draft-ietf-roll-unaware-leaves-04.txt   draft-ietf-roll-unaware-leaves-05.txt 
ROLL P. Thubert, Ed. ROLL P. Thubert, Ed.
Internet-Draft Cisco Internet-Draft Cisco Systems
Updates: 6550, 8505 (if approved) M. Richardson Updates: 6550, 8505 (if approved) M. Richardson
Intended status: Standards Track Sandelman Intended status: Standards Track Sandelman
Expires: March 12, 2020 September 9, 2019 Expires: 3 May 2020 31 October 2019
Routing for RPL Leaves Eliding and Querying RPL Information
draft-ietf-roll-unaware-leaves-04 draft-ietf-roll-unaware-leaves-05
Abstract Abstract
This specification extends RFC6550 and RFC8505 to provide unicast and This specification extends RFC6550 and RFC8505 to provide unicast and
multicast routing services in a RPL domain to 6LNs that are plain multicast routing services in a RPL domain to 6LNs that are plain
hosts and do not participate to RPL. hosts and do not participate to RPL.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
skipping to change at page 1, line 33 skipping to change at page 1, line 33
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 12, 2020. This Internet-Draft will expire on 3 May 2020.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. BCP 14 . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. BCP 14 . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. References . . . . . . . . . . . . . . . . . . . . . . . 4 2.2. References . . . . . . . . . . . . . . . . . . . . . . . 4
2.3. Glossary . . . . . . . . . . . . . . . . . . . . . . . . 5 2.3. Glossary . . . . . . . . . . . . . . . . . . . . . . . . 5
3. 6LoWPAN Neighbor Discovery . . . . . . . . . . . . . . . . . 6 3. 6LoWPAN Neighbor Discovery . . . . . . . . . . . . . . . . . 6
3.1. RFC 6775 . . . . . . . . . . . . . . . . . . . . . . . . 7 3.1. RFC 6775 . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2. RFC 8505 Extended ARO . . . . . . . . . . . . . . . . . . 7 3.2. RFC 8505 Extended ARO . . . . . . . . . . . . . . . . . . 7
3.2.1. R Flag . . . . . . . . . . . . . . . . . . . . . . . 8 3.2.1. R Flag . . . . . . . . . . . . . . . . . . . . . . . 8
3.2.2. TID, I Field and Opaque Fields . . . . . . . . . . . 8 3.2.2. TID, I Field and Opaque Fields . . . . . . . . . . . 8
3.2.3. ROVR . . . . . . . . . . . . . . . . . . . . . . . . 8 3.2.3. ROVR . . . . . . . . . . . . . . . . . . . . . . . . 8
3.3. RFC 8505 Extended DAR/DAC . . . . . . . . . . . . . . . . 9 3.3. RFC 8505 Extended DAR/DAC . . . . . . . . . . . . . . . . 9
4. Updating RFC 6550 . . . . . . . . . . . . . . . . . . . . . . 9 4. Updating RFC 6550 . . . . . . . . . . . . . . . . . . . . . . 9
5. Updating RFC 8505 . . . . . . . . . . . . . . . . . . . . . . 10 5. Updating RFC 8505 . . . . . . . . . . . . . . . . . . . . . . 10
6. 6LN Requirements to be a RPL-Unware Leaf . . . . . . . . . . 10 6. 6LN Requirements to be a RPL-Unware Leaf . . . . . . . . . . 10
6.1. Support of 6LoWPAN ND . . . . . . . . . . . . . . . . . . 10 6.1. Support of 6LoWPAN ND . . . . . . . . . . . . . . . . . . 10
6.2. External Routes and RPL Artifacts . . . . . . . . . . . . 11 6.2. External Routes and RPL Artifacts . . . . . . . . . . . . 11
6.2.1. Support of the HbH Header . . . . . . . . . . . . . . 11 6.2.1. Support of the HbH Header . . . . . . . . . . . . . . 12
6.2.2. Support of the Routing Header . . . . . . . . . . . . 11 6.2.2. Support of the Routing Header . . . . . . . . . . . . 12
6.2.3. Support of IPv6 Encapsulation . . . . . . . . . . . . 12 6.2.3. Support of IPv6 Encapsulation . . . . . . . . . . . . 12
7. Updated RPL Target option . . . . . . . . . . . . . . . . . . 12 7. Updated RPL Status . . . . . . . . . . . . . . . . . . . . . 12
8. Protocol Operations for Unicast Addresses . . . . . . . . . . 13 8. Updated RPL Target option . . . . . . . . . . . . . . . . . . 13
8.1. General Flow . . . . . . . . . . . . . . . . . . . . . . 13 9. Protocol Operations for Unicast Addresses . . . . . . . . . . 14
8.1.1. In RPL Non-Storing-Mode . . . . . . . . . . . . . . . 14 9.1. General Flow . . . . . . . . . . . . . . . . . . . . . . 14
8.1.2. In RPL Storing-Mode . . . . . . . . . . . . . . . . . 16 9.1.1. In RPL Non-Storing-Mode . . . . . . . . . . . . . . . 15
8.2. Operation . . . . . . . . . . . . . . . . . . . . . . . . 17 9.1.2. In RPL Storing-Mode . . . . . . . . . . . . . . . . . 18
8.2.1. By the 6LN . . . . . . . . . . . . . . . . . . . . . 17 9.2. Operation . . . . . . . . . . . . . . . . . . . . . . . . 18
8.2.2. By the 6LR . . . . . . . . . . . . . . . . . . . . . 18 9.2.1. By the 6LN . . . . . . . . . . . . . . . . . . . . . 19
8.2.3. By the RPL Root . . . . . . . . . . . . . . . . . . . 20 9.2.2. By the 6LR . . . . . . . . . . . . . . . . . . . . . 20
8.2.4. By the 6LBR . . . . . . . . . . . . . . . . . . . . . 21 9.2.3. By the RPL Root . . . . . . . . . . . . . . . . . . . 22
9. Protocol Operations for Multicast Addresses . . . . . . . . . 21 9.2.4. By the 6LBR . . . . . . . . . . . . . . . . . . . . . 23
10. Implementation Status . . . . . . . . . . . . . . . . . . . . 23 10. Protocol Operations for Multicast Addresses . . . . . . . . . 23
11. Security Considerations . . . . . . . . . . . . . . . . . . . 23 11. Implementation Status . . . . . . . . . . . . . . . . . . . . 25
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24 12. Security Considerations . . . . . . . . . . . . . . . . . . . 25
12.1. RPL Target Option Flags . . . . . . . . . . . . . . . . 24 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26
12.2. New Subsubregistry for the Status values of the RPL DAO- 13.1. RPL Target Option Flags . . . . . . . . . . . . . . . . 26
ACK Message . . . . . . . . . . . . . . . . . . . . . . 24 13.2. New Subsubregistry for the RPL Non-Rejection Status
13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 25 values . . . . . . . . . . . . . . . . . . . . . . . . . 26
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 26 13.3. New Subsubregistry for the RPL Rejection Status
14.1. Normative References . . . . . . . . . . . . . . . . . . 26 values . . . . . . . . . . . . . . . . . . . . . . . . . 26
14.2. Informative References . . . . . . . . . . . . . . . . . 28 14. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 26
Appendix A. Example Compression . . . . . . . . . . . . . . . . 29 15. Normative References . . . . . . . . . . . . . . . . . . . . 27
16. Informative References . . . . . . . . . . . . . . . . . . . 29
Appendix A. Example Compression . . . . . . . . . . . . . . . . 30
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 30 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 30
1. Introduction 1. Introduction
The design of Low Power and Lossy Networks (LLNs) is generally The design of Low Power and Lossy Networks (LLNs) is generally
focused on saving energy, which is the most constrained resource of focused on saving energy, which is the most constrained resource of
all. Other design constraints, such as a limited memory capacity, all. Other design constraints, such as a limited memory capacity,
duty cycling of the LLN devices and low-power lossy transmissions, duty cycling of the LLN devices and low-power lossy transmissions,
derive from that primary concern. derive from that primary concern.
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Root indicating their parent in Non-Storing Mode. This process Root indicating their parent in Non-Storing Mode. This process
effectively forms a DODAG back to the device that is a subset of the effectively forms a DODAG back to the device that is a subset of the
DODAG to the Root with all links reversed. DODAG to the Root with all links reversed.
When a routing protocol such as RPL is used to maintain reachability When a routing protocol such as RPL is used to maintain reachability
within a Non-Broadcast Multi-Access (NBMA) subnet, some nodes may act within a Non-Broadcast Multi-Access (NBMA) subnet, some nodes may act
as routers and participate to the routing operations whereas others as routers and participate to the routing operations whereas others
may be plain hosts. In [RFC6550] terms, a host that is reachable may be plain hosts. In [RFC6550] terms, a host that is reachable
over the RPL network is called a Leaf. over the RPL network is called a Leaf.
"When to use RFC 6553, 6554 and IPv6-in-IPv6" "When to use RFC 6553, 6554 and IPv6-in-IPv6" [USEofRPLinfo]
[I-D.ietf-roll-useofrplinfo] introduces the term RPL-Aware-Leaf (RAL) introduces the term RPL-Aware-Leaf (RAL) for a leaf that injects
for a leaf that injects routes in RPL to manage the reachability of routes in RPL to manage the reachability of its own IPv6 addresses.
its own IPv6 addresses. In contrast, a RPL-Unaware Leaf (RUL) In contrast, a RPL-Unaware Leaf (RUL) designates a leaf does not
designates a leaf does not participate to RPL at all. In that case, participate to RPL at all. In that case, the 6LN is a plain host
the 6LN is a plain host that needs an interface to its RPL router to that needs an interface to its RPL router to obtain routing services
obtain routing services over the LLN. This specification enables a over the LLN. This specification enables a RPL-Unaware Leaf (RUL) to
RPL-Unaware Leaf (RUL) to announce itself as a host and request that announce itself as a host and request that 6LRs that accept the
6LRs that accept the registration also inject the relevant routing registration also inject the relevant routing information for the
information for the Registered Address in the RPL domain on its Registered Address in the RPL domain on its behalf. The unicast
behalf. The unicast packet forwarding operation by the 6LR serving a packet forwarding operation by the 6LR serving a Leaf 6LN is
Leaf 6LN is described in [I-D.ietf-roll-useofrplinfo]. described in [USEofRPLinfo].
Examples of routing-agnostic 6LN may include lightly-powered sensors Examples of routing-agnostic 6LN may include lightly-powered sensors
such as window smash sensor (alarm system), or the kinetically such as window smash sensor (alarm system), or the kinetically
powered light switch. Other application of this specification may powered light switch. Other application of this specification may
include a smart grid network that controls appliances - such as include a smart grid network that controls appliances - such as
washing machines or the heating system - in the home. Applicances washing machines or the heating system - in the home. Applicances
may not participate to the RPL protocol operated in the smart grid may not participate to the RPL protocol operated in the smart grid
network but can still receive control packet from the smart grid. network but can still receive control packet from the smart grid.
2. Terminology 2. Terminology
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The Terminology used in this document is consistent with and The Terminology used in this document is consistent with and
incorporates that described in Terms Used in Routing for Low-Power incorporates that described in Terms Used in Routing for Low-Power
and Lossy Networks (LLNs). [RFC7102]. and Lossy Networks (LLNs). [RFC7102].
