draft-ietf-6lo-rfc6775-update-09.txt   draft-ietf-6lo-rfc6775-update-10.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 Intended status: Standards Track
Expires: March 24, 2018 S. Chakrabarti Expires: April 16, 2018 S. Chakrabarti
September 20, 2017
C. Perkins
Futurewei
October 13, 2017
An Update to 6LoWPAN ND An Update to 6LoWPAN ND
draft-ietf-6lo-rfc6775-update-09 draft-ietf-6lo-rfc6775-update-10
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.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 24, 2018. This Internet-Draft will expire on April 16, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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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. Applicability of Address Registration Options . . . . . . . . 3 2. Applicability of Address Registration Options . . . . . . . . 3
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Updating RFC 6775 . . . . . . . . . . . . . . . . . . . . . . 6 4. Updating RFC 6775 . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Extended Address Registration Option (EARO) . . . . . . . 7 4.1. Extended Address Registration Option (EARO) . . . . . . . 7
4.2. Transaction ID . . . . . . . . . . . . . . . . . . . . . 7 4.2. Transaction ID . . . . . . . . . . . . . . . . . . . . . 7
4.2.1. Comparing TID values . . . . . . . . . . . . . . . . 8 4.2.1. Comparing TID values . . . . . . . . . . . . . . . . 7
4.3. Owner Unique ID . . . . . . . . . . . . . . . . . . . . . 9 4.3. Owner Unique ID . . . . . . . . . . . . . . . . . . . . . 9
4.4. Extended Duplicate Address Messages . . . . . . . . . . . 10 4.4. Extended Duplicate Address Messages . . . . . . . . . . . 10
4.5. Registering the Target Address . . . . . . . . . . . . . 10 4.5. Registering the Target Address . . . . . . . . . . . . . 10
4.6. Link-Local Addresses and Registration . . . . . . . . . . 11 4.6. Link-Local Addresses and Registration . . . . . . . . . . 11
4.7. Maintaining the Registration States . . . . . . . . . . . 13 4.7. Maintaining the Registration States . . . . . . . . . . . 12
5. Detecting Enhanced ARO Capability Support . . . . . . . . . . 14 5. Detecting Enhanced ARO Capability Support . . . . . . . . . . 14
6. Extended ND Options And Messages . . . . . . . . . . . . . . 15 6. Extended ND Options And Messages . . . . . . . . . . . . . . 14
6.1. Enhanced Address Registration Option (EARO) . . . . . . . 15 6.1. Enhanced Address Registration Option (EARO) . . . . . . . 14
6.2. Extended Duplicate Address Message Formats . . . . . . . 18 6.2. Extended Duplicate Address Message Formats . . . . . . . 17
6.3. New 6LoWPAN Capability Bits in the Capability Indication 6.3. New 6LoWPAN Capability Bits in the Capability Indication
Option . . . . . . . . . . . . . . . . . . . . . . . . . 19 Option . . . . . . . . . . . . . . . . . . . . . . . . . 18
7. Backward Compatibility . . . . . . . . . . . . . . . . . . . 19 7. Backward Compatibility . . . . . . . . . . . . . . . . . . . 18
7.1. Discovering the capabilities of an ND peer . . . . . . . 19 7.1. Discovering the capabilities of an ND peer . . . . . . . 18
7.1.1. Using the "E" Flag in the 6CIO Option . . . . . . . . 19 7.1.1. Using the "E" Flag in the 6CIO . . . . . . . . . . . 19
7.1.2. Using the "T" Flag in the EARO . . . . . . . . . . . 20 7.1.2. Using the "T" Flag in the EARO . . . . . . . . . . . 19
7.2. Legacy 6LoWPAN Node . . . . . . . . . . . . . . . . . . . 21 7.2. Legacy 6LoWPAN Node . . . . . . . . . . . . . . . . . . . 20
7.3. Legacy 6LoWPAN Router . . . . . . . . . . . . . . . . . . 21 7.3. Legacy 6LoWPAN Router . . . . . . . . . . . . . . . . . . 20
7.4. Legacy 6LoWPAN Border Router . . . . . . . . . . . . . . 22 7.4. Legacy 6LoWPAN Border Router . . . . . . . . . . . . . . 21
8. Security Considerations . . . . . . . . . . . . . . . . . . . 22 8. Security Considerations . . . . . . . . . . . . . . . . . . . 21
9. Privacy Considerations . . . . . . . . . . . . . . . . . . . 23 9. Privacy Considerations . . . . . . . . . . . . . . . . . . . 22
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23
10.1. ARO Flags . . . . . . . . . . . . . . . . . . . . . . . 24 10.1. ARO Flags . . . . . . . . . . . . . . . . . . . . . . . 23
10.2. ICMP Codes . . . . . . . . . . . . . . . . . . . . . . . 24 10.2. ICMP Codes . . . . . . . . . . . . . . . . . . . . . . . 23
10.3. New ARO Status values . . . . . . . . . . . . . . . . . 25 10.3. New ARO Status values . . . . . . . . . . . . . . . . . 24
10.4. New 6LoWPAN capability Bits . . . . . . . . . . . . . . 26 10.4. New 6LoWPAN capability Bits . . . . . . . . . . . . . . 25
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 26 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 25
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 26 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
12.1. Normative References . . . . . . . . . . . . . . . . . . 26 12.1. Normative References . . . . . . . . . . . . . . . . . . 25
12.2. Informative References . . . . . . . . . . . . . . . . . 27 12.2. Informative References . . . . . . . . . . . . . . . . . 26
12.3. External Informative References . . . . . . . . . . . . 30 12.3. External Informative References . . . . . . . . . . . . 29
Appendix A. Applicability and Requirements Served . . . . . . . 30 Appendix A. Applicability and Requirements Served . . . . . . . 30
Appendix B. Requirements . . . . . . . . . . . . . . . . . . . . 31 Appendix B. Requirements . . . . . . . . . . . . . . . . . . . . 30
B.1. Requirements Related to Mobility . . . . . . . . . . . . 32 B.1. Requirements Related to Mobility . . . . . . . . . . . . 31
B.2. Requirements Related to Routing Protocols . . . . . . . . 32 B.2. Requirements Related to Routing Protocols . . . . . . . . 31
B.3. Requirements Related to the Variety of Low-Power Link B.3. Requirements Related to the Variety of Low-Power Link
types . . . . . . . . . . . . . . . . . . . . . . . . . . 33 types . . . . . . . . . . . . . . . . . . . . . . . . . . 32
B.4. Requirements Related to Proxy Operations . . . . . . . . 34 B.4. Requirements Related to Proxy Operations . . . . . . . . 33
B.5. Requirements Related to Security . . . . . . . . . . . . 34 B.5. Requirements Related to Security . . . . . . . . . . . . 33
B.6. Requirements Related to Scalability . . . . . . . . . . . 35 B.6. Requirements Related to Scalability . . . . . . . . . . . 34
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 36 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 35
1. Introduction 1. Introduction
The scope of this draft is an IPv6 Low Power Networks including star The scope of this draft is an IPv6 Low Power Networks 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 such as: [RFC6775] to enable additional capabilities and enhancements such as:
o Support for indicating mobility vs retry (T-bit) o Support for indicating mobility vs retry (T-bit)
o Ease up requirement of registration for link-local addresses o Reduce requirement of registration for link-local addresses
o Enhancement to Address Registration Option (ARO) o Enhancement to Address Registration Option (ARO)
o Permitting registration of target address o Permitting registration of a target address
o Clarification of support of privacy and temporary addresses o Clarification of support of privacy and temporary addresses
The applicability of 6LoWPAN ND registration is discussed in The applicability of 6LoWPAN ND registration is discussed in
Section 2, and new extensions and updates to RFC 6775 are presented Section 2, and new extensions and updates to [RFC6775] are presented
in Section 4. Considerations on Backward Compatibility, Security and in Section 4. Considerations on Backward Compatibility, Security and
Privacy are also elaborated upon in Section 7, Section 8 and in Privacy are also elaborated upon in Section 7, Section 8 and in
Section 9, respectively. Section 9, respectively.
