6lo
Internet Engineering Task Force (IETF) P. Thubert, Ed.
Request for Comments: 9685 November 2024
Updates: 4861, 6550, 6553, 8505, 9010 (if
approved)
Intended status:
Category: Standards Track
Expires: 17 November 2024
ISSN: 2070-1721
IPv6 Neighbor Discovery Multicast and Anycast Address Listener
Subscription
draft-ietf-6lo-multicast-registration-19
Abstract
This document updates the 6LoWPAN extensions to IPv6 Neighbor
Discovery (RFC 4861, RFC (specified in RFCs 4861 and 8505) to enable a listener to
subscribe to an IPv6 anycast or multicast address; the address. This document
also updates the Routing Protocol for Low-Power and Lossy Networks (RFC 6550, RFC
(RPL) (specified in RFCs 6550 and 6553) to add a new Non-Storing Multicast Mode
multicast mode and a new support for anycast addresses in Storing and
Non-Storing Modes. modes. This document extends RFC 9010 to enable a
6LoWPAN Router (6LR) to inject the anycast and multicast addresses in
RPL.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list It represents the consensus of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid the IETF community. It has
received public review and has been approved for a maximum publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of six months RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be updated, replaced, or obsoleted by other documents obtained at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 17 November 2024.
https://www.rfc-editor.org/info/rfc9685.
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 5
2.2. References . . . . . . . . . . . . . . . . . . . . . . . 5
2.3. Glossary . . . . . . . . . . . . . . . . . . . . . . . . 6 Abbreviations
2.4. New terms . . . . . . . . . . . . . . . . . . . . . . . . 7 Terms
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4. Updating RFC 4861 . . . . . . . . . . . . . . . . . . . . . . 13
5. Updating RFC 7400 . . . . . . . . . . . . . . . . . . . . . . 13
6. Updating RFC 6550 . . . . . . . . . . . . . . . . . . . . . . 13
6.1. Mandating the ROVR field . . . . . . . . . . . . . . . . 14 Field
6.2. Updating MOP 3 . . . . . . . . . . . . . . . . . . . . . 15
6.3. New Non-Storing Multicast MOP . . . . . . . . . . . . . . 16
6.4. RPL Anycast Operation . . . . . . . . . . . . . . . . . . 17
6.5. New Registered Address Type Indicator P-Field . . . . . . 18
6.6. New RPL Target Option P-Field . . . . . . . . . . . . . . 19
7. Updating RFC 8505 . . . . . . . . . . . . . . . . . . . . . . 20
7.1. Placing the New P-Field in the EARO . . . . . . . . . . . 20
7.2. Placing the New P-Field in the EDAR Message . . . . . . . 21
7.3. Registration Extensions . . . . . . . . . . . . . . . . . 22
8. Updating RFC 9010 . . . . . . . . . . . . . . . . . . . . . . 25
9. Leveraging RFC 8928 . . . . . . . . . . . . . . . . . . . . . 26
10. Consistent Uptime Option . . . . . . . . . . . . . . . . . . 27
11. Operational considerations . . . . . . . . . . . . . . . . . 29 Considerations
12. Security Considerations . . . . . . . . . . . . . . . . . . . 31
13. Backward Compatibility . . . . . . . . . . . . . . . . . . . 32
14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 32
14.1. New P-Field values Values Registry . . . . . . . . . . . . . . 33
14.2. New EDAR Message Flags Registry . . . . . . . . . . . . 33
14.3. New EARO flags . . . . . . . . . . . . . . . . . . . . . 34 Address Registration Option Flags
14.4. New RTO flags . . . . . . . . . . . . . . . . . . . . . 34 RPL Target Option Flags
14.5. New RPL Mode of Operation . . . . . . . . . . . . . . . 34
14.6. New 6LoWPAN Capability Bits . . . . . . . . . . . . . . 35 Bit
14.7. New Address Registration Option Status Values . . . . . 35
14.8. New IPv6 Neighbor Discovery Option . . . . . . . . . . . 35 Format
15. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 36
16. References
15.1. Normative References . . . . . . . . . . . . . . . . . . . . 36
17.
15.2. Informative References . . . . . . . . . . . . . . . . . . . 38
Acknowledgments
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 41
1. Introduction
The design of Low Power Low-Power and Lossy Networks (LLNs) is generally
focused on saving energy, which is the most constrained resource of
all. Other design constraints, such as a limited memory capacity,
duty cycling of the LLN devices and low-power lossy transmissions,
derive from that primary concern. The radio (both (when both transmitting
or simply listening) is a major energy drain drain, and the LLN protocols
must be adapted to allow the nodes to remain sleeping with the radio
turned off at most times.
The "Routing
"RPL: IPv6 Routing Protocol for Low Power Low-Power and Lossy Networks"
[RFC6550]
(RPL) provides IPv6 [RFC8200] routing services within such
constraints. To save signaling and routing state in constrained
networks, the RPL routing is only performed along a Destination-
Oriented Directed Acyclic Graph (DODAG) that is optimized to reach a
Root node, as opposed to along the shortest path between 2 two peers,
whatever that would mean in each LLN.
This trades the quality of peer-to-peer (P2P) paths for a vastly
reduced amount of control traffic and routing state that would be
required to operate an any-to-any shortest path protocol.
Additionally, broken routes may be fixed lazily and on-demand, on-demand based
on dataplane inconsistency discovery, which avoids wasting energy in
the proactive repair of unused paths.
RPL uses Destination Advertisement Object (DAO) messages to establish
Downward routes. DAO messages are an optional feature for
applications that require point-to-multipoint (P2MP) or point-to-
point (P2P) traffic. RPL supports two modes of Downward traffic:
Storing (fully stateful) or Non-Storing (fully source routed); see
Section 9 of [RFC6550]. The mode is signaled in the Mode of
Operation (MOP) field in the DODAG Information Object (DIO) messages
and applies to the whole RPL Instance.
Any given RPL Instance is either storing Storing or non-storing. Non-Storing. In both
cases, P2P packets travel Up toward a DODAG root then Down to the
final destination (unless the destination is on the Upward route).
In the Non-Storing case, the packet will travel all the way to a
DODAG root before traveling Down. In the Storing case, the packet
may be directed Down towards the destination by a common ancestor of
the source and the destination prior to reaching a DODAG root.
Section 12 of [RFC6550] details the "Storing Mode of Operation with
multicast support" with source-independent multicast routing in RPL.
The classical "IPv6 Neighbor "Neighbor Discovery (IPv6 ND) Protocol" for IP version 6 (IPv6)" [RFC4861]
[RFC4862] was defined for serial links and shared transit media such
as Ethernet at a time when broadcast was cheap on those media types was cheap,
while memory for neighbor cache was expensive. It was thus designed
as a reactive protocol that relies on caching and multicast
operations for the Address Discovery (aka Lookup) lookup) and Duplicate
Address Detection (DAD) of IPv6 unicast addresses. Those multicast
operations typically impact every node on-link when at most one is
really
targeted, which targeted. This is a waste of energy, energy and imply implies that all
nodes are awake to hear the request, which is inconsistent with power saving
power-saving (sleeping) modes.
The original specification for 6LoWPAN ND, Neighbor Discovery (ND),
"Neighbor Discovery Optimizations Optimization for
6LoWPAN networks" IPv6 over Low-Power Wireless
Personal Area Networks (6LoWPANs)" [RFC6775], was introduced to avoid
the excessive use of multicast messages and enable IPv6 ND for
operations over energy-constrained nodes. [RFC6775] changes the
classical IPv6 ND model to proactively establish the Neighbor Cache
Entry (NCE) associated to the unicast address of a 6LoWPAN Node (6LN)
in the one or more 6LoWPAN Router(s) (6LR) Routers (6LRs) that serve(s) serve it. To that effect,
[RFC6775] defines a new Address Registration Option (ARO) that is
placed in unicast Neighbor Solicitation (NS) and Neighbor
Advertisement (NA) messages between the 6LN and the 6LR.
"Registration Extensions for 6LoWPAN IPv6 over Low-Power Wireless Personal
Area Network (6LoWPAN) Neighbor Discovery" [RFC8505] updates
[RFC6775] into so that a generic Address Registration mechanism that can be
used to access services such as routing and ND proxy and introduces
the Extended Address Registration Option (EARO) for that purpose.
This provides a routing-agnostic interface for a host to request that
the router injects a unicast IPv6 address in the local routing
protocol and provide provides return reachability for that address.
"Routing for RPL (Routing Protocol for Low-Power and Lossy Networks)
Leaves" [RFC9010] provides the router counterpart of the mechanism
for a host that implements [RFC8505] to inject its unicast Unique
Local Addresses (ULAs) and Global Unicast Addresses (GUAs) in RPL. But though
Although RPL also provides multicast routing, 6LoWPAN ND supports
only the registration of unicast addresses addresses, and there is no
equivalent of [RFC9010] to specify the 6LR behavior upon the
subscription of one or more multicast address(es).
The addresses.
"Multicast Listener Discovery Version 2 (MLDv2) for IPv6" [RFC3810]
enables the router to learn which node listens to which multicast
address, but as the classical IPv6 ND protocol, MLD relies on
multicasting Queries queries to all nodes, which is unfit for low power low-power
operations. As for IPv6 ND, it makes sense to let the 6LNs control
when and how they maintain the state associated to their multicast
addresses in the 6LR, e.g., during their own wake time. In the case
of a constrained node that already implements [RFC8505] for unicast
reachability, it makes sense to extend to that support to subscribe the
multicast addresses they listen to.
This specification Extends [RFC8505] and [RFC9010] to add by adding the
capability for the 6LN to subscribe anycast and multicast addresses
and for the 6LR to inject them in RPL when appropriate. Note that
due to the unreliable propagation of packets in the LLN, it cannot be
guaranteed that any given packet is delivered once and only once. If
a breakage happens along the preferred parent tree that is normally
used for multicast forwarding, the packet going up may be rerouted to
an alternate parent, leading to potential failures and duplications,
whereas a packet going down will not be delivered in the subtree. It
is up to the Upper Layer Protocols (ULPs) to cope with both
situations.
2. Terminology
2.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
In addition, the terms "Extends" and "Amends" are used as a more specific term terms
for "Updates" per [I-D.kuehlewind-update-tag] section Section 3 of [UPDATES-TAG] as follows:
Amends/Amended by: This tag pair is used with an amending RFC that
changes the amended RFC. This could include bug fixes,
behavior changes changes, etc. This is intended to specify mandatory
changes to the protocol. The goal of this tag pair is to
signal to anyone looking to implement the amended RFC that
they MUST also implement the amending RFC.
Extends/Extended by: This tag pair is used with an extending RFC
that defines an optional addition to the extended RFC. This
can be used by documents that use existing extension points or
clarifications that do not change existing protocol behavior.