A glossary of classical 6LoWPAN acronyms is given in Section 2.3. A glossary of classical 6LoWPAN acronyms is given in Section 2.3.
The term "byte" is used in its now customary sense as a synonym for The term "byte" is used in its now customary sense as a synonym for
"octet". "octet".
"RPL", the "RPL Packet Information" (RPI), "RPL Instance" (indexed by "RPL", the "RPL Packet Information" (RPI), "RPL Instance" (indexed by
a RPLInstanceID)are defined in "RPL: IPv6 Routing Protocol for Low- a RPLInstanceID)are defined in "RPL: IPv6 Routing Protocol for
Power and Lossy Networks" [RFC6550] . The DODAG Information Low-Power and Lossy Networks" [RFC6550] . The DODAG Information
Solicitation (DIS), Destination Advertisement Object (DAO) and DODAG Solicitation (DIS), Destination Advertisement Object (DAO) and DODAG
Information Object (DIO) messages are also specified in [RFC6550]. Information Object (DIO) messages are also specified in [RFC6550].
The Destination Cleanup Object (DCO) message is defined in The Destination Cleanup Object (DCO) message is defined in
[I-D.ietf-roll-efficient-npdao]. [EFFICIENT-NPDAO].
This document uses the terms RPL-Unaware Leaf (RUL) and RPL Aware This document uses the terms RPL-Unaware Leaf (RUL) and RPL Aware
Leaf (RAL) consistently with [I-D.ietf-roll-useofrplinfo]. The term Leaf (RAL) consistently with [USEofRPLinfo]. The term RPL-Aware Node
RPL-Aware Node (RAN) is introduced to refer to a node that is either (RAN) is introduced to refer to a node that is either a RAL or a RPL
a RAL or a RPL router. As opposed to a RUL, a RAN manages the router. As opposed to a RUL, a RAN manages the reachability of its
reachability of its addresses and prefixes by injecting them in RPL addresses and prefixes by injecting them in RPL by itself.
by itself.
Other terms in use in LLNs are found in Terminology for Constrained- Other terms in use in LLNs are found in Terminology for
Node Networks [RFC7228]. Constrained-Node Networks [RFC7228].
Readers are expected to be familiar with all the terms and concepts Readers are expected to be familiar with all the terms and concepts
that are discussed in that are discussed in
o "Neighbor Discovery for IP version 6" [RFC4861], * "Neighbor Discovery for IP version 6" [RFC4861],
o "IPv6 Stateless Address Autoconfiguration" [RFC4862], * "IPv6 Stateless Address Autoconfiguration" [RFC4862],
o "Problem Statement and Requirements for IPv6 over Low-Power * "Problem Statement and Requirements for IPv6 over Low-Power
Wireless Personal Area Network (6LoWPAN) Routing" [RFC6606], Wireless Personal Area Network (6LoWPAN) Routing" [RFC6606],
o "IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs): * "IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs):
Overview, Assumptions, Problem Statement, and Goals" [RFC4919], Overview, Assumptions, Problem Statement, and Goals" [RFC4919],
o "Neighbor Discovery Optimization for Low-power and Lossy Networks" * "Neighbor Discovery Optimization for Low-power and Lossy Networks"
[RFC6775], and [RFC6775], and
o "Registration Extensions for IPv6 over Low-Power Wireless Personal * "Registration Extensions for IPv6 over Low-Power Wireless Personal
Area Network (6LoWPAN) Neighbor Discovery" [RFC8505]. Area Network (6LoWPAN) Neighbor Discovery" [RFC8505].
2.3. Glossary 2.3. Glossary
This document often uses the following acronyms: This document often uses the following acronyms:
AR: Address Resolution (aka Address Lookup) AR: Address Resolution (aka Address Lookup)
6LBR: 6LoWPAN Border Router 6LBR: 6LoWPAN Border Router
6LN: 6LoWPAN Node (a Low Power host or router) 6LN: 6LoWPAN Node (a Low Power host or router)
6LR: 6LoWPAN Router 6LR: 6LoWPAN Router
6CIO: Capability Indication Option 6CIO: Capability Indication Option
(E)ARO: (Extended) Address Registration Option (E)ARO: (Extended) Address Registration Option
(E)DAR: (Extended) Duplicate Address Request (E)DAR: (Extended) Duplicate Address Request
(E)DAC: (Extended) Duplicate Address Confirmation (E)DAC: (Extended) Duplicate Address Confirmation
DAD: Duplicate Address Detection DAD: Duplicate Address Detection
DAO: Destination Advertisement Object DAO: Destination Advertisement Object
DCO: Destination Cleanup Object DCO: Destination Cleanup Object
DIS: DODAG Information Solicitation DIS: DODAG Information Solicitation
DIO: DODAG Information Object DIO: DODAG Information Object
DODAG: Destination-Oriented Directed Acyclic Graph DODAG: Destination-Oriented Directed Acyclic Graph
LLN: Low-Power and Lossy Network LLN: Low-Power and Lossy Network
NA: Neighbor Advertisement NA: Neighbor Advertisement
NCE: Neighbor Cache Entry NCE: Neighbor Cache Entry
ND: Neighbor Discovery ND: Neighbor Discovery
NDP: Neighbor Discovery Protocol NDP: Neighbor Discovery Protocol
NS: Neighbor Solicitation NS: Neighbor Solicitation
RA: Router Advertisement RA: Router Advertisement
ROVR: Registration Ownership Verifier ROVR: Registration Ownership Verifier
RPI: RPL Packet Information (an Option in the Hop-By_Hop Header) RPI: RPL Packet Information (an Option in the Hop-By_Hop Header)
RAL: RPL-Aware Leaf RAL: RPL-Aware Leaf
RAN: RPL-Aware Node (either a RPL router or a RPL-Aware Leaf) RAN: RPL-Aware Node (either a RPL router or a RPL-Aware Leaf)
RUL: RPL-Unaware Leaf RUL: RPL-Unaware Leaf
TID: Transaction ID (a sequence counter in the EARO) TID: Transaction ID (a sequence counter in the EARO)
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The main functions of [RFC6775] are to proactively establish the The main functions of [RFC6775] are to proactively establish the
Neighbor Cache Entry in the 6LR and to avoid address duplication. Neighbor Cache Entry in the 6LR and to avoid address duplication.
There is no concept of registering the address for an external There is no concept of registering the address for an external
service such as RPL routing. That feature is introduced with service such as RPL routing. That feature is introduced with
"Registration Extensions for 6LoWPAN Neighbor Discovery" [RFC8505]. "Registration Extensions for 6LoWPAN Neighbor Discovery" [RFC8505].
3.2. RFC 8505 Extended ARO 3.2. RFC 8505 Extended ARO
[RFC8505] updates the behavior of RFC 6775 to enable a generic [RFC8505] updates the behavior of RFC 6775 to enable a generic
registration to services such as routing, and defines an Extended ARO registration to services such as routing, and defines an Extended
(EARO). The format of the EARO is shown in Figure 1: Address Registration Option (EARO). The format of the EARO is shown
in Figure 1:
0 1 2 3 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 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 | | Type | Length | Status | Opaque |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Rsvd | I |R|T| TID | Registration Lifetime | | Rsvd | I |R|T| TID | Registration Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
... Registration Ownership Verifier ... ... Registration Ownership Verifier ...
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: EARO Option Format Figure 1: EARO Option Format
3.2.1. R Flag 3.2.1. R Flag
[RFC8505] introduces the R flag in the EARO. The Registering Node [RFC8505] introduces the R flag in the EARO. The Registering Node
sets the R flag to indicate whether the 6LR should ensure sets the R flag to indicate whether the 6LR should ensure
reachability for the Registered Address, e.g., by means of routing or reachability for the Registered Address, e.g., by means of routing or
proxying ND. If the R flag is not set, then the Registering Node is proxying ND. If the R flag is not set, then the Registering Node is
expected to be a RAN that handles the reachability of the Registered expected to be a RAN that handles the reachability of the Registered
Address by itself. Address by itself.
skipping to change at page 8, line 30 skipping to change at page 8, line 30
depends on the setting of the R flag in the NS(EARO). depends on the setting of the R flag in the NS(EARO).
3.2.2. TID, I Field and Opaque Fields 3.2.2. TID, I Field and Opaque Fields
The EARO also includes a sequence counter called Transaction ID The EARO also includes a sequence counter called Transaction ID
(TID), which maps to the Path Sequence Field found in Transit Options (TID), which maps to the Path Sequence Field found in Transit Options
in RPL DAO messages. This is the reason why the support of [RFC8505] in RPL DAO messages. This is the reason why the support of [RFC8505]
by the RUL as opposed to only [RFC6775] is a prerequisite for this by the RUL as opposed to only [RFC6775] is a prerequisite for this
specification (more in Section 6.1). The EARO also transports an specification (more in Section 6.1). The EARO also transports an
Opaque field and an "I" field that describes what the Opaque field Opaque field and an "I" field that describes what the Opaque field
transports and how to use it. Section 8.2.1 specifies the use of the transports and how to use it. Section 9.2.1 specifies the use of the
"I" field and of the Opaque field by a RUL. "I" field and of the Opaque field by a RUL.
3.2.3. ROVR 3.2.3. ROVR
Section 5.3. of [RFC8505] introduces the Registration Ownership Section 5.3. of [RFC8505] introduces the Registration Ownership
Verifier (ROVR) field of a variable length from 64 to 256 bits. The Verifier (ROVR) field of a variable length from 64 to 256 bits. The
ROVR is a replacement of the EUI-64 field in the ARO [RFC6775] that ROVR is a replacement of the EUI-64 field in the ARO [RFC6775] that
was used to identify uniquely a registration based on the Link-Layer was used to identify uniquely a registration based on the Link-Layer
address of the owner but provided no protection against spoofing. address of the owner but provided no protection against spoofing.
"Address Protected Neighbor Discovery for Low-power and Lossy "Address Protected Neighbor Discovery for Low-power and Lossy
Networks" [I-D.ietf-6lo-ap-nd] leverages the ROVR field as a Networks" [AP-ND] leverages the ROVR field as a cryptographic proof
cryptographic proof of ownership to prevent a rogue third party from of ownership to prevent a rogue third party from misusing the
misusing the address. [I-D.ietf-6lo-ap-nd] adds a challenge/response address. [AP-ND] adds a challenge/response exchange to the [RFC8505]
exchange to the [RFC8505] registration and enables Source Address registration and enables Source Address Validation by a 6LR that will
Validation by a 6LR that will drop packets with a spoofed address. drop packets with a spoofed address.
This specification does not address how the protection by This specification does not address how the protection by [AP-ND]
[I-D.ietf-6lo-ap-nd] could be extended to RPL. On the other hand, it could be extended to RPL. On the other hand, it adds the ROVR to the
adds the ROVR to the DAO to build the proxied EDAR at the Root, which DAO to build the proxied EDAR at the Root, which means that nodes
means that nodes that are aware of the host route to the 6LN are now that are aware of the host route to the 6LN are now aware of the
aware of the associated ROVR as well. associated ROVR as well.