2. Applicability of Address Registration Options 2. Applicability of Address Registration Options
The original purpose of the Address Registration Option (ARO) in the The purpose of the Address Registration Option (ARO) in the legacy
original 6LoWPAN ND specification is to facilitate duplicate address 6LoWPAN ND specification is to facilitate duplicate address detection
detection (DAD) for hosts as well as populate Neighbor Cache Entries (DAD) for hosts as well as populate Neighbor Cache Entries (NCE)
(NCE) [RFC4861] in the routers. This reduces the reliance on [RFC4861] in the routers. This reduces the reliance on multicast
multicast operations, which are often as intrusive as broadcast, in operations, which are often as intrusive as broadcast, in IPv6 ND
IPv6 ND operations. operations.
With this specification, a registration can fail or become useless With this specification, a failed or useless registration can be
for reasons other than address duplication. Examples include: the detected for reasons other than address duplication. Examples
router having run out of space; a registration bearing a stale include: the router having run out of space; a registration bearing a
sequence number perhaps denoting a movement of the host after the stale sequence number perhaps denoting a movement of the host after
registration was placed; a host misbehaving and attempting to the registration was placed; a host misbehaving and attempting to
register an invalid address such as the unspecified address register an invalid address such as the unspecified address
[RFC4291]; or a host using an address which is not topologically [RFC4291]; or a host using an address which is not topologically
correct on that link. correct on that link.
In such cases the host will receive an error to help diagnose the In such cases the host will receive an error to help diagnose the
issue and may retry, possibly with a different address, and possibly issue and may retry, possibly with a different address, and possibly
registering to a different router, depending on the returned error. registering to a different router, depending on the returned error.
However, the ability to return errors to address registrations is not The ability to return errors to address registrations is not intended
intended to be used to restrict the ability of hosts to form and use to be used to restrict the ability of hosts to form and use
addresses, as recommended in "Host Address Availability addresses, as recommended in "Host Address Availability
Recommendations" [RFC7934]. Recommendations" [RFC7934].
In particular, the freedom to form and register addresses is needed In particular, the freedom to form and register addresses is needed
for enhanced privacy; each host may register a multiplicity of for enhanced privacy; each host may register a number of addresses
address using mechanisms such as "Privacy Extensions for Stateless using mechanisms such as "Privacy Extensions for Stateless Address
Address Autoconfiguration (SLAAC) in IPv6" [RFC4941]. Autoconfiguration (SLAAC) in IPv6" [RFC4941].
In the classical IPv6 ND [RFC4861], a router must have enough storage In IPv6 ND [RFC4861], a router must have enough storage to hold
to hold neighbor cache entries for all the addresses to which it may neighbor cache entries for all the addresses to which it may forward.
forward. A router using the Address Registration mechanism needs A router using the Address Registration mechanism also needs enough
enough storage to hold NCEs for all the addresses that may be storage to hold NCEs for all the addresses that may be registered to
registered to it, regardless of whether or not they are actively it, regardless of whether or not they are actively communicating.
communicating. For this reason, the number of registrations The number of registrations supported by a 6LoWPAN Router (6LR) or
supported by a 6LoWPAN Router (6LR) or 6LoWPAN Border Router (6LBR) 6LoWPAN Border Router (6LBR) must be clearly documented.
must be clearly documented.
A network administrator should deploy adapted 6LR/6LBRs to support A network administrator should deploy updated 6LR/6LBRs to support
the number and type of devices in his network, based on the number of the number and type of devices in his network, based on the number of
IPv6 addresses that those devices require and their renewal rate and IPv6 addresses that those devices require and their address renewal
behaviour. rate and behaviour.
3. Terminology 3. Terminology
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", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in [RFC2119].
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 "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], Overview, Assumptions, Problem Statement, and Goals" [RFC4919],
o "Neighbor Discovery Optimization for Low-power and Lossy Networks" o "Neighbor Discovery Optimization for Low-power and Lossy Networks"
[RFC6775] and [RFC6775] and
o "Multi-link Subnet Support in IPv6" o "Multi-link Subnet Support in IPv6"
[I-D.ietf-ipv6-multilink-subnets], [I-D.ietf-ipv6-multilink-subnets],
as well as the following terminology: as well as 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 a relatively high Backbone Routers. It is expected to be a higher speed device
speed compared to the LLN in order to support the trafic that speed compared to the LLN in order to carry the traffic that is
is required to federate multiple segments of the potentially required to federate multiple segments of the potentially large
large LLN into a single IPv6 subnet. Also referred to as a to LLN into a single IPv6 subnet.
as a Backbone, a LLN Backbone, and a Backbone Network.
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 the document onto the matching operations that run detailed in the document onto the matching operations that run
over the backbone, typically classical IPv6 ND. Note that 6BBR over the backbone, typically IPv6 ND. Note that 6BBR is a
is a logical function, just like 6LR and 6LBR, and that a same logical function, just like 6LR and 6LBR, and that a same
physical router may operate all three. physical router may operate all three.
Extended LLN The aggregation of multiple LLNs as defined in RFC 4919 Extended LLN: The aggregation of multiple LLNs as defined in
[RFC4919], interconnected by a Backbone Link via Backbone [RFC4919], interconnected by a Backbone Link via Backbone
Routers, and forming a single IPv6 MultiLink Subnet. Routers, and forming a single IPv6 MultiLink Subnet.
Registration The process during which a wireless Node registers its Registration: The process during which a 6LN registers its
address(es) with the Border Router so the 6BBR can serve as address(es) with the Border Router so the 6BBR can serve as
proxy for ND operations over the Backbone. proxy for ND operations over the Backbone.
Binding The association between an IP address with a MAC address, a Binding: The association between an IP address with a MAC address, a
port and/or other information about the node that owns the IP port and/or other information about the node that owns the IP
address. address.
Registered Node The node for which the registration is performed, Registered Node: The node for which the registration is performed,
and which owns the fields in the EARO option. and which owns the fields in the EARO option.
Registering Node The node that performs the registration to the Registering Node: The node that performs the registration to the
6BBR, which may proxy for the registered node. 6BBR, which may proxy for the registered node.
Registered Address An address owned by the Registered Node node that Registered Address: An address owned by the Registered Node node
was or is being registered. that was or is being registered.
legacy and original vs. updated In the context of this IPv6 ND: The IPv6 Neighbor Discovery protocol as specified in
specification, the terms "legacy" and "original" relate to the [RFC4861] and [RFC4862].
support of the RFC 6775 by a 6LN, a 6LR or a 6LBR, whereas the
term "updated" refers to the support of this specification.
classical In the context of this specification, the term "classical" legacy: a 6LN, a 6LR or a 6LBR that supports [RFC6775] but not this
relates to the support of the IPv6 Neighbor Discovery (IPv6 ND) specification.
protocol as specified in RFC 4861 and RFC 4862. This
specification does not deprecate the classical IPv6 ND updated: a 6LN, a 6LR or a 6LBR that supports this specification.
Protocol.
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 in RFC 6775 [RFC6775]; in Option (EARO) based on the ARO as defined in [RFC6775]; in particular
particular a "T" flag is added that MUST be set is NS messages when a "T" flag is added that MUST be set in NS messages when this
this specification is used, and echoed in NA messages to confirm that specification is used, and echoed in NA messages to confirm that the
the protocol is supported. protocol is supported.
The extensions to the ARO option are reported to the Duplicate The extensions to the ARO option are used in the Duplicate Address
Address Request (DAR) and Duplicate Address Confirmation (DAC) Request (DAR) and Duplicate Address Confirmation (DAC) messages, so
messages, so as to convey the additional information all the way to as to convey the additional information all the way to the 6LBR. In
the 6LBR, and in turn the 6LBR may proxy the registration using turn the 6LBR may proxy the registration using IPv6 ND over a
classical ND over a backbone as illustrated in Figure 1. backbone as illustrated in Figure 1. Note that this specification
avoids the extended DAR flow for Link Local Addresses in Route-Over
mode.
6LN 6LR 6LBR 6BBR 6LN 6LR 6LBR 6BBR
| | | | | | | |
| NS(EARO) | | | | NS(EARO) | | |
|--------------->| | | |--------------->| | |
| | Extended DAR | | | | Extended DAR | |
| |-------------->| | | |-------------->| |
| | | | | | | |
| | | proxy NS(EARO) | | | | proxy NS(EARO) |
| | |--------------->| | | |--------------->|
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4.1. Extended Address Registration Option (EARO) 4.1. Extended Address Registration Option (EARO)
The Extended ARO (EARO) deprecates the ARO and is backward compatible The Extended ARO (EARO) deprecates the ARO and is backward compatible
with it. More details on backward compatibility can be found in with it. More details on backward compatibility can be found in
Section 7. Section 7.