This signals to implementers and protocol designers that there
are changes to the extended RFC that they need to consider but
not necessarily implement.
2.2. References
This document uses terms and concepts that are discussed in:
* "Neighbor Discovery for IP version 6" [RFC4861] and 6 (IPv6)" [RFC4861],
* "IPv6 Stateless address Address Autoconfiguration" [RFC4862],
* "RPL: IPv6 Routing Protocol for Low-Power and Lossy Networks Networks"
[RFC6550],
* Neighbor "Neighbor Discovery Optimization for IPv6 over Low-Power and Lossy Wireless
Personal Area Networks (6LoWPANs)" [RFC6775], as well as
* "Registration Extensions for 6LoWPAN IPv6 over Low-Power Wireless Personal
Area Network (6LoWPAN) Neighbor Discovery" [RFC8505] [RFC8505], and
* "Using RPI Option Type, Routing Header for Source Routes, and
IPv6-in-IPv6 Encapsulation in the RPL Data Plane" [RFC9008].
2.3. Glossary Abbreviations
This document uses the following acronyms: abbreviations:
6BBR 6LoWPAN Backbone Router
6CIO Capability Indication Option
6LBR 6LoWPAN Border Router
6LN 6LoWPAN Node
6LR 6LoWPAN Router
AMC Address Mapping Confirmation
AMR Address Mapping Request
ARO Address Registration Option
DAC Duplicate Address Confirmation
DAD Duplicate Address Detection
DAO Destination Advertisement Object
DAR Duplicate Address Request
DIO DODAG Information Object
DMB Direct MAC Broadcast
DODAG Destination-Oriented Directed Acyclic Graph
EARO Extended Address Registration Option
EDAC Extended Duplicate Address Confirmation
EDAR Extended Duplicate Address Request
IR Ingress Replication
LLN Low-Power and Lossy Network
MOP Mode of Operation
NA Neighbor Advertisement
NCE Neighbor Cache Entry
ND Neighbor Discovery
NS Neighbor Solicitation
RA Router Advertisement
ROVR Registration Ownership Verifier, pronounced "rover" Verifier (pronounced "rover")
RPL Routing Protocol for Low-Power and Lossy Networks, pronounced
"ripple" Networks (pronounced
"ripple")
RS Router Solicitation
RTO RPL Target Option
TID Transaction ID
TIO Transit Information Option
2.4. New terms Terms
This document introduces the following terms:
Origin The node that issued an anycast or multicast advertisement,
either in the form of an NS(EARO) or as a DAO(TIO, RTO) RTO).
Merge/merging The action of receiving multiple anycast or multicast
advertisements, either internally from self, in the form of an
NS(EARO), or as a DAO(TIO, RTO), and generating a single
DAO(TIO, RTO). The RPL router maintains a state per origin
for each advertised address, address and merges the advertisements for
all subscriptions for the same address in a single
advertisement. A RPL router that merges multicast
advertisements from different origins becomes the origin of
the merged advertisement and uses its own values for the Path
Sequence and Registration Ownership Verifier (ROVR) fields.
Subscribe/subscription The special form of registration that
leverages NS(EARO) to register (subscribe (or subscribe to) a multicast
or an anycast address.
3. Overview
This specification Extends [RFC8505] and inherits from [RFC8928] to
provide a registration method - called subscription (called "subscription" in this case - case)
for anycast and multicast address. addresses. [RFC8505] is agnostic to the
routing protocol in which the address may be redistributed.
As opposed to unicast addresses, there might be multiple
registrations from multiple parties for the same address. The router
retains one registration per party per multicast or anycast address,
but injects the route into the routing protocol only once for each
address, asynchronously to the registration. On the other hand, the
validation exchange with the registrar (6LBR) is still needed if the
router checks the right for the host to listen to the anycast or
multicast address.
Figure 1 depicts the registration of an anycast or a multicast
address. As shown, the 6LBR receives and accepts multiple Extended
DAR EDAR
messages for the same address, and the address being registered by
multiple nodes is not treated as a duplication.
6LoWPAN Node 6LR 6LBR
(host1) (router) (registrar)
| | |
| DMB link | |
| | |
| ND-Classic RS | |
|----------------->| |
|------------> | |
|------------------------> |
| ND-Classic RA | |
|<-----------------| |
| | |
| NS(EARO) | |
|----------------->| |
| | Extended DAR EDAR |
| |-------------->|
| | |
| | Extended DAC EDAC |
| |<--------------|
| NA(EARO) |
|<-----------------|<inject route> ->
| |
...
(host2) (router) 6LBR
| NS(EARO) | |
|----------------->| |
| | |
| | Extended DAR EDAR |
| |-------------->|
| | |
| | Extended DAC EDAC |
| |<--------------|
| NA(EARO) | |
|<-----------------| |
...
(host1) (router)
| NS(EARO) | |
|----------------->| |
| | |
| NA(EARO) | |
|<-----------------| |
...
| |<maintain route> ->
...
Figure 1: Registration Flow for an anycast Anycast or multicast Multicast Address
In classical networks, [RFC8505] may be used for an ND proxy
operation as specified in [RFC8929], [RFC8929] or redistributed in a full-
fledged routing protocol such as what might be done in BGP for
Ethernet VPN [I-D.thubert-bess-secure-evpn-mac-signaling] [MAC-SIGNALING] or in the Routing In in Fat Trees (RIFT)
protocol [I-D.ietf-rift-rift]. [RIFT]. The device mobility can be gracefully supported as
long as the routers can exchange and make sense of the sequence
counter in the TID field of the EARO.
In the case of LLNs, RPL [RFC6550] is the routing protocol of choice
and [RFC9010] specifies how the unicast address advertised with
[RFC8505] is redistributed in RPL. This specification also provides
RPL extensions for anycast and multicast address operation and
redistribution. In the RPL case case, and unless specified otherwise, the
behavior of the 6LBR that acts as RPL Root, of the intermediate
routers down the RPL graph, of the 6LR 6LRs that act as access routers
and of the 6LNs that are the RPL-unaware destinations, is the same as
for unicast. In particular, forwarding a packet happens as specified
in
section Section 11 of [RFC6550], including loop avoidance and detection,
though in the case of multicast case, multiple copies might be generated.
[RFC8505] is a pre-requisite prerequisite to this specification. A node that
implements this MUST also implement [RFC8505]. This specification
modifies existing options and updates the associated behaviors to
enable the Registration for Multicast Addresses as an extension to
[RFC8505]. As with the unicast address registration, the
subscription to anycast and multicast addresses between a node and
its router(s) is agnostic (meaning, independent, unaware of) to (meaning it is independent or unaware) of
the routing protocol in which this information may be redistributed
or aggregated by the router to other routers, though protocol
extensions would be needed in the protocol when multicast services
are not available.
This specification also Extends [RFC6550] and [RFC9010] in the case
of a route-over multilink subnet based on the RPL routing protocol, to add
multicast ingress replication in Non-Storing Mode mode and anycast support
in both Storing and Non-Storing modes. modes in the case of a route-over
multilink subnet based on the RPL routing protocol. A 6LR that
implements the RPL extensions specified herein MUST also implement
[RFC9010].
Figure 2 illustrates the classical situation of an LLN as a single
IPv6 Subnet, subnet, with a 6LoWPAN Border Router (6LBR) 6LBR that acts as Root for RPL operations and
maintains a registry of the active registrations as an abstract data
structure called an Address
Registrar "Address Registrar" for 6LoWPAN ND.
The LLN may be a hub-and-spoke access link such as (Low-Power) Wi-Fi
[IEEE Std 802.11]
[IEEE-802.11] and (Low-Energy) Bluetooth (Low Energy) [IEEE Std 802.15.1], [IEEE-802.15.1] or a Route-Over Route-
Over LLN such as the Wi-SUN [Wi-SUN] and 6TiSCH IPv6 over the TSCH mode of
IEEE 802.15.4 (6TiSCH) [RFC9030] meshes that leverages leverage 6LoWPAN
[RFC4919] [RFC6282] and RPL [RFC6550] over [IEEE Std 802.15.4]. IEEE 802.15.4
[IEEE-802.15.4].
|
----+-------+------------
| Wire side
+------+
| 6LBR |
|(Root)|
+------+
o o o Wireless side
o o o o o o
o o o o o o o
o o o LLN o +---+
o o o o o |6LR|
o o o o o +---+
o o o o o o z
o o oo o o +---+
o |6LN|
+---+
Figure 2: Wireless Mesh
A leaf acting as a 6LN registers its unicast addresses to a RPL
router acting as a 6LR, 6LR using a layer-2 Layer 2 unicast NS message with an
EARO as specified in [RFC8505]. The registration state is
periodically renewed by the Registering Node, Node before the lifetime
indicated in the EARO expires. As for unicast IPv6 addresses, the
6LR uses an EDAR/EDAC exchange with the 6LBR to notify the 6LBR of
the presence of the listeners.
This specification updates the EARO with a new two-bit 2-bit field, the
P-Field, as detailed in Section 7.1. The existing R flag that
requests reachability for the registered address Registered Address gets new behavior.
With this extension extension, the 6LNs can now subscribe to the anycast and
multicast addresses they listen to, using a new P-Field in the EARO
to signal that the registration is for a multicast address. Multiple
6LNs may subscribe the same multicast address to the same 6LR. Note
the use of the term "subscribe": this means that when using the EARO
registration mechanism, a node registers the unicast addresses that
it owns, owns but subscribes to the multicast addresses that it listens to.
With this specification, the 6LNs can also subscribe the anycast
addresses they accept, accept using a new P-Field in the EARO to signal that
the registration is for an anycast address. As for multicast, For multicast addresses,
multiple 6LNs may subscribe the same anycast address to the same 6LR.
If the R flag is set in the subscription of one or more 6LNs for the
same address, the 6LR injects the anycast addresses and multicast
addresses of a scope larger than the link-scope in RPL, based on the
longest subscription lifetime across the active subscriptions for the
address.
In the RPL "Storing Mode of Operation with multicast support", support"
(Section 12 of [RFC6550]), the DAO messages for the multicast address
percolate along the RPL
preferred RPL-preferred parent tree and mark a subtree that
becomes the multicast tree for that multicast address, with 6LNs that
subscribed to the address as the leaves. As prescribed in section Section 12
of [RFC6550], the 6LR forwards a multicast packet as an individual
unicast MAC Medium Access Control (MAC) frame to each peer along the
multicast tree, except to the node it received the packet from.
In the new RPL "Non-Storing Mode of Operation with multicast support"
that is introduced here, the DAO messages announce the multicast
addresses as Targets though Targets, and never as Transit. Transits. The multicast
distribution is an ingress replication whereby the Root encapsulates
the multicast packets to all the 6LRs that are transit for the
multicast address, using the same source-routing header as for
unicast targets attached to the respective 6LRs.