3.3. RFC 8505 Extended DAR/DAC 3.3. RFC 8505 Extended DAR/DAC
[RFC8505] updates the periodic DAR/DAC exchange that takes place [RFC8505] updates the periodic DAR/DAC exchange that takes place
between the 6LR and the 6LBR using Extended DAR/DAC messages. The between the 6LR and the 6LBR using Extended DAR/DAC messages. The
Extended Duplicate Address messages can carry the ROVR field of Extended Duplicate Address messages can carry the ROVR field of
variable size. The periodic EDAR/EDAC exchange is triggered by a variable size. The periodic EDAR/EDAC exchange is triggered by a
NS(EARO) message and is intended to create and then refresh the NS(EARO) message and is intended to create and then refresh the
corresponding state in the 6LBR for a lifetime that is indicated by corresponding state in the 6LBR for a lifetime that is indicated by
the 6LN. Conversely, RPL [RFC6550] specifies a periodic DAO from the the 6LN. Conversely, RPL [RFC6550] specifies a periodic DAO from the
skipping to change at page 9, line 26 skipping to change at page 9, line 26
DAO. This means that there are two periodic messages that traverse DAO. This means that there are two periodic messages that traverse
the whole network to indicate that an address is still reachable, one the whole network to indicate that an address is still reachable, one
to the Root and one to the 6LBR. This represents a waste of to the Root and one to the 6LBR. This represents a waste of
bandwidth and energy that can be undesirable in an LLN. bandwidth and energy that can be undesirable in an LLN.
This specification saves the support of RPL in a 6LN called a RUL and This specification saves the support of RPL in a 6LN called a RUL and
avoids an extraneous periodic flow across the LLN. The RUL only avoids an extraneous periodic flow across the LLN. The RUL only
needs to perform a [RFC8505] registration to the 6LR. The 6LR turns needs to perform a [RFC8505] registration to the 6LR. The 6LR turns
it into a DAO message to the Root on behalf of the RUL. Upon the new it into a DAO message to the Root on behalf of the RUL. Upon the new
DAO, the Root proxies the EDAR exchange to the 6LBR on behalf of the DAO, the Root proxies the EDAR exchange to the 6LBR on behalf of the
6LR. This is illustrated in Figure 4. 6LR. This is illustrated in Figure 5.
4. Updating RFC 6550 4. Updating RFC 6550
This document specifies a new behavior whereby a 6LR injects DAO This document specifies a new behavior whereby a 6LR injects DAO
messages for unicast addresses (see Section 8) and multicast messages for unicast addresses (see Section 9) and multicast
addresses (see Section 9) on behalf of leaves that are not aware of addresses (see Section 10) on behalf of leaves that are not aware of
RPL. The Targets are exposed as External addresses. An IP-in-IP RPL. The Targets are exposed as External addresses. An IP-in-IP
encapsulation that terminates at the border 6LR is used to remove RPL encapsulation that terminates at the border 6LR is used to remove RPL
artifacts and compression techniques that may not be processed artifacts and compression techniques that may not be processed
correctly outside of the RPL domain. correctly outside of the RPL domain.
This document synchronizes the liveness monitoring at the Root and This document synchronizes the liveness monitoring at the Root and
the 6LBR. A same value of lifetime is used for both, and a single the 6LBR. A same value of lifetime is used for both, and a single
keep alive message, the RPL DAO, traverses the RPL network. A new keep alive message, the RPL DAO, traverses the RPL network. A new
behavior is introduced whereby the RPL Root proxies the EDAR message behavior is introduced whereby the RPL Root proxies the EDAR message
to the 6LBR on behalf of the 6LR (more in Section 5). [RFC6550] is to the 6LBR on behalf of the 6LR (more in Section 5).
updated with new RPL Status values for use in DAO-ACK and DCO that
map the 6LoWPAN ND values defined in Table 1 of [RFC8505]. The The RPL Status defined in section 6.5.1. of [RFC6550] for use in the
resulting set is shown in Table 1. DAO-Ack message is extended to be used in the DCO messages
[EFFICIENT-NPDAO] as well. Furthermore, this specification enables
to use a RPL status to transport the IPv6 ND status defined for use
in the EARO, more in Section 7.
Section 6.7. of [RFC6550] introduces the RPL Control Message Options Section 6.7. of [RFC6550] introduces the RPL Control Message Options
such as the RPL Target Option that can be included in a RPL Control such as the RPL Target Option that can be included in a RPL Control
Message such as the DAO. Section 7 updates the RPL Target Option to Message such as the DAO. Section 8 updates the RPL Target Option to
optionally transport the ROVR used in the IPv6 Registration (see optionally transport the ROVR used in the IPv6 Registration (see
Section 3.2.3) so the RPL Root can generate a full EDAR Message. Section 3.2.3) so the RPL Root can generate a full EDAR Message.
5. Updating RFC 8505 5. Updating RFC 8505
This document updates [RFC8505] to introduce a keep-alive EDAR This document updates [RFC8505] to introduce a keep-alive EDAR
message and a keep-alive NS(EARO) message. The keep-alive messages message and a keep-alive NS(EARO) message. The keep-alive messages
are used for backward compatibility, when the DAO does not transport are used for backward compatibility, when the DAO does not transport
a ROVR as specified in Section 7. The keep-alive messages have a a ROVR as specified in Section 8. The keep-alive messages have a
zero ROVR field and can only be used to refresh a pre-existing state zero ROVR field and can only be used to refresh a pre-existing state
associated to the Registered Address. More specifically, a keep- associated to the Registered Address. More specifically, a keep-
alive message can only increase the lifetime and/or increment the TID alive message can only increase the lifetime and/or increment the TID
of the existing state in a 6LBR. of the existing state in a 6LBR.
Upon the renewal of a 6LoWPAN ND registration, this specification Upon the renewal of a 6LoWPAN ND registration, this specification
changes the behavior of a RPL router acting as 6LR for the changes the behavior of a RPL router acting as 6LR for the
registration as follows. If the Root indicates the capability to registration as follows. If the Root indicates the capability to
proxy the EDAR/EDAC exchange to the 6LBR then the 6LR refrains from proxy the EDAR/EDAC exchange to the 6LBR then the 6LR refrains from
sending an EDAR message; if the Root is separated from the 6LBR, the sending an EDAR message; if the Root is separated from the 6LBR, the
skipping to change at page 10, line 48 skipping to change at page 11, line 5
routing services. The registrations SHOULD be performed in a rapid routing services. The registrations SHOULD be performed in a rapid
sequence, using the exact same EARO for a same Address. Gaps between sequence, using the exact same EARO for a same Address. Gaps between
the registrations will invalidate some of the routes till the the registrations will invalidate some of the routes till the
registration finally shows on those routes as well. registration finally shows on those routes as well.
[RFC8505] introduces error Status values in the NA(EARO) which can be [RFC8505] introduces error Status values in the NA(EARO) which can be
received synchronously upon an NS(EARO) or asynchronously. The RUL received synchronously upon an NS(EARO) or asynchronously. The RUL
MUST support both cases and refrain from using the Registered Address MUST support both cases and refrain from using the Registered Address
as specified by [RFC8505] depending on the Status value. as specified by [RFC8505] depending on the Status value.
A RUL SHOULD support [I-D.ietf-6lo-ap-nd] to protect the ownership of A RUL SHOULD support [AP-ND] to protect the ownership of its
its addresses. addresses.
6.2. External Routes and RPL Artifacts 6.2. External Routes and RPL Artifacts
Section 4.1. of [I-D.ietf-roll-useofrplinfo] provides a set of rules Section 4.1. of [USEofRPLinfo] provides a set of rules that MUST be
that MUST be followed when forwarding packets over an external route: followed when forwarding packets over an external route:
RPL data packets are often encapsulated using IP-in-IP and in Non- RPL data packets are often encapsulated using IP-in-IP and in Non-
Storing Mode, packets going down will carry an SRH as well. RPL data Storing Mode, packets going down will carry an SRH as well. RPL data
packets also typically carry a Hop-by-Hop Header to transport a RPL packets also typically carry a Hop-by-Hop Header to transport a RPL
Packet Information (RPI) [RFC6550]. These additional headers are Packet Information (RPI) [RFC6550]. These additional headers are
called RPL artifacts. When IP-in-IP is used and the outer headers called RPL artifacts. When IP-in-IP is used and the outer headers
terminate at a 6LR down the path (see Figure 8 for the compressed terminate at a 6LR down the path (see Figure 9 for the compressed
format in Storing Mode), then the 6LR decapsulates the IP-in-IP and format in Storing Mode), then the 6LR decapsulates the IP-in-IP and
the packet that is forwarded to the external destination is free of the packet that is forwarded to the external destination is free of
RPL artifacts - but possibly an RPI if packet was generated by a RAN RPL artifacts - but possibly an RPI if packet was generated by a RAN
in the same RPL domain as the destination RUL. in the same RPL domain as the destination RUL.
An IP-in-IP tunnel to a 6LR that injected the route is used for Non-Storing Mode DAO messages are used to signal external routes to
external routes unless the final destination is known to handle or the Root, even if the DODAG is operated in Storing Mode. This
ignore the RPL artifacts properly [RFC8200]. Non-Storing Mode enables to advertise the 6LR that injects the route for use as tunnel
signaling is used to signal external routes to the Root, which endpoint in the data path. For all external routes, the Root should
enables to advertise the tunnel endpoint. A RUL is an example of use an IP-in-IP tunnel to that 6LR, with the RPL artifacts in the
target that is reachable via an external host route and is expected outer header to be stripped by the 6LR. The IP-in-IP encapsulation
to ignore the RPI and the consumed SRH artifacts. In the case of a may be avoided in Storing Mode if the path to the external
RUL, tunneling may not be necessary. destination beyond the 6LR is known to handle or ignore the RPL
artifacts properly [RFC8200]. A RUL is an example of a destination
that is reachable via an external (host) route for which IP-in-IP
tunneling may be avoided as it ignores the RPI and the consumed SRH
artifacts. The use of non-Storing Mode signaling in Storing Mode and
the associated IP-in-IP encapsulation are transparent to intermediate
routers that only see packets back and forth between the Root and the
6LR and do not need a special support for external routes.
A RUL may not support IP-in-IP tunneling [RFC8504], so if IP-in-IP is A RUL may not support IP-in-IP tunneling [RFC8504], so if IP-in-IP is
used, and unless the Root as a better knowledge, the tunnel should used, and unless the Root as a better knowledge, the tunnel should
terminate at the 6LR that injected the external route to the RUL. terminate at the 6LR that injected the external route to the RUL.
Additionally, the RUL cannot be expected to support the compression Additionally, the RUL is not expected to support the compression
method defined in [RFC8138]. The 6LR that injected the route method defined in [RFC8138]. The 6LR that injected the route should
uncompresses the packet before forwarding over an external route, uncompress the packet before forwarding over an external route, even
even when delivering to a RUL, even when it is not the destination of when delivering to a RUL, even when it is not the destination in the
the incoming packet. outer header of the incoming packet.
