draft-ietf-6lo-rfc6775-update-01.txt   draft-ietf-6lo-rfc6775-update-02.txt 
6lo P. Thubert, Ed. 6lo P. Thubert, Ed.
Internet-Draft cisco Internet-Draft cisco
Updates: 6775 (if approved) E. Nordmark Updates: 6775, 7400 (if approved) E. Nordmark
Intended status: Standards Track Arista Networks Intended status: Standards Track
Expires: July 14, 2017 S. Chakrabarti Expires: October 9, 2017 S. Chakrabarti
January 10, 2017 April 7, 2017
An Update to 6LoWPAN ND An Update to 6LoWPAN ND
draft-ietf-6lo-rfc6775-update-01 draft-ietf-6lo-rfc6775-update-02
Abstract Abstract
This specification updates 6LoWPAN Neighbor Discovery (RFC6775), to This specification updates 6LoWPAN Neighbor Discovery (RFC 6775), 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, and provide simplify the registration operation in 6LoWPAN routers, and provide
enhancements to the registration capabilities, in particular for the enhancements to the registration capabilities, in particular for the
registration to a backbone router for proxy ND operations. registration to a Backbone Router for proxy ND operations.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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-
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
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time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
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This Internet-Draft will expire on July 14, 2017. This Internet-Draft will expire on October 9, 2017.
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.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Considerations On Registration Rejection . . . . . . . . . . 3
3. Updating RFC 6775 . . . . . . . . . . . . . . . . . . . . . . 4 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Transaction ID . . . . . . . . . . . . . . . . . . . . . 4 4. Updating RFC 7400 . . . . . . . . . . . . . . . . . . . . . . 5
3.2. Owner Unique ID . . . . . . . . . . . . . . . . . . . . . 5 5. Updating RFC 6775 . . . . . . . . . . . . . . . . . . . . . . 5
3.3. Extended Address Registration Option . . . . . . . . . . 5 5.1. Transaction ID . . . . . . . . . . . . . . . . . . . . . 6
3.4. Registering the Target Address . . . . . . . . . . . . . 6 5.2. Owner Unique ID . . . . . . . . . . . . . . . . . . . . . 6
3.5. Link-local Addresses and Registration . . . . . . . . . . 6 5.3. Extended Address Registration Option . . . . . . . . . . 7
4. Applicability and Requirements Served . . . . . . . . . . . . 8 5.4. Registering the Target Address . . . . . . . . . . . . . 7
5. The Enhanced Address Registration Option (EARO) . . . . . . . 8 5.5. Link-local Addresses and Registration . . . . . . . . . . 8
6. Backward Compatibility . . . . . . . . . . . . . . . . . . . 12 6. Updated ND Options . . . . . . . . . . . . . . . . . . . . . 9
6.1. Legacy 6LoWPAN Node . . . . . . . . . . . . . . . . . . . 12 6.1. New 6LoWPAN capability Bits in the Capability Indication
6.2. Legacy 6LoWPAN Router . . . . . . . . . . . . . . . . . . 12 Option . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.3. Legacy 6LoWPAN Border Router . . . . . . . . . . . . . . 13 6.2. The Enhanced Address Registration Option (EARO) . . . . . 10
7. Security Considerations . . . . . . . . . . . . . . . . . . . 13 7. Backward Compatibility . . . . . . . . . . . . . . . . . . . 13
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 7.1. Discovering the capabilities of an ND peer . . . . . . . 13
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14 7.1.1. Using the E Flag in the CIO . . . . . . . . . . . . . 13
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 7.1.2. Using the T Flag in the EARO . . . . . . . . . . . . 13
10.1. Normative References . . . . . . . . . . . . . . . . . . 14 7.2. Legacy 6LoWPAN Node . . . . . . . . . . . . . . . . . . . 14
10.2. Informative References . . . . . . . . . . . . . . . . . 15 7.3. Legacy 6LoWPAN Router . . . . . . . . . . . . . . . . . . 14
10.3. External Informative References . . . . . . . . . . . . 17 7.4. Legacy 6LoWPAN Border Router . . . . . . . . . . . . . . 14
Appendix A. Requirements . . . . . . . . . . . . . . . . . . . . 18 8. Security Considerations . . . . . . . . . . . . . . . . . . . 14
A.1. Requirements Related to Mobility . . . . . . . . . . . . 18 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
A.2. Requirements Related to Routing Protocols . . . . . . . . 18 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 16
A.3. Requirements Related to the Variety of Low-Power Link 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 16
types . . . . . . . . . . . . . . . . . . . . . . . . . . 19 11.1. Normative References . . . . . . . . . . . . . . . . . . 17
A.4. Requirements Related to Proxy Operations . . . . . . . . 20 11.2. Informative References . . . . . . . . . . . . . . . . . 18
A.5. Requirements Related to Security . . . . . . . . . . . . 20 11.3. External Informative References . . . . . . . . . . . . 20
A.6. Requirements Related to Scalability . . . . . . . . . . . 22 Appendix A. Applicability and Requirements Served . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22 Appendix B. Requirements . . . . . . . . . . . . . . . . . . . . 21
B.1. Requirements Related to Mobility . . . . . . . . . . . . 22
B.2. Requirements Related to Routing Protocols . . . . . . . . 22
B.3. Requirements Related to the Variety of Low-Power Link
types . . . . . . . . . . . . . . . . . . . . . . . . . . 23
B.4. Requirements Related to Proxy Operations . . . . . . . . 24
B.5. Requirements Related to Security . . . . . . . . . . . . 24
B.6. Requirements Related to Scalability . . . . . . . . . . . 25
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 26
1. Introduction 1. Introduction
IPv6 Neighbor Discovery (ND) Optimization for IPv6 over Low-Power RFC 6775, the "Neighbor Discovery Optimization for IPv6 over Low-
Wireless Personal Area Networks(6LoWPANs) [RFC6775] introduced a Power Wireless Personal Area Networks (6LoWPANs)" [RFC6775]
proactive registration mechanism to IPv6 ND services that is well introduced a proactive registration mechanism to IPv6 Neighbor
suited to nodes belonging to a LLN. Discovery (ND) services that is well suited to nodes belonging to a
Low Power Lossy Network (LLN).
