< draft-ietf-6lo-rfc6775-update-14.txt   draft-ietf-6lo-rfc6775-update-15.txt >
6lo P. Thubert, Ed. 6lo P. Thubert, Ed.
Internet-Draft cisco Internet-Draft Cisco
Updates: 6775 (if approved) E. Nordmark Updates: 6775 (if approved) E. Nordmark
Intended status: Standards Track Zededa Intended status: Standards Track Zededa
Expires: August 27, 2018 S. Chakrabarti Expires: September 5, 2018 S. Chakrabarti
Verizon Verizon
C. Perkins C. Perkins
Futurewei Futurewei
February 23, 2018 March 4, 2018
Registration Extensions for 6LoWPAN Neighbor Discovery Registration Extensions for 6LoWPAN Neighbor Discovery
draft-ietf-6lo-rfc6775-update-14 draft-ietf-6lo-rfc6775-update-15
Abstract Abstract
This specification updates RFC 6775 - 6LoWPAN Neighbor Discovery, to This specification updates RFC 6775 - 6LoWPAN Neighbor Discovery, to
clarify the role of the protocol as a registration technique, clarify the role of the protocol as a registration technique,
simplify the registration operation in 6LoWPAN routers, as well as to simplify the registration operation in 6LoWPAN routers, as well as to
provide enhancements to the registration capabilities and mobility provide enhancements to the registration capabilities and mobility
detection for different network topologies including the backbone detection for different network topologies including the backbone
routers performing proxy Neighbor Discovery in a low power network. routers performing proxy Neighbor Discovery in a low power network.
skipping to change at page 1, line 40 skipping to change at page 1, line 40
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
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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 August 27, 2018. This Internet-Draft will expire on September 5, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Applicability of Address Registration Options . . . . . . . . 4 2.1. BCP 14 . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Updating RFC 6775 . . . . . . . . . . . . . . . . . . . . . . 5 2.2. Subset of a 6LoWPAN Glossary . . . . . . . . . . . . . . 3
4.1. Extended Address Registration Option (EARO) . . . . . . . 6 2.3. References . . . . . . . . . . . . . . . . . . . . . . . 4
4.2. Transaction ID . . . . . . . . . . . . . . . . . . . . . 7 2.4. New Terms . . . . . . . . . . . . . . . . . . . . . . . . 4
4.2.1. Comparing TID values . . . . . . . . . . . . . . . . 8 3. Applicability of Address Registration Options . . . . . . . . 5
4.3. Registration Unique ID . . . . . . . . . . . . . . . . . 9 4. Updating RFC 6775 . . . . . . . . . . . . . . . . . . . . . . 6
4.4. Extended Duplicate Address Messages . . . . . . . . . . . 10 4.1. Extended Address Registration Option (EARO) . . . . . . . 7
4.5. Registering the Target Address . . . . . . . . . . . . . 10 4.2. Transaction ID . . . . . . . . . . . . . . . . . . . . . 8
4.6. Link-Local Addresses and Registration . . . . . . . . . . 11 4.2.1. Comparing TID values . . . . . . . . . . . . . . . . 9
4.7. Maintaining the Registration States . . . . . . . . . . . 12 4.3. Registration Ownership Verifier . . . . . . . . . . . . . 10
5. Detecting Enhanced ARO Capability Support . . . . . . . . . . 14 4.4. Extended Duplicate Address Messages . . . . . . . . . . . 11
6. Extended ND Options And Messages . . . . . . . . . . . . . . 14 4.5. Registering the Target Address . . . . . . . . . . . . . 12
6.1. Enhanced Address Registration Option (EARO) . . . . . . . 14 4.6. Link-Local Addresses and Registration . . . . . . . . . . 12
6.2. Extended Duplicate Address Message Formats . . . . . . . 17 4.7. Maintaining the Registration States . . . . . . . . . . . 14
5. Detecting Enhanced ARO Capability Support . . . . . . . . . . 15
6. Extended ND Options And Messages . . . . . . . . . . . . . . 16
6.1. Extended Address Registration Option (EARO) . . . . . . . 16
6.2. Extended Duplicate Address Message Formats . . . . . . . 18
6.3. New 6LoWPAN Capability Bits in the Capability Indication 6.3. New 6LoWPAN Capability Bits in the Capability Indication
Option . . . . . . . . . . . . . . . . . . . . . . . . . 18 Option . . . . . . . . . . . . . . . . . . . . . . . . . 19
7. Backward Compatibility . . . . . . . . . . . . . . . . . . . 18 7. Backward Compatibility . . . . . . . . . . . . . . . . . . . 20
7.1. Discovering the capabilities of an ND peer . . . . . . . 19 7.1. Discovering the Capabilities of an ND Peer . . . . . . . 20
7.1.1. Using the "E" Flag in the 6CIO . . . . . . . . . . . 19 7.2. RFC6775-only 6LoWPAN Node . . . . . . . . . . . . . . . . 21
7.1.2. Using the "T" Flag in the EARO . . . . . . . . . . . 19 7.3. RFC6775-only 6LoWPAN Router . . . . . . . . . . . . . . . 21
7.2. RFC6775-only 6LoWPAN Node . . . . . . . . . . . . . . . . 20 7.4. RFC6775-only 6LoWPAN Border Router . . . . . . . . . . . 22
7.3. RFC6775-only 6LoWPAN Router . . . . . . . . . . . . . . . 20 8. Security Considerations . . . . . . . . . . . . . . . . . . . 22
7.4. RFC6775-only 6LoWPAN Border Router . . . . . . . . . . . 21 9. Privacy Considerations . . . . . . . . . . . . . . . . . . . 23
8. Security Considerations . . . . . . . . . . . . . . . . . . . 21 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
9. Privacy Considerations . . . . . . . . . . . . . . . . . . . 22 10.1. ARO Flags . . . . . . . . . . . . . . . . . . . . . . . 24
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23 10.2. ICMP Codes . . . . . . . . . . . . . . . . . . . . . . . 25
10.1. ARO Flags . . . . . . . . . . . . . . . . . . . . . . . 23 10.3. New ARO Status values . . . . . . . . . . . . . . . . . 26
10.2. ICMP Codes . . . . . . . . . . . . . . . . . . . . . . . 24 10.4. New 6LoWPAN capability Bits . . . . . . . . . . . . . . 26
10.3. New ARO Status values . . . . . . . . . . . . . . . . . 25 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 27
10.4. New 6LoWPAN capability Bits . . . . . . . . . . . . . . 25 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 27
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 26 12.1. Normative References . . . . . . . . . . . . . . . . . . 27
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 26 12.2. Informative References . . . . . . . . . . . . . . . . . 29
12.1. Normative References . . . . . . . . . . . . . . . . . . 26 12.3. External Informative References . . . . . . . . . . . . 32
12.2. Informative References . . . . . . . . . . . . . . . . . 27
12.3. External Informative References . . . . . . . . . . . . 31 Appendix A. Applicability and Requirements Served (Not
Appendix A. Applicability and Requirements Served . . . . . . . 31 Normative) . . . . . . . . . . . . . . . . . . . . . 32
Appendix B. Requirements . . . . . . . . . . . . . . . . . . . . 32 Appendix B. Requirements (Not Normative) . . . . . . . . . . . . 33
B.1. Requirements Related to Mobility . . . . . . . . . . . . 32 B.1. Requirements Related to Mobility . . . . . . . . . . . . 33
B.2. Requirements Related to Routing Protocols . . . . . . . . 33 B.2. Requirements Related to Routing Protocols . . . . . . . . 34
B.3. Requirements Related to the Variety of Low-Power Link B.3. Requirements Related to the Variety of Low-Power Link
types . . . . . . . . . . . . . . . . . . . . . . . . . . 34 types . . . . . . . . . . . . . . . . . . . . . . . . . . 35
B.4. Requirements Related to Proxy Operations . . . . . . . . 35 B.4. Requirements Related to Proxy Operations . . . . . . . . 35
B.5. Requirements Related to Security . . . . . . . . . . . . 35 B.5. Requirements Related to Security . . . . . . . . . . . . 36
B.6. Requirements Related to Scalability . . . . . . . . . . . 36 B.6. Requirements Related to Scalability . . . . . . . . . . . 37
B.7. Requirements Related to Operations and Management . . . . 37 B.7. Requirements Related to Operations and Management . . . . 38
B.8. Matching Requirements with Specifications . . . . . . . . 38 B.8. Matching Requirements with Specifications . . . . . . . . 38
Appendix C. Subset of a 6LoWPAN Glossary . . . . . . . . . . . . 39 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 39
1. Introduction 1. Introduction
The scope of this draft is an IPv6 Low Power Network including star The scope of this draft is an IPv6 Low Power Network including star
and mesh topologies. This specification modifies and extends the and mesh topologies. This specification modifies and extends the
behavior and protocol elements of "Neighbor Discovery Optimization behavior and protocol elements of "Neighbor Discovery Optimization
for IPv6 over Low-Power Wireless Personal Area Networks" (6LoWPAN ND) for IPv6 over Low-Power Wireless Personal Area Networks" (6LoWPAN ND)
[RFC6775] to enable additional capabilities and enhancements such as: [RFC6775] to enable additional capabilities and enhancements
including:
o determining the freshest location in case of mobility (T-bit) o determining the freshest location in case of mobility (TID)
o Simplifying the registration flow for link-local addresses o Simplifying the registration flow for Link-Local Addresses
o Support of a Leaf node in a route-over network o Support of a Leaf Node in a Route-Over network
o Proxy registration in a route-over network o Proxy registration in a Route-Over network
o Registration to a IPv6 ND proxy over a Backbone Link o Registration to a IPv6 ND proxy over a Backbone Link (6BBR)
o Clarification of support for privacy and temporary addresses o Clarification of support for privacy and temporary addresses
2. Terminology 2. Terminology
2.1. BCP 14
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
document are to be interpreted as described in [RFC2119]. "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119][RFC8174] when, and only when, they appear in all
capitals, as shown here.
2.2. Subset of a 6LoWPAN Glossary
This document often uses the following acronyms:
6BBR: 6LoWPAN Backbone Router (proxy for the registration)
6LBR: 6LoWPAN Border Router (authoritative on DAD)
6LN: 6LoWPAN Node
6LR: 6LoWPAN Router (relay to the registration process)
6CIO: Capability Indication Option
(E)ARO: (Extended) Address Registration Option
DAD: Duplicate Address Detection
LLN: Low Power Lossy Network (a typical IoT network)
NA: Neighbor Advertisement
NCE: Neighbor Cache Entry
ND: Neighbor Discovery
NDP: Neighbor Discovery Protocol
NS: Neighbor Solicitation
ROVR: Registration Ownership Verifier
TSCH: TimeSlotted Channel Hopping
TID: Transaction ID (a sequence counter in the EARO)
2.3. References
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].
Other terms in use in LLNs are found in Terminology for Constrained- Other terms in use in LLNs are found in Terminology for Constrained-
Node Networks [RFC7228]. Node Networks [RFC7228].
A glossary of some classical 6LoWPAN acronyms such as ARO, 6LN, 6LBR
and 6CIO is given in Appendix C.
