rfc9926.original   rfc9926.txt 
6lo P. Thubert, Ed. Internet Engineering Task Force (IETF) P. Thubert, Ed.
Internet-Draft 20 August 2025 Request for Comments: 9926 January 2026
Updates: 4861, 6550, 8505, 8928, 9010 (if Updates: 4861, 6550, 8505, 8928, 9010
approved) Category: Standards Track
Intended status: Standards Track ISSN: 2070-1721
Expires: 21 February 2026
IPv6 Neighbor Discovery Prefix Registration IPv6 Neighbor Discovery Prefix Registration
draft-ietf-6lo-prefix-registration-18
Abstract Abstract
This document updates IPv6 Neighbor Discovery (RFC 4861) and IPv6 This document updates IPv6 Neighbor Discovery (RFC 4861) and IPv6
Subnet Neighbor Discovery (RFC 8505, RFC 8928) to enable a node that Subnet Neighbor Discovery (RFC 8505, RFC 8928) to enable a node that
owns or is directly connected to a prefix to register that prefix to owns or is directly connected to a prefix to register that prefix to
neighbor routers. The registration indicates that the registered neighbor routers. The registration indicates that the registered
prefix can be reached via the advertising node without a loop. The prefix can be reached via the advertising node without a loop. The
unicast prefix registration allows the node to request neighbor unicast prefix registration allows the node to request one or more
router(s) to redistribute the prefix in another routing domain neighbor routers to redistribute the prefix in another routing domain
regardless of the routing protocol used in that domain. This regardless of the routing protocol used in that domain. This
document updates Routing Protocol for Low-Power and Lossy Networks document updates the Routing Protocol for Low-Power and Lossy
(RPL) (RFC 6550, RFC 9010) to enable a 6LoWPAN Router (6LR) to inject Networks (RPL), as specified in RFCs 6550 and 9010, to enable a
the registered prefix in RPL. 6LoWPAN Router (6LR) to inject the registered prefix in RPL.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on 21 February 2026. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9926.
Copyright Notice Copyright Notice
Copyright (c) 2025 IETF Trust and the persons identified as the Copyright (c) 2026 IETF Trust and the persons identified as the
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Terminology
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 5 2.1. Requirements Language
2.2. Inherited Terms and Concepts . . . . . . . . . . . . . . 5 2.2. Inherited Terms and Concepts
2.3. Acronyms and Initialisms . . . . . . . . . . . . . . . . 6 2.3. Acronyms and Initialisms
2.4. New terms . . . . . . . . . . . . . . . . . . . . . . . . 7 2.4. New Terms
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3. Overview
4. Updating RFC 4861 . . . . . . . . . . . . . . . . . . . . . . 8 4. Updating RFC 4861
5. Updating RFC 7400 . . . . . . . . . . . . . . . . . . . . . . 9 5. Updating RFC 7400
6. Updating RFC 6550 . . . . . . . . . . . . . . . . . . . . . . 10 6. Updating RFC 6550
7. Updating RFC 8505 . . . . . . . . . . . . . . . . . . . . . . 11 7. Updating RFC 8505
7.1. New P-Field value . . . . . . . . . . . . . . . . . . . . 11 7.1. New P-Field Value
7.2. New EARO Prefix Length Field and F flag . . . . . . . . . 11 7.2. New EARO Prefix Length Field and F flag
7.3. New EDAR Prefix Length Field . . . . . . . . . . . . . . 13 7.3. New EDAR Prefix Length Field
7.4. Updating the Registration Operation . . . . . . . . . . . 15 7.4. Updating the Registration Operation
8. Updating RFC 9010 . . . . . . . . . . . . . . . . . . . . . . 18 8. Updating RFC 9010
9. Updating RFC 8928 . . . . . . . . . . . . . . . . . . . . . . 18 9. Updating RFC 8928
10. Updating RFC 8929 . . . . . . . . . . . . . . . . . . . . . . 19 10. Updating RFC 8929
11. Security Considerations . . . . . . . . . . . . . . . . . . . 19 11. Security Considerations
12. Operational Considerations . . . . . . . . . . . . . . . . . 20 12. Operational Considerations
12.1. Partially Upgraded Networks . . . . . . . . . . . . . . 20 12.1. Partially Upgraded Networks
12.2. Application to RPL-Based Route-Over LLNs . . . . . . . . 20 12.2. Application to RPL-Based Route-Over LLNs
12.3. Application to a Shared Link . . . . . . . . . . . . . . 22 12.3. Application to a Shared Link
12.4. Application to a Hub Link with Stub Spokes . . . . . . . 23 12.4. Application to a Hub Link with Stub Spokes
13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24 13. IANA Considerations
13.1. Updated P-Field Registry . . . . . . . . . . . . . . . . 24 13.1. Updated P-Field Registry
13.2. New 6LoWPAN Capability Bit . . . . . . . . . . . . . . . 24 13.2. New 6LoWPAN Capability Bit
14. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 25 14. Normative References
15. Normative References . . . . . . . . . . . . . . . . . . . . 25 15. Informative References
16. Informative References . . . . . . . . . . . . . . . . . . . 27 Acknowledgments
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 28 Author's Address
1. Introduction 1. Introduction
The design of Low Power and Lossy Networks (LLNs) is generally The design of Low Power and Lossy Networks (LLNs) is generally
focused on saving energy, which is the most constrained resource of focused on saving energy, which is the most constrained resource of
all. Other design constraints, such as a limited memory capacity, all. Other design constraints, such as a limited memory capacity,
duty cycling of the LLN devices and low-power lossy transmissions, duty cycling of the LLN devices, and low-power lossy transmissions,
derive from that primary concern. The radio (both transmitting or derive from that primary concern. The radio (both transmitting or
simply listening) is a major energy drain and the LLN protocols must simply listening) is a major energy drain, and the LLN protocols must
be adapted to allow the nodes to remain sleeping with the radio be adapted to allow the nodes to remain sleeping with the radio
turned off at most times. turned off at most times.
Examples of LLNs include hub-and-spoke access links such as (Low- Examples of LLNs include hub-and-spoke access links such as (Low-
Power) Wi-Fi [IEEE80211] and Bluetooth (Low Energy) [IEEE802151], Power) Wi-Fi [IEEE80211] and Bluetooth (Low Energy) [IEEE802151],
Mesh-Under networks where the routing operation is handled at Layer- Mesh-Under networks where the routing operation is handled at Layer 2
2, and Route-Over networks such as the Wi-SUN [WI-SUN] and 6TiSCH (L2), and route-over networks such as the Wi-SUN [WI-SUN] and 6TiSCH
[RFC9030] mesh networks, which leverage 6LoWPAN [RFC4919][RFC6282] [RFC9030] mesh networks, which leverage 6LoWPAN [RFC4919] [RFC6282]
and RPL [RFC6550] over [IEEE802154]. and RPL [RFC6550] over [IEEE802154].
LLNs and constrained devices are the original domain of application LLNs and constrained devices are the original domain of application
for 6LoWPAN protocols. It is thus a foremost concern, when designing for 6LoWPAN protocols. It is thus a foremost concern, when designing
those protocols, to minimize energy spendings. In non-LLN those protocols, to minimize energy spendings. In non-LLN
environments where lowering carbon emissions is also a priority, it environments where lowering carbon emissions is also a priority, it
could make sense to apply the 6LoWPAN designs and extend some of the could make sense to apply the 6LoWPAN designs and extend some of the
6LoWPAN protocols. The general design points include: 6LoWPAN protocols. The general design points include:
* Placing the protocol complexity in the less-constrained routers to * Placing the protocol complexity in the less-constrained routers to
simplify the host implementation and avoid expanding the control simplify the host implementation and avoid expanding the control
traffic to all nodes. traffic to all nodes.
* Using host-triggered operations to enable transient disconnections * Using host-triggered operations to enable transient disconnections
with the routers, e.g., to conserve power (sleep), but also to with the routers, e.g., to conserve power (sleep), but also to
cope with inconsistent connectivity. cope with inconsistent connectivity.
This translates into: This translates into:
* Stateful proactively-built knowledge in the routers that is * Stateful proactively built knowledge in the routers that is
available at any point of time. available at any point of time.
* Unicast host to router operations triggered by the host and its * Unicast host-to-router operations triggered by the host and its
applications. applications.
* Minimal use of asynchronous L2-broadcast operations that would * Minimal use of asynchronous L2 broadcast operations that would
keep the host awake and listening with no application-level need keep the host awake and listening with no application-level need
to do so. to do so.
The "Routing Protocol for Low Power and Lossy Networks" [RFC6550] "RPL: IPv6 Routing Protocol for Low-Power and Lossy Networks"
(RPL) provides IPv6 [RFC8200] routing services within such [RFC6550] provides IPv6 [RFC8200] routing services within such
constraints. To save signaling and routing state in constrained constraints. To save signaling and routing state in constrained
networks, the RPL routing is only performed along a Destination- networks, the RPL routing is only performed along a Destination-
Oriented Directed Acyclic Graph (DODAG) that is optimized to reach a Oriented Directed Acyclic Graph (DODAG) that is optimized to reach a
Root node, as opposed to along the shortest path between 2 peers, Root node, as opposed to along the shortest path between two peers,
whatever that would mean in each LLN. whatever that would mean in each LLN.
The classical Neighbor Discovery (IPv6 ND) Protocol (NDP) [RFC4861] The classical Neighbor Discovery Protocol (NDP) [RFC4861] [RFC4862]
[RFC4862] was defined for serial links and shared transit media such was defined for serial links and shared transit media such as
as Ethernet at a time when L2-broadcast was cheap on those media Ethernet at a time when L2 broadcast was cheap on those media, while
while memory for neighbor cache was expensive. It was thus designed memory for neighbor cache was expensive. It was thus designed as a
as a reactive protocol that relies on caching and multicast reactive protocol that relies on caching and multicast operations for
operations for the Address Resolution (AR, aka Address Discovery or the Address Resolution (AR) (aka Address Discovery or Address Lookup)
Address Lookup) and Duplicate Address Detection (DAD) of IPv6 unicast and Duplicate Address Detection (DAD) of IPv6 unicast addresses.
addresses. Those multicast operations typically impact every node Those multicast operations typically impact every node on-link when
on-link when at most one is really targeted, which is a waste of at most one is really targeted, which is a waste of energy, and imply
energy, and imply that all nodes are awake to hear the request, which that all nodes are awake to hear the request, which is inconsistent
is inconsistent with power saving (sleeping) modes. with power-saving (sleeping) modes.