The scope of this draft is an IPv6 Low Power Lossy Network (LLN), The scope of this draft is an IPv6 LLN, which can be a simple star or
which can be a simple star or a more complex mesh topology. The LLN a more complex mesh topology. The LLN may be anchored at an IPv6
may be anchored at an IPv6 Backbone Router (6BBR). The Backbone Backbone Router (6BBR) [I-D.ietf-6lo-backbone-router]. The 6BBRs
Routers interconnect the LLNs over a Backbone Link and emulate that interconnect the LLNs over a Backbone Link and emulate that the LLN
the LLN nodes are present on the Backbone using proxy-ND operations. nodes are present on the Backbone using proxy-ND operations.
This specification modifies and extends the behaviour and protocol This specification modifies and extends the behaviour and protocol
elements of [RFC6775] to enable additional capabilities, in elements of RFC 6775 [RFC6775] to enable additional capabilities, in
particular the registration to a 6BBR for proxy ND operations particular the registration to a 6BBR for proxy ND operations.
[I-D.ietf-6lo-backbone-router].
2. Terminology 2. Considerations On Registration Rejection
The purpose of the Address Registration Option (ARO) RFC 6775
[RFC6775] and of the Extended ARO (EARO) that is introduced in this
document is to facilitate duplicate address detection (DAD) for hosts
and pre-populate Neighbor Cache Entries (NCE) [RFC4861] in the
routers to reduce the need for sending multicast neighbor
solicitations and also to be able to support IPv6 Backbone Routers.
In some cases the address registration can fail or be useless for
reasons other than a duplicate address. Examples are the router
having run out of space, a registration bearing a stale sequence
number (e.g. denoting a movement of the host after this registration
was placed), a host misbehaving and attempting to register an invalid
address such as the unspecified address [RFC4291], or the host using
an address which is not topologically correct on that link. In such
cases the host will receive an error to help diagnose the issue and
may retry, possibly with a different address, and possibly
registering to a different 6LR, depending on the returned error.
However, the ability to return errors to address registrations MUST
NOT be used to restrict the ability of hosts to form and use
addresses as recommended in "Host Address Availability
Recommendations" [RFC7934]. In particular, this is needed for
enhanced privacy, which implies that each host will register a
multiplicity of address as part mechanisms like "Privacy Extensions
for Stateless Address Autoconfiguration (SLAAC) in IPv6" [RFC4941].
This implies that a 6LR or 6LBR which is intended to support N hosts
MUST have space to register at least on the order of 10N IPv6
addresses.
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 [RFC2119]. document are to be interpreted as described in RFC 2119 [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 "Neighbor Discovery for IP version 6" that are discussed in
[RFC4861], "IPv6 Stateless Address Autoconfiguration" [RFC4862],
"IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs):
Overview, Assumptions, Problem Statement, and Goals" [RFC4919],
Neighbor Discovery Optimization for Low-power and Lossy Networks
[RFC6775] and "Multi-link Subnet Support in IPv6"
[I-D.ietf-ipv6-multilink-subnets].
Additionally, this document uses terminology from "Terms Used in "Neighbor Discovery for IP version 6" [RFC4861],
Routing for Low-Power and Lossy Networks" [RFC7102] and
[I-D.ietf-6tisch-terminology], as well as this additional "IPv6 Stateless Address Autoconfiguration" [RFC4862],
terminology:
"IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs):
Overview, Assumptions, Problem Statement, and Goals" [RFC4919],
"Neighbor Discovery Optimization for Low-power and Lossy Networks"
[RFC6775] and
"Multi-link Subnet Support in IPv6"
[I-D.ietf-ipv6-multilink-subnets].