The semantics of the ARO are modified as follows: The semantics of 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 Neighbor Solicitation
(NS) with an EARO is now the Target Address, as opposed to the (NS) with an EARO is now the Target Address, as opposed to the
Source Address as specified in RFC 6775 [RFC6775] (see Source Address as specified in [RFC6775] (see Section 4.5). This
Section 4.5). This change enables a 6LBR to use one of its change enables a 6LBR to use one of its addresses as source to the
addresses as source to the proxy-registration of an address that proxy-registration of an address that belongs to a LLN Node to a
belongs to a LLN Node to a 6BBR. This also limits the use of an 6BBR. This also limits the use of an address as source address
address as source address before it is registered and the before it is registered and the associated DAD process is
associated DAD process is complete. complete.
o The Unique ID in the EARO Option is no longer required to be a MAC o The Unique ID in the EARO Option is not required to be a MAC
address (see Section 4.3). This enables in particular the use of address (see Section 4.3).
a Provable Temporary UID (PT-UID) as opposed to burn-in MAC
address; the PT-UID provides an anchor trusted by the 6LR and 6LBR
to protect the state associated to the node.
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
skipping to change at page 9, line 10 skipping to change at page 9, line 6
1. If (256 + B - A) is less than or equal to 1. If (256 + B - A) is less than or equal to
SEQUENCE_WINDOW, then B is greater than A, A is less than SEQUENCE_WINDOW, then B is greater than A, A is less than
B, and the two are not equal. B, and the two are not equal.
2. If (256 + B - A) is greater than SEQUENCE_WINDOW, then A 2. If (256 + B - A) is greater than SEQUENCE_WINDOW, then A
is greater than B, B is less than A, and the two are not is greater than B, B is less than A, and the two are not
equal. equal.
For example, if A is 240, and B is 5, then (256 + 5 - 240) is For example, if A is 240, and B is 5, then (256 + 5 - 240) is
21. 21 is greater than SEQUENCE_WINDOW (16), thus 240 is 21. 21 is greater than SEQUENCE_WINDOW (16), thus 240 is
greater than 5. As another example, if A is 250 and B is 5, greater than 5. As another example, if A is 250 and B is 5,
then (256 + 5 - 250) is 11. 11 is less than SEQUENCE_WINDOW then (256 + 5 - 250) is 11. 11 is less than SEQUENCE_WINDOW
(16), thus 250 is less than 5. (16), thus 250 is less than 5.
2. In the case where both sequence counters to be compared are 2. In the case where both sequence counters to be compared are
less than or equal to 127, and in the case where both less than or equal to 127, and in the case where both
sequence counters to be compared are greater than or equal to sequence counters to be compared are greater than or equal to
128: 128:
1. If the absolute magnitude of difference between the two 1. If the absolute magnitude of difference between the two
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4.3. Owner Unique ID 4.3. Owner Unique ID
The Owner Unique ID (OUID) enables a duplicate address registration The Owner Unique ID (OUID) enables a duplicate address registration
to be distinguished from a double registration or a movement. An ND to be distinguished from a double registration or a movement. An ND
message from the 6BBR over the Backbone that is proxied on behalf of message from the 6BBR over the Backbone that is proxied on behalf of
a Registered Node must carry the most recent EARO option seen for 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 that node. A NS/NA with an EARO and a NS/NA without a EARO thus
represent different nodes; if they relate to a same target then an represent different nodes; if they relate to a same target then an
address duplication is likely. address duplication is likely.
With RFC 6775, the Owner Unique ID carries an EUI-64 burn-in address, The Owner Unique ID in [RFC6775] is a EUI-64 preconfigured address,
which implies that duplicate EUI-64 addresses are avoided. With this under the assumption that duplicate EUI-64 addresses are avoided.
specification, the Owner Unique ID is allowed to be extended to With this specification, the Owner Unique ID is allowed to be
different types of identifier, as long as the type is clearly extended to different types of identifier, as long as the type is
indicated. For instance, the type can be a cryptographic string and clearly indicated. For instance, the type can be a cryptographic
used to prove the ownership of the registration as discussed in string and used to prove the ownership of the registration as
"Address Protected Neighbor Discovery for Low-power and Lossy discussed in "Address Protected Neighbor Discovery for Low-power and
Networks" [I-D.ietf-6lo-ap-nd]. Lossy Networks" [I-D.ietf-6lo-ap-nd].
In any fashion, it is recommended that the node stores the unique Id The node SHOULD store the unique ID, or a way to generate that ID, in
or the keys used to generate that ID in persistent memory. persistent memory. Otherwise, if a reboot causes a loss of memory,
Otherwise, it will be prevented to re-register a same address after a re-registering the same address could be impossible until the 6LBR
reboot that would cause a loss of memory until the 6LBR times out the times out the previous registration.
registration.
4.4. Extended Duplicate Address Messages 4.4. Extended Duplicate Address Messages
In order to map the new EARO content in the DAR/DAC messages, a new In order to map the new EARO content in the DAR/DAC messages, a new
TID field is added to the Extended DAR (EDAR) and the Extended DAC 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 (EDAC) messages as a replacement to a Reserved field, and an odd
value of the ICMP Code indicates support for the TID, to transport value of the ICMP Code indicates support for the TID, to transport
the "T" flag. the "T" flag.
In order to prepare for new extensions, and though no option had been In order to prepare for future extensions, and though no option has
earlier defined for the Duplicate Address messages, implementations been defined for the Duplicate Address messages, implementations
SHOULD expect ND options after the main body, and SHOULD ignore them. SHOULD expect ND options after the main body, and SHOULD ignore them.
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 original versions, and remarks concerning compatible with the legacy versions, and remarks concerning backwards
backwards compatibility between the 6LN and the 6LR apply similarly compatibility for the protocol between the 6LN and the 6LR apply
between a 6LR and a 6LBR. 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 inherited from RFC 6775, it may be the Registered Node the 6BBR. As in [RFC6775], it may be the Registered Node as well, in
as well, in which case it registers one of its own addresses, and which case it registers one of its own addresses, and indicates its
indicates its own MAC Address as Source Link Layer Address (SLLA) in own MAC Address as Source Link Layer Address (SLLA) in the NS(EARO).
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
mesh. In that case, if the Registered Node is reachable from the mesh. In that case, if the Registered Node is reachable from the
6BBR over a Mesh-Under mesh, the Registering Node indicates the MAC 6BBR over a Mesh-Under mesh, the Registering Node indicates the MAC
Address of the Registered Node as SLLA in the NS(EARO). If the Address of the Registered Node as 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. opposed to the Source Address. With this convention, a TLLA option
indicates the link-layer address of the 6LN that owns the address,
The reason for this change is to enable proxy-registrations on behalf whereas the SLLA Option in a NS message indicates that of the
of other nodes, for instance to enable a RPL root to register Registering Node, which can be the owner device, or a proxy.
addresses on behalf of other LLN nodes, as discussed in Appendix B.4.
In that case, the Registering Node MUST indicate its own address as
source of the ND message and its MAC address in the Source Link-Layer
Address Option (SLLAO), since it still expects to receive and route
the packets. Since the Registered Address belongs to the Registered
Node, that address is indicated in the Target Address field of the NS
message.
With this convention, a TLLA option 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 is reachable from the 6LR, and is also the one
expecting packets for the 6LN. Therefore, it MUST place its own Link expecting packets for the 6LN. Therefore, it MUST place its own Link
Layer Address in the SLLA Option that MUST always be placed in a Layer Address in the SLLA Option that MUST always be placed in a
registration NS(EARO) message. This maintains compatibility with the registration NS(EARO) message. This maintains compatibility with
original 6LoWPAN ND [RFC6775]. legacy 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 RFC 6775, 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 nodes that use it Local address is unique from the perspective of the two nodes that
to communicate (e.g. the 6LN and the 6LR in an NS/NA exchange). This use it to communicate (e.g. the 6LN and the 6LR in an NS/NA
simplifies the DAD process for Link-Local addresses, and there is no exchange). This simplifies the DAD process in Route-Over Mode for
exchange of Duplicate Address messages between the 6LR and a 6LBR for Link-Local addresses, and there is no exchange of Duplicate Address
Link-Local addresses. messages between the 6LR and a 6LBR for Link-Local addresses.
According to RFC 6775, a 6LoWPAN Node (6LN) uses the an address being
registered as the source of the registration message. This generates
complexities in the 6LR to be able to cope with a potential
duplication, in particular for global addresses.