The "Architecture and Framework for IPv6 over Non-Broadcast Access" "Architecture and Framework for IPv6 over Non-Broadcast Access"
(NBMA) [I-D.ietf-6man-ipv6-over-wireless] introduces an evolution of [IPv6-over-NBMA] introduces an evolution of IPv6 ND towards a
IPv6 ND towards a proactive AR method. Because the IPv6 model for proactive AR method. Because the IPv6 model for NBMA depends on a
NBMA depends on a routing protocol to reach inside the Subnet, the routing protocol to reach inside the Subnet, the IPv6 ND extension
IPv6 ND extension for NBMA is referred to as Subnet Neighbor for NBMA is referred to as Subnet Neighbor Discovery (SND). SND is
Discovery (SND). SND is based on work done in the context of IoT, based on work done in the context of Internet of Things (IoT), known
known as 6LoWPAN ND. As opposed to the classical IPv6 ND Protocol, as 6LoWPAN ND. As opposed to the classical IPv6 ND protocol, this
this evolution follows the energy conservation principles discussed evolution follows the energy conservation principles discussed above:
above:
* The original 6LoWPAN ND, "Neighbor Discovery Optimizations for * The original 6LoWPAN ND, "Neighbor Discovery Optimization for IPv6
6LoWPAN networks" [RFC6775], was introduced to avoid the excessive over Low-Power Wireless Personal Area Networks (6LoWPANs)"
use of multicast messages and enable IPv6 ND for operations over [RFC6775], was introduced to avoid the excessive use of multicast
energy-constrained nodes. [RFC6775] changes the classical IPv6 ND messages and enable IPv6 ND for operations over energy-constrained
model to proactively establish the Neighbor Cache Entry (NCE) nodes. [RFC6775] changes the classical IPv6 ND model to
associated to the unicast address of a 6LoWPAN Node (6LN) in the proactively establish the Neighbor Cache Entry (NCE) associated to
6LoWPAN Router(s) (6LRs) that serve it. To that effect, [RFC6775] the unicast address of a 6LoWPAN Node (6LN) in the one or more
6LoWPAN Routers (6LRs) that serve it. To that effect, [RFC6775]
defines a new Address Registration Option (ARO) that is placed in defines a new Address Registration Option (ARO) that is placed in
unicast Neighbor Solicitation (NS) and Neighbor Advertisement (NA) unicast Neighbor Solicitation (NS) and Neighbor Advertisement (NA)
messages between the 6LN and the 6LRs. messages between the 6LN and the 6LRs.
* "Registration Extensions for 6LoWPAN Neighbor Discovery" [RFC8505] * "Registration Extensions for IPv6 over Low-Power Wireless Personal
updates [RFC6775] into a generic Address Registration mechanism Area Network (6LoWPAN) Neighbor Discovery>" [RFC8505] updates
and is the foundation for Subnet Neighbor Discovery (SND). SND [RFC6775] into a generic Address Registration mechanism and is the
introduces the Extended Address Registration Option (EARO) to foundation for Subnet Neighbor Discovery (SND). SND introduces
enable the registering node to access services such as routing the Extended Address Registration Option (EARO) to enable the
inside a subnet and ND proxy [RFC8929] operations. This provides registering node to access services such as routing inside a
a routing-protocol-agnostic method for a host to request that the subnet and ND proxy operations [RFC8929]. This provides a
router injects a unicast IPv6 address in the local routing routing-protocol-agnostic method for a host to request that the
protocol and provide return reachability for that address. router inject a unicast IPv6 address in the local routing protocol
and provide return reachability for that address.
* "IPv6 Neighbor Discovery Multicast Address Listener Subscription" * "Listener Subscription for IPv6 Neighbor Discovery Multicast and
[RFC9685] updates [RFC8505] to enable a listener to subscribe to Anycast Addresses" [RFC9685] updates [RFC8505] to enable a
an IPv6 anycast or multicast address; the draft also updates listener to subscribe to an IPv6 anycast or multicast address; the
[RFC9010] to enable a 6LR to inject the anycast and multicast document also updates [RFC9010] to enable a 6LR to inject the
addresses in RPL. Similarly, this specification updates [RFC8505] anycast and multicast addresses in RPL. Similarly, this
and [RFC9010] to add the capability for a 6LN to register unicast specification updates [RFC8505] and [RFC9010] to add the
prefixes up to 120 bits long, as opposed to addresses, and to capability for a 6LN to register unicast prefixes up to 120 bits
signal in a routing-protocol-independent fashion to a 6LR that it long, as opposed to addresses, and to signal in a routing-
is expected to redistribute the prefixes. protocol-independent fashion to a 6LR that it is expected to
redistribute the prefixes.
This specification updates the above registration and subscription This specification updates the above registration and subscription
methods to enable a node to register a unicast prefix to the routing methods to enable a node to register a unicast prefix to the routing
system and get it injected in the routing protocol. As with system and get it injected in the routing protocol. As with
[RFC8505], the prefix registration is agnostic to the routing [RFC8505], the prefix registration is agnostic to the routing
protocol in which the router injects the prefix, and the router is protocol in which the router injects the prefix, and the router is
agnostic to the method that was used to allocate the prefix to the agnostic to the method that was used to allocate the prefix to the
node. The energy conservation principles in [RFC8505] are retained node. The energy conservation principles in [RFC8505] are retained
as well, meaning that the node does not have to send or expect as well, meaning that the node does not have to send or expect
asynchronous multicast messages. asynchronous multicast messages.
skipping to change at page 5, line 45 skipping to change at line 225
trusted for a safe injection in the routing protocol for the lack of trusted for a safe injection in the routing protocol for the lack of
the equivalent of the Registration Ownership Verifier (ROVR) the equivalent of the Registration Ownership Verifier (ROVR)
[RFC8928] in the EARO. [RFC8928] in the EARO.
2. Terminology 2. Terminology
2.1. Requirements Language 2.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in
14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
2.2. Inherited Terms and Concepts 2.2. Inherited Terms and Concepts
This document uses terms and concepts that are discussed in: This document uses terms and concepts that are discussed in:
* "Neighbor Discovery for IP version 6" [RFC4861] and * "TLS User Mapping Extension" [RFC4861] and
* "IPv6 Stateless Address Autoconfiguration" [RFC4862] for the * "IPv6 Stateless Address Autoconfiguration" [RFC4862] for the
Neighbor Solicitation operation, Neighbor Solicitation operation,
* Neighbor Discovery Optimization for IPv6 over Low-Power Wireless * "Neighbor Discovery Optimization for IPv6 over Low-Power Wireless
Personal Area Networks (6LoWPANs) [RFC6775], as well as Personal Area Networks (6LoWPANs)" [RFC6775], as well as
* "Registration Extensions for 6LoWPAN Neighbor Discovery" for SND * "Registration Extensions for IPv6 over Low-Power Wireless Personal
operations [RFC8505] and Area Network (6LoWPAN) Neighbor Discovery" [RFC8505], and
* "Routing Protocol for Low Power and Lossy Networks" [RFC6550] for * "RPL: IPv6 Routing Protocol for Low-Power and Lossy Networks"
RPL, which is the routing protocol used in LLNs for SND. [RFC6550] for RPL, which is the routing protocol used in LLNs for
SND.
2.3. Acronyms and Initialisms 2.3. Acronyms and Initialisms
This document uses the following abbreviations: This document uses the following abbreviations:
*6CIO:* 6LoWPAN Capability Indication Option [RFC7400] *6CIO:* 6LoWPAN Capability Indication Option [RFC7400]
*6LBR:* 6LoWPAN Border Router [RFC6775] *6LBR:* 6LoWPAN Border Router [RFC6775]
*6LN:* 6LoWPAN Node [RFC6775] *6LN:* 6LoWPAN Node [RFC6775]
*6LR:* 6LoWPAN Router [RFC6775] *6LR:* 6LoWPAN Router [RFC6775]
*ARO:* Address Registration Option [RFC6775] *ARO:* Address Registration Option [RFC6775]
*DAD:* Duplicate Address Detection [RFC4861] *DAD:* Duplicate Address Detection [RFC4861]
*DAO:* Destination Advertisement Object [RFC6550] *DAO:* Destination Advertisement Object [RFC6550]
*DODAG:* Destination-Oriented Directed Acyclic Graph *DODAG:* Destination-Oriented Directed Acyclic Graph
*EARO:* Extended Address Registration Option [RFC8505] *EARO:* Extended Address Registration Option [RFC8505]
*EDAC:* Extended Duplicate Address Confirmation [RFC8505] *EDAC:* Extended Duplicate Address Confirmation [RFC8505]
*EDAR:* Extended Duplicate Address Request [RFC8505] *EDAR:* Extended Duplicate Address Request [RFC8505]
*ESS:* Extended Service Set [IEEE80211] *ESS:* Extended Service Set [IEEE80211]
*IPAM:* IP Address Management *IPAM:* IP Address Management
*LLN:* Low-Power and Lossy Network *LLN:* Low-Power and Lossy Network
*LLA:* Link Layer Address *LLA:* Link-Layer Address
*LoWPAN:* Low-Rate Personal Area Network [IEEE802154] *LoWPAN:* Low-Power Wireless Personal Area Network [IEEE802154]
*MAC:* Medium Access Control *MAC:* Medium Access Control
*NA:* Neighbor Advertisement (message) [RFC4861] *NA:* Neighbor Advertisement (message) [RFC4861]
*NBMA:* Non-Broadcast Multi-Access (full mesh) *NBMA:* Non-Broadcast Multi-Access (full mesh)
*NCE:* Neighbor Cache Entry [RFC4861] *NCE:* Neighbor Cache Entry [RFC4861]
*ND:* Neighbor Discovery (protocol) *ND:* Neighbor Discovery (protocol)
*NDP:* Neighbor Discovery Protocol *NDP:* Neighbor Discovery Protocol
*NS:* Neighbor Solicitation (message) [RFC4861] *NS:* Neighbor Solicitation (message) [RFC4861]
*ROVR:* Registration Ownership Verifier (pronounced "rover") *ROVR:* Registration Ownership Verifier (pronounced "rover")
[RFC8505] [RFC8505]
*RPL:* IPv6 Routing Protocol for LLNs (pronounced "ripple") *RPL:* IPv6 Routing Protocol for LLNs (pronounced "ripple")
[RFC6550] [RFC6550]
*RA:* Router Advertisement (message) [RFC4861] *RA:* Router Advertisement (message) [RFC4861]
*RS:* Router Solicitation (message) [RFC4861] *RS:* Router Solicitation (message) [RFC4861]
*RTO:* RPL Target Option [RFC6550] *RTO:* RPL Target Option [RFC6550]
*SLLAO:* Source Link-Layer Address Option [RFC4861] *SLLAO:* Source Link-Layer Address Option [RFC4861]
*SND:* Subnet Neighbor Discovery (protocol) *SND:* Subnet Neighbor Discovery (protocol)
*TID:* Transaction ID [RFC8505] *TID:* Transaction ID [RFC8505]
*TIO:* Transit Information Option [RFC6550] *TIO:* Transit Information Option [RFC6550]
*TLLAO:* Target Link-Layer Address Option [RFC4861] *TLLAO:* Target Link-Layer Address Option [RFC4861]
2.4. New terms 2.4. New Terms
This document introduces the following terms: This document introduces the following terms:
*Origin:* The node that issued the prefix advertisement, either in *Origin:* The node that issued the prefix advertisement, either in
the form of a NS(EARO) or as a DAO(TIO, RTO) the form of a NS(EARO) or as a DAO(TIO, RTO)
*Merge:* The action of receiving multiple anycast or multicast *Merge:* The action of receiving multiple anycast or multicast
advertisements, either internally from self, in the form of a advertisements, either internally from self, in the form of a
NS(EARO), or as a DAO(TIO, RTO), and generating a single NS(EARO), or as a DAO(TIO, RTO), and generating a single
DAO(TIO, RTO). The 6RPL router maintains a state per origin DAO(TIO, RTO). The 6RPL router maintains a state per origin
for each advertised address, and merges the advertisements for for each advertised address, and merges the advertisements for
skipping to change at page 7, line 33 skipping to change at line 311
origin of the merged advertisement and uses its own values for origin of the merged advertisement and uses its own values for
the Path Sequence and ROVR fields. the Path Sequence and ROVR fields.