LLN links are typically Direct MAC Broadcast (DMB) (more (see more in
[I-D.ietf-6man-ipv6-over-wireless])
[IPv6-OVER-WIRELESS]) with no emulation to increase range (over
multiple radio hops) or reliability. In such links, broadcasting is
unreliable and asynchronous transmissions force a listener to remain
awake, so asynchronous broadcasting is generally inefficient. The Thus,
the expectation is thus that whenever possible, the 6LRs deliver the
multicast packets as individual unicast MAC frames to each of the
6LNs that subscribed to the multicast address. On the other hand, in
a network where nodes do not sleep, asynchronous broadcasting may
still help recovering faster when state is lost.
With this specification, anycast addresses can be injected in RPL in
both Storing and Non-Storing modes. In Storing Mode mode, the RPL router
accepts DAO from multiple children for the same anycast address, but
it only forwards a packet to one of the children. In Non-Storing Mode,
mode, the Root maintains the list of all the RPL nodes that announced
the anycast address as Target, but it forwards a given packet to only
one of them.
Operationally speaking, deploying a new MOP means that one cannot
update a live network. The network administrator must create a new
instance with MOP 5 and migrate nodes to that instance by allowing
them to join it.
For backward compatibility, this specification allows to build building a
single DODAG signaled as MOP 1, 1 that conveys anycast, unicast, and
multicast packets using the same source routing source-routing mechanism; see more
in Section 11.
It is also possible to leverage this specification between the 6LN
and the 6LR for the registration of unicast, anycast anycast, and multicast
IPv6 addresses in networks that are not necessarily LLNs, LLNs and/or where
the routing protocol between the 6LR and above is not necessarily
RPL. In that case, the distribution of packets between the 6LR and
the 6LNs may effectively rely on a broadcast or multicast support at
the lower layer, e.g., layer (e.g., using this specification as a replacement to
MLD in an Ethernet bridged Ethernet-bridged domain and still using either a plain MAC-layer MAC-
layer broadcast or snooping of this protocol to control the flooding.
flooding). It may also rely on overlay services to optimize the
impact of Broadcast, Unknown, and Multicast (BUM) over a fabric, e.g.
e.g., registering with [I-D.thubert-bess-secure-evpn-mac-signaling] [MAC-SIGNALING] and forwarding with [I-D.ietf-bess-evpn-optimized-ir]. [RFC9574].
For instance, it is possible to operate a RPL Instance in the new
"Non-Storing Mode of Operation with multicast support" (while
possibly signaling a MOP of 1) and use "Multicast Protocol for
Low-Power Low-
Power and Lossy Networks (MPL)" [RFC7731] for the multicast
operation. MPL floods the DODAG with the multicast messages
independently of the RPL DODAG topologies. Two variations are
possible:
* In one possible variation, all the 6LNs set the R flag in the EARO
for a multicast target, upon which the 6LRs send a unicast DAO
message to the Root; the Root filters out the multicast messages
for which there is no listener and only floods when there is.
* In a simpler variation, the 6LNs do not set the R flag and the
Root floods all the multicast packets over the whole DODAG. Using
this configuration, it is also possible to control the behavior of
the 6LR to ignore the R flag and either always or never send the
DAO message, and/or to control the Root and specify which groups
it should flood or not flood.
Note that if the configuration instructs the 6LR not to send the DAO,
then MPL can really by be used in conjunction with the RPL Storing Mode mode as
well.
4. Updating RFC 4861
Section 7.1 of [RFC4861] requires to silently discard discarding NS and NA
packets when the Target Address is a multicast address. This
specification Amends [RFC4861] by allowing to advertise the advertisement of
multicast and anycast addresses in the Target Address field when the
NS message is used for a registration, per section Section 5.5 of [RFC8505].
5. Updating RFC 7400
This specification Extends "6LoWPAN-GHC: Generic Header Compression
for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs)"
[RFC7400] by defining a new capability bit for use in the 6CIO.
[RFC7400] was already extended by [RFC8505] for use in IPv6 ND
messages.
The new "Registration for xcast Address Unicast, Multicast, and Anycast Addresses
Supported" (X) X flag indicates to the 6LN that the 6LR accepts unicast,
multicast, and anycast address registrations as specified in this
document and will ensure that packets for the Registered Address will
be routed to the 6LNs that registered with the R flag set
appropriately.
Figure 3 illustrates the X flag in its suggested position (8, counting 0 to 15
in network order in the 16-bit array), to be
confirmed by IANA. array); see Section 14.6 for the IANA
registration of capability bits.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length = 1 | Reserved |X|A|D|L|B|P|E|G|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: New Capability Bits in the 6CIO
New Option Field:
X
X: This is a 1-bit flag: flag for "Registration for Unicast, Multicast,
and Anycast Addresses Supported" Supported".
6. Updating RFC 6550
This specification Amends [RFC6550] to mandate the use of the ROVR
field as the indication of the origin of a Target advertisement in
the
RPL DAO messages, as specified as an option in section Section 6.1 of
[RFC9010].
This specification Extends [RFC6550] with a new P-Field in the RPL
Target Option. Option (RTO).
The specification also Amends the behaviors of the Modes of Operation
MOP 1 and MOP 3, 3 and Extends [RFC6550] with a new MOP 5.
6.1. Mandating the ROVR field Field
For anycast and multicast advertisements (in NS or DAO messages),
multiple origins may subscribe to the same address, in which case the
multiple advertisements from the different or unknown origins are
merged by the common parent; in that case, the common parent becomes
the origin of the merged advertisements and uses its own ROVR value.
On the other hand, a parent that propagates an advertisement from a
single origin uses the original ROVR in the propagated RTO, as it
does for unicast address advertisements, so the origin is recognised recognized
across multiple hops.
[RFC6550] uses the Path Sequence in the Transit Information Option
(TIO) to retain only the freshest unicast route and remove the stale
ones, e.g., in the case of mobility. [RFC9010] copies the TID
Transaction ID (TID) from the EARO into the Path Sequence, Sequence and the
ROVR field into the associated RPL Target Option (RTO). RTO. This way, it is possible to
identify both the registering node Registering Node and the order of registration in
RPL for each individual advertisement, so the most recent path and
lifetime values are used.
This specification Extends [RFC6550] to require that, for anycast and multicast advertisements,
advertisements to require that the Path Sequence is be used between between, and
only
between between, advertisements for the same Target and from the same
origin
(i.e, (i.e., with the same ROVR value); in value). In that case, only the
freshest advertisement is retained. But retained, but the freshness comparison
cannot apply if the origin is not determined (i.e., the origin did
not support this specification).
[RFC6550] uses the Path Lifetime in the TIO to indicate the remaining
time for which the advertisement is valid for unicast route
determination, and a Path Lifetime value of 0 invalidates that route.
[RFC9010] maps the Address Registration lifetime in the EARO and the
Path Lifetime in the TIO so they are comparable when both forms of
advertisements are received.
The RPL router that merges multiple advertisements for the same
anycast or multicast addresses MUST use and advertise the longest
remaining lifetime across all the origins of the advertisements for
that address. When the lifetime expires, the router sends a no-path
DAO (i.e., the lifetime is 0) using the same value for the ROVR value
as for the previous advertisements, that is either self or the single
descendant that advertised the Target.
Note that the Registration Lifetime, TID TID, and ROVR fields are also
placed in the EDAR message so the state created by the EDAR is also
comparable with that created upon an NS(EARO) or a DAO message. For
simplicity
simplicity, the text below mentions only NS(EARO) but applies it also applies
to EDAR.
6.2. Updating MOP 3
RPL supports multicast operations in the "Storing Mode of Operation
with multicast support" (MOP 3) 3), which provides source-independent
multicast routing in RPL, as prescribed in section Section 12 of [RFC6550].
MOP 3 is a storing Storing Mode of Operation. This operation builds a
multicast tree within the RPL DODAG for each multicast address. This
specification provides additional details for the MOP 3 operation.
The expectation in MOP 3 is that the unicast traffic also follows the
Storing Mode of Operation. But However, this is rarely the case in LLN
deployments of RPL where the "Non-Storing Mode of Operation" (MOP 1)
is the norm. Though it is preferred to build separate RPL Instances,
one in MOP 1 and one in MOP 3, this specification allows hybrid use
of the Storing Mode mode for multicast and the Non-Storing Mode mode for
unicast in the same RPL Instance, as is elaborated in more detail in
Section 11.
For anycast and multicast advertisements, including MOP 3, the ROVR
field is placed in the RPL Target Option as specified in [RFC9010]
for both MOP 3 and MOP 5 as it is for unicast advertisements.
Though it was implicit with [RFC6550], this specification clarifies
that the freshness comparison based on the Path Sequence is not used
when the origin cannot be determined, which is the case there. The
comparison is to be used only between advertisements from the same
origin, which is either an individual subscriber, subscriber or a descendant that
merged multiple advertisements.
A RPL router maintains a remaining Path Lifetime for each DAO that it
receives for a multicast target, target and sends its own DAO for that target
with the longest remaining lifetime across its listening children.
If the router has only one descendant listening, it propagates the
TID and ROVR as received. Conversely, if the router merges multiple
advertisements (including possibly (possibly including one for itself as a listener), the
router uses its own ROVR and TID values. This implies a possible
transition of ROVR and TID values when the number of listening
children changes from one to more or back to one, which should not be
considered as an error or a change of ownership by the parents above.
6.3. New Non-Storing Multicast MOP
This specification adds a "Non-Storing Mode of Operation with ingress
replication multicast support" (MOP to be RPL (as assigned by IANA) IANA; see
Section 14.5) whereby the non-storing Non-Storing Mode DAO to the Root may
advertise a multicast address in the RPL Target Option (RTO), RTO, whereas the Transit
Information Option (TIO) TIO cannot.
In that mode, the RPL Root performs an ingress replication Ingress Replication (IR)
operation on the multicast packets, meaning packets. This means that it transmits one
copy of each multicast packet to each 6LR that is a transit for the
multicast target, using the same source routing source-routing header and
encapsulation as it would for a unicast packet for a RPL Unaware RPL-Unaware Leaf
(RUL) attached to that 6LR.
For the intermediate routers, the packet appears as any source routed source-routed
unicast packet. The difference shows only at the 6LR, that which
terminates the source routed source-routed path and forwards the multicast packet
to all 6LNs that registered for the multicast address.
For a packet that is generated by the Root, this means that the Root builds a source source-
routing header as shown in section Section 8.1.3 of [RFC9008], but for which
the last and only the last address is multicast. For a packet that
is not generated by the Root, the Root encapsulates the multicast
packet as per section Section 8.2.4 of [RFC9008]. In that case, the outer
header is purely unicast, and the encapsulated packet is purely
multicast.