To simplify this, a 6LN and a 6LR that conform this specification
MUST always use Link-Local addresses as source and destination
addresses for the registration NS/NA exchange. As a result, the
registration is globally faster, and some of the complexity is
removed.
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 and that at least one of the 2 nodes
acts as a 6LR. A node MUST register a Link-Local address to a 6LR in acts as a 6LR. A node MUST register a Link-Local address to a 6LR in
order to obtain reachability from that 6LR beyond the current order to obtain reachability from that 6LR beyond the current
exchange, and in particular to use the Link-Local address as source exchange, and in particular to use the Link-Local address as source
address to register other addresses, e.g. global addresses. address to register other addresses, e.g. global 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, from the standpoint of this 6LR, this this 6LR by another 6LN, then the Link-Local address is unique from
Link-Local address is unique and the registration is acceptable. the standpoint of this 6LR and the registration is acceptable.
Conversely, it may possibly happen that two different 6LRs expose the Alternatively, two different 6LRs might expose the same Link-Local
same Link-Local address but different link-layer addresses. In that address but different link-layer addresses. In that case, a 6LN MUST
case, a 6LN may only interact with one of the 6LRs so as to avoid only interact with one of the 6LRs.
confusion in the 6LN neighbor cache.
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 Duplicate Address messages, does not need to take place
for Link-Local addresses. for Link-Local addresses.
It is desired that a 6LR does not need to modify its state associated It is preferable for a 6LR to avoid modifying its state associated to
to the Source Address of an NS(EARO) message. For that reason, when the Source Address of an NS(EARO) message. For that reason, when
possible, it is RECOMMENDED to use an address that is already possible, an address that is already registered with a 6LR SHOULD be
registered with a 6LR used by a 6LN.
When registering to a 6LR that conforms this specification, a node When registering to a 6LR that conforms 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 already registered. That Link-Local Address MUST be either already
registered, or the address that is being registered. registered, or the address that is being 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 burn-in MAC address. An EARO globally unique, e.g., derived from a globally unique hardware MAC
option in the response NA indicates that the 6LR supports this address. An EARO option in the response NA indicates that the 6LR
specification. supports this specification.
Since there is no Duplicate Address exchange for Link-Local Since there is no Duplicate Address exchange for Link-Local
addresses, the 6LR may answer immediately to the registration of a addresses, the 6LR may answer immediately to the registration of a
Link-Local address, based solely on its existing state and the Source Link-Local address, based solely on its existing state and the Source
Link-Layer Option that MUST be placed in the NS(EARO) message as Link-Layer Option that MUST be placed in the NS(EARO) message as
required in RFC 6775 [RFC6775]. required in [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 a 6LR that conforms addresses via that 6LR. When registering with an updated 6LR, a
this specification, a Registering Node does not use its GUA as Source Registering Node does not use its GUA as Source Address, in contrast
Address, in contrast to a node that complies to RFC 6775 [RFC6775]. to a node that complies to [RFC6775]. For non-Link-Local addresses,
For non-Link-Local addresses, the Duplicate Address exchange MUST the Duplicate Address exchange MUST conform to [RFC6775], but the
conform to RFC 6775, but the extended formats described in this extended formats described in this specification for the DAR and the
specification for the DAR and the DAC are used to relay the extended DAC are used to relay the extended information in the case of an
information in the case of an EARO. EARO.
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, which, as discussed in Section 4.6, 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 in a 6LR. 6LBRs and 6BBRs may store
additional registration information in more complex data structures additional registration information in more complex data structures
and use protocols that are out of scope of this document to keep them and use protocols that are out of scope of this document to keep them
synchonized when they are distributed. synchonized when they are distributed.
When its Neighbor Cache is full, a 6LR cannot accept a new When its Neighbor Cache is full, a 6LR cannot accept a new
registration. In that situation, the EARO is returned in a NA registration. In that situation, the EARO is returned in a NA
message with a Status of 2, and the Registering Node may attempt to message with a Status of 2, and the Registering Node may attempt to
register to another 6LR. register to another 6LR.
Conversely the registry in the 6LBR may be saturated, in which case If the registry in the 6LBR is be saturated, in which case the LBR
the LBR cannot guarantee that a new address is effectively not a cannot guarantee that a new address is effectively not a duplicate.
duplicate. In that case, the 6LBR replies to a EDAR message with a In that case, the 6LBR replies to a EDAR message with a EDAC message
EDAC message that carries a Status code 9 indicating "6LBR Registry that carries a Status code 9 indicating "6LBR Registry saturated",
saturated", and the address stays in TENTATIVE state. Note: this and the address stays in TENTATIVE state. Note: this code is used by
code is used by 6LBRs instead of Status 2 when responding to a 6LBRs instead of Status 2 when responding to a Duplicate Address
Duplicate Address message exchange and passed on to the Registering message exchange and passed on to the Registering Node by the 6LR.
Node by the 6LR. There is no point for the node to retry this There is no point for the node to retry this registration immediately
registration immediately via another 6LR, since the problem is global via another 6LR, since the problem is global to the network. The
to the network. The node may either abandon that address, deregister node may either abandon that address, deregister other addresses
other addresses first to make room, or keep the address in TENTATIVE first to make room, or keep the address in TENTATIVE state and retry
state and retry later. later.
A node renews an existing registration by repeatedly sending NS(EARO) A node renews an existing registration by sending a new NS(EARO)
messages for the Registered Address. In order to refresh the message for the Registered Address. In order to refresh the
registration state in the 6LBR, these registrations MUST be reported registration state in the 6LBR, the registration MUST be reported to
to the 6LBR. the 6LBR.
A node that ceases to use an address SHOULD attempt to deregister A node that ceases to use an address SHOULD attempt to deregister
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, which is achieved using an NS(EARO) message with a
Registration Lifetime of 0. Registration Lifetime of 0.
A node that moves away from a particular 6LR SHOULD attempt to A node that moves away from a particular 6LR SHOULD attempt to
deregister all of its addresses registered to that 6LR and register deregister all of its addresses registered to that 6LR and register
to a new 6LR with an incremented TID. When/if the node shows up to a new 6LR with an incremented TID. When/if the node shows up
elsewhere, an asynchronous NA(EARO) or EDAC message with a status of elsewhere, an asynchronous NA(EARO) or EDAC message with a status of
skipping to change at page 14, line 25 skipping to change at page 13, line 44
clean up its state. clean up its state.
Upon receiving a NS(EARO) message with a Registration Lifetime of 0 Upon receiving a 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, or an alternate protocol, Duplicate Address exchange with the 6LBR, or an alternate protocol,
indicating the null Registration Lifetime and the latest TID that indicating the null Registration Lifetime and the latest TID that
this 6LR is aware of. this 6LR is aware of.
Upon the Extended DAR message, the 6LBR evaluates if this is the Upon receiving the Extended DAR message, the 6LBR evaluates if this
freshest TID it has received for that particular registry entry. If is the most recent TID it has received for that particular registry
it is, then the entry is scheduled to be removed, and the EDAR is entry. If so, then the entry is scheduled to be removed, and the
answered with a EDAC message bearing a Status of 0 "Success". If it EDAR is answered with a EDAC message bearing a Status of 0
is not the freshest, then a Status 3 "Moved" is returned instead, and ("Success"). Otherwise, a Status 3 ("Moved") is returned instead,
the existing entry is conserved. and the existing entry is maintained.
Upon timing out a registration, a 6LR removes silently its binding
cache entry, and a 6LBR schedules its entry to be removed.
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 deregistered from one 6LR and did not protect a mobile node that deregistered 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 removes silently its entry. time is passed, the 6LBR removes silently 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. This specification indicate a node's capabilities to its peers. This specification
extends the format defined in RFC 7400 to signal the support for extends the format defined in [RFC7400] to signal support for EARO,
EARO, as well as the node's capability to act as a 6LR, 6LBR and as well as the node's capability to act as a 6LR, 6LBR and 6BBR.
6BBR.
With RFC 7400, the 6CIO is typically sent in a Router Solicitation The 6CIO is typically sent in a Router Solicitation (RS) message.
(RS) message. When used to signal the capabilities above per this When used to signal capabilities per this specification, the 6CIO is
specification, the 6CIO is typically present in Router Advertisement typically present in Router Advertisement (RA) messages but can also
(RA) messages but can also be present in RS, Neighbor Solicitation be present in RS, Neighbor Solicitation (NS) and Neighbor
(NS) and Neighbor Advertisement (NA) messages. Advertisement (NA) messages.