6.2.1. Support of the HbH Header 6.2.1. Support of the HbH Header
A RUL is expected to process an unknown Option Type in a Hop-by-Hop A RUL is expected to process an unknown Option Type in a Hop-by-Hop
Header as prescribed by section 4.2 of [RFC8200]. This means in Header as prescribed by section 4.2 of [RFC8200]. This means in
particular that an RPI with an Option Type of 0x23 particular that an RPI with an Option Type of 0x23 [USEofRPLinfo] is
[I-D.ietf-roll-useofrplinfo] is ignored when not understood. ignored when not understood.
6.2.2. Support of the Routing Header 6.2.2. Support of the Routing Header
A RUL is expected to process an unknown Routing Header Type as A RUL is expected to process an unknown Routing Header Type as
prescribed by section 4.4 of [RFC8200]. This means in particular prescribed by section 4.4 of [RFC8200]. This means in particular
that Routing Header with a Routing Type of 3 [RFC6553] is ignored that Routing Header with a Routing Type of 3 [RFC6553] is ignored
when the Segments Left is zero, and dropped otherwise. when the Segments Left is zero, and dropped otherwise.
6.2.3. Support of IPv6 Encapsulation 6.2.3. Support of IPv6 Encapsulation
Section 2.1 of [I-D.ietf-roll-useofrplinfo] sets the rules for Section 2.1 of [USEofRPLinfo] sets the rules for forwarding IP-in-IP
forwarding IP-in-IP either to the final 6LN or to a parent 6LR. In either to the final 6LN or to a parent 6LR. In order to enable IP-
order to enable IP-in-IP to the 6LN in Non-Storing Mode, the 6LN must in-IP to the 6LN in Non-Storing Mode, the 6LN must be able to
be able to decapsulate the tunneled packet and either drop the inner decapsulate the tunneled packet and either drop the inner packet if
packet if it is not the final destination, or pass it to the upper it is not the final destination, or pass it to the upper layer for
layer for further processing. Unless it is aware that the RUL can further processing. Unless it is aware that the RUL can handle IP-
handle IP-in-IP properly, the Root that encapsulates a packet to a in-IP properly, the Root that encapsulates a packet to a RUL
RUL terminates the IP-in-IP tunnel at the parent 6LR . For that terminates the IP-in-IP tunnel at the parent 6LR . For that reason,
reason, it is beneficial but not necessary for a RUL to support IP- it is beneficial but not necessary for a RUL to support IP-in-IP.
in-IP.
7. Updated RPL Target option 7. Updated RPL Status
The RPL Status is defined in section 6.5.1. of [RFC6550] for use in
the DAO-Ack message and values are assigned as follows:
+---------+--------------------------------+
| Range | Meaning |
+=========+================================+
| 0 | Success/Unqualified acceptance |
+---------+--------------------------------+
| 1-127 | Not an outright rejection |
+---------+--------------------------------+
| 128-255 | Rejection |
+---------+--------------------------------+
Table 1: RPL Status per RFC 6550
This specification extends the scope of the RPL status to be used in
RPL DCO messages. Furthermore, this specification enables to carry
the status values defined for use in the IPv6 ND Extended Address
Registration Option (EARO) and listed in table 1 of [RFC8505] in a
RPL status. Only EARO status values in the range 0-63 can be
transported.
The resulting RPL status is as follows:
0
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|E|A| Value |
+-+-+-+-+-+-+-+-+
Figure 2: RPL status Format
RPL Status subfields:
E: 1-bit flag. Set to indicate a rejection. When not set, a value
of 0 indicates Success/Unqualified acceptance and other values
indicate "not an outright rejection" as per RFC 6550.
A: 1-bit flag. Indicates the type of the status value.
Status Value: 6-bit unsigned integer. If the 'A' flag is set this
field transports a status value defined for IPv6 ND EARO. When
the 'A' flag is not set, the status value is defined in a RPL
extension.
When building a DCO or a DAO-ACK message upon an IPv6 ND NA or a DAC
message, the RPL Root MUST copy the ARO status unchanged in a RPL
status with the 'A' bit set. Conversely the 6LR MUST copy the value
of the RPL status unchanged in the EARO of an NA message that is
built upon a RPL status with the 'A' bit set in a DCO or a DAO-ACK
message.
8. Updated RPL Target option
This specification updates the RPL Target option to transport the This specification updates the RPL Target option to transport the
ROVR as illustrated in Figure 2. This enables the RPL Root to ROVR as illustrated in Figure 3. This enables the RPL Root to
generate a full EDAR Message as opposed to a keep-alive EDAR that has generate a full EDAR Message as opposed to a keep-alive EDAR that has
restricted properties. The Target Prefix MUST be aligned to the next restricted properties. The Target Prefix MUST be aligned to the next
4-byte boundary after the size indicated by the Prefix Length. if 4-byte boundary after the size indicated by the Prefix Length. if
necessary it is padded with zeros. The size of the ROVR is indicated necessary it is padded with zeros. The size of the ROVR is indicated
in a new ROVR Type field that is encoded to map the CodePfx in the in a new ROVR Type field that is encoded to map the CodePfx in the
EDAR message (see section 4.2 of [RFC8505]). With this specification EDAR message (see section 4.2 of [RFC8505]). With this specification
the ROVR is the remainder of the RPL Target Option. the ROVR is the remainder of the RPL Target Option.
0 1 2 3 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 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
skipping to change at page 12, line 46 skipping to change at page 14, line 21
+ + + +
| Target Prefix (Variable Length) | | Target Prefix (Variable Length) |
. Aligned to 4-byte boundary . . Aligned to 4-byte boundary .
. . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
... Registration Ownership Verifier (ROVR) ... ... Registration Ownership Verifier (ROVR) ...
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Updated Target Option Figure 3: Updated Target Option
New fields: New fields:
RVRsz: Indicates the Size of the ROVR. It MAY be 1, 2, 3, RVRsz: Indicates the Size of the ROVR. It MAY be 1, 2, 3, or 4,
or 4, denoting a ROVR size of 64, 128, 192, or 256 denoting a ROVR size of 64, 128, 192, or 256 bits, respectively.
bits, respectively.
Registration Ownership Verifier (ROVR): This is the same field as in Registration Ownership Verifier (ROVR): This is the same field as in
the EARO, see [RFC8505] the EARO, see [RFC8505]
8. Protocol Operations for Unicast Addresses 9. Protocol Operations for Unicast Addresses
8.1. General Flow 9.1. General Flow
This specification enables to save the exchange of Extended Duplicate This specification enables to save the exchange of Extended Duplicate
Address messages, EDAR and EDAC, from a 6LN all the way to the 6LBR Address messages, EDAR and EDAC, from a 6LN all the way to the 6LBR
across a RPL mesh, for the sole purpose of refreshing an existing across a RPL mesh, for the sole purpose of refreshing an existing
state in the 6LBR. Instead, the EDAR/EDAC exchange is proxied by the state in the 6LBR. Instead, the EDAR/EDAC exchange is proxied by the
RPL Root upon a DAO message that refreshes the RPL routing state. To RPL Root upon a DAO message that refreshes the RPL routing state. To
achieve this, the lifetimes and sequence counters in 6LoWPAN ND and achieve this, the lifetimes and sequence counters in 6LoWPAN ND and
RPL are aligned. In other words, the Path Sequence and the Path RPL are aligned. In other words, the Path Sequence and the Path
Lifetime in the DAO message are taken from the Transaction ID and the Lifetime in the DAO message are taken from the Transaction ID and the
registration lifetime in the NS(EARO) message from the 6LN. registration lifetime in the NS(EARO) message from the 6LN.
skipping to change at page 13, line 36 skipping to change at page 15, line 10
Consequently, only addresses that are injected in RPL will be kept Consequently, only addresses that are injected in RPL will be kept
alive by the RPL Root. If an additional routing protocol is deployed alive by the RPL Root. If an additional routing protocol is deployed
on a same network, that additional routing protocol may need to on a same network, that additional routing protocol may need to
handle the keep alive procedure for the addresses that it serves. handle the keep alive procedure for the addresses that it serves.
From the perspective of the 6LN, the registration flow happens From the perspective of the 6LN, the registration flow happens
transparently; it is not delayed by the proxy RPL operation, so the transparently; it is not delayed by the proxy RPL operation, so the
device does not need to change the amount of time it waits based upon device does not need to change the amount of time it waits based upon
whether RPL proxy operation happens or not. whether RPL proxy operation happens or not.
On the first registration, illustrated in Figure 3, from the On the first registration, illustrated in Figure 4, from the
perspective of the 6LR in Non-Storing Mode, the Extended Duplicate perspective of the 6LR in Non-Storing Mode, the Extended Duplicate
Address message takes place as prescribed by [RFC8505]. When Address message takes place as prescribed by [RFC8505]. When
successful, the flow creates a Neighbor Cache Entry (NCE) in the 6LR, successful, the flow creates a Neighbor Cache Entry (NCE) in the 6LR,
and the 6LR injects the Registered Address in RPL using DAO/DAO-ACK and the 6LR injects the Registered Address in RPL using DAO/DAO-ACK
exchanges all the way to the RPL DODAG Root. The protocol does not exchanges all the way to the RPL DODAG Root. The protocol does not
carry a specific information that the Extended Duplicate Address carry a specific information that the Extended Duplicate Address
messages were already exchanged, so the Root proxies them anyway. messages were already exchanged, so the Root proxies them anyway.
Note that any of the functions 6LR, Root and 6LBR might be collapsed Note that any of the functions 6LR, Root and 6LBR might be collapsed
in a single node, in which case the flow above happens internally, in a single node, in which case the flow above happens internally,
and possibly through internal API calls as opposed to messaging. and possibly through internal API calls as opposed to messaging.
8.1.1. In RPL Non-Storing-Mode 9.1.1. In RPL Non-Storing-Mode
In Non-Storing Mode, the flows can be nested as illustrated in In Non-Storing Mode, the flows can be nested as illustrated in
Figure 3 and it is possible to carry information such as an updated Figure 4 and it is possible to carry information such as an updated
lifetime from the 6LBR all the way to the 6LN. lifetime from the 6LBR all the way to the 6LN.
6LN 6LR Root 6LBR 6LN 6LR Root 6LBR
| | | | | | | |
| NS(EARO) | | | | NS(EARO) | | |
|--------------->| | |--------------->| |
| | Extended DAR | | | Extended DAR |
| |-------------------------------->| | |-------------------------------->|
| | | | | |
| | Extended DAC | | | Extended DAC |
skipping to change at page 14, line 39 skipping to change at page 16, line 33
|<---------------| | | |<---------------| | |
| | | | | | | |
(in case if an Error not reported in DAO-ACK) (in case if an Error not reported in DAO-ACK)
| | | | | | | |
| | DCO | | | | DCO | |
| |<--------------| | | |<--------------| |
| NA(EARO) | | | | NA(EARO) | | |
|<---------------| | | |<---------------| | |
| | | | | | | |
Figure 3: First Registration Flow in Non-Storing Mode Figure 4: First Registration Flow in Non-Storing Mode
A re-registration is performed by the 6LN to maintain the NCE in the A re-registration is performed by the 6LN to maintain the NCE in the
6LR alive before lifetime expires. Upon a re-registration, as 6LR alive before lifetime expires. Upon a re-registration, as
illustrated in Figure 4, the 6LR redistributes the Registered Address illustrated in Figure 5, the 6LR redistributes the Registered Address
NS(EARO) in RPL. NS(EARO) in RPL.