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], o "Neighbor Discovery for IP version 6" [RFC4861],
o "IPv6 Stateless Address Autoconfiguration" [RFC4862], o "IPv6 Stateless Address Autoconfiguration" [RFC4862],
o "Problem Statement and Requirements for IPv6 over Low-Power o "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): o "IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs):
Overview, Assumptions, Problem Statement, and Goals" [RFC4919] and Overview, Assumptions, Problem Statement, and Goals" [RFC4919] and
o "Neighbor Discovery Optimization for Low-power and Lossy Networks" o "Neighbor Discovery Optimization for Low-power and Lossy Networks"
[RFC6775]. [RFC6775].
as well as the following terminology: 2.4. New Terms
This specification introduces the following terminology:
Backbone Link: An IPv6 transit link that interconnects two or more Backbone Link: An IPv6 transit link that interconnects two or more
Backbone Routers. It is expected to be of high speed compared Backbone Routers. It is expected to be of high speed compared
to the LLN in order to carry the traffic that is required to to the LLN in order to carry the traffic that is required to
federate multiple segments of the potentially large LLN into a federate multiple segments of the potentially large LLN into a
single IPv6 subnet. single IPv6 subnet.
Backbone Router: A logical network function in an IPv6 router that Backbone Router: A logical network function in an IPv6 router that
federates a LLN over a Backbone Link. In order to do so, the federates a LLN over a Backbone Link. In order to do so, the
Backbone Router (6BBR) proxies the 6LoWPAN ND operations Backbone Router (6BBR) proxies the 6LoWPAN ND operations
detailed in this document onto the matching operations that run detailed in this document onto the matching operations that run
over the backbone, typically IPv6 ND. Note that 6BBR is a over the backbone, typically IPv6 ND. Note that 6BBR is a
logical function, just like 6LR and 6LBR, and that the same logical function, just like 6LR and 6LBR, and that the same
physical router may operate all three. physical router may operate all three.
Extended LLN: The aggregation of multiple LLNs as defined in Extended LLN: Multiple LLNs as defined in [RFC6550], interconnected
[RFC4919], interconnected by a Backbone Link via Backbone by a Backbone Link via Backbone Routers, and forming a single
Routers, and forming a single IPv6 MultiLink Subnet. IPv6 MultiLink Subnet.
Registration: The process during which a 6LN registers its Registration: The process during which a 6LN registers an IPv6
address(es) with the Border Router so the 6BBR can serve as Address with a 6LR in order to obtain services such as DAD and
proxy for ND operations over the Backbone. routing back. Duding that flow, the 6LBR may serve as proxy
Binding: The association between an IP address and a MAC address, a for the registration of the 6LN to the 6BBR so the 6BBR can
port and/or other information about the node that owns the IP provide IPv6 ND proxy services over the Backbone.
address. Binding: The association between an IP address, a MAC address, a
Registered Node: The node for which the registration is performed, port, and other information about the node that owns the IP
Address.
Registered Node: The 6LN for which the registration is performed,
and which owns the fields in the Extended ARO option. and which owns the fields in the Extended ARO option.
Registering Node: The node that performs the registration to the Registering Node: The node that performs the registration; this may
6BBR, which may proxy for the registered node. be the Registered Node, or a proxy such as a 6LBR performing a
registration to a 6BBR, on behalf of the Registered Node.
Registered Address: An address owned by the Registered Node that was Registered Address: An address owned by the Registered Node that was
or is being registered. or is being registered.
RFC6775-only: Applied to a type of node or a type of message, this RFC6775-only: Applied to a type of node or a type of message, this
adjective indicates a behavior that is strictly as specified by adjective indicates a behavior that is strictly as specified by
[RFC6775] as opposed to updated with this specification. [RFC6775] as opposed to updated with this specification.
updated: Qualifies a 6LN, a 6LR or a 6LBR that supports this updated: Qualifies a 6LN, a 6LR or a 6LBR that supports this
specification. specification.
3. Applicability of Address Registration Options 3. Applicability of Address Registration Options
skipping to change at page 5, line 48 skipping to change at page 6, line 30
to the network operator, e.g. to a management console. to the network operator, e.g. to a management console.
A network administrator MUST deploy updated 6LR/6LBRs to support the A network administrator MUST deploy updated 6LR/6LBRs to support the
number and type of devices in their network, based on the number of number and type of devices in their network, based on the number of
IPv6 addresses that those devices require and their address renewal IPv6 addresses that those devices require and their address renewal
rate and behavior. rate and behavior.
4. Updating RFC 6775 4. Updating RFC 6775
This specification introduces the Extended Address Registration This specification introduces the Extended Address Registration
Option (EARO) based on the ARO as defined [RFC6775]; in particular a Option (EARO) based on the ARO as defined [RFC6775]. A "T" flag is
"T" flag is added that MUST be set in NS messages when this added to indicate that a new field, the Transaction ID (TID) is
populated. The "T" flag MUST be set in NS messages when this
specification is used, and echoed in NA messages to confirm that the specification is used, and echoed in NA messages to confirm that the
protocol is supported. protocol is supported. The EUI-64 field is overloaded to carry
different types of information and its size may be increased when
backward compatibility is not an issue.
The extensions to the ARO option are used in the Duplicate Address The extensions to the ARO option are used in the Duplicate Address
Request (DAR) and Duplicate Address Confirmation (DAC) messages, so messages, the Duplicate Address Request (DAR) and Duplicate Address
as to convey the additional information all the way to the 6LBR. In Confirmation (DAC), so as to convey the additional information all
turn the 6LBR may proxy the registration using IPv6 ND over a the way to the 6LBR. In turn the 6LBR may proxy the registration
Backbone Link as illustrated in Figure 1. Note that this using IPv6 ND over a Backbone Link as illustrated in Figure 1. Note
specification avoids the extended DAR flow for Link Local Addresses that this specification avoids the Duplicate Address message flow for
in a Route-Over [RFC6606] topology. Link-Local Addresses in a Route-Over [RFC6606] topology.
6LN 6LR 6LBR 6BBR 6LN 6LR 6LBR 6BBR
| | | | | | | |
| NS(EARO) | | | | NS(EARO) | | |
|--------------->| | | |--------------->| | |
| | Extended DAR | | | | Extended DAR | |
| |-------------->| | | |-------------->| |
| | | | | | | |
| | | proxy NS(EARO) | | | | proxy NS(EARO) |
| | |--------------->| | | |--------------->|
skipping to change at page 6, line 42 skipping to change at page 7, line 34
| | | | | | | |
Figure 1: (Re-)Registration Flow Figure 1: (Re-)Registration Flow
In order to support various types of link layers, it is RECOMMENDED In order to support various types of link layers, it is RECOMMENDED
to allow multiple registrations, including for privacy / temporary to allow multiple registrations, including for privacy / temporary
addresses. It is also RECOMMENDED to provide new mechanisms to help addresses. It is also RECOMMENDED to provide new mechanisms to help
clean up stale registration state as soon as possible. clean up stale registration state as soon as possible.
Section 5 of [RFC6775] specifies how a 6LN bootstraps an interface Section 5 of [RFC6775] specifies how a 6LN bootstraps an interface
and locates available 6LRs; a Registering Node SHOULD prefer and locates available 6LRs. A Registering Node SHOULD prefer
registering to a 6LR that is found to support this specification, as registering to a 6LR that is found to support this specification, as
discussed in Section 7.1, over an RFC6775-only one. discussed in Section 5, over an RFC6775-only one and MUST operate in
a backward compatible fashion when attaching to an RFC6775-only 6LR.
4.1. Extended Address Registration Option (EARO) 4.1. Extended Address Registration Option (EARO)
The Extended ARO (EARO) replaces the ARO and is backward compatible The Extended ARO (EARO) replaces the ARO and is backward compatible
with it. More details on backward compatibility can be found in with the ARO if and only if the Length of the option is set to 2.
Section 7. Its format is presented in Section 6.1. More details on backward
compatibility can be found in Section 7.
The semantics of the ARO are modified as follows: The semantics of the Neighbor Solicitation (NS) and the ARO are
modified as follows:
o The address that is being registered with a Neighbor Solicitation o The address that is being registered with a NS with an EARO is now
(NS) with an EARO is now the Target Address, as opposed to the the Target Address, as opposed to the Source Address as specified
Source Address as specified in [RFC6775] (see Section 4.5). This in [RFC6775] (see Section 4.5). This change enables a 6LBR to use
change enables a 6LBR to use one of its addresses as source to the one of its addresses as source of the proxy-registration of an
proxy-registration of an address that belongs to a LLN Node to a address that belongs to a LLN Node to a 6BBR. This also limits
6BBR. This also limits the use of an address as source address the use of an address as source address before it is registered
before it is registered and the associated DAD process is and the associated DAD process is complete.
complete. o The EUI-64 field in the ARO Option is renamed Registration
o The Unique ID in the EARO Option is not required to be a MAC Ownership Verifier (ROVR) and is not required to be derived from a
address (see Section 4.3). MAC address (see Section 4.3).
o This document specifies a new flag in the EARO option, the 'R' o The option Length MAY be different than 2 and take a value between
flag, used by a 6LN, when registering, to indicate that this 6LN 3 and 5, in which case the EARO is not backward compatible with an
is not a router and that it will not handle its own reachability. ARO. The increase of size corresponds to a larger ROVR field, so
If the 'R' flag is set, the registering node expects that the 6LR the size of the ROVR is inferred from the option Length.
ensures reachability for the registered address by means of o This document specifies a new flag in the EARO, the 'R' flag, used
routing or proxying ND. A host SHOULD set the 'R' flag. When not by a 6LN, when registering, to indicate that this 6LN is not a
set, the 'R' flag indicates that the Registering Node is a router, router and that it will not handle its own reachability. If the
which for instance participates to a route-over routing protocol 'R' flag is set, the registering node expects that the 6LR ensures
such as RPL [RFC6550], and which will take care of injecting the reachability for the registered address by means of routing or
address over the routing protocol by itself. A router SHOULD NOT proxying ND. A host MUST set the 'R' flag. When not set, the 'R'
set the 'R' flag. flag indicates that the Registering Node is a router, which for
instance participates to a Route-Over routing protocol such as the
IPv6 Routing Protocol for Low-Power and Lossy Networks [RFC6550]
(RPL), and that it will take care of injecting its Address over
the routing protocol by itself. A router SHOULD NOT set the 'R'
flag; if it does, routes towards the router may be installed on
its behalf and may interfere with those it injects.
o The specification introduces a Transaction ID (TID) field in the o The specification introduces a Transaction ID (TID) field in the
EARO (see Section 4.2). The TID MUST be provided by a node that EARO (see Section 4.2). The TID MUST be provided by a node that
supports this specification and a new "T" flag MUST be set to supports this specification and a new "T" flag MUST be set to
indicate so. indicate so.
o Finally, this specification introduces new status codes to help o Finally, this specification introduces new status codes to help
diagnose the cause of a registration failure (see Table 1). diagnose the cause of a registration failure (see Table 1).
4.2. Transaction ID 4.2. Transaction ID
The Transaction ID (TID) is a sequence number that is incremented The TID is a sequence number that is incremented by the 6LN with each
with each re-registration. The TID is used to detect the freshness re-registration to a 6LR. The TID is used to detect the freshness of
of the registration request and to detect one single registration by the registration request and to detect one single registration by
multiple 6LoWPAN border routers (e.g., 6LBRs and 6BBRs) supporting multiple 6LoWPAN border routers (e.g., 6LBRs and 6BBRs) supporting
the same 6LoWPAN. The TID may also be used by the network to track the same 6LoWPAN. The TID may also be used by the network to route
the sequence of movements of a node in order to route to the current to the current (freshest known) location of a moving node by spotting
(freshest known) location of a moving node. the most recent TID.