3. Overview 3. Overview
This specification inherits from [RFC6550], [RFC8505], and [RFC9010] This specification inherits from [RFC6550], [RFC8505], and [RFC9010]
to register prefixes as opposed to addresses. to register prefixes as opposed to addresses.
An SND deployment consists of: An SND deployment consists of:
* One or more 6LBR(s) that act(s) as RPL Root * one or more 6LBRs that act as RPL Root,
* intermediate routers down the RPL graph that propagate routing * intermediate routers down the RPL graph that propagate routing
information on addresses and prefixes towards the Root information on addresses and prefixes towards the Root,
* 6LRs that are RPL-aware 6LNs and can leverage RPL directly to * 6LRs that are RPL-aware 6LNs and can leverage RPL directly to
expose their addresses and prefixes expose their addresses and prefixes, and
* and 6LNs that are the RPL-unaware destinations and need SND to * 6LNs that are the RPL-unaware destinations and need SND to obtain
obtain reachability tover the RPL LLN for their addresses and, reachability over the RPL LLN for their addresses and, with this
with this specification, their prefixes as well. specification, their prefixes as well.
The SND operation for prefixes inherits from that for unicast The SND operation for prefixes inherits from that for unicast
addresses, meaning that it is the same unless specified otherwise addresses, meaning that it is the same unless specified otherwise
herein. In particular, forwarding a packet happens as specified in herein. In particular, forwarding a packet happens as specified in
section 11 of [RFC6550], including loop avoidance and detection, Section 11 of [RFC6550], including loop avoidance and detection.
though in the case of multicast multiple copies might be generated. However, in the case of multicast, multiple copies might be
generated.
[RFC8505] is a pre-requisite to this specification. A node that [RFC8505] is a prerequisite to this specification. A node that
implements this MUST also implement [RFC8505]. This specification implements this MUST also implement [RFC8505]. This specification
does not introduce a new option; it modifies existing options and does not introduce a new option; it modifies existing options and
updates the associated behaviors to enable the Registration for updates the associated behaviors to enable the Registration for
prefixes as an extension to [RFC8505]. prefixes as an extension to [RFC8505].
This specification updates the P-Field introduced in [RFC9685] for This specification updates the P-Field introduced in [RFC9685] for
use in EARO, DAR, and RTO, with the new value of 3 to indicate the use in EARO, DAR, and RTO, with the new value of 3 to indicate the
registration of a prefix, as detailed in Section 7.2. With this registration of a prefix, as detailed in Section 7.2. With this
extension, the 6LN can now express its willingness to receive the extension, the 6LN can now express its willingness to receive the
traffic for all addresses in the range of a prefix, using the P-Field traffic for all addresses in the range of a prefix, using the P-Field
value of 3 in the EARO to signal that the registration is for such value of 3 in the EARO to signal that the registration is for such
prefix. Multiple 6LNs acting as border routers to the same external prefix. Multiple 6LNs acting as border routers to the same external
network or as access routers to the same subnet may register the same network or as access routers to the same subnet may register the same
prefix to the same 6LR or to different 6LRs. prefix to the same 6LR or to different 6LRs.
If the R flag is set in the registration of one or more 6LNs for the If the R flag is set in the registration of one or more 6LNs for the
same prefix, then, according to its redistribution policy, the 6LR same prefix, then, according to its redistribution policy, the 6LR
MUST redistribute the prefix in the routing protocol(s) (e.g., RPL) MUST redistribute the prefix in the routing protocol(s) (e.g., RPL)
that it participates in. The duration of the redistribution is based that it participates in. The duration of the redistribution is based
on the longest registration lifetime across the non-expired received on the longest registration lifetime across the non-expired received
registrations for the prefix. registrations for the prefix.`
Examples of use-cases where this specification may apply include Examples of use cases where this specification may apply include
virtual links, shared links, and hub links as shown in Section 12.3 virtual links, shared links, and hub links as shown in Sections 12.3
and Section 12.4, respectively. More generally, the 6LN may be a and 12.4, respectively. More generally, the 6LN may be a router
router running a different routing protocol in an external network, running a different routing protocol in an external network, e.g., a
e.g., a stub network, and acting as a border router. Using the stub network, and acting as a border router. Using the prefix
prefix registration method enables decoupling the routing protocol in registration method enables decoupling the routing protocol in the
the 6LN from the routing protocol that the 6LRs run in the main LLN 6LN from the routing protocol that the 6LRs run in the main LLN and
and provide signaling to stimulate the redistribution. provide signaling to stimulate the redistribution.
4. Updating RFC 4861 4. Updating RFC 4861
[RFC4861] expects that the NS/NA exchange is for a unicast address, [RFC4861] expects that the NS/NA exchange is for a unicast address,
which is indicated in the Target Address field of the ND message. which is indicated in the Target Address field of the ND message.
Section 5.5 of [RFC8505] updates [RFC4861] to signal the Registered Section 5.5 of [RFC8505] updates [RFC4861] to signal the Registered
Address in the Target Address field. Address in the Target Address field.
This specification updates [RFC4861] by allowing a 6LN to advertise a This specification updates [RFC4861] by allowing a 6LN to advertise a
prefix in the Target Address field when the NS or NA message is used prefix in the Target Address field when the NS or NA message is used
for a registration, per section 5.5 of [RFC8505]; in that case, the for a registration, per Section 5.5 of [RFC8505]. In that case, the
prefix length MUST be indicated in the EARO of the NS message, prefix length MUST be indicated in the EARO of the NS message,
overloading the field that is used in the NA response for the Status. overloading the field that is used in the NA response for the Status.
If the 6LN owns at least one an IPv6 address that is derived from the If the 6LN owns at least one IPv6 address that is derived from the
registered prefix with a non-0 interface ID, then it MUST indicate registered prefix with a non-zero interface ID, then it MUST indicate
one of these addresses in full in the Target Address field of the one of these addresses in full in the Target Address field of the
NS(EARO) message. Else, it MUST indicate the prefix padded with 0s NS(EARO) message. Else, it MUST indicate the prefix padded with
in the Target Address field. zeros in the Target Address field.
5. Updating RFC 7400 5. Updating RFC 7400
This specification updates "6LoWPAN-GHC: Generic Header Compression This specification updates "6LoWPAN-GHC: Generic Header Compression
for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs)" for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs)"
[RFC7400] by defining a new capability bit for use in the 6CIO. [RFC7400] by defining a new capability bit for use in the 6CIO.
[RFC7400] was already updated by [RFC8505] for use in IPv6 ND [RFC7400] was already updated by [RFC8505] for use in IPv6 ND
messages. messages.
The new "Registration for prefixes Supported" (F) flag indicates to The new "Registration for prefixes Supported" (F) flag indicates to
the 6LN that the 6LR accepts IPv6 prefix registrations as specified the 6LN that the 6LR (1) accepts IPv6 prefix registrations as
in this document and will ensure that packets for the addresses that specified in this document, (2) will ensure that packets for the
match this prefix will be routed to the 6LNs that registered the addresses that match this prefix will be routed to the 6LNs that
prefix, and the route to the prefix will be redistributed if the R registered the prefix, and (3) will ensure that the route to the
flag is set to 1. prefix will be redistributed if the R flag is set to 1.
Figure 1 illustrates the F flag in its position (16, counting 0 to 47 Figure 1 illustrates the F flag in its position (16, counting 0 to 47
in network order in the 48-bit array). in network order in the 48-bit array).