This causes the RPL DODAG Root to refresh the state in the 6LBR with This causes the RPL DODAG Root to refresh the state in the 6LBR with
a keep-alive EDAC message. The keep-alive EDAC lacks the a keep-alive EDAC message. The keep-alive EDAC lacks the
Registration Ownership Verifier (ROVR) information, since it is not Registration Ownership Verifier (ROVR) information, since it is not
present in RPL DAO messages, but the EDAC message sent in response by present in RPL DAO messages, but the EDAC message sent in response by
the 6LBR contains the actual value of the ROVR field for that the 6LBR contains the actual value of the ROVR field for that
registration. registration.
6LN 6LR Root 6LBR 6LN 6LR Root 6LBR
skipping to change at page 15, line 23 skipping to change at page 17, line 23
| | |---------------->| | | |---------------->|
| | | EDAC | | | | EDAC |
| | |<----------------| | | |<----------------|
| | DAO-ACK | | | | DAO-ACK | |
| |<--------------| | | |<--------------| |
| NA(EARO) | | | NA(EARO) | |
|<---------------| | | |<---------------| | |
| | | | | | | |
| | | | | | | |
Figure 4: Next Registration Flow in Non-Storing Mode Figure 5: Next Registration Flow in Non-Storing Mode
In case of an error on the keep-alive EDAR flow, the error SHOULD be In case of an error on the keep-alive EDAR flow, the error SHOULD be
returned in the DAO-ACK - if one was requested - using the mapping of returned in the DAO-ACK - if one was requested - using the mapping of
RPL Status and 6LoWPAN Status values discussed in Section 4. RPL Status and 6LoWPAN Status values discussed in Section 4.
If the Root could not return the negative Status in the DAO-ACK then If the Root could not return the negative Status in the DAO-ACK then
it sends an asynchronous Destination Cleanup Object (DCO) message it sends an asynchronous Destination Cleanup Object (DCO) message
[I-D.ietf-roll-efficient-npdao] to the 6LR indicating the issue with [EFFICIENT-NPDAO] to the 6LR placing the negative Status in the RPL
the mapped Status value. Note that if both are used in a short status with the 'A' flag set. Note that if both are used in a short
interval of time, the DAO-ACK and DCO messages are not guaranteed to interval of time, the DAO-ACK and DCO messages are not guaranteed to
arrive in the same order at the 6LR. So the 6LR must still expect a arrive in the same order at the 6LR. So the 6LR must still expect a
DAO-ACK even if it received a DCO while it was waiting for an DAO-ACK even if it received a DCO while it was waiting for an
acknowledgement for a short period of time, but the negative status acknowledgement for a short period of time, but the negative status
in the DCO supercedes a positive status in the DAO-ACK regardless of in the DCO supercedes a positive status in the DAO-ACK regardless of
the order in which they are received. the order in which they are received.
Upon the DAO-ACK - or the DCO if it arrives first - the 6LR responds Upon the DAO-ACK - or the DCO if it arrives first - the 6LR responds
to the RUL with a NA(EARO) and the 6LoWPAN ND Status value that is to the RUL with a NA(EARO) and the 6LoWPAN ND Status value that is
mapped from the RPL status in the RPL message. An asynchronous DCO copied from the RPL status in the RPL message. An asynchronous DCO
is also translated in an asynchronous NA(EARO) to the RUL with a is also translated in an asynchronous NA(EARO) to the RUL with a
mapped Status value. The RPL Status values that are mapped with copied Status value. The RPL Status values that are copied with
6LoWPAN ND are in the range 128 to 192 and listed in the same order 6LoWPAN ND are in the range 128 to 192 and listed in the same order
(see Table 1). A RPL Status Value of 128 maps to 6LoWPAN ND Status (see Table 2). A RPL Status Value of 128 maps to 6LoWPAN ND Status
Code of 1 and so on. Code of 1 and so on.
8.1.2. In RPL Storing-Mode 9.1.2. In RPL Storing-Mode
In Storing Mode, the DAO-ACK is optional. When it is used, it is In Storing Mode, the DAO-ACK is optional. When it is used, it is
generated by the RPL parent, which does not need to wait for the generated by the RPL parent, which does not need to wait for the
grand-parent to send the acknowledgement. A successful DAO-ACK is grand-parent to send the acknowledgement. A successful DAO-ACK is
not a guarantee that the DAO has yet reached the Root or that the not a guarantee that the DAO has yet reached the Root or that the
keep-alive EDAR has succeeded. keep-alive EDAR has succeeded.
If the keep alive fails, the path is cleaned up asynchronously using If the keep alive fails, the path is cleaned up asynchronously using
a DCO message [I-D.ietf-roll-efficient-npdao] as illustrated in a DCO message [EFFICIENT-NPDAO] as illustrated in Figure 6 and
Figure 5 and described in further details in Section 8.2.3. described in further details in Section 9.2.3.
6LN 6LR 6LR Root 6LBR 6LN 6LR 6LR Root 6LBR
| | | | | | | | | |
| NS(EARO) | | | | | NS(EARO) | | | |
|-------------->| | | | |-------------->| | | |
| NA(EARO) | | | | | NA(EARO) | | | |
|<--------------| | | | |<--------------| | | |
| | | | | | | | | |
| | DAO | | | | | DAO | | |
| |-------------->| | | | |-------------->| | |
skipping to change at page 16, line 47 skipping to change at page 18, line 47
| | | |<----------------| | | | |<----------------|
| | | | | | | | | |
(in case if an Error) (in case if an Error)
| | | | | | | | | |
| | DCO | | | | DCO | |
| |<------------------------------| | | |<------------------------------| |
| NA(EARO) | | | | | NA(EARO) | | | |
|<--------------| | | | |<--------------| | | |
| | | | | | | | | |
Figure 5: Next Registration Flow in Storing Mode Figure 6: Next Registration Flow in Storing Mode
8.2. Operation
8.2.1. By the 6LN 9.2. Operation
9.2.1. By the 6LN
This specification does not alter the operation of a 6LoWPAN ND- This specification does not alter the operation of a 6LoWPAN ND-
compliant 6LN, and a RUL is expected to operate as follows: compliant 6LN, and a RUL is expected to operate as follows:
o The 6LN obtains an IPv6 global address, for instance using * The 6LN obtains an IPv6 global address, for instance using
autoconfiguration [RFC4862] based on a Prefix Information Option autoconfiguration [RFC4862] based on a Prefix Information Option
(PIO) [RFC4861] found in a Router Advertisement message or by some (PIO) [RFC4861] found in a Router Advertisement message or by some
other means such as DHCPv6 [RFC3315]. other means such as DHCPv6 [RFC3315].
o Once it has formed an address, the 6LN (re)registers its address * Once it has formed an address, the 6LN (re)registers its address
periodically, within the Lifetime of the previous registration, as periodically, within the Lifetime of the previous registration, as
prescribed by [RFC6775]. prescribed by [RFC6775].
o A 6LN acting as a RUL sets the R flag in the EARO whereas a 6LN * A 6LN acting as a RUL sets the R flag in the EARO whereas a 6LN
acting as a RAN does not set the R flag as prescribed by [RFC8505] acting as a RAN does not set the R flag as prescribed by [RFC8505]
section 5.1. section 5.1.
o Upon each consecutive registration, the 6LN increases the TID * Upon each consecutive registration, the 6LN increases the TID
field in the EARO, as prescribed by [RFC8505] section 5.2. field in the EARO, as prescribed by [RFC8505] section 5.2.
o The 6LN can register to more than one 6LR at the same time. In * The 6LN can register to more than one 6LR at the same time. In
that case, a same value of TID is used for each registration. that case, a same value of TID is used for each registration.
o The 6LN may use any of the 6LRs to which it register to forward * The 6LN may use any of the 6LRs to which it register to forward
its packets. Using a 6LR to which the 6LN is not registered may its packets. Using a 6LR to which the 6LN is not registered may
result in packets dropped by a Source Address Validation function. result in packets dropped by a Source Address Validation function.
Even without support for RPL, a RUL may be aware of opaque values to Even without support for RPL, a RUL may be aware of opaque values to
be provided to the routing protocol. If the RUL has a knowledge of be provided to the routing protocol. If the RUL has a knowledge of
the RPL Instance the packet should be injected into, then it SHOULD the RPL Instance the packet should be injected into, then it SHOULD
set the Opaque field in the EARO to the RPLInstanceID, else it MUST set the Opaque field in the EARO to the RPLInstanceID, else it MUST
leave the Opaque field to zero. In any fashion the 6LN MUST set the leave the Opaque field to zero. In any fashion the 6LN MUST set the
"I" field to zero to indicate that topological information to be "I" field to zero to indicate that topological information to be
passed to a routing process as specified in [RFC8505] section 5.1. passed to a routing process as specified in [RFC8505] section 5.1.
A RUL is not expected to produce RPL artifacts in the data packets, A RUL is not expected to produce RPL artifacts in the data packets,
but it MAY do so. for instance, if the RUL has a minimal awareness of but it MAY do so. for instance, if the RUL has a minimal awareness of
the RPL Instance and can build an RPI. A RUL that places an RPI in a the RPL Instance and can build an RPI. A RUL that places an RPI in a
data packet MUST indicate the RPLInstanceID that corresponds to the data packet MUST indicate the RPLInstanceID that corresponds to the
RPL Instance the packet should be injected into. All the flags and RPL Instance the packet should be injected into. All the flags and
the Rank field are set to zero as specified by section 11.2 of the Rank field are set to zero as specified by section 11.2 of
[RFC6550]. [RFC6550].
8.2.2. By the 6LR 9.2.2. By the 6LR
Also as prescribed by [RFC8505], the 6LR generates a DAR message upon Also as prescribed by [RFC8505], the 6LR generates a DAR message upon
reception of a valid NS(EARO) message for the registration of a new reception of a valid NS(EARO) message for the registration of a new
IPv6 Address by a 6LN. If the Duplicate Address exchange succeeds, IPv6 Address by a 6LN. If the Duplicate Address exchange succeeds,
then the 6LR installs a Neighbor Cache Entry (NCE). If the R flag then the 6LR installs a Neighbor Cache Entry (NCE). If the R flag
was set in the EARO of the NS message, and this 6LR can manage the was set in the EARO of the NS message, and this 6LR can manage the
reachability of Registered Address, then the 6LR sets the R flag in reachability of Registered Address, then the 6LR sets the R flag in
the EARO of the NA message that is sent in response. the EARO of the NA message that is sent in response.
From then on, the 6LN periodically sends a new NS(EARO) to refresh From then on, the 6LN periodically sends a new NS(EARO) to refresh
skipping to change at page 18, line 47 skipping to change at page 20, line 47
registered address. registered address.
Upon a successful NS/NA(EARO) exchange: if the R flag was set in the Upon a successful NS/NA(EARO) exchange: if the R flag was set in the
EARO of the NS message, then the 6LR SHOULD inject the Registered EARO of the NS message, then the 6LR SHOULD inject the Registered
Address in RPL by sending a DAO message on behalf of the 6LN; else Address in RPL by sending a DAO message on behalf of the 6LN; else
the 6LR MUST NOT inject the Registered Address into RPL. the 6LR MUST NOT inject the Registered Address into RPL.