For anycast and multicast advertisements in NA messages (at the 6LR)
and DAO messages (at the Root) messages, Root), as discussed in Section 6.2, the
freshness comparison based on the TID field is applied only between
messages from the same origin, as determined by the same value in the
ROVR field.
The Root maintains a remaining Path Lifetime for each advertisement
it receives, and the 6LRs generate the DAO for multicast addresses
with the longest remaining lifetime across its registered 6LNs, using
its own ROVR and TID when multiple 6LNs subscribed, or if this 6LR is
one of the subscribers.
For this new mode as well, this
This specification allows to enable enabling the operation in a MOP 1 brown field,
field for this new mode as well; see more in Section 11.
6.4. RPL Anycast Operation
With multicast, the address has a recognizable format, and a
multicast packet is to be delivered to all the active subscribers.
In contrast, the format of an anycast address is not distinguishable
from that of unicast. a unicast address. A legacy node may issue a DAO
message without setting the P-Field to 2, 2; the unicast behavior may
apply to anycast traffic within a portion of the network, but the
packets will still be delivered. That message will be
undistinguishable from a unicast
advertisement advertisement, and the anycast
behavior in the dataplane can only happen if all the nodes that
advertise the same anycast address are synchronized with the same
TID. That way, the multiple paths can remain in the RPL DODAG.
With the P-Field set to 2, this specification alleviates the issue of
synchronizing the TIDs and ROVR fields. As for multicast, the
freshness comparison based on the TID (in the EARO) and the Path
Sequence (in the TIO) is ignored unless the messages have the same origin, as
origin; this is inferred by the same ROVR in the RTO and/or the EARO,
and the latest value of the lifetime is retained for each origin.
A RPL router that propagates an advertisement from a single origin
uses the ROVR and Path Sequence from that origin, whereas a router
that merges multiple subscriptions uses its own ROVR and Path
Sequence and the longest lifetime over the different advertisements.
A target is routed as anycast by a parent (or the Root) that received
at least one DAO message for that target with the P-Field set to 2.
As opposed to multicast, the anycast operation described therein
applies to both addresses and prefixes, and the P-Field can be set to
2 for both. An external destination (address or prefix) that may be
injected as a RPL target from multiple border routers should be
injected as anycast in RPL to enable load balancing. A mobile target
that is multihomed should in contrast be advertised as unicast over
the multiple interfaces to favor the TID comparison and vs. the
multipath load balancing.
For either multicast and or anycast, there can be multiple subscriptions
from multiple origins, each using a different value of the ROVR field
that identifies the individual subscription. The 6LR maintains a
subscription state per value of the ROVR per for a multicast or anycast
address, but it injects the route into RPL only once for each address,
and in
address. In the case of a multicast address, this occurs only if its
scope is larger than the link-scope (3 (three or more). Since the
subscriptions are considered separate, the check on the TID that acts
as the subscription sequence only applies to the subscription with
the same ROVR.
Like the 6LR, a RPL router in Storing Mode mode propagates the merged
advertisement to its parent(s) in DAO messages once and only once for
each address, but it retains a routing table entry for each of the
children that advertised the address.
When forwarding multicast packets down the DODAG, the RPL router
copies all the children that advertised the address in their DAO
messages. In contrast, when forwarding anycast packets down the
DODAG, the RPL router MUST copy one and only one of the children that
advertised the address in their DAO messages, messages and forward it to one
parent if there is no such child.
6.5. New Registered Address Type Indicator P-Field
The new Registered Address Type Indicator (RATInd) is created for use
in the RPL Target Option, the EARO, and the header of EDAR messages.
The RATInd indicates whether an address is unicast, multicast, or
anycast. The new 2-bit P-Field is defined to transport the RATInd in
different protocols.
The P-Field can take the following values:
+---------------+----------------------------------------------+
+-------+------------------------------------------+
| P-Field Value | Registered Address Type Indicator |
+---------------+----------------------------------------------+
+-------+------------------------------------------+
| 0 | Registration for a Unicast Address or prefix |
+---------------+----------------------------------------------+
+-------+------------------------------------------+
| 1 | Registration for a Multicast Address |
+---------------+----------------------------------------------+
+-------+------------------------------------------+
| 2 | Registration for an Anycast Address |
+---------------+----------------------------------------------+
+-------+------------------------------------------+
| 3 | Reserved, Reserved; MUST NOT be used by the sender. sender |
+---------------+----------------------------------------------+
+-------+------------------------------------------+
Table 1: P-Field Values
The intent for the value of 3 is a prefix registration (see
[I-D.ietf-6lo-prefix-registration],
[REGISTRATION]), which is expected to be published
soon after this
specification. At the time of this writing, RPL already advertises
prefixes, and treated treats unicast addresses as
prefgixes prefixes with a length of
128, so it does not really need that new value. On the other hand, 6LoWPAN
ND does not, and so the value of 3
meaning (meaning prefix registration registration) will not
be processed adequately. As a result:
* When the value of 3 is received in an RTO (see Section 6.6), this
value MUST be ignored by the receiver, meaning, receiver (meaning it is treated as a
value of 0, 0) but the message is processed normally (as per
[RFC6550] and [RFC9010]).
* In the case of an EARO (see Section 7.1) or an EDAR (see
Section 7.2), the message MUST be dropped, and the receiving node
MAY either reply with a status of 12 "Invalid Registration" or
remain silent.
6.6. New RPL Target Option P-Field
[RFC6550] recognizes a multicast address by its format (as specified
in section Section 2.7 of [RFC4291]) and applies the specified multicast
operation if the address is recognized as multicast. This
specification updates [RFC6550] to add the 2-bit P-Field (see
Section 6.5) to the RTO to indicate that the target address Target Address is to be
processed as unicast, multicast multicast, or anycast.
* An RTO that has the P-Field set to 0 is called a unicast RTO.
* An RTO that has the P-Field set to 1 is called a multicast RTO.
* An RTO that has the P-Field set to 2 is called an anycast RTO.
The suggested position for the P-Field is 2 counting from 0 to 7 in
network order as shown in Figure 4, based on figure Figure 4 of [RFC9010] [RFC9010],
which defines the flags in position positions 0 and 1:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0x05 | Option Length |F|X| P |ROVRsz | Prefix Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Target Prefix (Variable Length) |
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
... Registration Ownership Verifier (ROVR) ...
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Format of the RPL Target Option (RTO)
New and updated Option Fields: Field:
P: This is a 2-bit field; see Section 6.5 6.5.
7. Updating RFC 8505
This specification Extends [RFC8505] by adding the concept of a
subscription for anycast and multicast addresses and creating a new
field called the P-Field in the EARO and the EDAR/EDAC messages ti to signal
the type of registration.
7.1. Placing the New P-Field in the EARO
Section 4.1 of [RFC8505] defines the EARO as an extension to the ARO
option defined in [RFC6775]. This specification adds a new P-Field
that is placed in the EARO flags that and is set as follows:
* The P-Field is set to 1 to signal that the Registered Address is a
multicast address. When the P-Field is 1 and the R flag is set to
1 as well, the 6LR that conforms to this specification joins the
multicast stream, e.g., stream (e.g., by injecting the address in the RPL
multicast support that is extended in this specification for Non-
Storing Mode. the
Non-Storing mode).
* The P-Field is set to 2 to signal that the Registered Address is
an anycast address. When the P-Field is 2 and the R flag is 1,
the 6LR that conforms to this specification injects the anycast
address in the routing protocol(s) that it participates to, e.g., in (e.g.,
in the RPL anycast support that is introduced in this
specification for both the Storing and Non-Storing Modes. modes).
Figure 5 illustrates the P-Field in its suggested positions position (2, counting 0 to 7
in network order in the 8-bit array), to be confirmed
by IANA. array); see Section 14.1 for the IANA
registration of P-Field values.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Status | Opaque |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Rsv| P | I |R|T| TID | Registration Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
... Registration Ownership Verifier ...
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: EARO Extended Address Registration Option (EARO) Format
New and updated Option Fields:
Rsv: This is a 2-bit field; reserved, field. It is reserved and MUST be set to 0 and
ignored by the
receiver receiver.
P: This is a 2-bit P-Field; see Section 6.5 6.5.
7.2. Placing the New P-Field in the EDAR Message
Section 4 of [RFC6775] provides the same format for DAR and DAC
messages but the status Status field is only used in DAC messages and has to
be set to zero in DAR messages. [RFC8505] extends the DAC message as
an EDAC but does not change the status Status field in the EDAR.
This specification repurposes the status Status field in the EDAR as a Flags
field. It adds a new P-Field to the EDAR flags field to match the
P-Field in the EARO and signal the new types of registration. The
EDAC message is not modified.
Figure 6 illustrates the P-Field in its suggested position (0, counting 0 to 7
in network order in the 8-bit array), to be confirmed
by IANA. array); see Section 14.2 for the IANA
registration of EDAR message flags.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type |CodePfx|CodeSfx| Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| P | Reserved | TID | Registration Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
... Registration Ownership Verifier (ROVR) ...
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Registered Address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Extended Duplicate Address Request (EDAR) Message Format
New and updated Option Fields:
Reserved
Reserved: This is a 6-bit field: reserved, field. It is reserved and MUST be set to
0 and ignored by the
receiver receiver.
P: This is a 2-bit field; see Section 6.5 6.5.
7.3. Registration Extensions
[RFC8505] specifies the following behaviours: behaviors:
* A router that expects to reboot may send a final RA message, upon
which nodes should subscribe elsewhere or redo the subscription to
the same router upon reboot. In all other cases, a node reboot is
silent. When the node comes back to life, existing registration
state might be lost if it was not persisted, e.g., in persistent
memory.
* The registration method is specified only for unicast addresses.
* The 6LN must register all its ULA ULAs and GUA GUAs with an NS(EARO).
* The 6LN may set the R flag in the EARO to obtain return
reachability services by the 6LR, e.g., through ND proxy
operations,
operations or by injecting the route in a route-over subnet.
* the 6LR maintains a registration state per Registered Address,
including an NCE with the Link Layer Link-Layer Address (LLA) of the
Registered Node (the 6LN here).
This specification Amends une above behavior and Extends it with the
following behavior:
* The concept of subscription is introduced for anycast and
multicast addresses as an extension to the unicast address
registration. The respective operations are similar from the
perspective of the 6LN, but they show important differences on the
router side, which maintains a separate state for each origin and
merges them in its own advertisements.
* New ARO Statuses are introduced to indicate a "Registration
Refresh Request" and an "Invalid Registration" (see Table 9).
The former status is used in asynchronous NA(EARO) messages to
indicate to peer 6LNs that they are requested to reregister all
addresses that were previously registered to the originating node.
The NA message may be sent to a unicast or a multicast link-scope
address and should be contained within the L2 range where nodes
may effectively have effectively registered/subscribed to this router, e.g., router (e.g., a
radio broadcast domain. domain). The latter is generic to any error in
the
EARO, EARO and is used e.g., used, for example, to report that the P-Field is
not consistent with the Registered Address in NS(EARO) and EDAR
messages.