When a Registered Node is registered with multiple 6BBRs in parallel, When a Registered Node is registered with multiple 6BBRs in parallel,
the same TID SHOULD be used. This enables the 6BBRs to determine the same TID MUST be used. This enables the 6BBRs to determine that
that the registrations are the same, and distinguish that situation the registrations are the same, and distinguish that situation from a
from a movement (see section 4 of [I-D.ietf-6lo-backbone-router] and movement (see section 4 of [I-D.ietf-6lo-backbone-router] and
Section 4.7 below). Section 4.7 below).
4.2.1. Comparing TID values 4.2.1. Comparing TID values
The TID is a sequence counter and its operation is the exact match of The TID is a sequence counter and its operation is the exact match of
the path sequence specified in RPL, the IPv6 Routing Protocol for the path sequence specified in RPL, the IPv6 Routing Protocol for
Low-Power and Lossy Networks [RFC6550] specification. Low-Power and Lossy Networks [RFC6550] specification.
In order to keep this document self-contained and yet compatible, the In order to keep this document self-contained and yet compatible, the
text below is an exact copy from section 7.2. "Sequence Counter text below is an exact copy from section 7.2. "Sequence Counter
skipping to change at page 9, line 35 skipping to change at page 10, line 35
sequence counters is greater than SEQUENCE_WINDOW, then a sequence counters is greater than SEQUENCE_WINDOW, then a
desynchronization has occurred and the two sequence desynchronization has occurred and the two sequence
numbers are not comparable. numbers are not comparable.
4. If two sequence numbers are determined to be not comparable, i.e. 4. If two sequence numbers are determined to be not comparable, i.e.
the results of the comparison are not defined, then a node should the results of the comparison are not defined, then a node should
give precedence to the sequence number that was most recently give precedence to the sequence number that was most recently
incremented. Failing this, the node should select the sequence incremented. Failing this, the node should select the sequence
number in order to minimize the resulting changes to its own number in order to minimize the resulting changes to its own
state. state.
4.3. Registration Unique ID 4.3. Registration Ownership Verifier
The Registration Unique ID (RUID) generalizes the EUI-64 field of the The ROVR field generalizes the EUI-64 field of the ARO defined in
ARO in [RFC6775]. It is unique to a registration and enables to [RFC6775]. It is scoped to a registration and enables recognize and
identify the tentative to register a duplicate address, which is block a tentative to register a duplicate address, which is
characterized by a different RUID in the conflicting registrations characterized by a different ROVR in the conflicting registrations It
(more in Section 4.6) can also be used to protect the ownership of a Registered Address, if
the proof-of-ownership of the ROVR can be obtained (more in
Section 4.6).
With this specification, the Registration Unique ID is allowed to be The ROVR is allowed to be of different types, as ong as the type is
extended to different types of identifier, as long as the type is signaled in the message that carries the new type. For instance, the
clearly indicated. For instance, the type can be a cryptographic type can be a cryptographic string and used to prove the ownership of
string and used to prove the ownership of the registration as the registration as discussed in "Address Protected Neighbor
discussed in "Address Protected Neighbor Discovery for Low-power and Discovery for Low-power and Lossy Networks" [I-D.ietf-6lo-ap-nd]. In
Lossy Networks" [I-D.ietf-6lo-ap-nd]. In order to support the flows order to support the flows related to the proof-of-ownership, this
related to the proof of ownership, this specification introduces new specification introduces new status codes "Validation Requested" and
status codes "Validation Requested" and "Validation Failed" in the "Validation Failed" in the EARO.
EARO.
The Registering Node SHOULD store the unique ID, or a way to generate Note on ROVR collision: different techniques for forming the ROVR
that ID, in persistent memory. Otherwise, if a reboot causes a loss will operate in different name-spaces. [RFC6775] operates on EUI-64
of memory, re-registering the same address could be impossible until addresses. [I-D.ietf-6lo-ap-nd] generates cryptographic tokens.
the 6LBR times out the previous registration. While collisions are not expected in the EUI-64 name-space only, they
may happen in the case of [I-D.ietf-6lo-ap-nd] and in a mixed
situation. An implementation that understands the name-space MUST
consider that ROVRs from different name-spaces are different even if
they have the same value. An RFC6775-only will confuse the name-
spaces, which slightly increases the risk of a ROVR collision. A
collision of ROVR has no effect if the two Registering Nodes register
different addresses, since the ROVR is only significant within the
context of one registration. A ROVR is not expected to be unique to
one registration, as this specification allows a node to use the same
ROVR to register multiple IPv6 addresses. This is why the ROVR MUST
NOT be used as a key to identify the Registering Node, or as an index
to the registration. It is only used as a match to ensure that the
node that updates a registration for an IPv6 address is the node that
made the original registration for that IPv6 address. Also, when the
ROVR is not an EUI-64 address, then it MUST NOT be used as the
interface ID of the Registered Address. This way, a registration
that uses that ROVR will not collision with that of an IPv6 Address
derived from EUI-64 and using the EUI-64 as ROVR per [RFC6775].
4.4. Extended Duplicate Address Messages The Registering Node SHOULD store the ROVR, or enough information to
regenerate it, in persistent memory. If this is not done and an
event such as a reboot causes a loss of memory, re-registering the
same address could be impossible until the 6LRs and the 6LBR time out
the previous registration, or a management action is taken to clear
the relevant state in the network.
In order to map the new EARO content in the DAR/DAC messages, a new 4.4. Extended Duplicate Address Messages
TID field is added to the Extended DAR (EDAR) and the Extended DAC
(EDAC) messages as a replacement to a Reserved field, and an odd
value of the ICMP Code indicates support for the TID, to transport
the "T" flag.
In order to prepare for future extensions, and though no option has In order to map the new EARO content in the Extended Duplicate
been defined for the Duplicate Address messages, implementations MUST Address (EDA) messages, a new TID field is added to the Extended DAR
expect ND options after the main body, and MUST ignore them. (EDAR) and the Extended DAC (EDAC) messages as a replacement of a
Reserved field, and a non-null value of the ICMP Code indicates
support for this specification. The format of the EDA messages is
presented in Section 6.2.
As for the EARO, the Extended Duplicate Address messages are backward As for the EARO, the Extended Duplicate Address messages are backward
compatible with the RFC6775-only versions, and remarks concerning compatible with the RFC6775-only versions as long as the ROVR field
backwards compatibility for the protocol between the 6LN and the 6LR is 64 bits long. Remarks concerning backwards compatibility for the
apply similarly between a 6LR and a 6LBR. protocol between the 6LN and the 6LR apply similarly between a 6LR
and a 6LBR.
4.5. Registering the Target Address 4.5. Registering the Target Address
The Registering Node is the node that performs the registration to The Registering Node is the node that performs the registration to
the 6BBR. As in [RFC6775], it may be the Registered Node as well, in the 6BBR. As in [RFC6775], it may be the Registered Node as well, in
which case it registers one of its own addresses, and indicates its which case it registers one of its own addresses, and indicates its
own MAC Address as Source Link Layer Address (SLLA) in the NS(EARO). own MAC Address as Source Link Layer Address (SLLA) in the NS(EARO).
This specification adds the capability to proxy the registration This specification adds the capability to proxy the registration
operation on behalf of a Registered Node that is reachable over a LLN operation on behalf of a Registered Node that is reachable over a LLN
skipping to change at page 10, line 48 skipping to change at page 12, line 26
Address of the Registered Node as the SLLA in the NS(EARO). If the Address of the Registered Node as the SLLA in the NS(EARO). If the
Registered Node is reachable over a Route-Over mesh from the Registered Node is reachable over a Route-Over mesh from the
Registering Node, the SLLA in the NS(ARO) is that of the Registering Registering Node, the SLLA in the NS(ARO) is that of the Registering
Node. This enables the Registering Node to attract the packets from Node. This enables the Registering Node to attract the packets from
the 6BBR and route them over the LLN to the Registered Node. the 6BBR and route them over the LLN to the Registered Node.
In order to enable the latter operation, this specification changes In order to enable the latter operation, this specification changes
the behavior of the 6LN and the 6LR so that the Registered Address is the behavior of the 6LN and the 6LR so that the Registered Address is
found in the Target Address field of the NS and NA messages as found in the Target Address field of the NS and NA messages as
opposed to the Source Address. With this convention, a TLLA option opposed to the Source Address. With this convention, a TLLA option
indicates the link-layer address of the 6LN that owns the address, indicates the link-layer address of the 6LN that owns the address.
whereas the SLLA Option in a NS message indicates that of the
Registering Node, which can be the owner device, or a proxy.
The Registering Node is reachable from the 6LR, and is also the one The Registering Node expects packets for the 6LN. Therefore, it MUST
expecting packets for the 6LN. Therefore, it MUST place its own Link place its own Link Layer Address in the SLLA Option that MUST always
Layer Address in the SLLA Option that MUST always be placed in a be placed in a registration NS(EARO) message. This maintains
registration NS(EARO) message. This maintains compatibility with compatibility with RFC6775-only 6LoWPAN ND [RFC6775].
RFC6775-only 6LoWPAN ND [RFC6775].
4.6. Link-Local Addresses and Registration 4.6. Link-Local Addresses and Registration
Considering that LLN nodes are often not wired and may move, there is Considering that LLN nodes are often not wired and may move, there is
no guarantee that a Link-Local address stays unique between a no guarantee that a Link-Local Address stays unique between a
potentially variable and unbounded set of neighboring nodes. potentially variable and unbounded set of neighboring nodes.
Compared to [RFC6775], this specification only requires that a Link- Compared to [RFC6775], this specification only requires that a Link-
Local address is unique from the perspective of the two nodes that Local Address is unique from the perspective of the two nodes that
use it to communicate (e.g., the 6LN and the 6LR in an NS/NA use it to communicate (e.g., the 6LN and the 6LR in an NS/NA
exchange). This simplifies the DAD process in a Route-Over topology exchange). This simplifies the DAD process in a Route-Over topology
for Link-Local addresses, by avoiding an exchange of Duplicate for Link-Local Addresses, by avoiding an exchange of EDA messages
Address messages between the 6LR and a 6LBR for those addresses. between the 6LR and a 6LBR for those addresses.
In more details: In more details:
An exchange between two nodes using Link-Local addresses implies that An exchange between two nodes using Link-Local Addresses implies that
they are reachable over one hop and that at least one of the 2 nodes they are reachable over one hop. A node MUST register a Link-Local
acts as a 6LR. A node MUST register a Link-Local address to a 6LR in Address to a 6LR in order to obtain reachability from that 6LR beyond
order to obtain reachability from that 6LR beyond the current the current exchange, and in particular to use the Link-Local Address
exchange, and in particular to use the Link-Local address as source as source address to register other addresses, e.g., global
address to register other addresses, e.g., global addresses. addresses.
If there is no collision with an address previously registered to If there is no collision with an address previously registered to
this 6LR by another 6LN, then the Link-Local address is unique from this 6LR by another 6LN, then the Link-Local Address is unique from
the standpoint of this 6LR and the registration is acceptable. the standpoint of this 6LR and the registration is not a duplicate.
Alternatively, two different 6LRs might expose the same Link-Local Alternatively, two different 6LRs might expose the same Link-Local
address but different link-layer addresses. In that case, a 6LN MUST Address but different link-layer addresses. In that case, a 6LN MUST
only interact with at most one of the 6LRs. only interact with at most one of the 6LRs.
The DAD process between the 6LR and a 6LBR, which is based on an The DAD process between the 6LR and a 6LBR, which is based on an
exchange of Duplicate Address messages, does not need to take place exchange of EDA messages, does not need to take place for Link-Local
for Link-Local addresses. Addresses.