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. Enhanced 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) is intended to be The Enhanced Address Registration Option (EARO) updates the ARO
used as a replacement to the ARO option within Neighbor Discovery NS option within Neighbor Discovery NS and NA messages between a 6LN and
and NA messages between a 6LN and its 6LR. Conversely, the Extended its 6LR. On the other hand, the Extended Duplicate Address messages,
Duplicate Address messages, EDAR and EDAC, are to be used in EDAR and EDAC, replace the DAR and DAC messages so as to transport
replacement of the DAR and DAC messages so as to transport the new the new information between 6LRs and 6LBRs across LLNs meshes such as
information between 6LRs and 6LBRs across LLNs meshes such as 6TiSCH 6TiSCH networks.
networks.
An NS message with an EARO option is a registration if and only if it An NS message with an EARO option is a registration if and only if it
also carries an SLLAO option. The EARO option also used in NS and NA also carries an SLLAO option. The EARO option also used in NS and NA
messages between Backbone Routers over the Backbone link to sort out messages between Backbone Routers over the Backbone link to sort out
the distributed registration state; in that case, it does not carry the distributed registration state; in that case, it does not carry
the SLLAO option and is not confused with a registration. the SLLAO option and is not confused with a registration.
When using the EARO option, the address being registered is found in When using the EARO option, the address being registered is found in
the Target Address field of the NS and NA messages. This differs the Target Address field of the NS and NA messages.
from 6LoWPAN ND RFC 6775 [RFC6775] which specifies that the address
being registered is the source of the NS.
The EARO extends the ARO and is recognized 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 option 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 = 2 | Status | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved |T| TID | Registration Lifetime | | Reserved |T| TID | Registration Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
skipping to change at page 16, line 33 skipping to change at page 15, line 36
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. Always 2.
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 RFC 6775 [RFC6775]. Note: a Status of 1 "Duplicate | | 0..2 | See [RFC6775]. Note: a Status of 1 "Duplicate Address" |
| | Address" applies to the Registered Address. If the Source | | | applies to the Registered Address. If the Source Address |
| | Address conflicts with an existing registration, | | | conflicts with an existing registration, "Duplicate |
| | "Duplicate Source Address" should be used. | | | Source Address" should be used. |
| | | | | |
| 3 | Moved: The registration fails because it is not the | | 3 | Moved: The registration fails 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 OUI and a more recent TID. | | | done, as indicated by a same OUI 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 OUI collision. | | | recent one. It could also indicate a OUI collision. |
| | | | | |
| 4 | Removed: The binding state was removed. This may be | | 4 | Removed: The binding state was removed. This may be |
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associated state should be removed. associated state should be removed.
Owner Unique Identifier (OUI): A globally unique identifier for the Owner Unique Identifier (OUI): A globally unique identifier for the
node associated. This can be the EUI-64 derived IID node associated. This can be the EUI-64 derived IID
of an interface, or some provable ID obtained of an interface, or some provable ID obtained
cryptographically. cryptographically.
6.2. Extended Duplicate Address Message Formats 6.2. Extended Duplicate Address Message Formats
The Duplicate Address Request (DAR) and the Duplicate Address The Duplicate Address Request (DAR) and the Duplicate Address
Confirmation (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 The Duplicate Address Messages are extended to adapt to the Extended
ARO format, as follows: ARO format, 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 | Code | Checksum | | Type | Code | Checksum |
skipping to change at page 19, line 7 skipping to change at page 18, line 11
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 option as defined in Section 6.1.
Owner Unique Identifier (OUI): 8 bytes; same definition and Owner Unique Identifier (OUI): 8 bytes; same definition and
processing as the OUI in the EARO option as defined processing as the OUI in the EARO option as defined
in Section 6.1. 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 a number of capability bits in the 6CIO This specification defines new capability bits for use in the 6CIO,
that was introduced by RFC 7400 for use in IPv6 ND RA messages. which was introduced by [RFC7400] for use in IPv6 ND RA messages.
Routers that support this specification SHOULD set the "E" flag and Routers that support this specification SHOULD set the "E" flag and
6LN SHOULD favor 6LR routers that support this specification over 6LN SHOULD favor 6LR routers that support this specification over
those that do not. Routers that are capable of acting as 6LR, 6LBR those that do not. Routers that are capable of acting as 6LR, 6LBR
and 6BBR SHOULD set the "L", "B" and "P" flags, respectively. In and 6BBR SHOULD set the "L", "B" and "P" flags, respectively. In
particular, the function 6LR is usually collocated with that of 6LBR. particular, the function 6LR is often collocated with that of 6LBR.
Those flags are not mutually exclusive and if a router is capable of Those flags are not mutually exclusive and if a router is capable of
running multiple functions, it SHOULD set all the related flags. performing multiple functions, it SHOULD set all the related flags.
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 |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
skipping to change at page 19, line 44 skipping to change at page 19, line 4
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, proxying for nodes on this link.
E: This specification is supported and applied. E: This specification is supported and applied.
7. Backward Compatibility 7. Backward Compatibility
7.1. Discovering the capabilities of an ND peer 7.1. Discovering the capabilities of an ND peer
7.1.1. Using the "E" Flag in the 6CIO
7.1.1. Using the "E" Flag in the 6CIO Option
If the 6CIO is used in an ND message and the sending node supports If the 6CIO is used in an ND message and the sending node supports
this specification, then the "E" Flag MUST be set. this specification, then the "E" Flag MUST be set.
A router that supports this specification SHOULD indicate that with a A router that supports this specification SHOULD indicate that with a
6CIO Option, but this might not be practical if the link-layer MTU is 6CIO.
too small.
If the Registering Node (RN) receives a CIO in a Router Advertisement If the Registering Node (RN) receives a 6CIO in a Router
message, then the setting of the "E" Flag indicates whether or not Advertisement message, then the setting of the "E" Flag indicates
this specification is supported. RN SHOULD favor a router that whether or not this specification is supported.
supports this specification over those that do not.
7.1.2. Using the "T" Flag in the EARO 7.1.2. Using the "T" Flag in the EARO
One alternate way for a 6LN to discover the router's capabilities to One alternate way for a 6LN to discover the router's capabilities to
first register a Link Local address, placing the same address in the first register a Link Local address, placing the same address in the
Source and Target Address fields of the NS message, and setting the Source and Target Address fields of the NS message, and setting the
"T" Flag. The node may for instance register an address that is "T" Flag. The node may for instance register an address that is
based on EUI-64. For such address, DAD is not required and using the based on EUI-64. For such address, DAD is not required and using the
SLLAO option in the NS is actually more consistent with existing ND SLLAO option in the NS is actually more consistent with existing ND
specifications such as the "Optimistic Duplicate Address Detection specifications such as the "Optimistic Duplicate Address Detection
(DAD) for IPv6" [RFC4429]. (DAD) for IPv6" [RFC4429].
Once that first registration is complete, the node knows from the Once its first registration is complete, the node knows from the
setting of the "T" Flag in the response whether the router supports setting of the "T" Flag in the response whether the router supports
this specification. If support is verified, the node may register this specification. If support is verified, the node may register
other addresses that it owns, or proxy-register addresses on behalf other addresses that it owns, or proxy-register addresses on behalf
some another node, indicating those addresses being registered in the some another node, indicating those addresses being registered in the
Target Address field of the NS messages, while using one of its own Target Address field of the NS messages, while using one of its own
previously registered addresses as source. previously registered addresses as source.
A node that supports this specification MUST always use an EARO as a A node 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 RFC 6775 harmless since the "T" flag and TID field are reserved in [RFC6775],
are ignored by a legacy router. A router that supports this and are ignored by a legacy router. A router that supports this
specification answers an ARO with an ARO and answers an EARO with an specification answers an ARO with an ARO and answers an EARO with an
EARO. EARO.
This specification changes the behavior of the peers in a This specification changes the behavior of the peers in a
registration flows. To enable backward compatibility, a 6LB that registration flows. To enable backward compatibility, a 6LB that
registers to a 6LR that is not known to support this specification registers to a 6LR that is not known to support this specification
MUST behave in a manner that is compatible with RFC 6775. A 6LN can 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 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. 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 Once the 6LR is known to support this specification, the 6LN MUST
obey this specification. obey this specification.