The DAO message advertising the Registered Address MUST be The DAO message advertising the Registered Address MUST be
constructed as follows: constructed as follows:
o The Registered Address is placed in a RPL Target Option in the DAO * The Registered Address is placed in a RPL Target Option in the DAO
message as the Target Prefix, and the Prefix Length is set to 128; message as the Target Prefix, and the Prefix Length is set to 128;
o the External 'E' flag in the Transit Information Option (TIO) * the External 'E' flag in the Transit Information Option (TIO)
associated to the Target Option is set to indicate that the 6LR associated to the Target Option is set to indicate that the 6LR
redistributes an external target into the RPL network. When the redistributes an external target into the RPL network. When the
Root has to use an IP-in-IP [I-D.ietf-roll-useofrplinfo], then Root has to use an IP-in-IP [USEofRPLinfo], then this flag
this flag indicates the IP-in-IP should be addressed to this node; indicates the IP-in-IP should be addressed to this node;
o the Path Lifetime in the TIO is computed from the Lifetime in the * the Path Lifetime in the TIO is computed from the Lifetime in the
EARO Option to adapt it to the Lifetime Units used in the RPL EARO Option to adapt it to the Lifetime Units used in the RPL
operation. Note that if the lifetime is 0, then the 6LR generates operation. Note that if the lifetime is 0, then the 6LR generates
a No-Path DAO message that cleans up the routes down to the a No-Path DAO message that cleans up the routes down to the
Address of the 6LN; Address of the 6LN;
o the Path Sequence in the TIO is set to the TID value found in the * the Path Sequence in the TIO is set to the TID value found in the
EARO option; EARO option;
o Additionally, in Non-Storing Mode the 6LR indicates one of its * Additionally, in Non-Storing Mode the 6LR indicates one of its
global IPv6 unicast addresses as the Parent Address in the TIO. global IPv6 unicast addresses as the Parent Address in the TIO.
If a DAO-ACK is not requested, or has a Status that is less than 128, If a DAO-ACK is not requested, or has a Status that is less than 128,
indicating the DAO was accepted, respectively by a parent in Storing indicating the DAO was accepted, respectively by a parent in Storing
Mode or by the Root in non-Storing Mode,, the 6LR replies with a Mode or by the Root in non-Storing Mode,, the 6LR replies with a
NA(EARO) to the RUL with a status of 0 (Success). NA(EARO) to the RUL with a status of 0 (Success).
In case of a DAO-ACK or a DCO with a status of 132 (Validation In case of a DAO-ACK or a DCO with a status of 132 (Validation
Requested) the 6LR challenges the 6LN for ownership of the address, Requested) the 6LR challenges the 6LN for ownership of the address,
as described in section 6.1 of [RFC8505]. If the challenge succeeds as described in section 6.1 of [RFC8505]. If the challenge succeeds
then the operations continue as normal. In particular a DAO message then the operations continue as normal. In particular a DAO message
is generated upon the NS(EARO) that proves the ownership of the is generated upon the NS(EARO) that proves the ownership of the
address. If the challenge failed the 6LR MUST refrain from injecting address. If the challenge failed the 6LR MUST refrain from injecting
the address in RPL and may take actions to protect itself against DoS the address in RPL and may take actions to protect itself against DoS
attacks by a rogue 6LN, see Section 11 attacks by a rogue 6LN, see Section 12
Other status values above 128 indicate that the 6LR failed to inject Other status values above 128 indicate that the 6LR failed to inject
the address into the RPL network. In that case the the 6LR MUST send the address into the RPL network. In that case the the 6LR MUST send
a NA(EARO) to the RUL with the mapped Status value. If for any other a NA(EARO) to the RUL with the copied Status value. If for any other
reason the 6LR fails to inject the address into the RPL network, the reason the 6LR fails to inject the address into the RPL network, the
6LR SHOULD send a NA(EARO) to the RUL with a status of 2 (Out of 6LR SHOULD send a NA(EARO) to the RUL with a status of 2 (Out of
Storage) which indicates a possibility to retry later. Storage) which indicates a possibility to retry later.
If a 6LR receives a valid NS(EARO) message with the R flag reset and If a 6LR receives a valid NS(EARO) message with the R flag reset and
the 6LR was redistributing the Registered Address due to previous the 6LR was redistributing the Registered Address due to previous
NS(EARO) messages with the flag set, then it MUST stop injecting the NS(EARO) messages with the flag set, then it MUST stop injecting the
address. It is up to the Registering Node to maintain the address. It is up to the Registering Node to maintain the
corresponding route from then on, either keeping it active by sending corresponding route from then on, either keeping it active by sending
further DAO messages, or destroying it using a No-Path DAO. further DAO messages, or destroying it using a No-Path DAO.
Upon a DCO message indicating that the address of a RUL should be Upon a DCO message indicating that the address of a RUL should be
removed from the routing table, the 6LR issues an asynchronous removed from the routing table, the 6LR issues an asynchronous
NA(EARO) to the RUL with the mapped Status value. NA(EARO) to the RUL with the copied Status value.
8.2.3. By the RPL Root 9.2.3. By the RPL Root
In RPL Storing Mode of Operation (MOP), the DAO message is propagated In RPL Storing Mode of Operation (MOP), the DAO message is propagated
from child to parent all the way to the Root along the DODAG, from child to parent all the way to the Root along the DODAG,
populating routing state as it goes. In Non-Storing Mode, The DAO populating routing state as it goes. In Non-Storing Mode, The DAO
message is sent directly to the RPL Root. Upon reception of a DAO message is sent directly to the RPL Root. Upon reception of a DAO
message, for each RPL Target option that creates or updates an message, for each RPL Target option that creates or updates an
existing RPL state: existing RPL state:
o the Root notifies the 6LBR using an internal API if they are co- * the Root notifies the 6LBR using an internal API if they are co-
located, or performs an EDAR/EDAC exchange on behalf of the 6LR if located, or performs an EDAR/EDAC exchange on behalf of the 6LR if
they are separated. If the Target option transports a ROVR, then they are separated. If the Target option transports a ROVR, then
the Root MUST use it to build a full EDAR message as the 6LR the Root MUST use it to build a full EDAR message as the 6LR
would. Else, a keep-alive EDAR is used with the ROVR field set to would. Else, a keep-alive EDAR is used with the ROVR field set to
zero. zero.
An EDAR message MUST be constructed as follows: An EDAR message MUST be constructed as follows:
o The Target IPv6 address from in the RPL Target Option is placed in * The Target IPv6 address from in the RPL Target Option is placed in
the Registered Address field of the EDAR message and in the Target the Registered Address field of the EDAR message and in the Target
field of the NS message, respectively; field of the NS message, respectively;
o the Registration Lifetime is adapted from the Path Lifetime in the * the Registration Lifetime is adapted from the Path Lifetime in the
TIO by converting the Lifetime Units used in RPL into units of 60 TIO by converting the Lifetime Units used in RPL into units of 60
seconds used in the 6LoWPAN ND messages; seconds used in the 6LoWPAN ND messages;
o the RPL Root indicates its own MAC Address as Source Link Layer * the RPL Root indicates its own MAC Address as Source Link Layer
Address (SLLA) in the NS(EARO); Address (SLLA) in the NS(EARO);
o the TID value is set to the Path Sequence in the TIO and indicated * the TID value is set to the Path Sequence in the TIO and indicated
with an ICMP code of 1 in the EDAR message; with an ICMP code of 1 in the EDAR message;
o when present in the RPL Target option, the ROVR field is used as * when present in the RPL Target option, the ROVR field is used as
is in the EDAR and the ICMP Code Suffix is set to the appropriate is in the EDAR and the ICMP Code Suffix is set to the appropriate
value as shown in Table 4 of [RFC8505] depending on the length of value as shown in Table 4 of [RFC8505] depending on the length of
the ROVR field. If it is not present the ROVR field in the EDAR the ROVR field. If it is not present the ROVR field in the EDAR
is set to zero indicating that this is a keep-alive EDAR. The is set to zero indicating that this is a keep-alive EDAR. The
actual value of the ROVR for that registration is expected from actual value of the ROVR for that registration is expected from
the 6LBR in the response EDAC. the 6LBR in the response EDAC.
Upon a Status value in an EDAC message that is not "Success", the Upon a Status value in an EDAC message that is not "Success", the
Root SHOULD destroy the formed paths using either a DAO-ACK (in Non- Root SHOULD destroy the formed paths using either a DAO-ACK (in Non-
Storing Mode) or a DCO downwards as specified in Storing Mode) or a DCO downwards as specified in [EFFICIENT-NPDAO].
[I-D.ietf-roll-efficient-npdao]. Failure to destroy the former path Failure to destroy the former path would result in Stale routing
would result in Stale routing state and local black holes if the state and local black holes if the address belongs to another party
address belongs to another party elsewhere in the network. The RPL elsewhere in the network. The RPL Status value that maps the 6LowpAN
Status value that maps the 6LowpAN ND status value MUST be placed in ND status value MUST be placed in the DCO.
the DCO.
8.2.4. By the 6LBR 9.2.4. By the 6LBR
Upon reception of an EDAR message with the ROVR field is set to zero Upon reception of an EDAR message with the ROVR field is set to zero
indicating a keep-alive EDAR, the 6LBR checks whether an entry exists indicating a keep-alive EDAR, the 6LBR checks whether an entry exists
for the and computes whether the TID in the DAR message is fresher for the and computes whether the TID in the DAR message is fresher
than that in the entry as prescribed in section 4.2.1. of [RFC8505]. than that in the entry as prescribed in section 4.2.1. of [RFC8505].
If the entry does not exist, the 6LBR does not create the entry, and If the entry does not exist, the 6LBR does not create the entry, and
answers with a Status "Removed" in the EDAC message. answers with a Status "Removed" in the EDAC message.
If the entry exists but is not fresher, the 6LBR does not update the If the entry exists but is not fresher, the 6LBR does not update the
skipping to change at page 21, line 28 skipping to change at page 23, line 30
If the entry exists and the TID in the DAR message is fresher, the If the entry exists and the TID in the DAR message is fresher, the
6LBR updates the TID in the entry, and if the lifetime of the entry 6LBR updates the TID in the entry, and if the lifetime of the entry
is extended by the Registration Lifetime in the DAR message, it also is extended by the Registration Lifetime in the DAR message, it also
updates the lifetime of the entry. In that case, the 6LBR replies updates the lifetime of the entry. In that case, the 6LBR replies
with a Status "Success" in the DAC message. with a Status "Success" in the DAC message.
The EDAC that is constructed is the same as if the keep-alive EDAR The EDAC that is constructed is the same as if the keep-alive EDAR
was a full EDAR, and includes the ROVR that is associated to the was a full EDAR, and includes the ROVR that is associated to the
registration. registration.
9. Protocol Operations for Multicast Addresses 10. Protocol Operations for Multicast Addresses
Section 12 of [RFC6550] details the RPL support for multicast flows. Section 12 of [RFC6550] details the RPL support for multicast flows.