When registering to a 6LR that conforms to this specification, a node When registering to a 6LR that conforms to this specification, a node
MUST use a Link-Local address as the source address of the MUST use a Link-Local Address as the source address of the
registration, whatever the type of IPv6 address that is being registration, whatever the type of IPv6 address that is being
registered. That Link-Local Address MUST be either an address that registered. That Link-Local Address MUST be either an address that
is already registered to the 6LR, or the address that is being is already registered to the 6LR, or the address that is being
registered. registered.
When a Registering Node does not have an already-Registered Address, When a Registering Node does not have an already-registered Address,
it MUST register a Link-Local address, using it as both the Source it MUST register a Link-Local Address, using it as both the Source
and the Target Address of an NS(EARO) message. In that case, it is and the Target Address of an NS(EARO) message. In that case, it is
RECOMMENDED to use a Link-Local address that is (expected to be) RECOMMENDED to use a Link-Local Address that is (expected to be)
globally unique, e.g., derived from a globally unique hardware MAC globally unique, e.g., derived from a globally unique EUI-64 address.
address. An EARO option in the response NA indicates that the 6LR An EARO in the response NA indicates that the 6LR supports this
supports this specification. specification.
Since there is no Duplicate Address exchange for Link-Local Since there is no exchange of EDA messages for Link-Local Addresses,
addresses, the 6LR may answer immediately to the registration of a the 6LR may answer immediately to the registration of a Link-Local
Link-Local address, based solely on its existing state and the Source Address, based solely on its existing state and the Source Link-Layer
Link-Layer Option that MUST be placed in the NS(EARO) message as Option that is placed in the NS(EARO) message as required in
required in [RFC6775]. [RFC6775].
A node needs to register its IPv6 Global Unicast IPv6 Addresses A node needs to register its IPv6 Global Unicast IPv6 Addresses
(GUAs) to a 6LR in order to establish global reachability for these (GUAs) to a 6LR in order to establish global reachability for these
addresses via that 6LR. When registering with an updated 6LR, a addresses via that 6LR. When registering with an updated 6LR, a
Registering Node does not use a GUA as Source Address, in contrast to Registering Node does not use a GUA as Source Address, in contrast to
a node that complies to [RFC6775]. For non-Link-Local addresses, the a node that complies to [RFC6775]. For non-Link-Local Addresses, the
Duplicate Address exchange MUST conform to [RFC6775], but the exchange of EDA messages MUST conform to [RFC6775], but the extended
extended formats described in this specification for the DAR and the formats described in this specification for the DAR and the DAC are
DAC are used to relay the extended information in the case of an used to relay the extended information in the case of an EARO.
EARO.
An ND message from the 6BBR over the Backbone Link that is proxied on
behalf of a Registered Node MUST carry the most recent EARO option
seen for that node. A NS/NA with an EARO and a NS/NA without a EARO
thus represent different nodes; this is considered as an address
duplication and the first owner wins. If the first owner is the
registration (i.e. with an NS(EARO)) then the 6BBR defends the
address over the Backbone Link as prescribed by [RFC4862]. If the
first owner is a node over the Backbone Link (no ARO), then the 6BBR
rejects the proxy-registration with a Status of "Duplicate Address".
4.7. Maintaining the Registration States 4.7. Maintaining the Registration States
This section discusses protocol actions that involve the Registering This section discusses protocol actions that involve the Registering
Node, the 6LR and the 6LBR. It must be noted that the portion that Node, the 6LR and the 6LBR. It must be noted that the portion that
deals with a 6LBR only applies to those addresses that are registered deals with a 6LBR only applies to those addresses that are registered
to it; as discussed in Section 4.6, this is not the case for Link- to it; as discussed in Section 4.6, this is not the case for Link-
Local addresses. The registration state includes all data that is Local Addresses. The registration state includes all data that is
stored in the router relative to that registration, in particular, stored in the router relative to that registration, in particular,
but not limited to, an NCE in a 6LR. 6LBRs and 6BBRs may store but not limited to, an NCE. 6LBRs and 6BBRs may store additional
additional registration information in more complex data structures registration information in more complex abstract data structures and
and use protocols that are out of scope of this document to keep them use protocols that are out of scope of this document to keep them
synchronized when they are distributed. synchronized when they are distributed.
When its resource available for Neighbor Cache Entries are exhausted, When its resource available to store registration states are
a 6LR cannot accept a new registration. In that situation, the EARO exhausted, a 6LR cannot accept a new registration. In that
is returned in a NA message with a Status Code of "Neighbor Cache situation, the EARO is returned in a NA message with a Status Code of
Full", and the Registering Node may attempt to register to another "Neighbor Cache Full", and the Registering Node may attempt to
6LR. register to another 6LR.
If the registry in the 6LBR is saturated, then the LBR cannot decide If the registry in the 6LBR is saturated, then the 6LBR cannot decide
whether a new address is a duplicate. In that case, the 6LBR replies whether a registration for a new address is a duplicate. In that
to a EDAR message with an EDAC message that carries a new Status Code case, the 6LBR replies to a EDAR message with an EDAC message that
indicating "6LBR Registry saturated" Table 1. Note: this code is carries a new Status Code indicating "6LBR Registry saturated"
used by 6LBRs instead of "Neighbor Cache Full" when responding to a Table 1. Note: this code is used by 6LBRs instead of "Neighbor Cache
Duplicate Address message exchange and is passed on to the Full" when responding to a Duplicate Address message exchange and is
Registering Node by the 6LR. There is no point for the node to retry passed on to the Registering Node by the 6LR. There is no point for
this registration immediately via another 6LR, since the problem is the node to retry this registration immediately via another 6LR,
global to the network. The node may either abandon that address, de- since the problem is global to the network. The node may either
register other addresses first to make room, or keep the address in abandon that address, de-register other addresses first to make room,
TENTATIVE state and retry later. or keep the address in TENTATIVE state and retry later.
A node renews an existing registration by sending a new NS(EARO) A node renews an existing registration by sending a new NS(EARO)
message for the Registered Address. In order to refresh the message for the Registered Address. In order to refresh the
registration state in the 6LBR, the registration MUST be reported to registration state in the 6LBR, the registration MUST be reported to
the 6LBR. the 6LBR.
A node that ceases to use an address SHOULD attempt to de-register A node that ceases to use an address SHOULD attempt to de-register
that address from all the 6LRs to which it has registered the that address from all the 6LRs to which it has registered the
address, which is achieved using an NS(EARO) message with a address. This is achieved using an NS(EARO) message with a
Registration Lifetime of 0. Registration Lifetime of 0. If this is not done, a state will remain
in the network for its Lifetime.
A node that moves away from a particular 6LR SHOULD attempt to de- A node that moves away from a particular 6LR SHOULD attempt to de-
register all of its addresses registered to that 6LR and register to register all of its addresses registered to that 6LR and register to
a new 6LR with an incremented TID. When/if the node shows up a new 6LR with an incremented TID. When/if the node shows up
elsewhere, an asynchronous NA(EARO) or EDAC message with a Status elsewhere, an asynchronous NA(EARO) or EDAC message with a Status
Code of "Moved" SHOULD be used to clean up the state in the previous Code of "Moved" SHOULD be used to clean up the state in the previous
location. For instance, as described in location. For instance, as described in
[I-D.ietf-6lo-backbone-router], the "Moved" status can be used by a [I-D.ietf-6lo-backbone-router], the "Moved" status can be used by a
6BBR in an NA(EARO) message to indicate that the ownership of the 6BBR in an NA(EARO) message to indicate that the ownership of the
proxy state on the Backbone Link was transferred to another 6BBR, as proxy state on the Backbone Link was transferred to another 6BBR, as
the consequence of a movement of the device. If the receiver of the the consequence of a movement of the device. If the receiver of the
message has a state corresponding to the related address, it SHOULD message has a state corresponding to the related address, it SHOULD
propagate the status down the forwarding path to the Registered node propagate the status down the forwarding path to the Registered node
(e.g. reversing an existing RPL [RFC6550] path as prescribed in (e.g., reversing an existing RPL [RFC6550] path as prescribed in
[I-D.ietf-roll-efficient-npdao]) and whether it could or not do so, [I-D.ietf-roll-efficient-npdao]). Whether it could or not do so, the
the receiver MUST clean up the said state. receiver MUST clean up the said state.
Upon receiving an NS(EARO) message with a Registration Lifetime of 0 Upon receiving an NS(EARO) message with a Registration Lifetime of 0
and determining that this EARO is the freshest for a given NCE (see and determining that this EARO is the freshest for a given NCE (see
Section 4.2), a 6LR cleans up its NCE. If the address was registered Section 4.2), a 6LR cleans up its NCE. If the address was registered
to the 6LBR, then the 6LR MUST report to the 6LBR, through a to the 6LBR, then the 6LR MUST report to the 6LBR, through a
Duplicate Address exchange with the 6LBR, indicating the null Duplicate Address exchange with the 6LBR, indicating the null
Registration Lifetime and the latest TID that this 6LR is aware of. Registration Lifetime and the latest TID that this 6LR is aware of.
Upon receiving the Extended DAR message, the 6LBR evaluates if this Upon receiving the EDAR message, the 6LBR evaluates if this is the
is the most recent TID it has received for that particular registry most recent TID it has received for that particular registry entry.
entry. If so, then the entry is scheduled to be removed, and the If so, then the EDAR is answered with an EDAC message bearing a
EDAR is answered with an EDAC message bearing a Status of "Success". Status of "Success" and the entry is scheduled to be removed.
Otherwise, a Status Code of "Moved" is returned instead, and the Otherwise, a Status Code of "Moved" is returned instead, and the
existing entry is maintained. existing entry is maintained.
When an address is scheduled to be removed, the 6LBR SHOULD keep its When an address is scheduled to be removed, the 6LBR SHOULD keep its
entry in a DELAY state for a configurable period of time, so as to entry in a DELAY state for a configurable period of time, so as to
protect a mobile node that de-registered from one 6LR and did not protect a mobile node that de-registered from one 6LR and did not
register yet to a new one, or the new registration did not reach yet register yet to a new one, or the new registration did not reach yet
the 6LBR due to propagation delays in the network. Once the DELAY the 6LBR due to propagation delays in the network. Once the DELAY
time is passed, the 6LBR silently removes its entry. time is passed, the 6LBR silently removes its entry.
5. Detecting Enhanced ARO Capability Support 5. Detecting Enhanced ARO Capability Support
The "Generic Header Compression for IPv6 over 6LoWPANs" [RFC7400] The "Generic Header Compression for IPv6 over 6LoWPANs" [RFC7400]
introduces the 6LoWPAN Capability Indication Option (6CIO) to introduces the 6LoWPAN Capability Indication Option (6CIO) to
indicate a node's capabilities to its peers. indicate a node's capabilities to its peers. The 6CIO MUST be
present in Router Advertisement (RA) messages, unless the
Section 6.3 defines new flags for the 6CIO to signal support for capabilities of the 6LR are already known by the 6LN. This can be
EARO, as well as the node's capability to act as a 6LR, 6LBR and determined by the 6LR if there is an existing registration in place
6BBR. Section 7.1.1 specifies how the "E" flag can be used to for the 6LN that is based on EARO. This can also be implicit, or
provide backward compatibility. configured in all nodes in a network.
The 6CIO is typically sent in a Router Solicitation (RS) message. Section 6.3 defines a new flag for the 6CIO to signal support for
When used to signal capabilities per this specification, the 6CIO is EARO by the issuer of the message, and Section 7.1 specifies how the
typically present in Router Advertisement (RA) messages but can also flag is to be used. A similar flag indicates the support of EDA
be present in RS, Neighbor Solicitation (NS) and Neighbor messages by the 6LBR - note that other information on the 6LBR is
Advertisement (NA) messages. found in a separate Authoritative Border Router Option (ABRO) that
MUST also be present in RA messages [RFC6775]. New flags are also
added to signal the router's capability to act as a 6LR, 6LBR and
6BBR (see Section 6.3).