7.2. Legacy 6LoWPAN Node 7.2. Legacy 6LoWPAN Node
A legacy 6LN will use the Registered Address as source and will not A legacy 6LN will use the Registered Address as source and will not
use an EARO option. An updated 6LR MUST accept that registration if use an EARO option. An updated 6LR MUST accept that registration if
it is valid per RFC 6775, and it MUST manage the binding cache it is valid per [RFC6775], and it MUST manage the binding cache
accordingly. The updated 6LR MUST then use the original Duplicate accordingly. The updated 6LR MUST then use the legacy Duplicate
Address messages as specified in RFC 6775 to indicate to the 6LBR Address messages as specified in [RFC6775] to indicate to the 6LBR
that the TID is not present in the messages. that the TID is not present in the messages.
The main difference with RFC 6775 is that Duplicate Address exchange The main difference with [RFC6775] is that Duplicate Address exchange
for DAD is avoided for Link-Local addresses. In any case, the 6LR for DAD is avoided for Link-Local addresses. In any case, the 6LR
SHOULD use an EARO in the reply, and may use any of the Status codes SHOULD use an EARO in the reply, and may use any of the Status codes
defined in this specification. defined in this specification.
7.3. Legacy 6LoWPAN Router 7.3. Legacy 6LoWPAN Router
The first registration by an updated 6LN MUST be for a Link-Local The first registration by an updated 6LN MUST be for a Link-Local
address, using that Link-Local address as source. A legacy 6LR will address, using that Link-Local address as source. A legacy 6LR will
not make a difference and accept -or reject- that registration as if not make a difference and treat that registration as if the 6LN was a
the 6LN was a legacy node. legacy node.
An updated 6LN will always use an EARO option in the registration NS An updated 6LN will always use an EARO option in the registration NS
message, whereas a legacy 6LR will always reply with an ARO option in message, whereas a legacy 6LR will always reply with an ARO option in
the NA message. So from that first registration, the updated 6LN can the NA message. From that first registration, the updated 6LN can
figure whether the 6LR supports this specification or not. determine whether or not the 6LR supports this specification.
After detecting a legacy 6LR, an updated 6LN may attempt to find an After detecting a legacy 6LR, an updated 6LN may attempt to find an
alternate 6LR that is updated. In order to be backward compatible, alternate 6LR that is updated.
after detecting that a 6LR is legacy, the 6LN MUST adhere to RFC 6775
in future protocol exchanges with that 6LR, and source the packet
with the Registered Address.
Note that the updated 6LN SHOULD use an EARO in the request An updated 6LN SHOULD use an EARO in the request regardless of the
regardless of the type of 6LR, legacy or updated, which implies that type of 6LR, legacy or updated, which implies that the "T" flag is
the "T" flag is set. set.
If an updated 6LN moves from an updated 6LR to a legacy 6LR, the If an updated 6LN moves from an updated 6LR to a legacy 6LR, the
legacy 6LR will send a legacy DAR message, which can not be compared legacy 6LR will send a legacy DAR message, which can not be compared
with an updated one for freshness. with an updated one for freshness.
Allowing legacy DAR messages to replace a state established by the Allowing legacy DAR messages to replace a state established by the
updated protocol in the 6LBR would be an attack vector and that updated protocol in the 6LBR would be an attack vector and that
cannot be the default behavior. cannot be the default behavior.
But if legacy and updated 6LRs coexist temporarily in a network, then But if legacy and updated 6LRs coexist temporarily in a network, then
skipping to change at page 22, line 14 skipping to change at page 21, line 14
7.4. Legacy 6LoWPAN Border Router 7.4. Legacy 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 updated 6LBR devices always use the Extended Duplicate Address
messages and all the associated behavior so they can amlways be messages and all the associated behavior so they can amlways be
differentiated from legacy ones. differentiated from legacy ones.
Note that a legacy 6LBR will accept and process an EDAR message as if Note that a legacy 6LBR will accept and process an EDAR message as if
it was an original one, so the original support of DAD is preserved. it was a legacy DAR, so legacy support of DAD is preserved.
8. Security Considerations 8. Security Considerations
This specification extends RFC 6775 [RFC6775], and the security This specification extends [RFC6775], and the security section of
section of that draft also applies to this as well. In particular, that draft also applies to this as well. In particular, it is
it is expected that the link layer is sufficiently protected to expected that the link layer is sufficiently protected to prevent a
prevent a rogue access, either by means of physical or IP security on rogue access, either by means of physical or IP security on the
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 from the unicast to/from the Backbone Router and secure Broadcast from the
Backbone Router in a way that prevents tempering with or replaying Backbone Router in a way that prevents tempering with or replaying
the RA messages. the RA messages.
This specification recommends to using privacy techniques (see This specification recommends to 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
skipping to change at page 22, line 46 skipping to change at page 21, line 46
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 registration, which effectively denies the and cannot take any more registration, which effectively denies the
requesting a node the capability to use a new address. In order to requesting a 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:
o A node that ceases to use an address SHOULD attempt to deregister o A node that ceases to use an address SHOULD attempt to deregister
that address from all the 6LRs to which it is registered. The that address from all the 6LRs to which it is registered. See
flow is propagated to the 6LBR when needed, and a sequence number Section 4.2 for the mechanism to avoid replay attacks and avoiding
is used to make sure that only the freshest command is acted upon. the use of stale registration information.
o The Registration lifetimes SHOULD be individually configurable for o The Registration lifetimes SHOULD be individually configurable for
each address or group of addresses. The nodes SHOULD be each address or group of addresses. The nodes SHOULD be
configured with a Registration Lifetime that reflects their configured with a Registration Lifetime that reflects their
expectation of how long they will use the address with the 6LR to expectation of how long they will use the address with the 6LR to
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, as number of addresses that can be registered by a single node, as
identified at least by MAC address and preferably by security identified at least by MAC address and preferably by security
credentials. When that maximum is reached, the router should use credentials. When that maximum is reached, the router should use
a Least-Recently-Used (LRU) logic so as to clean up the addresses a Least-Recently-Used (LRU) algorithm to clean up the addresses,
that were not used for the longest time, keeping at least one keeping at least one Link-Local address. The router SHOULD
Link-Local address, and attempting to keep one or more stable attempt to keep one or more stable addresses if stability can be
addresses if such can be recognized, e.g. from the way the IID is determined, e.g. from the way the IID is formed or because they
formed or because they are used over a much longer time span than are used over a much longer time span than other (privacy,
other (privacy, shorter-lived) addresses. The address lifetimes shorter-lived) addresses. Address lifetimes SHOULD be
SHOULD be individually configurable. 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
become saturated, a particular deployment SHOULD distribute the become saturated, a particular deployment should distribute the
6LBR functionality, for instance by leveraging a high speed 6LBR functionality, for instance by leveraging a high speed
Backbone and Backbone Routers to aggregate multiple LLNs into a Backbone and Backbone Routers to aggregate multiple LLNs into a
larger subnet. larger subnet.
The LLN nodes depend on the 6LBR and the 6BBR for their operation. A The LLN nodes depend on the 6LBR and the 6BBR for their operation. A
trust model must be put in place to ensure that the right devices are trust model must be put in place to ensure that the right devices are
acting in these roles, so as to avoid threats such as black-holing, acting in these roles, so as to avoid threats such as black-holing,
or bombing attack whereby an impersonated 6LBR would destroy state in or bombing attack whereby an impersonated 6LBR would destroy state in
the network by using the "Removed" Status code. the network by using the "Removed" Status code.
skipping to change at page 24, line 30 skipping to change at page 23, line 30
IANA is requested to create a new subregistry for "ARO Flags". This IANA is requested to create a new subregistry for "ARO Flags". This
specification defines 8 positions, bit 0 to bit 7, and assigns bit 7 specification defines 8 positions, bit 0 to bit 7, and assigns bit 7
for the "T" flag in Section 6.1. The policy is "IETF Review" or for the "T" flag in Section 6.1. The policy is "IETF Review" or
"IESG Approval" [RFC8126]. The initial content of the registry is as "IESG Approval" [RFC8126]. The initial content of the registry is as
shown in Table 2. shown in Table 2.