This support is not source-specific and only operates as an extension This support is not source-specific and only operates as an extension
to the Storing Mode of Operation for unicast packets. Note that it to the Storing Mode of Operation for unicast packets. Note that it
is the RPL model that the multicast packet is passed as a Layer-2 is the RPL model that the multicast packet is passed as a Layer-2
unicast to each if the interested children. This remains true when unicast to each if the interested children. This remains true when
forwarding between the 6LR and the listener 6LN. forwarding between the 6LR and the listener 6LN.
"Multicast Listener Discovery (MLD) for IPv6" [RFC2710] and its "Multicast Listener Discovery (MLD) for IPv6" [RFC2710] and its
updated version "Multicast Listener Discovery Version 2 (MLDv2) for updated version "Multicast Listener Discovery Version 2 (MLDv2) for
IPv6" [RFC3810] provide an interface for a listener to register to IPv6" [RFC3810] provide an interface for a listener to register to
multicast flows. MLDv2 is backwards compatible with MLD, and adds in multicast flows. MLDv2 is backwards compatible with MLD, and adds in
particular the capability to filter the sources via black lists and particular the capability to filter the sources via black lists and
white lists. In the MLD model, the router is a "querier" and the white lists. In the MLD model, the router is a "querier" and the
host is a multicast listener that registers to the querier to obtain host is a multicast listener that registers to the querier to obtain
copies of the particular flows it is interested in. copies of the particular flows it is interested in.
On the first registration, as illustrated in Figure 6, the 6LN, as an On the first registration, as illustrated in Figure 7, the 6LN, as an
MLD listener, sends an unsolicited Report to the 6LR in order to MLD listener, sends an unsolicited Report to the 6LR in order to
start receiving the flow immediately. Since multicast Layer-2 start receiving the flow immediately. Since multicast Layer-2
messages are avoided, it is important that the asynchronous messages messages are avoided, it is important that the asynchronous messages
for unsolicited Report and Done are sent reliably, for instance using for unsolicited Report and Done are sent reliably, for instance using
an Layer-2 acknoledgement, or attempted multiple times. an Layer-2 acknoledgement, or attempted multiple times.
The 6LR acts as a generic MLD querier and generates a DAO for the The 6LR acts as a generic MLD querier and generates a DAO for the
multicast target. The lifetime of the DAO is set to be in the order multicast target. The lifetime of the DAO is set to be in the order
of the Query Interval, yet larger to account for variable propagation of the Query Interval, yet larger to account for variable propagation
delays. delays.
skipping to change at page 22, line 31 skipping to change at page 24, line 33
| | DAO | | | | DAO | |
| |-------------->| | | |-------------->| |
| | DAO-ACK | | | | DAO-ACK | |
| |<--------------| | | |<--------------| |
| | | <if not listening> | | | | <if not listening> |
| | | unsolicited Report | | | | unsolicited Report |
| | |------------------->| | | |------------------->|
| | | | | | | |
| | | | | | | |
Figure 6: First Multicast Registration Flow Figure 7: First Multicast Registration Flow
A re-registration is pulled by 6LR acting as querier. Note that the A re-registration is pulled by 6LR acting as querier. Note that the
message may sent unicast to all the known individual listeners. Upon message may sent unicast to all the known individual listeners. Upon
a time out of the Query Interval, the 6LR sends a Query to each of a time out of the Query Interval, the 6LR sends a Query to each of
its listeners, and gets a Report back that is mapped into a DAO, as its listeners, and gets a Report back that is mapped into a DAO, as
illustrated in Figure 7, illustrated in Figure 8,
6LN 6LR Root 6LBR 6LN 6LR Root 6LBR
| | | | | | | |
| Query | | | | Query | | |
|<-------------------| | | |<-------------------| | |
| Report | | | | Report | | |
|------------------->| | | |------------------->| | |
| | DAO | | | | DAO | |
| |-------------->| | | |-------------->| |
| | DAO-ACK | | | | DAO-ACK | |
| |<--------------| | | |<--------------| |
| | | | | | | |
| | | Query | | | | Query |
| | |<-------------------| | | |<-------------------|
| | | Report | | | | Report |
| | |------------------->| | | |------------------->|
| | | | | | | |
| | | | | | | |
Figure 7: Next Registration Flow Figure 8: Next Registration Flow
Note that any of the functions 6LR, Root and 6LBR might be collapsed Note that any of the functions 6LR, Root and 6LBR might be collapsed
in a single node, in which case the flow above happens internally, in a single node, in which case the flow above happens internally,
and possibly through internal API calls as opposed to messaging. and possibly through internal API calls as opposed to messaging.
10. Implementation Status 11. Implementation Status
11. Security Considerations 12. Security Considerations
The LLN nodes depend on the 6LBR and the RPL participants for their The LLN nodes depend on the 6LBR and the RPL participants for their
operation. A trust model must be put in place to ensure that the operation. A trust model must be put in place to ensure that the
right devices are acting in these roles, so as to avoid threats such right devices are acting in these roles, so as to avoid threats such
as black-holing, (see [RFC7416] section 7) or bombing attack whereby as black-holing, (see [RFC7416] section 7) or bombing attack whereby
an impersonated 6LBR would destroy state in the network by using the an impersonated 6LBR would destroy state in the network by using the
"Removed" Status code. This trust model could be at a minimum based "Removed" Status code. This trust model could be at a minimum based
on a Layer-2 access control, or could provide role validation as on a Layer-2 access control, or could provide role validation as
well. This is a generic 6LoWPAN requirement, see Req5.1 in well. This is a generic 6LoWPAN requirement, see Req5.1 in
Appendix of [RFC8505]. Appendix of [RFC8505].
skipping to change at page 24, line 7 skipping to change at page 26, line 7
in the 6LBR. The 6LBR MUST NOT create an entry based on a keep-alive in the 6LBR. The 6LBR MUST NOT create an entry based on a keep-alive
EDAR that does not match an existing entry. All it can do is refresh EDAR that does not match an existing entry. All it can do is refresh
the lifetime and the TID of an existing entry. the lifetime and the TID of an existing entry.
At the time of this writing RPL does not have a zerotrust model At the time of this writing RPL does not have a zerotrust model
whereby the it is possible to validate the origin of an address that whereby the it is possible to validate the origin of an address that
is injected in a DAO. This specification makes a first step in that is injected in a DAO. This specification makes a first step in that
direction by allowing the Root to challenge the RUL by the 6LR that direction by allowing the Root to challenge the RUL by the 6LR that
serves it. serves it.
12. IANA Considerations 13. IANA Considerations
12.1. RPL Target Option Flags 13.1. RPL Target Option Flags
Section 20.15 of [RFC6550] creates a registry for the 8-bit RPL Section 20.15 of [RFC6550] creates a registry for the 8-bit RPL
Target Option Flags field. This specification reduces the field to 4 Target Option Flags field. This specification reduces the field to 4
bits. The IANA is requested to reduce the size of the registry bits. The IANA is requested to reduce the size of the registry
accordingly. accordingly.
12.2. New Subsubregistry for the Status values of the RPL DAO-ACK 13.2. New Subsubregistry for the RPL Non-Rejection Status values
Message
This specification creates a new subsubregistry for the Status values This specification creates a new subsubregistry for the RPL Non-
of the RPL DAO-ACK Message, under the ICMPv6 parameters registry. Rejection Status values for use in RPL DAO-ACK and RCO Messages,
under the ICMPv6 parameters registry.
o Possible values are 8-bit unsigned integers (0..255). * Possible values are 6-bit unsigned integers (0..63).
o Registration procedure is "Standards Action" [RFC8126]. * Registration procedure is "Standards Action" [RFC8126].
o Initial allocation is as indicated in Table 1: * Initial allocation is as indicated in Table 2:
+---------+-----------------------+---------------------------------+ +-------+------------------------+---------------+
| Value | Meaning | Defining Spec | | Value | Meaning | Defining Spec |
+---------+-----------------------+---------------------------------+ +=======+========================+===============+
| 0 | Unqualified | [RFC6550] | | 0 | Unqualified acceptance | RFC 6550 |
| | acceptance | | +-------+------------------------+---------------+
| | | |
| 1-127 | Reserved for Warning | [RFC6550] |
| | Codes | |
| | | |
| 128 | Duplicate Address | This RFC |
| | | |
| 129 | Out of Storage | This RFC |
| | | |
| 130 | Moved | [I-D.ietf-roll-efficient-npdao] |
| | | |
| 131 | Removed | This RFC |
| | | |
| 132 | Validation Requested | This RFC |
| | | |
| 133 | Duplicate Source | This RFC |
| | Address | |
| | | |
| 134 | Invalid Source | This RFC |
| | Address | |
| | | |
| 135 | Address topologically | This RFC |
| | incorrect | |
| | | |
| 136 | 6LBR Registry | This RFC |
| | saturated | |
| | | |
| 137 | Validation Failed | This RFC |
| | | |
| 138-192 | Reserved for 6LoWPAN | This RFC |
| | ND code mapping | |
| | | |
| 193-255 | Reserved for other | [RFC6550] |
| | Rejection Codes | |
+---------+-----------------------+---------------------------------+
Table 1: Status values of the RPL DAO-ACK Message Table 2: Status values of the RPL DAO-ACK Message
13. Acknowledgments 13.3. New Subsubregistry for the RPL Rejection Status values
The authors wish to thank Georgios Papadopoulos for their early This specification creates a new subsubregistry for the RPL Non-
reviews of and contributions to this document Rejection Status values for use in RPL DAO-ACK and RCO Messages,
under the ICMPv6 parameters registry.
14. References * Possible values are 6-bit unsigned integers (0..63).
14.1. Normative References * Registration procedure is "Standards Action" [RFC8126].
[I-D.ietf-6lo-ap-nd] * There is no initial allocation
Thubert, P., Sarikaya, B., Sethi, M., and R. Struik,
"Address Protected Neighbor Discovery for Low-power and
Lossy Networks", draft-ietf-6lo-ap-nd-12 (work in
progress), April 2019.
[I-D.ietf-roll-efficient-npdao] 14. Acknowledgments
Jadhav, R., Thubert, P., Sahoo, R., and Z. Cao, "Efficient
Route Invalidation", draft-ietf-roll-efficient-npdao-16
(work in progress), September 2019.
[I-D.ietf-roll-useofrplinfo] The authors wish to thank Georgios Papadopoulos for their early
Robles, I., Richardson, M., and P. Thubert, "Using RPL reviews of and contributions to this document
Option Type, Routing Header for Source Routes and IPv6-in-
IPv6 encapsulation in the RPL Data Plane", draft-ietf- 15. Normative References
roll-useofrplinfo-31 (work in progress), August 2019.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC2710] Deering, S., Fenner, W., and B. Haberman, "Multicast [RFC2710] Deering, S., Fenner, W., and B. Haberman, "Multicast
Listener Discovery (MLD) for IPv6", RFC 2710, Listener Discovery (MLD) for IPv6", RFC 2710,
DOI 10.17487/RFC2710, October 1999, DOI 10.17487/RFC2710, October 1999,
<https://www.rfc-editor.org/info/rfc2710>. <https://www.rfc-editor.org/info/rfc2710>.