6. Extended ND Options And Messages 6. Extended ND Options And Messages
This specification does not introduce new options, but it modifies This specification does not introduce new options, but it modifies
existing ones and updates the associated behaviors as specified in existing ones and updates the associated behaviors as specified in
the following subsections. the following subsections.
6.1. Enhanced Address Registration Option (EARO) 6.1. Extended Address Registration Option (EARO)
The Address Registration Option (ARO) is defined in section 4.1 of The Address Registration Option (ARO) is defined in section 4.1 of
[RFC6775]. [RFC6775].
The Enhanced Address Registration Option (EARO) updates the ARO The Extended Address Registration Option (EARO) replaces the ARO used
option within Neighbor Discovery NS and NA messages between a 6LN and within Neighbor Discovery NS and NA messages between a 6LN and its
its 6LR. On the other hand, the Extended Duplicate Address messages, 6LR. Similarly, the EDA messages, EDAR and EDAC, replace the DAR and
EDAR and EDAC, replace the DAR and DAC messages so as to transport DAC messages so as to transport the new information between 6LRs and
the new information between 6LRs and 6LBRs across LLN meshes such as 6LBRs across LLN meshes such as 6TiSCH networks.
6TiSCH networks.
An NS message with an EARO option is a registration if and only if it An NS message with an EARO is a registration if and only if it also
also carries an SLLAO option. The EARO option also used in NS and NA carries an SLLA Option. The EARO also used in NS and NA messages
messages between Backbone Routers [I-D.ietf-6lo-backbone-router] over between Backbone Routers [I-D.ietf-6lo-backbone-router] over the
the Backbone Link to sort out the distributed registration state; in Backbone Link to sort out the distributed registration state; in that
that case, it does not carry the SLLAO option and is not confused case, it does not carry the SLLA Option and is not confused with a
with a registration. registration.
When using the EARO option, the address being registered is found in When using the EARO, the address being registered is found in the
the Target Address field of the NS and NA messages. Target Address field of the NS and NA messages.
The EARO extends the ARO and is indicated by the "T" flag set. The The EARO extends the ARO and is indicated by the "T" flag set. The
format of the EARO option is as follows: format of the EARO is as follows:
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 = 2 | Status | Reserved | | Type | Length | Status | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |R|T| TID | Registration Lifetime | | Reserved |R|T| TID | Registration Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
+ Registration Unique ID (EUI-64 or equivalent) + + Registration Ownership Verifier +
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: EARO Figure 2: EARO
Option Fields Option Fields
Type: 33 Type: 33
Length: 8-bit unsigned integer. The length of the option in Length: 8-bit unsigned integer. The length of the option in
units of 8 bytes. Always 2. units of 8 bytes. It MUST be 2 when operating in
backward-compatible mode. It MAY be 3, 4 or 5,
denoting a ROVR size of 128, 192 and 256 bits
respectively.
Status: 8-bit unsigned integer. Indicates the status of a Status: 8-bit unsigned integer. Indicates the status of a
registration in the NA response. MUST be set to 0 in registration in the NA response. MUST be set to 0 in
NS messages. See Table 1 below. NS messages. See Table 1 below.
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
| Value | Description | | Value | Description |
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
| 0..2 | See [RFC6775]. Note: a Status of 1 "Duplicate Address" | | 0..2 | See [RFC6775]. Note: a Status of 1 "Duplicate Address" |
| | applies to the Registered Address. If the Source Address | | | applies to the Registered Address. If the Source Address |
| | conflicts with an existing registration, "Duplicate | | | conflicts with an existing registration, "Duplicate |
| | Source Address" should be used. | | | Source Address" MUST be used. |
| | | | | |
| 3 | Moved: The registration failed because it is not the | | 3 | Moved: The registration failed because it is not the |
| | freshest. This Status indicates that the registration is | | | freshest. This Status indicates that the registration is |
| | rejected because another more recent registration was | | | rejected because another more recent registration was |
| | done, as indicated by a same RUID and a more recent TID. | | | done, as indicated by a same ROVR and a more recent TID. |
| | One possible cause is a stale registration that has | | | One possible cause is a stale registration that has |
| | progressed slowly in the network and was passed by a more | | | progressed slowly in the network and was passed by a more |
| | recent one. It could also indicate a RUID collision. | | | recent one. It could also indicate a ROVR collision. |
| | | | | |
| 4 | Removed: The binding state was removed. This may be | | 4 | Removed: The binding state was removed. This may be |
| | placed in an asynchronous NS(ARO) message, or as the | | | placed in an asynchronous NS(ARO) message, or as the |
| | rejection of a proxy registration to a Backbone Router | | | rejection of a proxy registration to a Backbone Router |
| | | | | |
| 5 | Validation Requested: The Registering Node is challenged | | 5 | Validation Requested: The Registering Node is challenged |
| | for owning the Registered Address or for being an | | | for owning the Registered Address or for being an |
| | acceptable proxy for the registration. This Status is | | | acceptable proxy for the registration. This Status is |
| | expected in asynchronous messages from a registrar (6LR, | | | expected in asynchronous messages from a registrar (6LR, |
| | 6LBR, 6BBR) to indicate that the registration state is | | | 6LBR, 6BBR) to indicate that the registration state is |
| | removed, for instance due to a movement of the device. | | | removed, for instance due to a movement of the device. |
| | | | | |
| 6 | Duplicate Source Address: The address used as source of | | 6 | Duplicate Source Address: The address used as source of |
| | the NS(ARO) conflicts with an existing registration. | | | the NS(ARO) conflicts with an existing registration. |
| | | | | |
| 7 | Invalid Source Address: The address used as source of the | | 7 | Invalid Source Address: The address used as source of the |
| | NS(ARO) is not a Link-Local address as prescribed by this | | | NS(ARO) is not a Link-Local Address as prescribed by this |
| | document. | | | document. |
| | | | | |
| 8 | Registered Address topologically incorrect: The address | | 8 | Registered Address topologically incorrect: The address |
| | being registered is not usable on this link, e.g., it is | | | being registered is not usable on this link, e.g., it is |
| | not topologically correct | | | not topologically correct |
| | | | | |
| 9 | 6LBR Registry saturated: A new registration cannot be | | 9 | 6LBR Registry saturated: A new registration cannot be |
| | accepted because the 6LBR Registry is saturated. Note: | | | accepted because the 6LBR Registry is saturated. Note: |
| | this code is used by 6LBRs instead of Status 2 when | | | this code is used by 6LBRs instead of Status 2 when |
| | responding to a Duplicate Address message exchange and is | | | responding to a Duplicate Address message exchange and is |
skipping to change at page 16, line 46 skipping to change at page 18, line 20
| 10 | Validation Failed: The proof of ownership of the | | 10 | Validation Failed: The proof of ownership of the |
| | registered address is not correct. | | | registered address is not correct. |
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
Table 1: EARO Status Table 1: EARO Status
Reserved: This field is unused. It MUST be initialized to zero Reserved: This field is unused. It MUST be initialized to zero
by the sender and MUST be ignored by the receiver. by the sender and MUST be ignored by the receiver.
R: If the 'R' flag is set, the registering node expects R: If the 'R' flag is set, the registering node expects
that the 6LR ensures reachability for the registered that the 6LR ensures reachability for the registered
address, e.g. by injecting the address in a route- address, e.g. by injecting the address in a Route-
over routing protocol or proxying ND over a Backbone Over routing protocol or proxying ND over a Backbone
Link. Link.
T: One bit flag. Set if the next octet is used as a T: One bit flag. Set if the next octet is used as a
TID. TID.
TID: 1-byte integer; a transaction id that is maintained TID: 1-byte integer; a transaction id that is maintained
by the node and incremented with each transaction. by the node and incremented with each transaction.
The node SHOULD maintain the TID in a persistent
storage.
Registration Lifetime: 16-bit integer; expressed in minutes. 0 Registration Lifetime: 16-bit integer; expressed in minutes. 0
means that the registration has ended and the means that the registration has ended and the
associated state should be removed. associated state MUST be removed.
Registration Unique IDentifier (RUID): A globally unique identifier Registration Ownership Verifier (ROVR): Enables to correlate
for the node associated. This can be the EUI-64 multiple registrations for a same IPv6 Address. This
derived IID of an interface, or some provable ID can be a unique ID of the Registering Node, such as
obtained cryptographically. the EUI-64 address of an interface. This can also be
a token obtained with cryptographic methods and used
as proof of ownership of the registration. The scope
of a ROVR is one registration and it cannot be used
to correlate different registrations.
6.2. Extended Duplicate Address Message Formats 6.2. Extended Duplicate Address Message Formats
The Duplicate Address Request (DAR) and the Duplicate Address The DAR and DAC messages are defined in section 4.4 of [RFC6775].
Confirmation (DAC) messages are defined in section 4.4 of [RFC6775].
Those messages follow a common base format, which enables information Those messages follow a common base format, which enables information
from the ARO to be transported over multiple hops. from the ARO to be transported over multiple hops.
The Duplicate Address Messages are extended to adapt to the Extended Those messages are extended to adapt to the new EARO format, as
ARO format, as follows: follows:
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 | Code | Checksum | | Type | Code | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status | TID | Registration Lifetime | | Status | TID | Registration Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
+ Registration Unique ID (EUI-64 or equivalent) + + Registration Ownership Verifier +
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
+ + + +
| | | |
+ Registered Address + + Registered Address +
| | | |
+ + + +
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Duplicate Address Messages Format Figure 3: Duplicate Address Messages Format
Modified Message Fields Modified Message Fields
Code: The ICMP Code as defined in [RFC4443]. The ICMP Code Code: The ICMP Code as defined in [RFC4443]. The ICMP Code
MUST be set to 1 with this specification. An odd MUST be set to 1 with this specification. An odd
value of the ICMP Code indicates that the TID field value of the ICMP Code indicates that the TID field
is present and obeys this specification. is present and obeys this specification.
TID: 1-byte integer; same definition and processing as the TID: 1-byte integer; same definition and processing as the
TID in the EARO option as defined in Section 6.1. TID in the EARO as defined in Section 6.1.
Registration Unique IDentifier (RUID): 8 bytes; same definition and Registration Ownership Verifier (ROVR): The size of the ROVR is
processing as the RUID in the EARO option as defined computed from the overall size of the IPv6 packet.
in Section 6.1. It MUST be 64bits long when operating in backward-
compatible mode. This field has the same definition
and processing as the ROVR in the EARO option as
defined in Section 6.1.
6.3. New 6LoWPAN Capability Bits in the Capability Indication Option 6.3. New 6LoWPAN Capability Bits in the Capability Indication Option
This specification defines new capability bits for use in the 6CIO, This specification defines 5 new capability bits for use in the 6CIO,
which was introduced by [RFC7400] for use in IPv6 ND RA messages. which was introduced by [RFC7400] for use in IPv6 ND RA messages.
Routers that support this specification MUST set the "E" flag and 6LN This specification introduces the "E" flag to indicate that extended
SHOULD favor 6LR routers that support this specification over those ARO can be used in a registration. A 6LR that supports this
that do not. Routers that are capable of acting as 6LR, 6LBR and specification MUST set the "E" flag.
6BBR SHOULD set the "L", "B" and "P" flags, respectively. In
particular, the function 6LR is often collocated with that of 6LBR.