A router that wishes to refresh its state, e.g., state (e.g., upon reboot or in
any situation where it may have missed a registration or lost a
registration state, state) SHOULD send an asynchronous NA(EARO) with this
new status value. Failure to do so will delay the recovery of the
network till until the next periodic registration by the attached 6LNs
and packets may be lost till until then. That asynchronous multicast
NA(EARO) MUST be sent to the all-nodes link scope link-scope multicast
address (ff02::1) (ff02::1), and the Target MUST be set to the link local
address that was exposed previously by this node to accept
registrations.
The TID field in the multicast NA(EARO) is the one associated to
the Target and follows the same rules as the TID in the NS(EARO)
for the same Target, Target; see section Section 5.2 of [RFC8505], which points at
section to
Section 7.2 of [RFC6550] for the lollipop mechanism used in the
TID operation. It is incremented by the sender each time it sends
a new series of NS and/or NA with the EARO about the Target. The
TID indicates a reboot when it is in the "straight" part of the
lollipop, between the initial value and 255. After that that, the TID
remains below 128 as long as the device is alive. An asynchronous
multicast NA(EARO) with a TID below 128 MUST NOT be considered as
indicating a reboot.
The asynchronous multicast NA(EARO) indicating a "Registration
Refresh Request" MAY be reissued a few times within a short
period, to increase the chances that the message is received by
all registered nodes despite the unreliable transmissions within
the LLN; the TID MUST be incremented each time. The receiver 6LN
MUST consider that multiple NA(EARO) messages indicating a
"Registration Refresh Request" from the same 6LR received within
that short period with comparable (their and increasing TID values (i.e.,
their absolute difference is less than SEQUENCE_WINDOW, the SEQUENCE_WINDOW; see section
Section 7.2 of [RFC6550]) and
increasing TID values are in fact indicative of the same request;
the
request. The 6LN MUST process one and only one of the series of
messages. If the TIDs are desynchronized (not comparable), comparable) or
decreased, then the NA(EARO) is considered as a new request and it
MUST be processed.
The multicast NA(EARO) SHOULD be resent enough times for the TID
to be issued with the value of 255 so the next NA(EARO) after the
initial series is outside the lollipop and is not confused with a
reboot. By default default, the TID initial setting after boot is 252,
the SEQUENCE_WINDOW is 4, the duration of the short period is 10
seconds, the interval between retries is 1 second, and the number
of retries is 3. To reach 255 at boot time, the sender MAY either
issue at least 4 NA messages, skip a TID value, or start with a
value that is more than 252. The best values for the short
period, the number of retries, and the TID initial setting depend
on the environment and SHOULD be configurable.
* A new IPv6 ND Consistent Uptime option Option (CUO) is introduced to be
placed in IPv6 ND messages. The CUO allows to figure figuring out the state
consistency between the sender and the receiver. For instance, a
node that rebooted needs to reset its uptime to 0. A Router router that
changed information like a prefix information option has to
advertise an incremented state sequence. To that effect, the CUO
carries a Node State Sequence Information (NSSI) and a Consistent
Uptime. See Section 10 for the option details.
A node that receives the CUO checks whether it is indicative of a
desynchronization between peers. A peer that discovers that a
router has changed should reassess which addresses it formed based
on the new PIOs from that router, router and resync the state that it
installed in the router, e.g., router (e.g., the registration state for its
addresses.
addresses). In the process, the peer may attempt to to:
- form new addresses and register them,
- deprecate old addresses and deregister them using a Lifetime of
0, and
- reform any potentially lost state, e.g., state (e.g., by registering again
an existing address that it will keep using. using).
A loss of state is inferred if the Consistent Uptime of the peer
is less than the time since the state was installed, or if the
NSSI is incremented for a consistent uptime. Consistent Uptime.
* Registration for multicast and anycast addresses is now supported.
The P-Field is added to the EARO to signal when the registered
address Registered
Address is anycast or multicast. If the The value of the P-Field is not
consistent with the Registered Address, that is if Address if:
- the Registered Address is a multicast address (section (Section 2.4 of
[RFC4291]) and the P-Field indicates a value that is not 1, or
- the Registered Address is not a multicast address and the
P-Field indicates a value that is 1.
If this occurs, then the message, NS(EARO) or EDAR, MUST be
dropped, and the receiving node MAY either reply with a status of
12 "Invalid Registration" or remain silent.
* The Status field in the EDAR message that was reserved and not
used in RFC 8505 [RFC8505] is repurposed to transport the flags to signal
multicast and anycast.
* The 6LN MUST also subscribe all the IPv6 multicast addresses that
it listens to, and it MUST set the P-Field to 1 in the EARO for
those addresses. The one exception is the all-nodes link-scope
multicast address ff02::1 [RFC4291] [RFC4291], which is implicitly
registered by all nodes, meaning that all nodes are expected to
accept messages sent to ff02::1 but are not expected to register
it.
* The 6LN MAY set the R flag in the EARO to obtain the delivery of
the multicast packets by the 6LR, e.g., 6LR (e.g., by MLD proxy operations,
or by injecting the address in a route-over subnet or in the
Protocol Independent Multicast [RFC7761] protocol. protocol).
* The 6LN MUST also subscribe all the IPv6 anycast addresses that it
supports
supports, and it MUST set the P-Field in the EARO to 2 for those
addresses.
* The 6LR and the 6LBR are extended to accept more than one
subscription for the same address when it is anycast or multicast,
since multiple 6LNs may subscribe to the same address of these
types. In both cases, the Registration Ownership Verifier (ROVR) ROVR in the EARO identifies uniquely identifies a
registration within the namespace of the Registered Address.
* The 6LR MUST also consider that all the nodes that registered an
address to it (as known by the Source Link-Layer Address Option) Option
(SLLAO)) also registered to the all nodes link-scope multicast
address ff02::1 [RFC4291].
* The 6LR MUST maintain a subscription state per tuple (IPv6
address, ROVR) for both anycast and multicast types of address. addresses.
It SHOULD notify the 6LBR with an EDAR message, unless it
determined that the 6LBR is legacy and does not support this
specification. In turn, the 6LBR MUST maintain a subscription
state per tuple (IPv6 address, ROVR) for both anycast and
multicast types of address.
8. Updating RFC 9010
[RFC9010] specifies the following behaviours: behaviors:
* The 6LR has no specified procedure to inject multicast and anycast
routes in RPL even though RPL supports multicast.
* Upon a registration with the R flag set to 1 in the EARO, the 6LR
injects the address in the RPL unicast support.
* Upon receiving a packet directed to a unicast address for which it
has an active registration, the 6LR delivers the packet as a
unicast layer-2 Layer 2 frame to the LLA of the node that registered the
unicast address.
This specification Extends [RFC9010] by adding the following
behavior:
* Upon a subscription with the R flag and the P-Field both set to 1
in the EARO, if the scope of the multicast address is above link-
scope [RFC7346], then the 6LR injects the address in the RPL
multicast support and sets the P field P-Field in the RTO to 1 as well.
* Upon a subscription with the R set to 1 and the P-Field set to 2
in the EARO, the 6LR injects the address in the new RPL anycast
support and sets the P-Field to 2 in the RTO.
* Upon receiving a packet directed to a multicast address for which
it has at least one subscription, the 6LR delivers a copy of the
packet as a unicast layer-2 Layer 2 frame to the LLA of each of the nodes
that registered to that multicast address.
* Upon receiving a packet directed to an anycast address for which
it has at least one subscription, the 6LR delivers a copy of the
packet as a unicast layer-2 Layer 2 frame to the LLA of exactly one of the
nodes that registered to that multicast address.
9. Leveraging RFC 8928
Address-Protected
"Address-Protected Neighbor Discovery for Low-Power and Lossy Networks
Networks" [RFC8928] was defined to protect the ownership of unicast
IPv6 addresses that are registered with [RFC8505].
With [RFC8928], it is possible for a node to autoconfigure a pair of
public and private keys and use them to sign the registration of
addresses that are either autoconfigured or obtained through other
methods.
The first hop router (the 6LR) may then validate a registration and
perform source address validation on packets coming from the sender
node (the 6LN).
Anycast and multicast addresses are not owned by one node. Multiple
nodes may subscribe to the same address. In that context, the method
specified in [RFC8928] cannot be used with autoconfigured keypairs key pairs
to protect a single ownership.
For an anycast or a multicast address, it is still possible to
leverage [RFC8928] to enforce the right to subscribe. If [RFC8928]
is used, a keypair key pair MUST be associated with the address before it is
deployed, and a ROVR MUST be generated from that keypair key pair as
specified in [RFC8928]. The address and the ROVR MUST then be
installed in the 6LBR so it can recognize the address and compare the
ROVR on the first subscription.
The keypair key pair MUST then be provisioned in each node that needs to
subscribe to the anycast or multicast address, so the node can follow
the steps in [RFC8928] to subscribe to the address.
10. Consistent Uptime Option
This specification introduces a new option that characterizes the
uptime of the sender. The option may be used by routers in RA
messages and by any node in NS, NA, and RS messages. It is used by
the receiver to infer whether some state synchronization might be
lost, e.g.,
lost (e.g., due to reboot. reboot).
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Exponent | Uptime Mantissa |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|S|U| flags | NSSI | Peer NSSI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: Consistent Uptime Option (CUO) Format
Type: To be assigned Assigned by IANA, IANA; see Table 10 10.
Length: 1
Uptime Exponent: A 6-bit unsigned integer: The integer and the Exponent to the
base 2 of the uptime unit unit.
Uptime Mantissa: A 10-bit unsigned integer: The integer and the mantissa of the
uptime
value value.
S: A 1-bit flag, flag set to 1 to indicate that the sender is low-power
and may sleep.
U: A 1-bit flag, flag set to 1 to indicate that the Peer NSSI field is
valid; it MUST be set to 0 when the message is not unicast and
MUST be set to 1 when the message is unicast and the sender has an
NSSI state for the intended receiver.
flags: 6-bit, reserved. MUST be set to 0 by the sender and ignored
by the receiver.
NSSI: A 12-bit unsigned integer: The integer that represents the Node State
Sequence Information, Information (NSSI). It MUST be stored by the receiver if
it has a dependency on information advertised or stored at the
sender.
Peer NSSI: A 12-bit unsigned integer: Echoes integer that echoes the last known NSSI
from the peer.
The Consistent Uptime indicates how long the sender has been
continuously up and running (though possibly sleeping) without loss
of state. It is expressed by the Uptime Mantissa in units of 2 to
the power of the Uptime Exponent in milliseconds. The receiver
derives the boot time of the sender as the current time minus the
sender's Consistent Uptime.
