6 MANET Local Address (MLA) Format In this format, the node sets the first 10 bits of the address to the constant string '1111111011' then sets the 11th bit (i.e., the "(L)ocal" bit) to 1. The node next sets subnet ID to a 53 bit random value calculated the same as specified in Section 3.2.1 of [RFC4193] for the Unique Local Address Global ID. The node finally generates and assigns an interface ID as specified in [RFC7217]; the resulting 128-bit MLA then has the proper format of an IPv6 address with a 64-bit "prefix" followed by a 64-bit interface identifier as required by the IPv6 addressing architecture. For example: fee7:6c29:de12:4b74:884e:9d2a:73fc:2d94 After a node creates an MLA, it can use the address within the context of spontaneously-organized local networks in which two or more nodes come together in the absence of supporting infrastructure and can still exchange IPv6 packets with little or no chance of address collisions. The use could be limited to bootstrapping the assignment of topologically correct IPv6 addresses through other means mentioned earlier, or it could extend to longer term usage patterns such as sustained communications with single-hop neighbors on a local link or even between multi-hop peers within a MANET. Note: the above MLA generation procedures apply when the L bit is set to 1; MLA generation procedures for L=0 may be specified by future documents. 3. Assigning IPv6 MLAs to an Interface IPv6 MLAs have no topological orientation and can therefore be assigned to any of a node's IPv6 interfaces. The addresses may serve as a basis for multihop forwarding over a MANET interface and/or for local neighborhood discovery over other IPv6 interface types. Due to their uniqueness properties, the node can assign an IPv6 MLA to an interface without invoking (pre-service) Duplicate Address Detection (DAD), however it should configure and assign a new IPv6 MLA if it later detects a duplicate through (in-service) DAD. 4. Reclaiming fec0::/10 Returning to a debate from more than 20 years ago, this document now proposes to reclaim the deprecated prefix "fec0::/10" for use as the MLA top-level prefix [RFC3879]. Templin Expires 23 November 2024 [Page 4] Internet-Draft IPv6 MLAs May 2024 The prefix (formerly known as the "Site-Local IPv6 Address") has the distinct advantage that it is reserved and available for reclamation by a future standards track publication, for which this document qualifies. Upon publication as a standards track RFC, the RFC Editor is instructed to recategorize [RFC3879] as obsolete and update [RFC4291] to reflect this new use for "fec0::/10". 5. Requirements IPv6 nodes MAY assign self-generated IPv6 MLAs to their interface connections to local networks (or MANETs). If the node later becomes aware that the address is already in use by another node, it instead generates and assigns a new MLA. IPv6 routers MAY forward IPv6 packets with MLA source or destination addresses over multiple hops within the same local network (or MANET). IPv6 routers MUST NOT forward packets with MLA source or destination addresses to a link outside the packet's local network (or MANET) of origin. IPv6 routers MUST NOT advertise the prefix fec0::/10 in routing protocol exchanges with correspondents outside the local network (or MANET). 6. Implementation Status In progress. 7. IANA Considerations This document has no requirements for IANA. 8. Security Considerations TBD. 9. Acknowledgements This work was inspired by continued investigations into 5G MANET operations in cooperation with the Virginia Tech National Security Institute (VTNSI). Emerging discussions on the IPv6 maintenance (6man) mailing list are expected to shape future versions of this document. The author acknowledges all those whose useful comments have helped further the understanding of this proposal. Templin Expires 23 November 2024 [Page 5] Internet-Draft IPv6 MLAs May 2024 Kyzer Davis (RFC9562 author) is acknowledged for his review and comments that helped shape the document. Honoring life, liberty and the pursuit of happiness. 10. References 10.1. Normative References [RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005, . [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture", RFC 4291, DOI 10.17487/RFC4291, February 2006, . [RFC7217] Gont, F., "A Method for Generating Semantically Opaque Interface Identifiers with IPv6 Stateless Address Autoconfiguration (SLAAC)", RFC 7217, DOI 10.17487/RFC7217, April 2014, . [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", STD 86, RFC 8200, DOI 10.17487/RFC8200, July 2017, . 10.2. Informative References [RFC3879] Huitema, C. and B. Carpenter, "Deprecating Site Local Addresses", RFC 3879, DOI 10.17487/RFC3879, September 2004, . [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless Address Autoconfiguration", RFC 4862, DOI 10.17487/RFC4862, September 2007, . [RFC8415] Mrugalski, T., Siodelski, M., Volz, B., Yourtchenko, A., Richardson, M., Jiang, S., Lemon, T., and T. Winters, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 8415, DOI 10.17487/RFC8415, November 2018, . Templin Expires 23 November 2024 [Page 6] Internet-Draft IPv6 MLAs May 2024 [RFC9374] Moskowitz, R., Card, S., Wiethuechter, A., and A. Gurtov, "DRIP Entity Tag (DET) for Unmanned Aircraft System Remote ID (UAS RID)", RFC 9374, DOI 10.17487/RFC9374, March 2023, . Appendix A. Change Log << RFC Editor - remove prior to publication >> Differences from earlier versions: * First draft publication. Author's Address Fred L. Templin (editor) Boeing Research & Technology P.O. Box 3707 Seattle, WA 98124 United States of America Email: fltemplin@acm.org Templin Expires 23 November 2024 [Page 7]