- to be confirmed by IANA 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
- and updated by RFC Editor if needed. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length = 1 | Experimental |X|A|D|L|B|P|E|G|
0 1 2 3 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 |F| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length = 1 | Experimental |X|A|D|L|B|P|E|G|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|F| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: New Capability Bit in the 6CIO Figure 1: New Capability Bit in the 6CIO
New Option Field: New Option Field:
*F:* 1-bit flag, set to 1 to indicate "Registration for prefixes *F:* 1-bit flag, set to 1 to indicate "Registration for prefixes
Supported" Supported"
6. Updating RFC 6550 6. Updating RFC 6550
skipping to change at page 10, line 18 skipping to change at line 427
(TIO) to retain only the freshest unicast route and remove stale (TIO) to retain only the freshest unicast route and remove stale
ones, e.g., in the case of mobility. [RFC9010] copies the TID from ones, e.g., in the case of mobility. [RFC9010] copies the TID from
the EARO into the Path Sequence, and the ROVR field into the the EARO into the Path Sequence, and the ROVR field into the
associated RPL Target Option (RTO). This way, it is possible to associated RPL Target Option (RTO). This way, it is possible to
identify both the registering node and the order of registration in identify both the registering node and the order of registration in
RPL for each individual advertisement, so the most recent path and RPL for each individual advertisement, so the most recent path and
lifetime values are used. lifetime values are used.
[RFC9685] requires the use of the ROVR field as the indication of the [RFC9685] requires the use of the ROVR field as the indication of the
origin of a Target advertisement in the RPL DAO messages, as origin of a Target advertisement in the RPL DAO messages, as
specified in section 6.1 of [RFC9010]. For anycast and multicast specified in Section 6.1 of [RFC9010]. For anycast and multicast
advertisements (in NS or DAO messages), multiple origins may advertisements (in NS or DAO messages), multiple origins may
subscribe to the same address, in which case the multiple subscribe to the same address, in which case the multiple
advertisements from the different or unknown origins are merged by advertisements from the different or unknown origins are merged by
the common parent; in that case, the common parent becomes the origin the common parent. In that case, the common parent becomes the
of the merged advertisements and uses its own ROVR value. On the origin of the merged advertisements and uses its own ROVR value. On
other hand, a parent that propagates an advertisement from a single the other hand, a parent that propagates an advertisement from a
origin uses the original ROVR in the propagated RTO, as it does for single origin uses the original ROVR in the propagated RTO, as it
unicast address advertisements, so the origin is recognized across does for unicast address advertisements, so the origin is recognized
multiple hops. across multiple hops.
This specification updates [RFC6550] to require that, for prefix This specification updates [RFC6550] to require that, for prefix
routes, the Path Sequence is used between and only between routes, the Path Sequence is used between and only between
advertisements for the same Target and from the same origin (i.e., advertisements for the same Target and from the same origin (i.e.,
with the same ROVR value); in that case, only the freshest with the same ROVR value); in that case, only the freshest
advertisement is retained. But the freshness comparison cannot apply advertisement is retained. However, the freshness comparison cannot
if the origin is not determined (i.e., the origin did not support apply if the origin is not determined (i.e., the origin did not
this specification). support this specification).
[RFC6550] uses the Path Lifetime in the TIO to indicate the remaining [RFC6550] uses the Path Lifetime in the TIO to indicate the remaining
time for which the advertisement is valid for unicast route time for which the advertisement is valid for unicast route
determination, and a Path Lifetime value of 0 invalidates that route. determination, and a Path Lifetime value of 0 invalidates that route.
[RFC9010] maps the Address Registration lifetime in the EARO and the [RFC9010] maps the Address Registration lifetime in the EARO and the
Path Lifetime in the TIO so they are comparable when both forms of Path Lifetime in the TIO so they are comparable when both forms of
advertisements are received. advertisements are received.
The RPL router that merges multiple advertisements for the same The RPL router that merges multiple advertisements for the same
prefix uses and advertises the longest remaining lifetime across all prefix uses and advertises the longest remaining lifetime across all
the origins of the advertisements for that prefix. When the lifetime the origins of the advertisements for that prefix. When the lifetime
expires, the router sends a no-path DAO (i.e., the lifetime is 0) expires, the router sends a no-path DAO (i.e., the lifetime is 0)
using the same value for ROVR value as for the previous using the same value for the ROVR value as for the previous
advertisements, that is either itself or the single descendant that advertisements. This value refers to either the router itself or the
advertised the Target. single descendant that advertised the Target.
Note that the Registration Lifetime, TID and ROVR fields are also Note that the Registration Lifetime, TID, and ROVR fields are also
placed in the EDAR message so the state created by EDAR is also placed in the EDAR message, so the state created by EDAR is also
comparable with that created upon an NS(EARO) or a DAO message. For comparable with that created upon an NS(EARO) or a DAO message. For
simplicity the text below mentions only NS(EARO) but applies also to simplicity, the text below mentions only NS(EARO) but it also applies
EDAR. to EDAR.
7. Updating RFC 8505 7. Updating RFC 8505
This specification updates the EARO and EDAR messages to enable the This specification updates the EARO and EDAR messages to enable the
registration of prefixes and updates the Registration operation in registration of prefixes and updates the Registration operation in
the case of a prefix, in particular from the standpoint of the 6LR, the case of a prefix, in particular from the standpoint of the 6LR,
e.g., to enable the Registration of overlapping prefixes. e.g., to enable the Registration of overlapping prefixes.
7.1. New P-Field value 7.1. New P-Field Value
[RFC9685] defines a 2-bit P-Field with values 0 through 2 and [RFC9685] defines a 2-bit P-Field with values 0 through 2 and
reserves the value 3 for future use. This specification defines the reserves the value 3 for future use. This specification defines the
semantics of P-Field value 3. semantics of P-Field value 3.
When the P-Field is set to 3, it indicates that the Registered When the P-Field is set to 3, it indicates that the Registered
Address represents a prefix rather than a single address. Upon Address represents a prefix rather than a single address. Upon
receiving an NS(EARO) message with the P-Field set to 3, the receiver receiving an NS(EARO) message with the P-Field set to 3, the receiver
MUST install a route to the indicated prefix via the source address MUST install a route to the indicated prefix via the source address
of the NS(EARO) message. of the NS(EARO) message.
This specification assigns the value 3 to the P-Field, resulting in This specification assigns the value 3 to the P-Field, resulting in
the following complete set of defined values: the following complete set of defined values:
+-------+--------------------------------------+ +=======+======================================+
| Value | Meaning | | Value | Meaning |
+-------+--------------------------------------+ +=======+======================================+
| *0* | Registration for a Unicast Address | | *0* | Registration for a Unicast Address |
+-------+--------------------------------------+ +-------+--------------------------------------+
| *1* | Registration for a Multicast Address | | *1* | Registration for a Multicast Address |
+-------+--------------------------------------+ +-------+--------------------------------------+
| *2* | Registration for an Anycast Address | | *2* | Registration for an Anycast Address |
+-------+--------------------------------------+ +-------+--------------------------------------+
| *3* | Registration for a Unicast prefix | | *3* | Registration for a Prefix |
+-------+--------------------------------------+ +-------+--------------------------------------+
Table 1: P-Field Values Table 1: P-Field Values
7.2. New EARO Prefix Length Field and F flag 7.2. New EARO Prefix Length Field and F flag
Section 4.1 of [RFC8505] defines the EARO as an extension to the ARO Section 4.1 of [RFC8505] defines the EARO as an extension to the ARO
option defined in [RFC6775]. option defined in [RFC6775].
The Status field is used only when the EARO is placed in an NA The Status field is used only when the EARO is placed in an NA
message. This specification repurposes that field to carry the message. This specification repurposes that field to carry the
prefix length when the EARO is placed in an NS message as illustrated prefix length when the EARO is placed in an NS message as illustrated
in Figure 2. The prefix length is expressed as 7 bits and the most in Figure 2. The prefix length is expressed as 7 bits, and the most
significant bit of the field is reserved. A 7-bit value of 0 is significant bit of the field is reserved. A 7-bit value of 0 is
understood as a truncated 128, meaning that this registration is for understood as a truncated 128, meaning that this registration is for
an address as opposed to a prefix. This approach is backward an address as opposed to a prefix. This approach is backward
compatible with [RFC8505] and spans both addresses and prefixes. compatible with [RFC8505] and spans both addresses and prefixes.
This specification adds a new F flag to signal that the Registered This specification adds a new F flag to signal that the Registered
Prefix is topologically correct through the Registering Node. This Prefix is topologically correct through the Registering Node. This
means that the Registering Node relays packets that are sourced in means that the Registering Node relays packets that are sourced in
the Registered Prefix to the outside, in accordance with "Network the Registered Prefix to the outside, in accordance with "Network
Ingress Filtering" [BCP38] . The receiver forwards packets to the Ingress Filtering: Defeating Denial of Service Attacks which employ
Registering Node address when the source address of the packets IP Source Address Spoofing" [BCP38]. The receiver forwards packets
derives from the Registered Prefix. Note that to avoid loops, the to the Registering Node address when the source address of the
receiver must be in the inside so packets sent by the sender towards packets derives from the Registered Prefix. Note that to avoid
the outside may never reach the receiver. The notion of inside and loops, the receiver must be in the inside so packets sent by the
outside are administratively defined, e.g., inside is a particular sender towards the outside may never reach the receiver. The notion
Layer-2 network such as an Ethernet fabric. of "inside" and "outside" are administratively defined, e.g.,
"inside" is a particular L2 network such as an Ethernet fabric.
When the F flag is not set, the Registering Node owns the prefix and When the F flag is not set, the Registering Node owns the prefix and
will deliver packets to the destination if the destination address will deliver packets to the destination if the destination address
derives from the prefix. Conversely, if the F flag is set, the derives from the prefix. Conversely, if the F flag is set, the
Registering Node will forward traffic whose source address derives Registering Node will forward traffic whose source address derives
from the Registered Prefix into a network location (e.g., to an ISP from the Registered Prefix into a network location (e.g., to an ISP
Provider Edge) where this source address is topologically correct Provider Edge) where this source address is topologically correct
(e.g., derives from a prefix assigned by that ISP). The F flag is (e.g., derives from a prefix assigned by that ISP). The F flag is
encoded in the most significant bit of the EARO Status field when the encoded in the most significant bit of the EARO Status field when the
Status field is used to transport a Prefix Length as shown in Status field is used to transport a Prefix Length as shown in
skipping to change at page 14, line 19 skipping to change at line 599
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|P=3| Reserved | TID | Registration Lifetime | |P=3| Reserved | TID | Registration Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
... ROVR ... ... ROVR ...