Those flags are not mutually exclusive and if a router is capable of A similar flag "D" indicates the support of Extended Duplicate
performing multiple functions, it SHOULD set all the related flags. Address Messages by the 6LBR; A 6LBR that supports this specification
MUST set the "D" flag. The "D" flag is learned from advertisements
by a 6LBR, and is propagated down a graph of 6LRs as a node acting as
6LN registers to a 6LR (which could be the 6LBR), and in turn becomes
a 6LR to which other 6LNs will register.
The new "L", "B" and "P" flags, indicate whether a router is capable
of acting as 6LR, 6LBR and 6BBR, respectively. These flags are not
mutually exclusive and a node MUST set all the flags that are
relevant to it.
As an example, a 6LBR sets the "B" and "D" flags. If it acts as a
6LR, then it sets the "L" and "E" flags. If it is collocated with a
6BBR, then it also sets the "P" flag.
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 = 1 | Reserved |L|B|P|E|G| | Type | Length = 1 | Reserved |D|L|B|P|E|G|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved | | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: New capability Bits L, B, P, E in the 6CIO Figure 4: New capability Bits L, B, P, E in the 6CIO
Option Fields Option Fields
Type: 36 Type: 36
L: Node is a 6LR, it can take registrations. L: Node is a 6LR.
B: Node is a 6LBR. B: Node is a 6LBR.
P: Node is a 6BBR, proxying for nodes on this link. P: Node is a 6BBR.
E: This specification is supported and applied. E: Node supports registrations based on EARO.
D: 6LBR supports EDA messages.
7. Backward Compatibility 7. Backward Compatibility
7.1. Discovering the capabilities of an ND peer
7.1.1. Using the "E" Flag in the 6CIO 7.1. Discovering the Capabilities of an ND Peer
If the 6CIO is used in an ND message and the sending node supports
this specification, then the "E" Flag MUST be set.
A router that supports this specification SHOULD indicate that with a
6CIO.
If the Registering Node receives a 6CIO in a Router Advertisement
message, then the setting of the "E" Flag indicates whether or not
this specification is supported.
7.1.2. Using the "T" Flag in the EARO
One alternate way for a 6LN to discover the router's capabilities is A 6LR that supports this specification MUST place a 6CIO in its RA
to start by registering a Link Local address, placing the same messages. A typical flow when a node starts up is that it sends a
address in the Source and Target Address fields of the NS message, multicast RS and receives one or more unicast RA messages. If the
and setting the "T" Flag. The node may for instance register an 6LR can process Extended ARO, then the "E" Flag is set in the RA.
address that is based on an EUI-64. For such an address, DAD is not
required and using the SLLAO option in the NS is actually more
consistent with existing ND specifications such as the "Optimistic
Duplicate Address Detection (ODAD) for IPv6" [RFC4429].
Once its first registration is complete, the node knows from the This specification changes the behavior of the peers in a
setting of the "T" Flag in the response whether the router supports registration flow. To enable backward compatibility, a 6LN that
this specification. If support is verified, the node may register registers to a 6LR that is not known to support this specification
other addresses that it owns, or proxy-register addresses on behalf MUST behave in a manner that is compatible with [RFC6775]. On the
of some another node, indicating those addresses being registered in contrary, if the 6LR is known to support this specification, then the
the Target Address field of the NS messages, while using one of its 6LN MUST conform this specification.
own previously registered addresses as source.
A node that supports this specification MUST always use an EARO as a A 6LN that supports this specification MUST always use an EARO as a
replacement to an ARO in its registration to a router. This is replacement to an ARO in its registration to a router. This is
harmless since the "T" flag and TID field are reserved in [RFC6775], harmless since the "T" flag and TID field are reserved in [RFC6775],
and are ignored by an RFC6775-only router. A router that supports and are ignored by an RFC6775-only router. A router that supports
this specification answers an ARO with an ARO and answers an EARO this specification MUST answer an NS(ARO) and an NS(EARO) with an
with an EARO. NA(EARO). A router that does not support this specification will
consider the ROVR as an EUI-64 and treat it the same, which has no
This specification changes the behavior of the peers in a consequence if the Registered Addresses are different.
registration flow. To enable backward compatibility, a 6LN that
registers to a 6LR that is not known to support this specification
MUST behave in a manner that is compatible with [RFC6775]. A 6LN can
achieve that by sending a NS(EARO) message with a Link-Local Address
used as both Source and Target Address, as described in Section 4.6.
Once the 6LR is known to support this specification, the 6LN MUST
obey this specification.
7.2. RFC6775-only 6LoWPAN Node 7.2. RFC6775-only 6LoWPAN Node
an RFC6775-only 6LN will use the Registered Address as source and an RFC6775-only 6LN will use the Registered Address as source and
will not use an EARO option. An updated 6LR MUST accept that will not use an EARO. An updated 6LR MUST accept that registration
registration if it is valid per [RFC6775], and it MUST manage the if it is valid per [RFC6775], and it MUST manage the binding cache
binding cache accordingly. The updated 6LR MUST then use the accordingly. The updated 6LR MUST then use the RFC6775-only EDA
RFC6775-only Duplicate Address messages as specified in [RFC6775] to messages as specified in [RFC6775] to indicate to the 6LBR that the
indicate to the 6LBR that the TID is not present in the messages. TID is not present in the messages.
The main difference from [RFC6775] is that the Duplicate Address The main difference from [RFC6775] is that the exchange of EDA
exchange for DAD is avoided for Link-Local addresses. In any case, messages for the purpose of DAD is avoided for Link-Local Addresses.
the 6LR SHOULD use an EARO in the reply, and can use any of the In any case, the 6LR MUST use an EARO in the reply, and can use any
Status codes defined in this specification. of the Status codes defined in this specification.
7.3. RFC6775-only 6LoWPAN Router 7.3. RFC6775-only 6LoWPAN Router
The first registration by an updated 6LN MUST be for a Link-Local An updated 6LN discovers the capabilities of the 6LR in the 6CIO in
address, using that Link-Local address as source. an RFC6775-only 6LR RA messages from that 6LR; if the 6CIO was not present in the RA,
will treat that registration as if the 6LN was an RFC6775-only node. then the 6LR is assumed to be a RFC6775-only 6LoWPAN Router.
An updated 6LN will always use an EARO option in the registration NS
message, whereas an RFC6775-only 6LR will always reply with an ARO
option in the NA message. From that first registration, the updated
6LN can determine whether or not the 6LR supports this specification.
After detecting an RFC6775-only 6LR, an updated 6LN SHOULD attempt to
find an alternate 6LR that is updated for a reasonable time that
depends on the type of device and the expected deployment.
An updated 6LN SHOULD use an EARO in the request regardless of the An updated 6LN MUST use an EARO in the request regardless of the type
type of 6LR, RFC6775-only or updated, which implies that the "T" flag of 6LR, RFC6775-only or updated, which implies that the "T" flag is
is set. set. It MUST use a ROVR of 64 bits if the 6LR is an RFC6775-only
6LoWPAN Router.
If an updated 6LN moves from an updated 6LR to an RFC6775-only 6LR, If an updated 6LN moves from an updated 6LR to an RFC6775-only 6LR,
the RFC6775-only 6LR will send an RFC6775-only DAR message, which can the RFC6775-only 6LR will send an RFC6775-only DAR message, which can
not be compared with an updated one for freshness. not be compared with an updated one for freshness. Allowing
RFC6775-only DAR messages to replace a state established by the
Allowing RFC6775-only DAR messages to replace a state established by updated protocol in the 6LBR would be an attack vector and that
the updated protocol in the 6LBR would be an attack vector and that cannot be the default behavior. But if RFC6775-only and updated 6LRs
cannot be the default behavior. coexist temporarily in a network, then it makes sense for an
administrator to install a policy that allows so, and the capability
But if RFC6775-only and updated 6LRs coexist temporarily in a to install such a policy should be configurable in a 6LBR though it
network, then it makes sense for an administrator to install a policy is out of scope for this document.
that allows so, and the capability to install such a policy should be
configurable in a 6LBR though it is out of scope for this document.
7.4. RFC6775-only 6LoWPAN Border Router 7.4. RFC6775-only 6LoWPAN Border Router
With this specification, the Duplicate Address messages are extended With this specification, the Duplicate Address messages are extended
to transport the EARO information. Similarly to the NS/NA exchange, to transport the EARO information. Similarly to the NS/NA exchange,
updated 6LBR devices always use the Extended Duplicate Address an updated 6LBR MUST always use the EDA messages.
messages and all the associated behavior so they can always be
differentiated from RFC6775-only ones.
Note that an RFC6775-only 6LBR will accept and process an EDAR Note that an RFC6775-only 6LBR will accept and process an EDAR
message as if it were an RFC6775-only DAR, so the support of DAD is message as if it were an RFC6775-only DAR, as long as the ROVR is 64
preserved. bits long. An updated 6LR discovers the capabilities of the 6LBR in
the 6CIO in RA messages from the 6LR; if the 6CIO was not present in
any RA, then the 6LBR si assumed to be a RFC6775-only 6LoWPAN Border
Router.
If the 6LBR is RFC6775-only, and the ROVR in the NS(EARO) was more
than 64 bits long, then the 6LR MUST truncate the ROVR to the 64
rightmost bit and place the result in the EDAR message to maintain
compatibility. This way, the support of DAD is preserved.
8. Security Considerations 8. Security Considerations
This specification extends [RFC6775], and the security section of This specification extends [RFC6775], and the security section of
that standard also applies to this as well. In particular, it is that document also applies to this as well. In particular, it is
expected that the link layer is sufficiently protected to prevent a expected that the link layer is sufficiently protected to prevent a
rogue access, either by means of physical or IP security on the rogue access, either by means of physical or IP security on the
Backbone Link and link layer cryptography on the LLN. Backbone Link and link layer cryptography on the LLN.
This specification also expects that the LLN MAC provides secure This specification also expects that the LLN MAC provides secure
unicast to/from the Backbone Router and secure Broadcast or Multicast unicast to/from the Backbone Router and secure Broadcast or Multicast
from the Backbone Router in a way that prevents tampering with or from the Backbone Router in a way that prevents tampering with or
replaying the RA messages. replaying the RA messages.
This specification recommends using privacy techniques (see This specification recommends using privacy techniques (see
Section 9), and protection against address theft such as provided by Section 9), and protection against address theft such as provided by
"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], which guarantees the ownership of the Networks" [I-D.ietf-6lo-ap-nd], which guarantees the ownership of the
Registered Address using a cryptographic RUID. Registered Address using a cryptographic ROVR.
The registration mechanism may be used by a rogue node to attack the The registration mechanism may be used by a rogue node to attack the
6LR or the 6LBR with a Denial-of-Service attack against the registry. 6LR or the 6LBR with a Denial-of-Service attack against the registry.