If the boot time of the sender is updated to a newer time, any state
that the receiver installed in the sender before the reboot is
probably lost. The receiver MUST reassess all the state it installed
in the server (e.g., any registration) and reinstall if it is still
needed.
The U flag not set in a unicast message from the sender indicates
that it has lost all state from this node. If the U flag is set,
then the Peer NSSI field can be used to assess which changes the
sender missed. The For the other way around, any state that was
installed in the receiver from information by the sender before it
rebooted MUST be removed and may or may not be reinstalled later.
The value of the uptime is reset to 0 at some point of the sender's
reboot sequence, but it may not be still be 0 when the first message is
sent, so the receiver must not expect a value of 0 as the signal of a
reboot.
+----------+----------+------------+-----------+
| Mantissa | Exponent | Resolution | Uptime |
+----------+----------+------------+-----------+
| 1 | 0 | 1ms 1 ms | 1ms 1 ms |
+----------+----------+------------+-----------+
| 5 | 10 | 1s 1 s | 5 seconds |
+----------+----------+------------+-----------+
| 2 | 15 | 30s 30 s | 1mn 1 mn |
+----------+----------+------------+-----------+
| 2 | 21 | 33mn 33 mn | 1 hour |
+----------+----------+------------+-----------+
Table 2: Consistent Uptime Rough Values
The NSSI SHOULD be stored in persistent memory by the sender and
incremented when it may have missed or lost state about a peer, or
when it has updated some state in a fashion that will impact a peer, e.g., peer
(e.g., a host formed a new address or a router advertises a new prefix.
prefix). When persisting is not possible, then the NSSI is randomly
generated.
As long as the NSSI remains constant, the cross-dependent state (such
as addresses in a host that depend on a prefix in a router) can
remain stable, meaning less checks in the receiver. Any change in
the value of the NSSI is an indication that the sender updated some
state and that the dependent state in the receiver should be
reassessed, e.g.,
reassessed (e.g., addresses that were formed based on an RA with a
previous NSSI should be checked, or new addresses may be formed and
registered.
registered).
11. Operational considerations Considerations
With this specification, a RPL DODAG forms a realm, and multiple RPL
DODAGs may be federated in a single RPL Instance administratively.
This means that a multicast address that needs to span a RPL DODAG
MUST use a scope of Realm-Local whereas a multicast address that
needs to span a RPL Instance MUST use a scope of Admin-Local as
discussed in section Section 3 of [RFC7346], "IPv6 Multicast Address Scopes" [RFC7346]. Scopes".
"IPv6 Addressing of IPv4/IPv6 Translators" [RFC6052] enables to embed
embedding IPv4 addresses in IPv6 addresses. The Root of a DODAG may
leverage that technique to translate IPv4 traffic in IPv6 and route
along the RPL domain. When encapsulating a packet with an IPv4
multicast Destination Address, it MUST use a multicast address with
the appropriate scope, Realm-Local or Admin-Local.
"Unicast-Prefix-based IPv6 Multicast Addresses" [RFC3306] enables to
form
forming 2^32 multicast addresses from a single /64 prefix. If an
IPv6 prefix is associated to an Instance or a RPL DODAG, this
provides a namespace that can be used in any desired fashion. It For
instance, it is for
instance possible for a standard defining organization to form
its own registry and allocate 32-bit values from that namespace to
network functions or device types. When used within a RPL deployment
that is associated with a /64 prefix prefix, the IPv6 multicast addresses
can be automatically derived from the prefix and the 32-bit value for
either a Realm-Local or an Admin-Local multicast address as needed in
the configuration.
This specification introduces the new RPL MOP 5. Operationally
speaking, deploying a new RPL MOP means that one cannot update a live
network. The network administrator must create a new instance with
MOP 5 and migrate nodes to that instance by allowing them to join it.
In a "green field" deployment where all nodes support this
specification, it is possible to deploy a single RPL Instance using a
multicast MOP for unicast, multicast, and anycast addresses.
In a "brown field" where legacy devices that do not support this
specification co-exist coexist with upgraded devices, it is RECOMMENDED to
deploy one RPL Instance in any Mode of Operation (typically MOP 1)
for unicast that legacy nodes can join, join and a separate RPL Instance
dedicated to multicast and anycast operations using a multicast MOP.
To deploy a Storing Mode mode multicast operation using MOP 3 in a RPL
domain, it is required that there is enough density of the RPL routers that support MOP 3 have
enough density to build a DODAG that covers all the potential
listeners and include includes the spanning multicast trees that are needed
to distribute the multicast flows. This might not be the case when
extending the capabilities of an existing network.
In the case of the new Non-Storing multicast MOP, arguably the new
support is only needed at the 6LRs that will accept multicast
listeners. It is still required that each listener can be able to reach
at least one such 6LR, so the upgraded 6LRs must be deployed to cover
all the 6LN 6LNs that need multicast services.
Using separate RPL Instances for in the one hand unicast traffic and
in the other hand anycast and multicast traffic allows to use
different objective function, one favoring the link quality up for
unicast collection and one favoring downwards link quality for
multicast distribution.
But
However, this might be impractical in some use cases where the
signaling and the state to be installed in the devices are very
constrained, the upgraded devices are too sparse, or the devices do
not support more multiple instances.
When using a single RPL Instance, MOP 3 expects the Storing Mode of
Operation for both unicast and multicast, which is an issue in
constrained networks that typically use MOP 1 for unicast. This
specification allows a mixed mode that is signaled as MOP 1 in the
DIO messages for backward compatibility, where limited multicast and/
or anycast is available, under the following conditions:
* There MUST be enough density of the 6LRs that support the mixed
mode to cover all the 6LNs that require multicast or anycast
services. In Storing Mode, mode, there MUST be enough density of the
6LRs that support the mixed mode to also form a DODAG to the Root.
* The RPL routers that support the mixed mode are configured to
operate in accordance with the desired operation in the network.
* The MOP signaled in the RPL DIO messages is MOP 1 to enable the
legacy nodes to operate as leaves.
* The support of multicast and/or anycast in the RPL Instance SHOULD
be signaled by the 6LRs to the 6LN using a 6CIO, 6CIO; see Section 5.
* Alternatively, the support of multicast in the RPL domain can be
globally known by other means such as including configuration or external
information such as support of a version of an industry standard
that mandates it. In that case, all the routers MUST support the
mixed mode.
12. Security Considerations
This specification Extends [RFC8505] and [RFC9010], [RFC9010] and leverages
[RFC9008]. The security section sections in these documents also apply to
this document. In particular, the link layer SHOULD be sufficiently
protected to prevent rogue access.
RPL [RFC6550] already supports routing on multicast addresses,
whereby the endpoint that subscribes to the group and to do so
injects the multicast address participates to RPL as a RPL aware node RPL-Aware Node
(RAN). Using an extension of RFC 8505 [RFC8505] as opposed to RPL to
subscribe the address allows a RPL unaware leaf RPL-Unaware Leaf (RUL) to subscribe as
well. As noted in [RFC9010], this provides a better security posture
for the RPL network, since the nodes that do not really need to speak
RPL, or are not trusted enough to inject RPL messages, can be
forbidden from doing so, which bars a number of attacks attack vectors from
within RPL. Acting as an RUL, those nodes may still leverage the RPL
network through the capabilities that are opened via ND operations.
With this draft, specification, a node that needs multicast delivery can now
obtain the service in a RPL domain while not being allowed to inject
RPL messages.
Compared to [RFC6550], this draft specification enables to track tracking the origin
of the multicast subscription inside the RPL network. This is a
first step to enable a form of Route Ownership Validation (ROV) (see
[RFC6811]) in RPL using the ROVR field in the EARO as proof of
ownership.
Section 9 leverages [RFC8928] to prevent a rogue node to register from
registering a unicast address that it does not own. The mechanism
could be extended to anycast and multicast addresses if the values of
the ROVR they use is are known in advance, but how this is done is not
in scope for this specification. One way would be to authorize in advance the
ROVR of the valid users. users in advance. A less preferred way could would be to
synchronize the ROVR and TID values across the valid subscribers as a
preshared key material.
In the latter case, it could be possible to update the keys
associated to an address in all the 6LNs, but the flow is not clearly
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
over a period of time, and switch the traffic to that address when
the migration is complete.
13. Backward Compatibility
A legacy 6LN will not subscribe multicast addresses addresses, and the service
will be the same when the network is upgraded. A legacy 6LR will not
set the X flag in the 6CIO 6CIO, and an upgraded 6LN will not subscribe
multicast addresses.
Upon receiving an EDAR message, a legacy 6LBR may not realize that
the address being registered is anycast or multicast, multicast and will return
that it is a duplicate in the EDAC status. The 6LR MUST ignore a
duplicate status in the EDAC for anycast and multicast addresses.
As detailed in Section 11, it is possible to add multicast on an
existing MOP 1 deployment.
The combination of a multicast address and the P-Field set to 0 in an
RTO in a MOP 3 RPL Instance is understood by an indication to the receiver that
supports this specification (the parent) as an indication that the sender (child) does
not support this specification, but specification. However, the RTO is accepted and
processed as if the P-Field was set to 1 for backward compatibility.
When the DODAG is operated in MOP 3, a legacy node will not set the
P-Field and still expect multicast service as specified in section Section 12
of [RFC6550]. In MOP 3 3, an RTO that is received with a target that
is multicast and the P-Field set to 0 MUST be considered as multicast
and MUST be processed as if the P-Field is set to 1.
14. IANA Considerations
Note to RFC Editor, to be removed: please replace "This RFC"
throughout this document by the RFC number for this specification
once it is allocated; also, requests to IANA must be edited to
reflect the
IANA actions once performed.
Note to IANA, to be removed: the I Field is defined in [RFC9010] but
is missing from the registry, so the bit positions must be added for
completeness in conformance with the RFC.
IANA is requested to make has made 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: groupings;
see details in the subsections that follow.
14.1. New P-Field values Values Registry
IANA is requested to create has created a new "P-Field values" Values" registry under the
heading "Internet
Control Message Protocol version 6 (ICMPv6) Parameters" registry
group to store the expression of the Registered Address Type
Indicator as a P-Field.
Registration
The registration procedure is "Standards Action" Standards Action [RFC8126]. The
initial
allocation is allocations are as indicated in Table 3:
+-------+--------------------------------------+-----------+
| Value | Registered Address Type Indicator | Reference |
+-------+--------------------------------------+-----------+
| 0 | Registration for a Unicast Address | This RFC 9685 |
+-------+--------------------------------------+-----------+
| 1 | Registration for a Multicast Address | This RFC 9685 |
+-------+--------------------------------------+-----------+
| 2 | Registration for an Anycast Address | This RFC 9685 |
+-------+--------------------------------------+-----------+
| 3 | Unassigned | This RFC 9685 |
+-------+--------------------------------------+-----------+
Table 3: P-Field values Values Registry
14.2. New EDAR Message Flags Registry
IANA is requested to create has created a new "EDAR Message Flags" registry under the heading
"Internet Control Message Protocol version 6 (ICMPv6)
Parameters".