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
+ Prefix + + Prefix +
| | | |
+ (up to 120 bits, padded with 0s) + + (up to 120 bits, padded with zeros) +
| | | |
+ +-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+
| |r|Prefix Length| | |r|Prefix Length|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Options ... | Options ...
+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-+-+-+-
Figure 3: EDAR Message Format with P == 3 Figure 3: EDAR Message Format with P == 3
0 1 2 3 0 1 2 3
skipping to change at page 14, line 43 skipping to change at line 623
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status | TID | Registration Lifetime | | Status | TID | Registration Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
... ROVR ... ... ROVR ...
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
+ Prefix + + Prefix +
| | | |
+ (up to 120 bits, padded with 0s) + + (up to 120 bits, padded with zeros) +
| | | |
+ +-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+
| |r|Prefix Length| | |r|Prefix Length|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Options ... | Options ...
+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-+-+-+-
Figure 4: EDAC Message Format Figure 4: EDAC Message Format
New and updated EDAR/EDAC Message Fields: New and updated EDAR/EDAC Message Fields:
*Prefix:* A 15-byte field that carries up to 120 bits of the prefix. *Prefix:* A 15-byte field that carries up to 120 bits of the prefix.
If the prefix isshorter than 120 bits, the remaining bits MUST be If the prefix is shorter than 120 bits, the remaining bits MUST be
padded with zeros. The receiver MUST treat the padding as zeroed padded with zeros. The receiver MUST treat the padding as zeroed
and MUST overwrite any unused bits with zeros before using the and MUST overwrite any unused bits with zeros before using the
prefix. prefix.
*r* (reserved): A 1-bit reserved field. It MUST be set to zero by *r* (reserved): A 1-bit reserved field. It MUST be set to zero by
the sender and MUST be ignored by the receiver. the sender and MUST be ignored by the receiver.
*Prefix Length:* A 7-bit unsigned integer indicating the length of *Prefix Length:* A 7-bit unsigned integer indicating the length of
the prefix in bits. The value MUST be in the inclusive range of the prefix in bits. The value MUST be in the inclusive range of
16 to 120. 16 to 120.
The capability to place The P-Field and the contiguous "Reserved" The capability to place the P-Field and the contiguous "Reserved"
field in the EDAR message are specified in section 7.2 of [RFC9685]. field in the EDAR message is specified in Section 7.2 of [RFC9685].
The capability to append ND options to the EDAR and EDAC messages is The capability to append ND options to the EDAR and EDAC messages is
introduced in section 3.1 of [RFC8929]. introduced in Section 3.1 of [RFC8929].
All other fields follow the same definition as specified in All other fields follow the same definition as specified in
[RFC8505]. The values for these fields and RFC references are [RFC8505]. The values for these fields and RFC references are
maintained by IANA under the "Internet Control Message Protocol maintained by IANA under the "Internet Control Message Protocol
version 6 (ICMPv6) Parameters" [IANA.ICMP] registry grouping. version 6 (ICMPv6) Parameters" [IANA.ICMP] registry group.
7.4. Updating the Registration Operation 7.4. Updating the Registration Operation
With [RFC8505]: With [RFC8505]:
* A router that expects to reboot may send a final RA message, upon * A router that expects to reboot may send a final RA message, upon
which nodes should register elsewhere or redo the registration to which nodes should register elsewhere or redo the registration to
the same router upon reboot. In all other cases, a node reboot is the same router upon reboot. In all other cases, a node reboot is
silent. When the node comes back to life, existing registration silent. When the node comes back to life, existing registration
state might be lost if it was not safely stored, e.g., in state might be lost if it was not safely stored, e.g., in
skipping to change at page 16, line 32 skipping to change at line 706
node. The NA message MAY be sent to a unicast or a multicast node. The NA message MAY be sent to a unicast or a multicast
link-scope address and SHOULD be contained within the L2 range link-scope address and SHOULD be contained within the L2 range
where nodes may effectively have registered/subscribed to this where nodes may effectively have registered/subscribed to this
router, e.g., a radio broadcast domain to preserve energy and router, e.g., a radio broadcast domain to preserve energy and
spectrum. spectrum.
A device that wishes to refresh its state, e.g., upon reboot if it A device that wishes to refresh its state, e.g., upon reboot if it
may have lost some registration state, SHOULD send an asynchronous may have lost some registration state, SHOULD send an asynchronous
NA(EARO) with this new status value. That asynchronous NA(EARO) NA(EARO) with this new status value. That asynchronous NA(EARO)
SHOULD be sent to the all-nodes link-scope multicast address SHOULD be sent to the all-nodes link-scope multicast address
(ff02::1) and Target MUST be set to the link-local address that (ff02::1), and Target MUST be set to the link-local address that
was exposed previously by this node to accept registrations, and was exposed previously by this node to accept registrations, and
the TID MUST be set to 0; the ROVR field MUST be set to all zeroes the TID MUST be set to 0; the ROVR field MUST be set to all zeros
and ignored by the receiver. and ignored by the receiver.
In an environment with unreliable transmissions, the multicast In an environment with unreliable transmissions, the multicast
NA(EARO) message may be resent in a fast sequence, in which case NA(EARO) message may be resent in a fast sequence, in which case
the TID is incremented each time. A 6LN that has recently the TID is incremented each time. A 6LN that has recently
processed the NA(EARO) indicating a "Registration Refresh Request" processed the NA(EARO) indicating a "Registration Refresh Request"
ignores the additional NA(EARO) also indicating a "Registration ignores the additional NA(EARO) also indicating a "Registration
Refresh Request" within the duration of the fast sequence. That Refresh Request" within the duration of the fast sequence. That
duration depends on the environment and has to be configured. By duration depends on the environment and has to be configured. By
default, it is 10 seconds. default, it is 10 seconds.
* Registration for prefixes is now supported. The value of 3 in the * Registration for prefixes is now supported. The value of 3 in the
P-Field of the EARO and the EDAR message signals when the P-Field of the EARO and the EDAR message signals when the
registration is for a prefix as opposed to an address. DAD for registration is for a prefix as opposed to an address. DAD for
prefixes and addresses becomes a prefix overlap match. Whether prefixes and addresses becomes a prefix overlap match. Whether
overlapping addresses and prefixes may be registered is a network overlapping addresses and prefixes may be registered is a network
policy decision and out of scope. The same prefix may be injected policy decision and out of scope. The same prefix may be injected
twice (multiple routes) as long as they use the same value of the twice (multiple routes) as long as they use the same value of the
ROVR. ROVR.
Overlaps may be desirable. It may happen for instance that a Overlaps may be desirable. For instance, it may happen that a
router or a proxy (see Section 10) registers a prefix or an router or a proxy (see Section 10) registers a prefix or an
aggregation while a host using an address from that prefix or a aggregation while a host using an address from that prefix or a
prefix from that aggregation also registers its piece. prefix from that aggregation also registers its piece.
In case of an overlapping registration, the longest prefix match In case of an overlapping registration, the longest prefix match
wins, meaning that if the network policy allows for overlapping wins, meaning that if the network policy allows for overlapping
registrations, then the routes for the registered prefixes are registrations, then the routes for the registered prefixes are
installed towards the node that registered with the longest prefix installed towards the node that registered with the longest prefix
match, all the way to /128. match, all the way to /128.
* If the 6LR acts as a border router to external prefixes or owns * If the 6LR acts as a border router to external prefixes or owns
the prefixes entirely, it SHOULD register all those prefixes on the prefixes entirely, it SHOULD register all those prefixes on
all interfaces from which it might be needed to relay traffic to all interfaces from which it might be needed to relay traffic to
that prefix. It MUST set the P-Field in the EARO to 3 for those that prefix. It MUST set the P-Field in the EARO to 3 for those
prefixes, and the set R flag to receive the traffic associated to prefixes and set the R flag to receive the traffic associated to
the prefixes. It MAY refrain from registering a prefix on one the prefixes. It MAY refrain from registering a prefix on one
interface if that prefix is already successfully registered on interface if that prefix is already successfully registered on
another interface, or the router handled the EDAR / EDAC flow by another interface, or the router handled the EDAR/EDAC flow by
itself, to ensure that the prefix ownership is known and validated itself, to ensure that the prefix ownership is known and validated
by the 6LBR. Additionally, if the router expect to receive by the 6LBR. Additionally, if the router expects to receive
traffic for that prefix on that interface, it needs to ensure that traffic for that prefix on that interface, it needs to ensure that
the prefix is advertised some other way, e.g., over a routing the prefix is advertised some other way, e.g., over a routing
protocol such as RPL. protocol such as RPL.
* The 6LN MAY set the R flag in the EARO to request the 6LR to * The 6LN MAY set the R flag in the EARO to request the 6LR to
redistribute the prefix on other links using a routing protocol. redistribute the prefix on other links using a routing protocol.
The 6LR MUST NOT reregister that prefix to yet another router The 6LR MUST NOT reregister that prefix to yet another router
unless loops are avoided some way, e.g., following a tree unless loops are avoided some way, e.g., following a tree
structure. structure.
skipping to change at page 18, line 19 skipping to change at line 783
With [RFC9010]: With [RFC9010]:
* The 6LR injects only unicast routes in RPL. * The 6LR injects only unicast routes in RPL.
* Upon a registration with the R flag set to 1 in the EARO, the 6LR * Upon a registration with the R flag set to 1 in the EARO, the 6LR
injects the address in the RPL unicast support. injects the address in the RPL unicast support.
* Upon receiving a packet directed to a unicast address for which it * Upon receiving a packet directed to a unicast address for which it
has an active registration, the 6LR delivers the packet as a has an active registration, the 6LR delivers the packet as a
unicast layer-2 frame to the LLA of the node that registered the unicast L2 frame to the LLA of the node that registered the
unicast address. unicast address.
This specification adds the following behavior: This specification adds the following behavior:
* Upon a registration with the R flag set to 1 and the P-Field set * Upon a registration with the R flag set to 1 and the P-Field set
to 3 in the EARO, the 6LR injects the prefix in RPL using a prefix to 3 in the EARO, the 6LR injects the prefix in RPL using a prefix
RTO. The P-Field in the RTP MUST be set to 3. RTO. The P-Field in the RTP MUST be set to 3.