New subregistry for ARO Flags under the "Internet Control Message New subregistry for ARO Flags under the "Internet Control Message
Protocol version 6 (ICMPv6) [RFC4443] Parameters" Protocol version 6 (ICMPv6) [RFC4443] Parameters"
+------------+--------------+-----------+ +-------------+--------------+-----------+
| ARO Status | Description | Document | | ARO Status | Description | Document |
+------------+--------------+-----------+ +-------------+--------------+-----------+
| 0..6 | Unassigned | | | 0..6 | Unassigned | |
| 7 | "T" Flag | RFC This | | 7 | "T" Flag | This RFC |
+------------+--------------+-----------+ +-------------+--------------+-----------+
Table 2: new ARO Flags Table 2: new ARO Flags
10.2. ICMP Codes 10.2. ICMP Codes
IANA is requested to create a new entry in the ICMPv6 "Code" Fields IANA is requested to create a new entry in the ICMPv6 "Code" Fields
subregistry of the Internet Control Message Protocol version 6 subregistry of the Internet Control Message Protocol version 6
(ICMPv6) Parameters for the ICMP codes related to the ICMP type 157 (ICMPv6) Parameters for the ICMP codes related to the ICMP type 157
and 158 Duplicate Address Request (shown in Table 3) and Confirmation and 158 Duplicate Address Request (shown in Table 3) and Confirmation
(shown in Table 4), respectively, as follows: (shown in Table 4), respectively, as follows:
New entries for ICMP types 157 DAR message New entries for ICMP types 157 DAR message
+------+----------------------+------------+ +-------+----------------------+------------+
| Code | Name | Reference | | Code | Name | Reference |
+------+----------------------+------------+ +-------+----------------------+------------+
| 0 | Original DAR message | RFC 6775 | | 0 | Original DAR message | RFC 6775 |
| 1 | Extended DAR message | RFC This | | 1 | Extended DAR message | This RFC |
+------+----------------------+------------+ +-------+----------------------+------------+
Table 3: new ICMPv6 Code Fields Table 3: new ICMPv6 Code Fields
New entries for ICMP types 158 DAC message New entries for ICMP types 158 DAC message
+------+----------------------+------------+ +-------+----------------------+------------+
| Code | Name | Reference | | Code | Name | Reference |
+------+----------------------+------------+ +-------+----------------------+------------+
| 0 | Original DAC message | RFC 6775 | | 0 | Original DAC message | RFC 6775 |
| 1 | Extended DAC message | RFC This | | 1 | Extended DAC message | This RFC |
+------+----------------------+------------+ +-------+----------------------+------------+
Table 4: new ICMPv6 Code Fields Table 4: new ICMPv6 Code Fields
10.3. New ARO Status values 10.3. New ARO Status values
IANA is requested to make additions to the Address Registration IANA is requested to make additions to the Address Registration
Option Status Values Registry as follows: Option Status Values Registry as follows:
Address Registration Option Status Values Registry Address Registration Option Status Values Registry
+------------+------------------------------------------+-----------+ +-------------+-----------------------------------------+-----------+
| ARO Status | Description | Document | | ARO Status | Description | Document |
+------------+------------------------------------------+-----------+ +-------------+-----------------------------------------+-----------+
| 3 | Moved | RFC This | | 3 | Moved | This RFC |
| 4 | Removed | RFC This | | 4 | Removed | This RFC |
| 5 | Validation Requested | RFC This | | 5 | Validation Requested | This RFC |
| 6 | Duplicate Source Address | RFC This | | 6 | Duplicate Source Address | This RFC |
| 7 | Invalid Source Address | RFC This | | 7 | Invalid Source Address | This RFC |
| 8 | Registered Address topologically | RFC This | | 8 | Registered Address topologically | This RFC |
| | incorrect | | | | incorrect | |
| 9 | 6LBR registry saturated | RFC This | | 9 | 6LBR registry saturated | This RFC |
| 10 | Validation Failed | RFC This | | 10 | Validation Failed | This RFC |
+------------+------------------------------------------+-----------+ +-------------+-----------------------------------------+-----------+
Table 5: New ARO Status values Table 5: New ARO Status values
10.4. New 6LoWPAN capability Bits 10.4. New 6LoWPAN capability Bits
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 |
+----------------+----------------------+-----------+ +-----------------+----------------------+-----------+
| 11 | 6LR capable (L bit) | RFC This | | 11 | 6LR capable (L bit) | This RFC |
| 12 | 6LBR capable (B bit) | RFC This | | 12 | 6LBR capable (B bit) | This RFC |
| 13 | 6BBR capable (P bit) | RFC This | | 13 | 6BBR capable (P bit) | This RFC |
| 14 | EARO support (E bit) | RFC This | | 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 Charlie Perkins for his in-depth reviews and Many thanks to Sedat Gormus, Rahul Jadhav and Lorenzo Colitti for
constructive suggestions, as well as to Sedat Gormus, Rahul Jadhav their various contributions and reviews. Also many thanks to Thomas
and Lorenzo Colitti for their various contributions and reviews. Watteyne for his early implementation of a 6LN that was instrumental
Also many thanks to Thomas Watteyne for his early implementation of a to the early tests of the 6LR, 6LBR and Backbone Router.
6LN that was instrumental 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 28, line 8 skipping to change at page 27, line 8
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
802.11ah", draft-delcarpio-6lo-wlanah-01 (work in 802.11ah", draft-delcarpio-6lo-wlanah-01 (work in
progress), October 2015. progress), October 2015.
[I-D.ietf-6lo-ap-nd] [I-D.ietf-6lo-ap-nd]
Sarikaya, B., Thubert, P., and M. Sethi, "Address Sarikaya, B., Thubert, P., and M. Sethi, "Address
Protected Neighbor Discovery for Low-power and Lossy Protected Neighbor Discovery for Low-power and Lossy
Networks", draft-ietf-6lo-ap-nd-02 (work in progress), May Networks", draft-ietf-6lo-ap-nd-03 (work in progress),
2017. September 2017.
[I-D.ietf-6lo-backbone-router] [I-D.ietf-6lo-backbone-router]
Thubert, P., "IPv6 Backbone Router", draft-ietf-6lo- Thubert, P., "IPv6 Backbone Router", draft-ietf-6lo-
backbone-router-04 (work in progress), July 2017. backbone-router-04 (work in progress), July 2017.
[I-D.ietf-6lo-nfc] [I-D.ietf-6lo-nfc]
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-07 (work in progress), Communication", draft-ietf-6lo-nfc-07 (work in progress),
June 2017. June 2017.
skipping to change at page 30, line 39 skipping to change at page 29, line 39
[RFC8163] Lynn, K., Ed., Martocci, J., Neilson, C., and S. [RFC8163] Lynn, K., Ed., Martocci, J., Neilson, C., and S.
Donaldson, "Transmission of IPv6 over Master-Slave/Token- Donaldson, "Transmission of IPv6 over Master-Slave/Token-
Passing (MS/TP) Networks", RFC 8163, DOI 10.17487/RFC8163, Passing (MS/TP) Networks", RFC 8163, DOI 10.17487/RFC8163,
May 2017, <https://www.rfc-editor.org/info/rfc8163>. May 2017, <https://www.rfc-editor.org/info/rfc8163>.
12.3. External Informative References 12.3. External Informative References
[IEEEstd802154] [IEEEstd802154]
IEEE, "IEEE Standard for Low-Rate Wireless Networks", IEEE, "IEEE Standard for Low-Rate Wireless Networks",
IEEE Standard 802.15.4, DOI 10.1109/IEEESTD.2016.7460875, IEEE Standard 802.15.4, DOI 10.1109/IEEE
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
skipping to change at page 31, line 20 skipping to change at page 30, line 26
connect to the Internet via a RPL mesh Network, but this requires connect to the Internet via a RPL mesh Network, but this requires
additions to the 6LOWPAN ND protocol to support mobility and additions to the 6LOWPAN ND protocol to support mobility and
reachability in a secured and manageable environment. This reachability in a secured and manageable environment. This
specification details the new operations that are required to specification details the new operations that are required to
implement the 6TiSCH architecture and serves the requirements listed implement the 6TiSCH architecture and serves the requirements listed
in Appendix B.2. in Appendix B.2.
The term LLN is used loosely in this specification to cover multiple The term LLN is used loosely in this specification to cover multiple
types of WLANs and WPANs, including Low-Power Wi-Fi, BLUETOOTH(R) Low types of WLANs and WPANs, including Low-Power Wi-Fi, BLUETOOTH(R) Low
Energy, IEEE Std.802.11AH and IEEE Std.802.15.4 wireless meshes, so Energy, IEEE Std.802.11AH and IEEE Std.802.15.4 wireless meshes, so
as to address the requirements discussed in Appendix B.3 as to address the requirements discussed in Appendix B.3.