Registration Parameters"
registry group.
The registration procedure is "IETF Review" IETF Review or "IESG Approval" IESG Approval [RFC8126].
The initial allocation is allocations are as indicated in Table 4:
+------------------+------------------------------------+-----------+
+------------+------------------+------------------------+
| Bit Number | Meaning | Reference |
+------------------+------------------------------------+-----------+
+------------+------------------+------------------------+
| 0..1 (suggested) 0-1 | P-Field (2 bits), bits) | This RFC |
| | see 9685, Section 14.1 |
+------------+------------------+------------------------+
|
+------------------+------------------------------------+-----------+
| 2..7 2-7 | Unassigned | |
+------------------+------------------------------------+-----------+
+------------+------------------+------------------------+
Table 4: EDAR Message flags Flags Registry
14.3. New EARO flags Address Registration Option Flags
IANA is requested to make additions has made an addition to the "Address Registration Option Flags" [IANA.ICMP.ARO.FLG]
registry [IANA.ICMP.ARO.FLG] under the heading "Internet Control Message
Protocol version 6 (ICMPv6) Parameters" registry group as indicated
in Table 5:
+------------------+------------------------------------+-----------+
+------------+------------------+------------------------+
| ARO flag Bit Number | Meaning Description | Reference |
+------------------+------------------------------------+-----------+
+------------+------------------+------------------------+
| 2..3 (suggested) 2-3 | P-Field (2 bits), bits) | This RFC |
| | see 9685, Section 14.1 | |
+------------------+------------------------------------+-----------+
+------------+------------------+------------------------+
Table 5: New ARO flags Address Registration Option Flags
14.4. New RTO flags RPL Target Option Flags
IANA is requested to make additions has made an addition to the "RPL Target Option Flags"
[IANA.RPL.RTO.FLG] registry
[IANA.RPL.RTO.FLG] under the heading "Routing Protocol for Low Power and
Lossy Networks (RPL)" registry group as indicated in Table 6:
+------------------+------------------------------------+-----------+
+------------+------------------------+------------------------+
| Bit Number | Meaning Capability Description | Reference |
+------------------+------------------------------------+-----------+
+------------+------------------------+------------------------+
| 2..3 (suggested) 2-3 | P-Field (2 bits), bits) | This RFC |
| | see 9685, Section 14.1 | |
+------------------+------------------------------------+-----------+
+------------+------------------------+------------------------+
Table 6: New RTO flags RPL Target Option Flags
14.5. New RPL Mode of Operation
IANA is requested to make has made an addition to the "Mode of Operation"
[IANA.RPL.MOP] registry
[IANA.RPL.MOP] under the heading "Routing Protocol for Low Power and Lossy
Networks (RPL)" registry group as indicated in Table 7:
+---------------+---------------------------------------+-----------+
+-------+---------------------------------------+-----------+
| Value | Description | Reference |
+---------------+---------------------------------------+-----------+
+-------+---------------------------------------+-----------+
| 5 | Non-Storing Mode of Operation with | This RFC 9685 |
| (suggested) | ingress replication multicast support | |
+---------------+---------------------------------------+-----------+
+-------+---------------------------------------+-----------+
Table 7: New RPL Mode of Operation
14.6. New 6LoWPAN Capability Bits Bit
IANA is requested to make has made an addition to the "6LoWPAN Capability Bits" [IANA.ICMP.6CIO] registry
[IANA.ICMP.6CIO] under the heading "Internet Control Message Protocol version
6 (ICMPv6) Parameters" registry group as indicated in Table 8:
+-------------+-----------------------------+-----------+
| Capability | Meaning | Reference |
+-----+--------------------------------------------+-----------+
| Bit | Description | Reference |
+-------------+-----------------------------+-----------+
+-----+--------------------------------------------+-----------+
| 8 | X flag: Registration for Unicast, | This RFC 9685 |
| (suggested) | Unicast, Multicast, and | |
| | Anycast Addresses Supported | |
+-------------+-----------------------------+-----------+
+-----+--------------------------------------------+-----------+
Table 8: New 6LoWPAN Capability Bits Bit
14.7. New Address Registration Option Status Values
IANA is requested to make has made additions to the "Address Registration Option Status
Values" [IANA.ICMP.ARO.STAT] registry [IANA.ICMP.ARO.STAT] under the heading "Internet Control
Message Protocol version 6 (ICMPv6) Parameters", Parameters" registry group as
follows:
+----------------+------------------------------+-----------+
indicated in Table 9:
+-------+------------------------------+-----------+
| Value | Description | Reference |
+----------------+------------------------------+-----------+
+-------+------------------------------+-----------+
| 11 (suggested) | Registration Refresh Request | This RFC 9685 |
+----------------+------------------------------+-----------+
+-------+------------------------------+-----------+
| 12 (suggested) | Invalid Registration | This RFC 9685 |
+----------------+------------------------------+-----------+
+-------+------------------------------+-----------+
Table 9: New Address Registration Option Status Values"
Values
14.8. New IPv6 Neighbor Discovery Option Format
IANA is requested to make additions has made an addition to the "IPv6 Neighbor Discovery Option
Formats" registry under the heading "Internet Control Message Protocol
version 6 (ICMPv6) Parameters", Parameters" registry group as follows:
+----------------+--------------------------+-----------+ indicated in
Table 10:
+------+--------------------------+-----------+
| Value Type | Description | Reference |
+----------------+--------------------------+-----------+
+------+--------------------------+-----------+
| 42 (suggested) | Consistent Uptime Option | This RFC 9685 |
+----------------+--------------------------+-----------+
+------+--------------------------+-----------+
Table 10: New IPv6 Neighbor Discovery Option"
Option Format
15. Acknowledgments
This work is a production of an effective collaboration between the
IETF 6lo WG and the Wi-Sun FAN WG. Thanks to all in both WGs who
contributed reviews and productive suggestions, in particular Carsten
Bormann, Paul Duffy, Klaus Hueske, Adnan Rashid, Rahul Jadhav, Gene
Falendysz, Don Sturek, Dario Tedeschi, Saurabh Jain, and Chris Hett,
with special thanks to Esko Dijk for his useful WGLC reviews and
proposed changes. Also many thanks to Eric Vyncke, Sandy Ginoza,
Zaheduzzaman Sarker, Paul Wouters, Roman Danyliw, John Scudder, Dirk
Von Hugo, Murray Kucherawy, Kyle Rose, Scott Kelly, and Dan Romascanu
for their suggestions and comments during the IETF last call and IESG
review cycle.
16. References
15.1. Normative References
[IANA.ICMP]
IANA, "Internet Control Message Protocol version 6
(ICMPv6) Parameters",
<https://www.iana.org/assignments/icmpv6-parameters>.
[IANA.ICMP.6CIO]
IANA, "6LoWPAN Capability Bits",
<https://www.iana.org/assignments/icmpv6-parameters>.
[IANA.ICMP.ARO.FLG]
IANA, "Address Registration Option Flags",
<https://www.iana.org/assignments/icmpv6-parameters>.
[IANA.ICMP.ARO.STAT]
IANA, "Address Registration Option Status Values",
<https://www.iana.org/assignments/icmpv6-parameters>.
[IANA.RPL] IANA, "Routing Protocol for Low Power and Lossy Networks
(RPL)", <https://www.iana.org/assignments/rpl>.
[IANA.RPL.MOP]
IANA, "Mode of Operation",
<https://www.iana.org/assignments/rpl>.
[IANA.RPL.RTO.FLG]
IANA, "RPL Target Option Flags",
<https://www.iana.org/assignments/rpl>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3306] Haberman, B. and D. Thaler, "Unicast-Prefix-based IPv6
Multicast Addresses", RFC 3306, DOI 10.17487/RFC3306,
August 2002, <https://www.rfc-editor.org/info/rfc3306>.
[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>.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007,
<https://www.rfc-editor.org/info/rfc4861>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007,
<https://www.rfc-editor.org/info/rfc4862>.
[RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J.,
Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur,
JP., and R. Alexander, "RPL: IPv6 Routing Protocol for
Low-Power and Lossy Networks", RFC 6550,
DOI 10.17487/RFC6550, March 2012,
<https://www.rfc-editor.org/info/rfc6550>.
[RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
Bormann, "Neighbor Discovery Optimization for IPv6 over
Low-Power Wireless Personal Area Networks (6LoWPANs)",
RFC 6775, DOI 10.17487/RFC6775, November 2012,
<https://www.rfc-editor.org/info/rfc6775>.
[RFC7346] Droms, R., "IPv6 Multicast Address Scopes", RFC 7346,
DOI 10.17487/RFC7346, August 2014,
<https://www.rfc-editor.org/info/rfc7346>.
[RFC7400] Bormann, C., "6LoWPAN-GHC: Generic Header Compression for
IPv6 over Low-Power Wireless Personal Area Networks
(6LoWPANs)", RFC 7400, DOI 10.17487/RFC7400, November
2014, <https://www.rfc-editor.org/info/rfc7400>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[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>.
[RFC8505] Thubert, P., Ed., Nordmark, E., Chakrabarti, S., and C.
Perkins, "Registration Extensions for IPv6 over Low-Power
Wireless Personal Area Network (6LoWPAN) Neighbor
Discovery", RFC 8505, DOI 10.17487/RFC8505, November 2018,
<https://www.rfc-editor.org/info/rfc8505>.
[RFC8928] Thubert, P., Ed., Sarikaya, B., Sethi, M., and R. Struik,
"Address-Protected Neighbor Discovery for Low-Power and
Lossy Networks", RFC 8928, DOI 10.17487/RFC8928, November
2020, <https://www.rfc-editor.org/info/rfc8928>.
[RFC9010] Thubert, P., Ed. and M. Richardson, "Routing for RPL
(Routing Protocol for Low-Power and Lossy Networks)
Leaves", RFC 9010, DOI 10.17487/RFC9010, April 2021,
<https://www.rfc-editor.org/info/rfc9010>.
[RFC9030] Thubert, P., Ed., "An Architecture for IPv6 over the Time-
Slotted Channel Hopping Mode of IEEE 802.15.4 (6TiSCH)",
RFC 9030, DOI 10.17487/RFC9030, May 2021,
<https://www.rfc-editor.org/info/rfc9030>.
[IANA.ICMP]
IANA, "IANA Registry for ICMPv6", IANA,
https://www.iana.org/assignments/icmpv6-parameters/
icmpv6-parameters.xhtml.