* Upon receiving a packet directed to an address that derives from a * Upon receiving a packet directed to an address that derives from a
prefix for which it has at least one registration, the 6LR prefix for which it has at least one registration, the 6LR
delivers a copy of the packet as a unicast layer-2 frame to the delivers a copy of the packet as a unicast L2 frame to the LLA of
LLA of exactly one of the nodes that registered to that prefix, exactly one of the nodes that registered to that prefix, using the
using the longest prefix match derivation to find the best 6LN. longest prefix match derivation to find the best 6LN.
9. Updating RFC 8928 9. Updating RFC 8928
Address-Protected Neighbor Discovery for Low-Power and Lossy Networks "Address-Protected Neighbor Discovery for Low-Power and Lossy
[RFC8928] was defined to protect the ownership of unicast IPv6 Networks" [RFC8928] was defined to protect the ownership of unicast
addresses that are registered with [RFC8505]. IPv6 addresses that are registered with [RFC8505].
With [RFC8928], it is possible for a node to autoconfigure a pair of With Address-Protected Neighbor Discovery (AP-ND) [RFC8928], it is
public and private keys and use them to sign the registration of possible for a node to autoconfigure a pair of public and private
addresses that are either autoconfigured or obtained through other keys and use them to sign the registration of addresses that are
methods. either autoconfigured or obtained through other methods.
The first hop router (the 6LR) can then validate a registration and The first-hop router (the 6LR) can then validate a registration and
perform source address validation on packets coming from the sender perform source address validation on packets coming from the sender
node (the 6LN). node (the 6LN).
As multiple nodes may register the same prefix, the method specified As multiple nodes may register the same prefix, the method specified
in [RFC8928] cannot be used with node-local autoconfigured keypairs, in [RFC8928] cannot be used with node-local autoconfigured keypairs,
which protect a single ownership only. which protect a single ownership only.
For a prefix, as for an anycast or a multicast address, it is still For a prefix, as for an anycast or a multicast address, it is still
possible to leverage [RFC8928] to enforce the right to register. If possible to leverage AP-ND [RFC8928] to enforce the right to
[RFC8928] is used, a keypair MUST be created and associated with the register. If AP-ND [RFC8928] is used, a keypair MUST be created and
prefix before the prefix is deployed, and a ROVR MUST be generated associated with the prefix before the prefix is deployed, and a ROVR
from that keypair as specified in [RFC8928]. The prefix and the ROVR MUST be generated from that keypair as specified in [RFC8928]. The
MUST then be installed in the 6LBR at the first registration, or by prefix and the ROVR MUST then be installed in the 6LBR at the first
an external mechanism such as IP Address Management (IPAM) or DHCPv6 registration, or by an external mechanism such as IP Address
snooping prior to the first registration. This way, the 6LBR can Management (IPAM) or DHCPv6 snooping prior to the first registration.
recognize the prefix on the future registrations and validate the This way, the 6LBR can recognize the prefix on the future
right to register based on the ROVR. registrations and validate the right to register based on the ROVR.
The keypair MUST then be provisioned in each node that needs to The keypair MUST then be provisioned in each node that needs to
register the prefix or a prefix within, so the node can follow the register the prefix or a prefix within, so the node can follow the
steps in [RFC8928] to register the prefix. steps in [RFC8928] to register the prefix.
Upon receiving an NA message with the status set to 5 "Validation Upon receiving an NA message with the status set to 5 "Validation
Requested", the node that registered the address or prefix performs Requested", the node that registered the address or prefix performs
the proof of ownership based on that longest prefix match. the proof of ownership based on that longest prefix match.
10. Updating RFC 8929 10. Updating RFC 8929
"IPv6 Backbone Router" [RFC8929] defines a proxy operation whereby a "IPv6 Backbone Router" [RFC8929] defines a proxy operation whereby a
6LoWPAN Border Router (6LBR) may impersonate a 6LN when performing an 6LoWPAN Border Router (6LBR) may impersonate a 6LN when performing an
address registration. In that case, [RFC8505] messages are used as address registration. In that case, [RFC8505] messages are used as
is, with one change that the SLLAO in the proxied NS(EARO) messages is, with one change that the SLLAO in the proxied NS(EARO) messages
indicates the Registering Node (the 6LBR) as opposed to the indicates the Registering Node (the 6LBR) as opposed to the
Registered Node (the 6LN). See figure 5 of [RFC8929] for an example Registered Node (the 6LN). See Figure 5 of [RFC8929] for an example
of proxy operation by the 6LBR, which generates an NS(EARO) upon of proxy operation by the 6LBR, which generates an NS(EARO) upon
receiving an EDAR message. receiving an EDAR message.
This specification updates that proxy operation with the updates in This specification updates that proxy operation with the updates in
[RFC9685] and this on the formats and content of the EARO, the EDAR, [RFC9685] and this on the formats and content of the EARO, the EDAR,
and the EDAC messages, to support the P-Field and the signaling of and the EDAC messages, to support the P-Field and the signaling of
prefixes. The proxy MUST use the P-Field as received in the EDAR or prefixes. The proxy MUST use the P-Field as received in the EDAR or
NS(EARO) message to generate the proxied NS(EARO), and it MUST use NS(EARO) message to generate the proxied NS(EARO), and it MUST use
the exact same prefix and prefix length as received in the case of a the exact same prefix and prefix length as received in the case of a
prefix registration. prefix registration.
11. Security Considerations 11. Security Considerations
This specification updates [RFC8505], and the security section of This specification updates [RFC8505], and the security considerations
that document also applies to this document. In particular, the link of that document also apply to this document. In particular, the
layer SHOULD be sufficiently protected to prevent rogue access, else link layer SHOULD be sufficiently protected to prevent rogue access,
a rogue node with physical Access to the network may inject packets else a rogue node with physical access to the network may inject
and perform an attack from within. packets and perform an attack from within.
Section 9 leverages [RFC8928] to prevent a rogue node to register a Section 9 leverages AP-ND [RFC8928] to prevent a rogue node from
unicast address that it does not own. The mechanism could be registering a unicast address that it does not own. The mechanism
extended to anycast and multicast addresses if the values of the ROVR could be extended to anycast and multicast addresses if the values of
they use are known in advance, but how this is done is not in scope the ROVR they use are known in advance, but how this is done is not
for this specification. One way would be to authorize in advance the in scope for this specification. One way would be to authorize in
ROVR of the valid users. A less preferred way could be to advance the ROVR of the valid users. A less preferred way could be
synchronize the ROVR and TID values across the valid registering to synchronize the ROVR and TID values across the valid registering
nodes as a preshared key material. nodes as a preshared key material.
In the latter case, it could be possible to update the keys In the latter case, it could be possible to update the keys
associated to a prefix in all the 6LNs, but the flow is not clearly associated to a prefix in all the 6LNs, but the flow is not clearly
documented and may not complete in due time for all nodes in LLN use documented and may not complete in due time for all nodes in LLN use
cases. It may be simpler to install an all-new address with new keys cases. It may be simpler to install an all-new address with new keys
over a period of time, and switch the traffic to that address when over a period of time and switch the traffic to that address when the
the migration is complete. migration is complete.
12. Operational Considerations 12. Operational Considerations
12.1. Partially Upgraded Networks 12.1. Partially Upgraded Networks
A mix of devices that support only [RFC8505], both [RFC8505] and A mix of devices that support only [RFC8505], both [RFC8505] and
[RFC9685], and all of the above plus this specification, may coexist. [RFC9685], and all of the above plus this specification, may coexist.
Different cases may occur: Different cases may occur:
* A legacy 6LN will not register prefixes and the service will be * A legacy 6LN will not register prefixes, and the service will be
the same when the network is upgraded. the same when the network is upgraded.
* A legacy 6LR will not set the F flag in the 6CIO and an upgraded * A legacy 6LR will not set the F flag in the 6CIO and an upgraded
6LN will not register prefixes with that router, though it may 6LN will not register prefixes with that router, though it may
with other 6LRs that do support this specification. with other 6LRs that do support this specification.
* Upon an EDAR message, a legacy 6LBR may not realize that the * Upon an EDAR message, a legacy 6LBR may not realize that the
address being registered comes with a whole prefix, and return address being registered comes with a whole prefix, and return
that it is duplicate in the EDAC status. The 6LR MUST ignore a that it is duplicate in the EDAC status. The 6LR MUST ignore a
duplicate status in the EDAR for prefixes. duplicate status in the EDAR for prefixes.
skipping to change at page 21, line 31 skipping to change at line 937
o o o o +-------+ o o o o +-------+
o o o o +-------+ RPL o o o o +-------+ RPL
o | 6LN | leaf o | 6LN | leaf
+-------+ L +-------+ L
o : LLN node o : LLN node
Figure 5: RPL-Based Route-Over LLN Figure 5: RPL-Based Route-Over LLN
A RPL leaf L acting as a 6LN registers its addresses and prefixes to A RPL leaf L acting as a 6LN registers its addresses and prefixes to
a RPL router acting as a 6LR, using a layer-2 unicast NS message with a RPL router acting as a 6LR, using a L2 unicast NS message with an
an EARO as specified in [RFC8505] and [RFC9685]. Note that a RPL EARO as specified in [RFC8505] and [RFC9685]. Note that a RPL leaf
leaf acting as 6LN may still be a border router for another routing acting as 6LN may still be a border router for another routing
protocol, an access router for an IP link, or a virtual Router protocol, an access router for an IP link, or a virtual Router
serving virtual machines or applications within the same physical serving virtual machines or applications within the same physical
node. Note also that a RPL-aware Leaf would preferably leverage RPL node. Note also that a RPL-aware Leaf would preferably leverage RPL
directly to inject routes, to fully leverage the routing protocol. directly to inject routes, to fully leverage the routing protocol.