It may also happen that the registry of a 6LR or a 6LBR is saturated It may also happen that the registry of a 6LR or a 6LBR is saturated
and cannot take any more registrations, which effectively denies the and cannot take any more registrations, which effectively denies the
requesting node the capability to use a new address. In order to requesting node the capability to use a new address. In order to
alleviate those concerns, Section 4.7 provides a number of alleviate those concerns, Section 4.7 provides a number of
recommendations that ensure that a stale registration is removed as recommendations that ensure that a stale registration is removed as
soon as possible from the 6LR and 6LBR. In particular, this soon as possible from the 6LR and 6LBR. In particular, this
specification recommends that: specification recommends that:
skipping to change at page 22, line 15 skipping to change at page 23, line 23
which it is registered. In particular, use cases that involve which it is registered. In particular, use cases that involve
mobility or rapid address changes SHOULD use lifetimes that are mobility or rapid address changes SHOULD use lifetimes that are
larger yet of a same order as the duration of the expectation of larger yet of a same order as the duration of the expectation of
presence. presence.
o The router (6LR or 6LBR) SHOULD be configurable so as to limit the o The router (6LR or 6LBR) SHOULD be configurable so as to limit the
number of addresses that can be registered by a single node, but number of addresses that can be registered by a single node, but
as a protective measure only. A node may be identified by MAC as a protective measure only. A node may be identified by MAC
address, but a stringer identification (e.g., by security address, but a stringer identification (e.g., by security
credentials) is RECOMMENDED. When that maximum is reached, the credentials) is RECOMMENDED. When that maximum is reached, the
router should use a Least-Recently-Used (LRU) algorithm to clean router should use a Least-Recently-Used (LRU) algorithm to clean
up the addresses, keeping at least one Link-Local address. The up the addresses, keeping at least one Link-Local Address. The
router SHOULD attempt to keep one or more stable addresses if router SHOULD attempt to keep one or more stable addresses if
stability can be determined, e.g., because they are used over a stability can be determined, e.g., because they are used over a
much longer time span than other (privacy, shorter-lived) much longer time span than other (privacy, shorter-lived)
addresses. Address lifetimes SHOULD be individually configurable. addresses. Address lifetimes SHOULD be individually configurable.
o In order to avoid denial of registration for the lack of o In order to avoid denial of registration for the lack of
resources, administrators should take great care to deploy resources, administrators should take great care to deploy
adequate numbers of 6LRs to cover the needs of the nodes in their adequate numbers of 6LRs to cover the needs of the nodes in their
range, so as to avoid a situation of starving nodes. It is range, so as to avoid a situation of starving nodes. It is
expected that the 6LBR that serves a LLN is a more capable node expected that the 6LBR that serves a LLN is a more capable node
then the average 6LR, but in a network condition where it may then the average 6LR, but in a network condition where it may
skipping to change at page 22, line 50 skipping to change at page 24, line 9
As indicated in Section 3, this protocol does not aim at limiting the As indicated in Section 3, this protocol does not aim at limiting the
number of IPv6 addresses that a device can form and if placed, a number of IPv6 addresses that a device can form and if placed, a
limit should be a protective measure only, that is high enough not to limit should be a protective measure only, that is high enough not to
interfere with the normal behavior of devices in the network. A host interfere with the normal behavior of devices in the network. A host
should be able to form and register any address that is topologically should be able to form and register any address that is topologically
correct in the subnet(s) advertised by the 6LR/6LBR. correct in the subnet(s) advertised by the 6LR/6LBR.
This specification does not mandate any particular way for forming This specification does not mandate any particular way for forming
IPv6 addresses, but it discourages using EUI-64 for forming the IPv6 addresses, but it discourages using EUI-64 for forming the
Interface ID in the Link-Local address because this method prevents Interface ID in the Link-Local Address because this method prevents
the usage of "SEcure Neighbor Discovery (SEND)" [RFC3971] and the usage of "SEcure Neighbor Discovery (SEND)" [RFC3971] and
"Cryptographically Generated Addresses (CGA)" [RFC3972], and that of "Cryptographically Generated Addresses (CGA)" [RFC3972], and that of
address privacy techniques. address privacy techniques.
"Privacy Considerations for IPv6 Adaptation-Layer Mechanisms" "Privacy Considerations for IPv6 Adaptation-Layer Mechanisms"
[RFC8065] explains why privacy is important and how to form privacy- [RFC8065] explains why privacy is important and how to form privacy-
aware addresses. All implementations and deployment must consider aware addresses. All implementations and deployment must consider
the option of privacy addresses in their own environment. the option of privacy addresses in their own environment.
The IPv6 address of the 6LN in the IPv6 header can be compressed The IPv6 address of the 6LN in the IPv6 header can be compressed
skipping to change at page 26, line 11 skipping to change at page 27, line 11
IANA is requested to make additions to the Subregistry for "6LoWPAN IANA is requested to make additions to the Subregistry for "6LoWPAN
capability Bits" as follows: capability Bits" as follows:
Subregistry for "6LoWPAN capability Bits" under the "Internet Control Subregistry for "6LoWPAN capability Bits" under the "Internet Control
Message Protocol version 6 (ICMPv6) Parameters" Message Protocol version 6 (ICMPv6) Parameters"
+-----------------+----------------------+-----------+ +-----------------+----------------------+-----------+
| Capability Bit | Description | Document | | Capability Bit | Description | Document |
+-----------------+----------------------+-----------+ +-----------------+----------------------+-----------+
| 10 | EDA Support (D bit) | This RFC |
| | | |
| 11 | 6LR capable (L bit) | This RFC | | 11 | 6LR capable (L bit) | This RFC |
| | | | | | | |
| 12 | 6LBR capable (B bit) | This RFC | | 12 | 6LBR capable (B bit) | This RFC |
| | | | | | | |
| 13 | 6BBR capable (P bit) | This RFC | | 13 | 6BBR capable (P bit) | This RFC |
| | | | | | | |
| 14 | EARO support (E bit) | This RFC | | 14 | EARO support (E bit) | This RFC |
+-----------------+----------------------+-----------+ +-----------------+----------------------+-----------+
Table 6: New 6LoWPAN capability Bits Table 6: New 6LoWPAN capability Bits
11. Acknowledgments 11. Acknowledgments
Kudos to Eric Levy-Abegnoli who designed the First Hop Security Kudos to Eric Levy-Abegnoli who designed the First Hop Security
infrastructure upon which the first backbone router was implemented. infrastructure upon which the first backbone router was implemented.
Many thanks to Sedat Gormus, Rahul Jadhav, Tim Chown, Juergen Many thanks to Sedat Gormus, Rahul Jadhav, Tim Chown, Juergen
Schoenwaelder, Chris Lonvick and Lorenzo Colitti for their various Schoenwaelder, Chris Lonvick, Dave Thaler and Lorenzo Colitti for
contributions and reviews. Also many thanks to Thomas Watteyne for their various contributions and reviews. Also many thanks to Thomas
his early implementation of a 6LN that was instrumental to the early Watteyne for his early implementation of a 6LN that was instrumental
tests of the 6LR, 6LBR and Backbone Router. to the early tests of the 6LR, 6LBR and Backbone Router.
12. References 12. References
12.1. Normative References 12.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
skipping to change at page 27, line 15 skipping to change at page 28, line 15
[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>.
[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>.
[RFC6606] Kim, E., Kaspar, D., Gomez, C., and C. Bormann, "Problem
Statement and Requirements for IPv6 over Low-Power
Wireless Personal Area Network (6LoWPAN) Routing",
RFC 6606, DOI 10.17487/RFC6606, May 2012,
<https://www.rfc-editor.org/info/rfc6606>.
[RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
Bormann, "Neighbor Discovery Optimization for IPv6 over Bormann, "Neighbor Discovery Optimization for IPv6 over
Low-Power Wireless Personal Area Networks (6LoWPANs)", Low-Power Wireless Personal Area Networks (6LoWPANs)",
RFC 6775, DOI 10.17487/RFC6775, November 2012, RFC 6775, DOI 10.17487/RFC6775, November 2012,
<https://www.rfc-editor.org/info/rfc6775>. <https://www.rfc-editor.org/info/rfc6775>.
[RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and
Lossy Networks", RFC 7102, DOI 10.17487/RFC7102, January
2014, <https://www.rfc-editor.org/info/rfc7102>.
[RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for
Constrained-Node Networks", RFC 7228,
DOI 10.17487/RFC7228, May 2014,
<https://www.rfc-editor.org/info/rfc7228>.
[RFC7400] Bormann, C., "6LoWPAN-GHC: Generic Header Compression for [RFC7400] Bormann, C., "6LoWPAN-GHC: Generic Header Compression for
IPv6 over Low-Power Wireless Personal Area Networks IPv6 over Low-Power Wireless Personal Area Networks
(6LoWPANs)", RFC 7400, DOI 10.17487/RFC7400, November (6LoWPANs)", RFC 7400, DOI 10.17487/RFC7400, November
2014, <https://www.rfc-editor.org/info/rfc7400>. 2014, <https://www.rfc-editor.org/info/rfc7400>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26, Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>. <https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
12.2. Informative References 12.2. Informative References
[I-D.chakrabarti-nordmark-6man-efficient-nd] [I-D.chakrabarti-nordmark-6man-efficient-nd]
Chakrabarti, S., Nordmark, E., Thubert, P., and M. Chakrabarti, S., Nordmark, E., Thubert, P., and M.
Wasserman, "IPv6 Neighbor Discovery Optimizations for Wasserman, "IPv6 Neighbor Discovery Optimizations for
Wired and Wireless Networks", draft-chakrabarti-nordmark- Wired and Wireless Networks", draft-chakrabarti-nordmark-
6man-efficient-nd-07 (work in progress), February 2015. 6man-efficient-nd-07 (work in progress), February 2015.
[I-D.delcarpio-6lo-wlanah] [I-D.delcarpio-6lo-wlanah]
Vega, L., Robles, I., and R. Morabito, "IPv6 over Vega, L., Robles, I., and R. Morabito, "IPv6 over
skipping to change at page 28, line 26 skipping to change at page 29, line 48
Choi, Y., Hong, Y., Youn, J., Kim, D., and J. Choi, Choi, Y., Hong, Y., Youn, J., Kim, D., and J. Choi,
"Transmission of IPv6 Packets over Near Field "Transmission of IPv6 Packets over Near Field
Communication", draft-ietf-6lo-nfc-09 (work in progress), Communication", draft-ietf-6lo-nfc-09 (work in progress),
January 2018. January 2018.
[I-D.ietf-6tisch-architecture] [I-D.ietf-6tisch-architecture]
Thubert, P., "An Architecture for IPv6 over the TSCH mode Thubert, P., "An Architecture for IPv6 over the TSCH mode
of IEEE 802.15.4", draft-ietf-6tisch-architecture-13 (work of IEEE 802.15.4", draft-ietf-6tisch-architecture-13 (work
in progress), November 2017. in progress), November 2017.
[I-D.ietf-ipv6-multilink-subnets]
Thaler, D. and C. Huitema, "Multi-link Subnet Support in
IPv6", draft-ietf-ipv6-multilink-subnets-00 (work in
progress), July 2002.
[I-D.ietf-mboned-ieee802-mcast-problems] [I-D.ietf-mboned-ieee802-mcast-problems]
Perkins, C., McBride, M., Stanley, D., Kumari, W., and J. Perkins, C., McBride, M., Stanley, D., Kumari, W., and J.
Zuniga, "Multicast Considerations over IEEE 802 Wireless Zuniga, "Multicast Considerations over IEEE 802 Wireless
Media", draft-ietf-mboned-ieee802-mcast-problems-01 (work Media", draft-ietf-mboned-ieee802-mcast-problems-01 (work
in progress), February 2018. in progress), February 2018.
[I-D.ietf-roll-efficient-npdao] [I-D.ietf-roll-efficient-npdao]
Jadhav, R., Sahoo, R., and Z. Cao, "No-Path DAO Jadhav, R., Sahoo, R., and Z. Cao, "No-Path DAO
modifications", draft-ietf-roll-efficient-npdao-01 (work modifications", draft-ietf-roll-efficient-npdao-01 (work
in progress), October 2017. in progress), October 2017.
skipping to change at page 29, line 40 skipping to change at page 31, line 9
<https://www.rfc-editor.org/info/rfc3971>. <https://www.rfc-editor.org/info/rfc3971>.
[RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)", [RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)",
RFC 3972, DOI 10.17487/RFC3972, March 2005, RFC 3972, DOI 10.17487/RFC3972, March 2005,
<https://www.rfc-editor.org/info/rfc3972>. <https://www.rfc-editor.org/info/rfc3972>.
[RFC4429] Moore, N., "Optimistic Duplicate Address Detection (DAD) [RFC4429] Moore, N., "Optimistic Duplicate Address Detection (DAD)
for IPv6", RFC 4429, DOI 10.17487/RFC4429, April 2006, for IPv6", RFC 4429, DOI 10.17487/RFC4429, April 2006,
<https://www.rfc-editor.org/info/rfc4429>. <https://www.rfc-editor.org/info/rfc4429>.
[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>.
[RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in Extensions for Stateless Address Autoconfiguration in
IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007, IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007,
<https://www.rfc-editor.org/info/rfc4941>. <https://www.rfc-editor.org/info/rfc4941>.
[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>.
[RFC6606] Kim, E., Kaspar, D., Gomez, C., and C. Bormann, "Problem
Statement and Requirements for IPv6 over Low-Power
Wireless Personal Area Network (6LoWPAN) Routing",
RFC 6606, DOI 10.17487/RFC6606, May 2012,
<https://www.rfc-editor.org/info/rfc6606>.
[RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and
Lossy Networks", RFC 7102, DOI 10.17487/RFC7102, January
2014, <https://www.rfc-editor.org/info/rfc7102>.
[RFC7217] Gont, F., "A Method for Generating Semantically Opaque [RFC7217] Gont, F., "A Method for Generating Semantically Opaque
Interface Identifiers with IPv6 Stateless Address Interface Identifiers with IPv6 Stateless Address
Autoconfiguration (SLAAC)", RFC 7217, Autoconfiguration (SLAAC)", RFC 7217,
DOI 10.17487/RFC7217, April 2014, DOI 10.17487/RFC7217, April 2014,
<https://www.rfc-editor.org/info/rfc7217>. <https://www.rfc-editor.org/info/rfc7217>.
[RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for
Constrained-Node Networks", RFC 7228,
DOI 10.17487/RFC7228, May 2014,
<https://www.rfc-editor.org/info/rfc7228>.
[RFC7428] Brandt, A. and J. Buron, "Transmission of IPv6 Packets [RFC7428] Brandt, A. and J. Buron, "Transmission of IPv6 Packets
over ITU-T G.9959 Networks", RFC 7428, over ITU-T G.9959 Networks", RFC 7428,
DOI 10.17487/RFC7428, February 2015, DOI 10.17487/RFC7428, February 2015,
<https://www.rfc-editor.org/info/rfc7428>. <https://www.rfc-editor.org/info/rfc7428>.
[RFC7668] Nieminen, J., Savolainen, T., Isomaki, M., Patil, B., [RFC7668] Nieminen, J., Savolainen, T., Isomaki, M., Patil, B.,
Shelby, Z., and C. Gomez, "IPv6 over BLUETOOTH(R) Low Shelby, Z., and C. Gomez, "IPv6 over BLUETOOTH(R) Low
Energy", RFC 7668, DOI 10.17487/RFC7668, October 2015, Energy", RFC 7668, DOI 10.17487/RFC7668, October 2015,
<https://www.rfc-editor.org/info/rfc7668>. <https://www.rfc-editor.org/info/rfc7668>.
skipping to change at page 31, line 40 skipping to change at page 32, line 36
IEEE Standard 802.15.4, DOI 10.1109/IEEE IEEE Standard 802.15.4, DOI 10.1109/IEEE
P802.15.4-REVd/D01, June 2017, P802.15.4-REVd/D01, June 2017,
<http://ieeexplore.ieee.org/document/7460875/>. <http://ieeexplore.ieee.org/document/7460875/>.
[Perlman83] [Perlman83]
Perlman, R., "Fault-Tolerant Broadcast of Routing Perlman, R., "Fault-Tolerant Broadcast of Routing
Information", North-Holland Computer Networks 7: 395-405, Information", North-Holland Computer Networks 7: 395-405,
1983, <http://www.cs.illinois.edu/~pbg/courses/cs598fa09/ 1983, <http://www.cs.illinois.edu/~pbg/courses/cs598fa09/
readings/p83.pdf>. readings/p83.pdf>.
Appendix A. Applicability and Requirements Served Appendix A. Applicability and Requirements Served (Not Normative)
This specification extends 6LoWPAN ND to provide a sequence number to This specification extends 6LoWPAN ND to provide a sequence number to
the registration and serves the requirements expressed in the registration and serves the requirements expressed in
Appendix B.1 by enabling the mobility of devices from one LLN to the Appendix B.1 by enabling the mobility of devices from one LLN to the
next based on the complementary work in the "IPv6 Backbone Router" next based on the complementary work in the "IPv6 Backbone Router"
[I-D.ietf-6lo-backbone-router] specification. [I-D.ietf-6lo-backbone-router] specification.
In the context of the TimeSlotted Channel Hopping (TSCH) mode of IEEE In the context of the TimeSlotted Channel Hopping (TSCH) mode of IEEE
Std. 802.15.4 [IEEEstd802154], the "6TiSCH architecture" Std. 802.15.4 [IEEEstd802154], the "6TiSCH architecture"
[I-D.ietf-6tisch-architecture] introduces how a 6LoWPAN ND host could [I-D.ietf-6tisch-architecture] introduces how a 6LoWPAN ND host could
skipping to change at page 32, line 40 skipping to change at page 33, line 36
packets is not sufficiently efficient in terms of delivery ratio or packets is not sufficiently efficient in terms of delivery ratio or
energy consumption in the end devices, in particular to enable energy consumption in the end devices, in particular to enable
energy-constrained sleeping nodes. The value of such extension is energy-constrained sleeping nodes. The value of such extension is
especially apparent in the case of mobile wireless nodes, to reduce especially apparent in the case of mobile wireless nodes, to reduce
the multicast operations that are related to IPv6 ND ([RFC4861], the multicast operations that are related to IPv6 ND ([RFC4861],
[RFC4862]) and affect the operation of the wireless medium [RFC4862]) and affect the operation of the wireless medium
[I-D.ietf-mboned-ieee802-mcast-problems] [I-D.ietf-mboned-ieee802-mcast-problems]
[I-D.perkins-intarea-multicast-ieee802]. This serves the scalability [I-D.perkins-intarea-multicast-ieee802]. This serves the scalability
requirements listed in Appendix B.6. requirements listed in Appendix B.6.
Appendix B. Requirements Appendix B. Requirements (Not Normative)
This section lists requirements that were discussed at 6lo for an This section lists requirements that were discussed at 6lo for an
update to 6LoWPAN ND. How those requirements are matched with update to 6LoWPAN ND. How those requirements are matched with
existing specifications at the time of this writing is shown in existing specifications at the time of this writing is shown in
Appendix B.8 . Appendix B.8 .
B.1. Requirements Related to Mobility B.1. Requirements Related to Mobility
Due to the unstable nature of LLN links, even in a LLN of immobile Due to the unstable nature of LLN links, even in a LLN of immobile
nodes a 6LN may change its point of attachment to a 6LR, say 6LR-a, nodes a 6LN may change its point of attachment to a 6LR, say 6LR-a,
skipping to change at page 37, line 32 skipping to change at page 38, line 24
A Network Administrator should be able to validate that the network A Network Administrator should be able to validate that the network
is operating within capacity, and that in particular a 6LBR does not is operating within capacity, and that in particular a 6LBR does not
get overloaded with an excessive amount of registration, so he can get overloaded with an excessive amount of registration, so he can
take actions such as adding a Backbone Link with additional 6LBRs and take actions such as adding a Backbone Link with additional 6LBRs and
6BBRs to his network. 6BBRs to his network.
Related requirements are: Related requirements are:
Req7.1: A management model SHOULD be provided providing access to the Req7.1: A management model SHOULD be provided providing access to the
6LBR and its capacity. It is recommended that the 6LBR be reachable 6LBR, monitor its usage vs. capacity, and alert in case of
over a non-LLN link. congestion. It is recommended that the 6LBR be reachable over a non-
LLN link.
Req7.2: A management model SHOULD be provided providing access to the Req7.2: A management model SHOULD be provided providing access to the
6LR and its capacity to host additional NCE. This management model 6LR and its capacity to host additional NCE. This management model
SHOULD avoid polling individual 6LRs n a way that could disrupt the SHOULD avoid polling individual 6LRs n a way that could disrupt the
operation of the LLN. operation of the LLN.
Req7.3: information on successful and failed registration SHOULD be Req7.3: information on successful and failed registration SHOULD be
provided, including information such as the RUID of the 6LN, the provided, including information such as the ROVR of the 6LN, the
Registered Address, the Address of the 6LR and the duration of the Registered Address, the Address of the 6LR and the duration of the
registration flow. registration flow.
Req7.4: In case of a failed registration, information on the failure Req7.4: In case of a failed registration, information on the failure
including the identification of the node that rejected the including the identification of the node that rejected the
registration and the status in the EARO SHOULD be provided registration and the status in the EARO SHOULD be provided.
B.8. Matching Requirements with Specifications B.8. Matching Requirements with Specifications
I-drafts/RFCs addressing requirements I-drafts/RFCs addressing requirements
+-------------+-----------------------------------------+ +-------------+-----------------------------------------+
| Requirement | Document | | Requirement | Document |
+-------------+-----------------------------------------+ +-------------+-----------------------------------------+
| Req1.1 | [I-D.ietf-6lo-backbone-router] | | Req1.1 | [I-D.ietf-6lo-backbone-router] |
| | | | | |
skipping to change at page 39, line 24 skipping to change at page 40, line 13
| | | | | |
| Req7.2 | | | Req7.2 | |
| | | | | |
| Req7.3 | | | Req7.3 | |
| | | | | |
| Req7.4 | | | Req7.4 | |
+-------------+-----------------------------------------+ +-------------+-----------------------------------------+
Table 7: Work Addressing requirements Table 7: Work Addressing requirements
Appendix C. Subset of a 6LoWPAN Glossary
This document often uses the following acronyms:
6BBR: 6LoWPAN Backbone Router (proxy for the registration)
6LBR: 6LoWPAN Border Router (authoritative on DAD)
6LN: 6LoWPAN Node
6LR: 6LoWPAN Router (relay to the registration process)
6CIO: Capability Indication Option
(E)ARO: (Extended) Address Registration Option
DAD: Duplicate Address Detection
LLN: Low Power Lossy Network (a typical IoT network)
NA: Neighbor Advertisement
NCE: Neighbor Cache Entry
ND: Neighbor Discovery
NDP: Neighbor Discovery Protocol
NS: Neighbor Solicitation
RUID: Registration Unique ID
TSCH: TimeSlotted Channel Hopping
TID: Transaction ID (a sequence counter in the EARO)
Authors' Addresses Authors' Addresses
Pascal Thubert (editor) Pascal Thubert (editor)
Cisco Systems, Inc Cisco Systems, Inc
Building D (Regus) 45 Allee des Ormes Building D (Regus) 45 Allee des Ormes
Mougins - Sophia Antipolis Mougins - Sophia Antipolis
France France
Phone: +33 4 97 23 26 34 Phone: +33 4 97 23 26 34
Email: pthubert@cisco.com Email: pthubert@cisco.com
Erik Nordmark Erik Nordmark
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