[RFC3810] Vida, R., Ed. and L. Costa, Ed., "Multicast Listener [RFC3810] Vida, R., Ed. and L. Costa, Ed., "Multicast Listener
Discovery Version 2 (MLDv2) for IPv6", RFC 3810, Discovery Version 2 (MLDv2) for IPv6", RFC 3810,
DOI 10.17487/RFC3810, June 2004, DOI 10.17487/RFC3810, June 2004,
<https://www.rfc-editor.org/info/rfc3810>. <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>.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007, DOI 10.17487/RFC4861, September 2007,
<https://www.rfc-editor.org/info/rfc4861>. <https://www.rfc-editor.org/info/rfc4861>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007, DOI 10.17487/RFC4862, September 2007,
<https://www.rfc-editor.org/info/rfc4862>. <https://www.rfc-editor.org/info/rfc4862>.
[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>.
[RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J., [RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J.,
Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur, Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur,
JP., and R. Alexander, "RPL: IPv6 Routing Protocol for JP., and R. Alexander, "RPL: IPv6 Routing Protocol for
Low-Power and Lossy Networks", RFC 6550, Low-Power and Lossy Networks", RFC 6550,
DOI 10.17487/RFC6550, March 2012, DOI 10.17487/RFC6550, March 2012,
<https://www.rfc-editor.org/info/rfc6550>. <https://www.rfc-editor.org/info/rfc6550>.
[RFC6553] Hui, J. and JP. Vasseur, "The Routing Protocol for Low- [RFC6553] Hui, J. and JP. Vasseur, "The Routing Protocol for Low-
Power and Lossy Networks (RPL) Option for Carrying RPL Power and Lossy Networks (RPL) Option for Carrying RPL
Information in Data-Plane Datagrams", RFC 6553, Information in Data-Plane Datagrams", RFC 6553,
skipping to change at page 28, line 16 skipping to change at page 28, line 39
(IPv6) Specification", STD 86, RFC 8200, (IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017, DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>. <https://www.rfc-editor.org/info/rfc8200>.
[RFC8505] Thubert, P., Ed., Nordmark, E., Chakrabarti, S., and C. [RFC8505] Thubert, P., Ed., Nordmark, E., Chakrabarti, S., and C.
Perkins, "Registration Extensions for IPv6 over Low-Power Perkins, "Registration Extensions for IPv6 over Low-Power
Wireless Personal Area Network (6LoWPAN) Neighbor Wireless Personal Area Network (6LoWPAN) Neighbor
Discovery", RFC 8505, DOI 10.17487/RFC8505, November 2018, Discovery", RFC 8505, DOI 10.17487/RFC8505, November 2018,
<https://www.rfc-editor.org/info/rfc8505>. <https://www.rfc-editor.org/info/rfc8505>.
14.2. Informative References [AP-ND] Thubert, P., Sarikaya, B., Sethi, M., and R. Struik,
"Address Protected Neighbor Discovery for Low-power and
Lossy Networks", Work in Progress, Internet-Draft, draft-
ietf-6lo-ap-nd-12, 10 April 2019,
<https://tools.ietf.org/html/draft-ietf-6lo-ap-nd-12>.
[USEofRPLinfo]
Robles, I., Richardson, M., and P. Thubert, "Using RPL
Option Type, Routing Header for Source Routes and IPv6-in-
IPv6 encapsulation in the RPL Data Plane", Work in
Progress, Internet-Draft, draft-ietf-roll-useofrplinfo-31,
7 August 2019, <https://tools.ietf.org/html/draft-ietf-
roll-useofrplinfo-31>.
[EFFICIENT-NPDAO]
Jadhav, R., Thubert, P., Sahoo, R., and Z. Cao, "Efficient
Route Invalidation", Work in Progress, Internet-Draft,
draft-ietf-roll-efficient-npdao-17, 30 October 2019,
<https://tools.ietf.org/html/draft-ietf-roll-efficient-
npdao-17>.
16. Informative References
[RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins, [RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins,
C., and M. Carney, "Dynamic Host Configuration Protocol C., and M. Carney, "Dynamic Host Configuration Protocol
for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July
2003, <https://www.rfc-editor.org/info/rfc3315>. 2003, <https://www.rfc-editor.org/info/rfc3315>.
[RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6 [RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6
Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
DOI 10.17487/RFC6282, September 2011, DOI 10.17487/RFC6282, September 2011,
<https://www.rfc-editor.org/info/rfc6282>. <https://www.rfc-editor.org/info/rfc6282>.
skipping to change at page 29, line 11 skipping to change at page 30, line 7
Wireless Personal Area Network (6LoWPAN) Paging Dispatch", Wireless Personal Area Network (6LoWPAN) Paging Dispatch",
RFC 8025, DOI 10.17487/RFC8025, November 2016, RFC 8025, DOI 10.17487/RFC8025, November 2016,
<https://www.rfc-editor.org/info/rfc8025>. <https://www.rfc-editor.org/info/rfc8025>.
[RFC8504] Chown, T., Loughney, J., and T. Winters, "IPv6 Node [RFC8504] Chown, T., Loughney, J., and T. Winters, "IPv6 Node
Requirements", BCP 220, RFC 8504, DOI 10.17487/RFC8504, Requirements", BCP 220, RFC 8504, DOI 10.17487/RFC8504,
January 2019, <https://www.rfc-editor.org/info/rfc8504>. January 2019, <https://www.rfc-editor.org/info/rfc8504>.
Appendix A. Example Compression Appendix A. Example Compression
Figure 8 illustrates the case in Storing mode where the packet is Figure 9 illustrates the case in Storing Mode where the packet is
received from the Internet, then the Root encapsulates the packet to received from the Internet, then the Root encapsulates the packet to
insert the RPI and deliver to the 6LR that is the parent and last hop insert the RPI and deliver to the 6LR that is the parent and last hop
to the final destination, which is not known to support [RFC8138]. to the final destination, which is not known to support [RFC8138].
The difference with the format presented in Figure 19 of [RFC8138] is The difference with the format presented in Figure 19 of [RFC8138] is
the addition of a SRH-6LoRH before the RPI-6LoRH to transport the the addition of a SRH-6LoRH before the RPI-6LoRH to transport the
destination address of the outer IPv6 header. destination address of the outer IPv6 header.
+-+ ... -+-+ ... +-+- ... -+-+ ... -+-+-+ ... +-+-+ ... -+ ... +-... +-+ ... -+-+ ... +-+- ... -+-+ ... -+-+-+ ... +-+-+ ... -+ ... +-...
|11110001|SRH-6LoRH| RPI- |IP-in-IP| NH=1 |11110CPP| UDP | UDP |11110001|SRH-6LoRH| RPI- |IP-in-IP| NH=1 |11110CPP| UDP | UDP
|Page 1 |Type1 S=0| 6LoRH | 6LoRH |LOWPAN_IPHC| UDP | hdr |Payld |Page 1 |Type1 S=0| 6LoRH | 6LoRH |LOWPAN_IPHC| UDP | hdr |Payld
+-+ ... -+-+ ... +-+- ... -+-+ ... -+-+-+ ... +-+-+ ... -+ ... +-... +-+ ... -+-+ ... +-+- ... -+-+ ... -+-+-+ ... +-+-+ ... -+ ... +-...
<-4bytes-> <- RFC 6282 -> <-4bytes-> <- RFC 6282 ->
No RPL artifact No RPL artifact
Figure 8: Encapsulation to Parent 6LR in Storing Mode Figure 9: Encapsulation to Parent 6LR in Storing Mode
In Figure 8, the source of the IP-in-IP encapsulation is the Root, so In Figure 9, the source of the IP-in-IP encapsulation is the Root, so
it is elided in the IP-in-IP 6LoRH. The destination is the parent it is elided in the IP-in-IP 6LoRH. The destination is the parent
6LR of the destination of the inner packet so it cannot be elided. 6LR of the destination of the inner packet so it cannot be elided.
In Storing Mode, it is placed as the single entry in an SRH-6LoRH as In Storing Mode, it is placed as the single entry in an SRH-6LoRH as
the first 6LoRH. Since there is a single entry so the SRH-6LoRH Size the first 6LoRH. Since there is a single entry so the SRH-6LoRH Size
is 0. In this particular example, the 6LR address can be compressed is 0. In this particular example, the 6LR address can be compressed
to 2 bytes so a Type of 1 is used. It results that the total length to 2 bytes so a Type of 1 is used. It results that the total length
of the SRH-6LoRH is 4 bytes. of the SRH-6LoRH is 4 bytes.
In Non-Storing Mode, the encapsulation from the Root would be similar In Non-Storing Mode, the encapsulation from the Root would be similar
to that represented in Figure 8 with possibly more hops in the SRH- to that represented in Figure 9 with possibly more hops in the SRH-
6LoRH and possibly multiple SRH-6LoRHs if the various addresses in 6LoRH and possibly multiple SRH-6LoRHs if the various addresses in
the routing header are not compressed to the same format. Note that the routing header are not compressed to the same format. Note that
on the last hop to the parent 6LR, the RH3 is consumed and removed on the last hop to the parent 6LR, the RH3 is consumed and removed
from the compressed form, so the use of Non-Storing Mode vs. Storing from the compressed form, so the use of Non-Storing Mode vs. Storing
Mode is indistinguishable from the packet format. Mode is indistinguishable from the packet format.
Follows the RPI-6LoRH and then the IP-in-IP 6LoRH. When the IP-in-IP Follows the RPI-6LoRH and then the IP-in-IP 6LoRH. When the IP-in-IP
6LoRH is removed, all the router headers that precede it are also 6LoRH is removed, all the router headers that precede it are also
removed. removed.
skipping to change at page 30, line 8 skipping to change at page 31, line 4
6LoRH is removed, all the router headers that precede it are also 6LoRH is removed, all the router headers that precede it are also
removed. removed.
The Paging Dispatch [RFC8025] may also be removed if there was no The Paging Dispatch [RFC8025] may also be removed if there was no
previous Page change to a Page other than 0 or 1, since the previous Page change to a Page other than 0 or 1, since the
LOWPAN_IPHC is encoded in the same fashion in the default Page 0 and LOWPAN_IPHC is encoded in the same fashion in the default Page 0 and
in Page 1. The resulting packet to the destination is the inner in Page 1. The resulting packet to the destination is the inner
packet compressed with [RFC6282]. packet compressed with [RFC6282].
Authors' Addresses Authors' Addresses
Pascal Thubert (editor) Pascal Thubert (editor)
Cisco Systems, Inc Cisco Systems, Inc
Building D Building D, 45 Allee des Ormes - BP1200
45 Allee des Ormes - BP1200 06254 Mougins - Sophia Antipolis
MOUGINS - Sophia Antipolis 06254 France
FRANCE
Phone: +33 497 23 26 34 Phone: +33 497 23 26 34
Email: pthubert@cisco.com Email: pthubert@cisco.com
Michael C. Richardson Michael C. Richardson
Sandelman Software Works Sandelman Software Works
Email: mcr+ietf@sandelman.ca Email: mcr+ietf@sandelman.ca
URI: http://www.sandelman.ca/ URI: http://www.sandelman.ca/
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