The registration state is periodically renewed by the Registering The registration state is periodically renewed by the Registering
Node (the 6LN), before the lifetime indicated in the EARO expires (at Node (the 6LN), before the lifetime indicated in the EARO expires (at
the 6LR). As for unicast IPv6 addresses, the 6LR uses an Extended the 6LR). As for unicast IPv6 addresses, the 6LR uses an Extended
Duplicate Address Request/Confirmation (EDAR/EDAC) exchange with the Duplicate Address Request/Confirmation (EDAR/EDAC) exchange with the
6LBR to notify the 6LBR of the presence of the listeners. With this 6LBR to notify the 6LBR of the presence of the listeners. With this
specification, a router that owns a prefix or provides reachability specification, a router that owns a prefix or provides reachability
to an external prefix but is not a RPL router can also register those to an external prefix but is not a RPL router can also register those
prefixes with the R flag set, to enable reachability to the Prefix prefixes with the R flag set, to enable reachability to the Prefix
within the RPL domain. within the RPL domain.
12.3. Application to a Shared Link 12.3. Application to a Shared Link
A shared link is a situation where more than one prefix is deployed A shared link is a situation where more than one prefix is deployed
over a L2 link (say a switched Ethernet fabric, or a Wi-Fi Extended over an L2 link (say, a switched Ethernet fabric or a Wi-Fi Extended
Service Set (ESS) federating multiple Access Points (APs)), and not Service Set (ESS) federating multiple Access Points (APs)), and not
necessarily all nodes are aware of all prefixes. Figure 6 depicts necessarily all nodes are aware of all prefixes. Figure 6 depicts
such a situation, with 2 routers 6LR1 and 6LR2 that own respective such a situation, with two routers 6LR1 and 6LR2 that own respective
prefixes P1:: and P2::, and expose those in their RA messages over prefixes P1:: and P2:: and expose those in their RA messages over the
the same link. Note that the shared link maybe operated with any same link. Note that the shared link maybe operated with any
combination of NDP and SND as discussed in section 7 of combination of NDP and SND as discussed in Section 7 of
[I-D.ietf-6man-ipv6-over-wireless]. [IPv6-over-NBMA].
.- -- . .- -- .
.-( ). .-( ).
( Internet ) ( Internet )
(___.________.___) (___.________.___)
| |
+----+--+ +-------+ +----+--+ +-------+
| P1::a | | P2::b | | P1::a | | P2::b |
| 6LR1 | | 6LR2 | | 6LR1 | | 6LR2 |
+---+---+ +---+---+ +---+---+ +---+---+
skipping to change at page 22, line 37 skipping to change at line 986
----+--+------+---------+-+-------+---------+---- ----+--+------+---------+-+-------+---------+----
| | | | | | | | | |
+--+--+ +--+--+ +--+--+ +--+--+ +--+--+ +--+--+ +--+--+ +--+--+ +--+--+ +--+--+
|P1::c| |P2::d| |P2::e| |P1::f| |P1::g| |P1::c| |P2::d| |P2::e| |P1::f| |P1::g|
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+
Figure 6: Shared Link Figure 6: Shared Link
Say that 6LR1 is the router providing access to the outside, and 6LR2 Say that 6LR1 is the router providing access to the outside, and 6LR2
is aware of 6LR1 as its default gateway. With this specification, is aware of 6LR1 as its default gateway. With this specification,
6LR2 registers P2:: to 6LR1 and 6LR1 installs a route to P2:: via 6LR2 registers P2:: to 6LR1, and 6LR1 installs a route to P2:: via
6LR2. This way, addresses that derive from P2:: can still be reached 6LR2. This way, addresses that derive from P2:: can still be reached
via 6LR1 and then 6LR2. 6LR2 may then leverage ICMP Redirect via 6LR1 and then 6LR2. 6LR2 may then leverage ICMP Redirect
messages [RFC4861] to shorten the path between 6LR1 and the nodes messages [RFC4861] to shorten the path between 6LR1 and the nodes
that own those addresses. that own those addresses.
If P2 was delegated by 6LR1, e.g., using the "Dynamic Host If P2 were delegated by 6LR1, e.g., using DHCPv6 [RFC8415], then the
Configuration Protocol for IPv6" [RFC8415] (DHCPv6), then the
expectation is that 6LR1 aggregates P1:: and P2:: in its expectation is that 6LR1 aggregates P1:: and P2:: in its
advertisements to the outside, and there is no need to set the R advertisements to the outside, and there is no need to set the R
flag. But unless 6LR2 knows about such a situation, e.g., through flag. However, unless 6LR2 knows about such a situation, e.g.,
configuration, 6LR2 SHOULD set the R flag requesting 6LR1 to through configuration, 6LR2 SHOULD set the R flag requesting 6LR1 to
advertise P2:: so as to obtain reachability. advertise P2:: so as to obtain reachability.
12.4. Application to a Hub Link with Stub Spokes 12.4. Application to a Hub Link with Stub Spokes
A hub link is a situation where stub links are deployed around a A hub link is a situation where stub links are deployed around a
backbone and interconnected by routers. Figure 7 depicts such a backbone and interconnected by routers. Figure 7 depicts such a
situation, with one router 6LR1 serving the hub link and at least one situation, with one router 6LR1 serving the hub link and at least one
router like 6LR2 and 6LR3 providing connectivity from the stub links router like 6LR2 and 6LR3 providing connectivity from the stub links
to the hub link. In this example, say that there is one prefix on to the hub link. In this example, say that there is one prefix on
each link, P1:: on the hub link and P2:: and P3:: on the stub links. each link -- P1:: on the hub link, and P2:: and P3:: on the stub
links.
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+
|P2::s| |P2::d| |P2::e| |P2::f| |P2::s| |P2::d| |P2::e| |P2::f|
+--+--+ +--+--+ +--+--+ +--+--+ +--+--+ +--+--+ +--+--+ +--+--+
| | | | | | | |
----+----+----+---------+--STUB-LINK--+----- ----+----+----+---------+--STUB-LINK--+-----
| |
+---+---+ +-------+ +---+---+ +-------+
| P2::r | | | .- --.. | P2::r | | | .- --..
| 6LR2 | | 6LR1 +---- .-( ). | 6LR2 | | 6LR1 +---- .-( ).
skipping to change at page 23, line 44 skipping to change at line 1039
----+--+------+---------+--STUB-LINK--+-+----- ----+--+------+---------+--STUB-LINK--+-+-----
| | | | | | | |
+--+--+ +--+--+ +--+--+ +--+--+ +--+--+ +--+--+ +--+--+ +--+--+
|P3::h| |P3::i| |P3::j| |P3::k| |P3::h| |P3::i| |P3::j| |P3::k|
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+
Figure 7: Hub and Stubs Figure 7: Hub and Stubs
As before, say that 6LR1 is the router providing access to the As before, say that 6LR1 is the router providing access to the
outside, and 6LR2 is aware of 6LR1 as its default gateway. With this outside, and 6LR2 is aware of 6LR1 as its default gateway. With this
specification, 6LR2 registers P2:: to 6LR1 and 6LR1 installs a route specification, 6LR2 registers P2:: to 6LR1, and 6LR1 installs a route
to P2:: via 6LR2. This way, nodes on the stub link behind 6LR2 that to P2:: via 6LR2. This way, nodes on the stub link behind 6LR2 that
derive their addresses from P2:: can still be reached via 6LR1 and derive their addresses from P2:: can still be reached via 6LR1 and
then 6LR2. The same goes for 6LR3 and any other routers serving stub then 6LR2. The same goes for 6LR3 and any other routers serving stub
links. links.
If P2 was delegated by 6LR1, then the expectation is that 6LR1 If P2 were delegated by 6LR1, then the expectation is that 6LR1
aggregates P1:: and P2:: in its advertisements to the outside, and aggregates P1:: and P2:: in its advertisements to the outside, and
there is no need to set the R flag. But unless 6LR2 knows about such there is no need to set the R flag. However, unless 6LR2 knows about
a situation, e.g., through configuration, 6LR2 SHOULD set the R flag such a situation, e.g., through configuration, 6LR2 SHOULD set the R
requesting 6LR1 to advertise P2:: so as to obtain reachability. flag requesting 6LR1 to advertise P2:: so as to obtain reachability.
In this example, routers 6LR3 and 6LR4 both connect to the same stub In this example, routers 6LR3 and 6LR4 both connect to the same stub
link where subnet P3 is installed. They may both register P3 to link where subnet P3 is installed. They may both register P3 to
6LR1, and 6LR1 will apply its own load balancing logic to use either 6LR1, and 6LR1 will apply its own load-balancing logic to use either
of the routers. of the routers.
13. IANA Considerations 13. IANA Considerations
Note to RFC Editor, to be removed: please replace "This RFC" IANA has made changes under the "Internet Control Message Protocol
throughout this document by the RFC number for this specification version 6 (ICMPv6) Parameters" [IANA.ICMP] and the "Routing Protocol
once it is allocated. for Low Power and Lossy Networks (RPL)" [IANA.RPL] registry groups,
as follows.
IANA is requested to make changes under the "Internet Control Message
Protocol version 6 (ICMPv6) Parameters" [IANA.ICMP] and the "Routing
Protocol for Low Power and Lossy Networks (RPL)" [IANA.RPL] registry
groupings, as follows:
13.1. Updated P-Field Registry 13.1. Updated P-Field Registry
This specification updates the P-Field introduced in [RFC9685] to This specification updates the P-Field introduced in [RFC9685] to
assign the value of 3, which is the only remaining unassigned value assign the value of 3, which is the only remaining unassigned value
for the 2-bit field. To that effect, IANA is requested to update the for the 2-bit field. To that effect, IANA has updated the "P-Field
"P-Field values" registry under the heading "Internet Control Message Values" registry in the "Internet Control Message Protocol version 6
Protocol version 6 (ICMPv6) Parameters" as indicated in Table 2: (ICMPv6) Parameters" registry group as indicated in Table 2:
+-------+---------------------------+-----------+ +=======+===========================+===========+
| Value | Meaning | Reference | | Value | Meaning | Reference |
+-------+---------------------------+-----------+ +=======+===========================+===========+
| *3* | Registration for a prefix | This RFC | | *3* | Registration for a Prefix | RFC 9926 |
+-------+---------------------------+-----------+ +-------+---------------------------+-----------+
Table 2: New P-Field value Table 2: New P-Field Value
13.2. New 6LoWPAN Capability Bit 13.2. New 6LoWPAN Capability Bit
IANA is requested to make an addition to the "6LoWPAN Capability IANA has made an addition to the "6LoWPAN Capability Bits"
Bits" [IANA.ICMP.6CIO] registry under the heading "Internet Control [IANA.ICMP.6CIO] registry in the "Internet Control Message Protocol
Message Protocol version 6 (ICMPv6) Parameters" as indicated in version 6 (ICMPv6) Parameters" registry group as indicated in
Table 3: Table 3:
IANA is also requested to fix the description of bit 9 (the "A" flag IANA has fixed the description of bit 9 (the "A" flag defined in
defined in [RFC8928]). It is not called "1" but "A". [RFC8928]). It is not called "1" but "A".