[IANA.ICMP.ARO.FLG]
IANA, "IANA Registry for the Address Registration Option
Flags", IANA, https://www.iana.org/assignments/icmpv6-
parameters/icmpv6-parameters.xhtml#icmpv6-adress-
registration-option-flags.
[IANA.ICMP.ARO.STAT]
IANA, "IANA Registry
15.2. Informative References
[IEEE-802.11]
IEEE, "IEEE Standard for the Address Registration Option
Status Value", IANA, https://www.iana.org/assignments/
icmpv6-parameters/icmpv6-parameters.xhtml#address-
registration.
[IANA.ICMP.6CIO]
IANA, "IANA Registry Information Technology--
Telecommunications and Information Exchange between
Systems - Local and Metropolitan Area Networks--Specific
Requirements - Part 11: Wireless LAN Medium Access Control
(MAC) and Physical Layer (PHY) Specifications",
DOI 10.1109/IEEESTD.2021.9363693, IEEE Std 802.11-2020,
<https://ieeexplore.ieee.org/document/9363693>.
[IEEE-802.15.1]
IEEE, "IEEE Standard for the 6LoWPAN Capability Bits",
IANA, https://www.iana.org/assignments/icmpv6-parameters/
icmpv6-parameters.xhtml#sixlowpan-capability-bits.
[IANA.RPL] IANA, "IANA Registry Information technology - Local
and metropolitan area networks - Specific requirements -
Part 15.1a: Wireless Medium Access Control (MAC) and
Physical Layer (PHY) specifications for the RPL",
IANA, https://www.iana.org/assignments/rpl/rpl.xhtml.
[IANA.RPL.RTO.FLG]
IANA, "IANA Sub-Registry Wireless Personal
Area Networks (WPAN)", IEEE Std 802.15.1-2005,
DOI 10.1109/IEEESTD.2005.96290,
<https://ieeexplore.ieee.org/document/1490827>.
[IEEE-802.15.4]
IEEE, "IEEE Standard for the RTO Flags", IANA,
https://www.iana.org/assignments/rpl/rpl.xhtml#rpl-target-
option-flags.
[IANA.RPL.MOP]
IANA, "IANA Sub-Registry Low-Rate Wireless Networks",
DOI 10.1109/IEEESTD.2020.9144691, IEEE Std 802.15.4-2020,
<https://ieeexplore.ieee.org/document/9144691>.
[IPv6-OVER-WIRELESS]
Thubert, P., Ed. and M. Richardson, "Architecture and
Framework for the RPL Mode of Operation",
IANA, https://www.iana.org/assignments/rpl/rpl.xhtml#MOP.
17. Informative References IPv6 over Non-Broadcast Access", Work in
Progress, Internet-Draft, draft-ietf-6man-ipv6-over-
wireless-06, 23 May 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-6man-
ipv6-over-wireless-06>.
[MAC-SIGNALING]
Thubert, P., Ed., Przygienda, T., and J. Tantsura, "Secure
EVPN MAC Signaling", Work in Progress, Internet-Draft,
draft-thubert-bess-secure-evpn-mac-signaling-04, 13
September 2023, <https://datatracker.ietf.org/doc/html/
draft-thubert-bess-secure-evpn-mac-signaling-04>.
[REGISTRATION]
Thubert, P., Ed., "IPv6 Neighbor Discovery Prefix
Registration", Work in Progress, Internet-Draft, draft-
ietf-6lo-prefix-registration-05, 5 November 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-6lo-
prefix-registration-05>.
[RFC3810] Vida, R., Ed. and L. Costa, Ed., "Multicast Listener
Discovery Version 2 (MLDv2) for IPv6", RFC 3810,
DOI 10.17487/RFC3810, June 2004,
<https://www.rfc-editor.org/info/rfc3810>.
[RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6
over Low-Power Wireless Personal Area Networks (6LoWPANs):
Overview, Assumptions, Problem Statement, and Goals",
RFC 4919, DOI 10.17487/RFC4919, August 2007,
<https://www.rfc-editor.org/info/rfc4919>.
[RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,
DOI 10.17487/RFC6052, October 2010,
<https://www.rfc-editor.org/info/rfc6052>.
[RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6
Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
DOI 10.17487/RFC6282, September 2011,
<https://www.rfc-editor.org/info/rfc6282>.
[RFC7731] Hui, J. and R. Kelsey, "Multicast Protocol for Low-Power
and Lossy Networks (MPL)", RFC 7731, DOI 10.17487/RFC7731,
February 2016, <https://www.rfc-editor.org/info/rfc7731>.
[RFC6811] Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R.
Austein, "BGP Prefix Origin Validation", RFC 6811,
DOI 10.17487/RFC6811, January 2013,
<https://www.rfc-editor.org/info/rfc6811>.
[RFC7731] Hui, J. and R. Kelsey, "Multicast Protocol for Low-Power
and Lossy Networks (MPL)", RFC 7731, DOI 10.17487/RFC7731,
February 2016, <https://www.rfc-editor.org/info/rfc7731>.
[RFC7761] Fenner, B., Handley, M., Holbrook, H., Kouvelas, I.,
Parekh, R., Zhang, Z., and L. Zheng, "Protocol Independent
Multicast - Sparse Mode (PIM-SM): Protocol Specification
(Revised)", STD 83, RFC 7761, DOI 10.17487/RFC7761, March
2016, <https://www.rfc-editor.org/info/rfc7761>.
[RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,
DOI 10.17487/RFC6052, October 2010,
<https://www.rfc-editor.org/info/rfc6052>.
[RFC8929] Thubert, P., Ed., Perkins, C.E., and E. Levy-Abegnoli,
"IPv6 Backbone Router", RFC 8929, DOI 10.17487/RFC8929,
November 2020, <https://www.rfc-editor.org/info/rfc8929>.
[RFC9008] Robles, M.I., Richardson, M., and P. Thubert, "Using RPI
Option Type, Routing Header for Source Routes, and IPv6-
in-IPv6 Encapsulation in the RPL Data Plane", RFC 9008,
DOI 10.17487/RFC9008, April 2021,
<https://www.rfc-editor.org/info/rfc9008>.
[I-D.ietf-bess-evpn-optimized-ir]
[RFC9574] Rabadan, J., Ed., Sathappan, S., Lin, W., Katiyar, M., and
A. Sajassi, "Optimized Ingress Replication Solution for
Ethernet VPN (EVPN)", Work in Progress, Internet-Draft,
draft-ietf-bess-evpn-optimized-ir-12, 25 January 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-bess-
evpn-optimized-ir-12>.
[I-D.ietf-rift-rift] VPNs (EVPNs)", RFC 9574, DOI 10.17487/RFC9574,
May 2024, <https://www.rfc-editor.org/info/rfc9574>.
[RIFT] Przygienda, T., Head, J., Ed., Sharma, A., Ed., Thubert,
P., Rijsman, B., and D. Afanasiev, "RIFT: Routing in Fat
Trees", Work in Progress, Internet-Draft, draft-ietf-rift-
rift-23, 1
rift-24, 23 May 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-rift-
rift-23>.
[I-D.ietf-6lo-prefix-registration]
Thubert, P., "IPv6 Neighbor Discovery Prefix
Registration", Work in Progress, Internet-Draft, draft-
ietf-6lo-prefix-registration-02, 13 February 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-6lo-
prefix-registration-02>.
[I-D.ietf-6man-ipv6-over-wireless]
Thubert, P. and M. Richardson, "Architecture and Framework
for IPv6 over Non-Broadcast Access", Work in Progress,
November 2023, <https://datatracker.ietf.org/doc/html/
draft-ietf-6man-ipv6-over-wireless-05>.
[I-D.kuehlewind-update-tag]
rift-24>.
[UPDATES-TAG]
Kühlewind, M. and S. Krishnan, "Definition of new tags for
relations between RFCs", Work in Progress, Internet-Draft,
draft-kuehlewind-update-tag-04, 12
draft-kuehlewind-rswg-updates-tag-02, 8 July 2021, 2024,
<https://datatracker.ietf.org/doc/html/draft-kuehlewind-
update-tag-04>.
rswg-updates-tag-02>.
[Wi-SUN] Robert, H., Liu, B. R., B., Zhang, M., and C. E. Perkins, "Wi-
SUN "Wi-SUN
FAN Overview", Work in Progress, Internet-Draft,
draft-heile-lpwan-wisun-overview-00, draft-
heile-lpwan-wisun-overview-00, 3 July 2017,
<https://datatracker.ietf.org/doc/html/draft-heile-lpwan-
wisun-overview-00>.
[I-D.thubert-bess-secure-evpn-mac-signaling]
Thubert, P., Przygienda, T.,
Acknowledgments
This work is a production of an effective collaboration between the
IETF 6lo WG and J. Tantsura, "Secure EVPN
MAC Signaling", Work the Wi-Sun FAN WG. Thanks to all in Progress, Internet-Draft, draft-
thubert-bess-secure-evpn-mac-signaling-04, 13 September
2023, <https://datatracker.ietf.org/doc/html/draft-
thubert-bess-secure-evpn-mac-signaling-04>.
[IEEE Std 802.15.4]
IEEE standard for Information Technology, "IEEE Std
802.15.4, Part. 15.4: Wireless Medium Access Control (MAC) both WGs who
contributed reviews and Physical Layer (PHY) Specifications for Low-Rate
Wireless Personal Area Networks".
[IEEE Std 802.11]
IEEE standard for Information Technology, "IEEE Standard
802.11 - IEEE Standard for Information Technology -
Telecommunications productive suggestions, in particular:
Carsten Bormann, Paul Duffy, Klaus Hueske, Adnan Rashid, Rahul
Jadhav, Gene Falendysz, Don Sturek, Dario Tedeschi, Saurabh Jain, and information exchange between
systems Local
Chris Hett, with special thanks to Esko Dijk for his useful WGLC
reviews and metropolitan area networks - Specific
requirements - Part 11: Wireless LAN Medium Access Control
(MAC) proposed changes. Also many thanks to Éric Vyncke, Sandy
Ginoza, Zaheduzzaman Sarker, Paul Wouters, Roman Danyliw, John
Scudder, Dirk Von Hugo, Murray Kucherawy, Kyle Rose, Scott Kelly, and Physical Layer (PHY) Specifications.",
<https://ieeexplore.ieee.org/document/9363693>.
[IEEE Std 802.15.1]
IEEE standard for Information Technology, "IEEE Standard
Dan Romascanu for Information Technology - Telecommunications and
Information Exchange Between Systems - Local their suggestions and
Metropolitan Area Networks - Specific Requirements. - Part
15.1: Wireless Medium Access Control (MAC) comments during the IETF last
call and Physical
Layer (PHY) Specifications for Wireless Personal Area
Networks (WPANs)". IESG review cycle.
Author's Address
Pascal Thubert (editor)
06330 Roquefort-les-Pins
France
Email: pascal.thubert@gmail.com