This specification can be used by any wireless node to associate at This specification can be used by any wireless node to associate at
Layer-3 with a 6BBR and register its IPv6 addresses to obtain routing Layer-3 with a 6BBR and register its IPv6 addresses to obtain routing
services including proxy-ND operations over the Backbone, effectively services including proxy-ND operations over the Backbone, effectively
providing a solution to the requirements expressed in Appendix B.4. providing a solution to the requirements expressed in Appendix B.4.
"Efficiency aware IPv6 Neighbor Discovery Optimizations" "Efficiency aware IPv6 Neighbor Discovery Optimizations"
[I-D.chakrabarti-nordmark-6man-efficient-nd] suggests that 6LoWPAN ND [I-D.chakrabarti-nordmark-6man-efficient-nd] suggests that 6LoWPAN ND
[RFC6775] can be extended to other types of links beyond IEEE Std. [RFC6775] can be extended to other types of links beyond IEEE Std.
802.15.4 for which it was defined. The registration technique is 802.15.4 for which it was defined. The registration technique is
beneficial when the Link-Layer technique used to carry IPv6 multicast beneficial when the Link-Layer technique used to carry IPv6 multicast
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 classical ND ([RFC4861], the multicast operations that are related to IPv6 ND ([RFC4861],
[RFC4862]) and plague the wireless medium. This serves scalability [RFC4862]) and plague the wireless medium. This serves scalability
requirements listed in Appendix B.6. requirements listed in Appendix B.6.
Appendix B. Requirements Appendix B. Requirements
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. This specification meets most of them, but update to 6LoWPAN ND. This specification meets most of them, but
those listed in Appendix B.5 which are deferred to a different those listed in Appendix B.5 which are deferred to a different
specification such as [I-D.ietf-6lo-ap-nd], and those related to specification such as [I-D.ietf-6lo-ap-nd], and those related to
multicast. multicast.
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characteristics. It is required that a 6LoWPAN Node attached via ND characteristics. It is required that a 6LoWPAN Node attached via ND
to a 6LR would need to participate in the selected routing protocol to a 6LR would need to participate in the selected routing protocol
to obtain reachability via the 6LR. to obtain reachability via the 6LR.
Next to the 6LBR unicast address registered by ND, other addresses Next to the 6LBR unicast address registered by ND, other addresses
including multicast addresses are needed as well. For example a including multicast addresses are needed as well. For example a
routing protocol often uses a multicast address to register changes routing protocol often uses a multicast address to register changes
to established paths. ND needs to register such a multicast address to established paths. ND needs to register such a multicast address
to enable routing concurrently with discovery. to enable routing concurrently with discovery.
Multicast is needed for groups. Groups MAY be formed by device type Multicast is needed for groups. Groups may be formed by device type
(e.g. routers, street lamps), location (Geography, RPL sub-tree), or (e.g. routers, street lamps), location (Geography, RPL sub-tree), or
both. both.
The Bit Index Explicit Replication (BIER) Architecture The Bit Index Explicit Replication (BIER) Architecture
[I-D.ietf-bier-architecture] proposes an optimized technique to [I-D.ietf-bier-architecture] proposes an optimized technique to
enable multicast in a LLN with a very limited requirement for routing enable multicast in a LLN with a very limited requirement for routing
state in the nodes. state in the nodes.
Related requirements are: Related requirements are:
Req2.1: The ND registration method SHOULD be extended in such a Req2.1: The ND registration method SHOULD be extended so that the 6LR
fashion that the 6LR MAY advertise the Address of a 6LoWPAN Node over is able to advertise the Address of a 6LoWPAN Node over the selected
the selected routing protocol and obtain reachability to that Address routing protocol and obtain reachability to that Address using the
using the selected routing protocol. selected routing protocol.
Req2.2: Considering RPL, the Address Registration Option that is used Req2.2: Considering RPL, the Address Registration Option that is used
in the ND registration SHOULD be extended to carry enough information in the ND registration SHOULD be extended to carry enough information
to generate a DAO message as specified in [RFC6550] section 6.4, in to generate a DAO message as specified in [RFC6550] section 6.4, in
particular the capability to compute a Path Sequence and, as an particular the capability to compute a Path Sequence and, as an
option, a RPLInstanceID. option, a RPLInstanceID.
Req2.3: Multicast operations SHOULD be supported and optimized, for Req2.3: Multicast operations SHOULD be supported and optimized, for
instance using BIER or MPL. Whether ND is appropriate for the instance using BIER or MPL. Whether ND is appropriate for the
registration to the 6BBR is to be defined, considering the additional registration to the 6BBR is to be defined, considering the additional
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Req3.3: The Address Registration Option used in the ND registration Req3.3: The Address Registration Option used in the ND registration
SHOULD be extended to carry the relevant forms of unique Identifier. SHOULD be extended to carry the relevant forms of unique Identifier.
Req3.4: The Neighbour Discovery should specify the formation of a Req3.4: The Neighbour Discovery should specify the formation of a
site-local address that follows the security recommendations from site-local address that follows the security recommendations from
[RFC7217]. [RFC7217].
B.4. Requirements Related to Proxy Operations B.4. Requirements Related to Proxy Operations
Duty-cycled devices may not be able to answer themselves to a lookup Duty-cycled devices may not be able to answer themselves to a lookup
from a node that uses classical ND on a Backbone and may need a from a node that uses IPv6 ND on a Backbone and may need a proxy.
proxy. Additionally, the duty-cycled device may need to rely on the Additionally, the duty-cycled device may need to rely on the 6LBR to
6LBR to perform registration to the 6BBR. perform registration to the 6BBR.
The ND registration method SHOULD defend the addresses of duty-cycled The ND registration method SHOULD defend the addresses of duty-cycled
devices that are sleeping most of the time and not capable to defend devices that are sleeping most of the time and not capable to defend
their own Addresses. their own Addresses.
Related requirements are: Related requirements are:
Req4.1: The registration mechanism SHOULD enable a third party to Req4.1: The registration mechanism SHOULD enable a third party to
proxy register an Address on behalf of a 6LoWPAN node that may be proxy register an Address on behalf of a 6LoWPAN node that may be
sleeping or located deeper in an LLN mesh. sleeping or located deeper in an LLN mesh.
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B.5. Requirements Related to Security B.5. Requirements Related to Security
In order to guarantee the operations of the 6LoWPAN ND flows, the In order to guarantee the operations of the 6LoWPAN ND flows, the
spoofing of the 6LR, 6LBR and 6BBRs roles should be avoided. Once a spoofing of the 6LR, 6LBR and 6BBRs roles should be avoided. Once a
node successfully registers an address, 6LoWPAN ND should provide node successfully registers an address, 6LoWPAN ND should provide
energy-efficient means for the 6LBR to protect that ownership even energy-efficient means for the 6LBR to protect that ownership even
when the node that registered the address is sleeping. when the node that registered the address is sleeping.
In particular, the 6LR and the 6LBR then should be able to verify In particular, the 6LR and the 6LBR then should be able to verify
whether a subsequent registration for a given Address comes from the whether a subsequent registration for a given address comes from the
original node. original node.
In a LLN it makes sense to base security on layer-2 security. During In a LLN it makes sense to base security on layer-2 security. During
bootstrap of the LLN, nodes join the network after authorization by a bootstrap of the LLN, nodes join the network after authorization by a
Joining Assistant (JA) or a Commissioning Tool (CT). After joining Joining Assistant (JA) or a Commissioning Tool (CT). After joining
nodes communicate with each other via secured links. The keys for nodes communicate with each other via secured links. The keys for
the layer-2 security are distributed by the JA/CT. The JA/CT can be the layer-2 security are distributed by the JA/CT. The JA/CT can be
part of the LLN or be outside the LLN. In both cases it is needed part of the LLN or be outside the LLN. In both cases it is needed
that packets are routed between JA/CT and the joining node. that packets are routed between JA/CT and the joining node.
skipping to change at line 1674 skipping to change at page 35, line 35
Santa Clara, CA Santa Clara, CA
USA USA
Email: nordmark@sonic.net Email: nordmark@sonic.net
Samita Chakrabarti Samita Chakrabarti
San Jose, CA San Jose, CA
USA USA
Email: samitac.ietf@gmail.com Email: samitac.ietf@gmail.com
Charles E. Perkins
Futurewei
2330 Central Expressway
Santa Clara 95050
Unites States
Email: charliep@computer.org
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