+------------------+---------------------------+-----------+ +======+=============================================+===========+
| Bit | Description | Reference | | Bit | Description | Reference |
+------------------+---------------------------+-----------+ +======+=============================================+===========+
| *9* | AP-ND Enabled (A bit) | [RFC8928] | | *9* | AP-ND Enabled (A bit) | [RFC8928] |
+------------------+---------------------------+-----------+ +------+---------------------------------------------+-----------+
| *16 (suggested)* | Registration for prefixes | This RFC | | *16* | Registration for prefixes Supported (F bit) | RFC 9926 |
| | Supported (F bit) | | +------+---------------------------------------------+-----------+
+------------------+---------------------------+-----------+
Table 3: New 6LoWPAN Capability Bit Table 3: New 6LoWPAN Capability Bit
14. Acknowledgments 14. Normative References
Many thanks to Dave Thaler and Dan Romascanu for their early reviews,
Adnan Rashid for all his contributions, and Eric Vyncke for his in-
depth AD review. Many thanks as well to the reviewers of the IETF
last call and IESG rounds, Dan Romascanu, Shuping Peng, Mohamed
Boucadair, Paul Wouters, Ketan Talaulikar, Gunter Van de Velde, Mike
Bishop, Roman Danyliw, ...
15. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007, DOI 10.17487/RFC4861, September 2007,
<https://www.rfc-editor.org/info/rfc4861>. <https://www.rfc-editor.org/info/rfc4861>.
skipping to change at page 27, line 6 skipping to change at line 1169
(Routing Protocol for Low-Power and Lossy Networks) (Routing Protocol for Low-Power and Lossy Networks)
Leaves", RFC 9010, DOI 10.17487/RFC9010, April 2021, Leaves", RFC 9010, DOI 10.17487/RFC9010, April 2021,
<https://www.rfc-editor.org/info/rfc9010>. <https://www.rfc-editor.org/info/rfc9010>.
[RFC9685] Thubert, P., Ed., "Listener Subscription for IPv6 Neighbor [RFC9685] Thubert, P., Ed., "Listener Subscription for IPv6 Neighbor
Discovery Multicast and Anycast Addresses", RFC 9685, Discovery Multicast and Anycast Addresses", RFC 9685,
DOI 10.17487/RFC9685, November 2024, DOI 10.17487/RFC9685, November 2024,
<https://www.rfc-editor.org/info/rfc9685>. <https://www.rfc-editor.org/info/rfc9685>.
[IANA.ICMP] [IANA.ICMP]
IANA, "IANA Registry for ICMPv6", IANA, IANA, "Internet Control Message Protocol version 6
https://www.iana.org/assignments/icmpv6-parameters/ (ICMPv6) Parameters",
icmpv6-parameters.xhtml. <https://www.iana.org/assignments/icmpv6-parameters>.
[IANA.ICMP.6CIO] [IANA.ICMP.6CIO]
IANA, "IANA Registry for the 6LoWPAN Capability Bits", IANA, "6LoWPAN Capability Bits",
IANA, https://www.iana.org/assignments/icmpv6-parameters/ <https://www.iana.org/assignments/icmpv6-parameters>.
icmpv6-parameters.xhtml#sixlowpan-capability-bits.
[IANA.RPL] IANA, "IANA Registry for the RPL", [IANA.RPL] IANA, "Routing Protocol for Low Power and Lossy Networks
IANA, https://www.iana.org/assignments/rpl/rpl.xhtml. (RPL)", <https://www.iana.org/assignments/rpl>.
16. Informative References 15. Informative References
[BCP38] Ferguson, P. and D. Senie, "Network Ingress Filtering: [BCP38] Best Current Practice 38,
<https://www.rfc-editor.org/info/bcp38>.
At the time of writing, this BCP comprises the following:
Ferguson, P. and D. Senie, "Network Ingress Filtering:
Defeating Denial of Service Attacks which employ IP Source Defeating Denial of Service Attacks which employ IP Source
Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827, Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827,
May 2000, <https://www.rfc-editor.org/info/rfc2827>. May 2000, <https://www.rfc-editor.org/info/rfc2827>.
[RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and [RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and
More-Specific Routes", RFC 4191, DOI 10.17487/RFC4191, More-Specific Routes", RFC 4191, DOI 10.17487/RFC4191,
November 2005, <https://www.rfc-editor.org/info/rfc4191>. November 2005, <https://www.rfc-editor.org/info/rfc4191>.
[RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6 [RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6
over Low-Power Wireless Personal Area Networks (6LoWPANs): over Low-Power Wireless Personal Area Networks (6LoWPANs):
skipping to change at page 28, line 5 skipping to change at line 1217
Richardson, M., Jiang, S., Lemon, T., and T. Winters, Richardson, M., Jiang, S., Lemon, T., and T. Winters,
"Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)",
RFC 8415, DOI 10.17487/RFC8415, November 2018, RFC 8415, DOI 10.17487/RFC8415, November 2018,
<https://www.rfc-editor.org/info/rfc8415>. <https://www.rfc-editor.org/info/rfc8415>.
[RFC9030] Thubert, P., Ed., "An Architecture for IPv6 over the Time- [RFC9030] Thubert, P., Ed., "An Architecture for IPv6 over the Time-
Slotted Channel Hopping Mode of IEEE 802.15.4 (6TiSCH)", Slotted Channel Hopping Mode of IEEE 802.15.4 (6TiSCH)",
RFC 9030, DOI 10.17487/RFC9030, May 2021, RFC 9030, DOI 10.17487/RFC9030, May 2021,
<https://www.rfc-editor.org/info/rfc9030>. <https://www.rfc-editor.org/info/rfc9030>.
[I-D.ietf-6man-ipv6-over-wireless] [IPv6-over-NBMA]
Thubert, P. and M. Richardson, "Architecture and Framework Thubert, P. and M. Richardson, "Architecture and Framework
for IPv6 over Non-Broadcast Access", Work in Progress, for IPv6 over Non-Broadcast Access", Work in Progress,
Internet-Draft, draft-ietf-6man-ipv6-over-wireless-08, 19 Internet-Draft, draft-ietf-6man-ipv6-over-wireless-09, 9
May 2025, <https://datatracker.ietf.org/doc/html/draft- November 2025, <https://datatracker.ietf.org/doc/html/
ietf-6man-ipv6-over-wireless-08>. draft-ietf-6man-ipv6-over-wireless-09>.
[IEEE802154] [IEEE802154]
IEEE standard for Information Technology, "IEEE Std IEEE, "IEEE Standard for Information technology -- Local
802.15.4, Part. 15.4: Wireless Medium Access Control (MAC) and metropolitan area networks -- Specific requirements --
and Physical Layer (PHY) Specifications for Low-Rate Part 15.4: Wireless Medium Access Control (MAC) and
Wireless Personal Area Networks". Physical Layer (PHY) Specifications for Low Rate Wireless
Personal Area Networks (WPANs)", IEEE Std 802.15.4-2006,
DOI 10.1109/IEEESTD.2006.232110, 2006,
<https://ieeexplore.ieee.org/document/1700009>.
[IEEE80211] [IEEE80211]
IEEE standard for Information Technology, "IEEE Standard IEEE, "IEEE Standard for Information Technology --
802.11 - IEEE Standard for Information Technology - Telecommunications and Information Exchange between
Telecommunications and information exchange between Systems - Local and Metropolitan Area Networks -- Specific
systems Local and metropolitan area networks - Specific Requirements - Part 11: Wireless LAN Medium Access Control
requirements - Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications", IEEE
(MAC) and Physical Layer (PHY) Specifications.", Std 802.11-2022, DOI 10.1109/IEEESTD.2021.9363693,
<https://ieeexplore.ieee.org/document/9363693>. <https://ieeexplore.ieee.org/document/9363693>.
[WI-SUN] "Wi-SUN Alliance", <https://wi-sun.org/>. [WI-SUN] "Wi-SUN Alliance", <https://wi-sun.org/>.
[IEEE802151] [IEEE802151]
IEEE standard for Information Technology, "IEEE Standard IEEE, "IEEE Standard for Telecommunications and
for Information Technology - Telecommunications and Information Exchange Between Systems - LAN/MAN - Specific
Information Exchange Between Systems - Local and Requirements - Part 15: Wireless Medium Access Control
Metropolitan Area Networks - Specific Requirements. - Part (MAC) and Physical Layer (PHY) Specifications for Wireless
15.1: Wireless Medium Access Control (MAC) and Physical Personal Area Networks (WPANs)", IEEE Std 802.15.1-2002,
Layer (PHY) Specifications for Wireless Personal Area DOI 10.1109/IEEESTD.2002.93621, 2002,
Networks (WPANs)". <https://ieeexplore.ieee.org/document/1016473>.
Acknowledgments
Many thanks to Dave Thaler and Dan Romascanu for their early reviews,
Adnan Rashid for all his contributions, and Éric Vyncke for his in-
depth AD review. Many thanks as well to the reviewers of the IETF
Last Call and IESG rounds: Dan Romascanu, Shuping Peng, Mohamed
Boucadair, Paul Wouters, Ketan Talaulikar, Gunter Van de Velde, Mike
Bishop, and Roman Danyliw.
Author's Address Author's Address
Pascal Thubert (editor) Pascal Thubert (editor)
06330 Roquefort-les-Pins 06330 Roquefort-les-Pins
France France
Email: pascal.thubert@gmail.com Email: pascal.thubert@gmail.com
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