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
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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.
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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 |
+----------+-+-----------------------+----------------------------+
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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].
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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.
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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,
<https://www.rfc-editor.org/info/rfc4193>.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, DOI 10.17487/RFC4291, February
2006, <https://www.rfc-editor.org/info/rfc4291>.
[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,
<https://www.rfc-editor.org/info/rfc7217>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>.
10.2. Informative References
[RFC3879] Huitema, C. and B. Carpenter, "Deprecating Site Local
Addresses", RFC 3879, DOI 10.17487/RFC3879, September
2004, <https://www.rfc-editor.org/info/rfc3879>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007,
<https://www.rfc-editor.org/info/rfc4862>.
[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,
<https://www.rfc-editor.org/info/rfc8415>.
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[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,
<https://www.rfc-editor.org/info/rfc9374>.
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
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