Additionally, this document uses terminology from
"Terms Used in Routing for Low-Power and Lossy Networks" [RFC7102]
and
the "6TiSCH Terminology" [I-D.ietf-6tisch-terminology],
as well as this additional terminology:
Backbone This is an IPv6 transit link that interconnects 2 or more Backbone This is an IPv6 transit link that interconnects 2 or more
Backbone Routers. It is expected to be deployed as a high Backbone Routers. It is expected to be deployed as a high
speed backbone in order to federate a potentially large set of speed backbone in order to federate a potentially large set of
LLNS. Also referred to as a LLN backbone or Backbone network. LLNS. Also referred to as a LLN backbone or Backbone network.
Backbone Router An IPv6 router that federates the LLN using a Backbone Router An IPv6 router that federates the LLN using a
Backbone link as a backbone. A 6BBR acts as a 6LoWPAN Border Backbone link as a backbone. A 6BBR acts as a 6LoWPAN Border
Routers (6LBR) and an Energy Aware Default Router (NEAR). Routers (6LBR) and an Energy Aware Default Router (NEAR).
Extended LLN This is the aggregation of multiple LLNs as defined in Extended LLN This is the aggregation of multiple LLNs as defined in
[RFC4919], interconnected by a Backbone Link via Backbone RFC 4919 [RFC4919], interconnected by a Backbone Link via
Routers, and forming a single IPv6 MultiLink Subnet. Backbone Routers, and forming a single IPv6 MultiLink Subnet.
Registration The process during which a wireless Node registers its Registration The process during which a wireless Node registers its
address(es) with the Border Router so the 6BBR can proxy ND for address(es) with the Border Router so the 6BBR can proxy ND for
it over the backbone. it over the backbone.
Binding The state in the 6BBR that associates an IP address with a Binding The state in the 6BBR that associates an IP address with a
MAC address, a port and some other information about the node MAC address, a port and some other information about the node
that owns the IP address. that owns the IP address.
Registered Node The node for which the registration is performed, Registered Node The node for which the registration is performed,
which owns the fields in the EARO option. 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, either for one of its own addresses, in which case it is 6BBR, either for one of its own addresses, in which case it is
Registered Node and indicates its own MAC Address as SLLA in Registered Node and indicates its own MAC Address as Source
the NS(ARO), or on behalf of a Registered Node that is Link Layer Address (SLLA) in the NS(EARO), or on behalf of a
reachable over a LLN mesh. In the latter case, if the Registered Node that is reachable over a LLN mesh. In the
Registered Node is reachable from the 6BBR over a Mesh-Under latter case, if the Registered Node is reachable from the 6BBR
mesh, the Registering Node indicates the MAC Address of the over a Mesh-Under mesh, the Registering Node indicates the MAC
Registered Node as SLLA in the NS(ARO). Otherwise, it is Address of the Registered Node as SLLA in the NS(EARO).
expected that the Registered Device is reachable over a Route- Otherwise, it is expected that the Registered Device is
Over mesh from the Registering Node, in which case the SLLA in reachable over a Route-Over mesh from the Registering Node, in
the NS(ARO) is that of the Registering Node, which causes it to which case the SLLA in the NS(ARO) is that of the Registering
attract the packets from the 6BBR to the Registered Node and Node, which causes it to attract the packets from the 6BBR to
route them over the LLN. the Registered Node and route them over the LLN.
Registered Address The address owned by the Registered Node node Registered Address The address owned by the Registered Node node
that is being registered. that is being registered.
3. Updating RFC 6775 4. Updating RFC 7400
The support of this specification is signaled in Router Advertisement RFC 7400 [RFC7400] introduces the 6LoWPAN Capability Indication
(RA) messages by 6LoWPAN Router (6LR) (how: tbd). Support for this Option (6CIO) to indicate a node's capabilities to its peers. This
specification can also be inferred from the update of the ARO option specification extends the format defined in RFC 7400 to signal the
in the ND exchanges. support for EARO, as well as the capability to act as a 6LR, 6LBR and
6BBR.
With RFC 7400 [RFC7400], the 6CIO is typically sent Router
Solicitation (RS) messages. When used to signal the capabilities
above per this specification, the 6CIO is typically present Router
Advertisement (RA) messages but can also be present in RS, Neighbor
Solicitation (NS) and Neighbor Advertisement (NA) messages.
5. Updating RFC 6775
This specification extends the Address Registration Option (ARO)
defined in RFC 6775 [RFC6775]; in particular a "T" flag is added that
must be set is NS messages when this specification is used, and
echo'ed in NA messages to confirm that the protocol effectively
supported. Support for this specification can thus be inferred from
the presence of the Extended ARO ("T" flag set) in ND messages.
A Registering Node that supports this specification will favor A Registering Node that supports this specification will favor
registering to a 6LR that indicates support for this specification registering to a 6LR that indicates support for this specification
over that of [RFC6775]. over that of RFC 6775 [RFC6775].
3.1. Transaction ID 5.1. Transaction ID
The specification expects that the Registered Node can provide a The specification expects that the Registered Node can provide a
sequence number called Transaction ID (TID) that is incremented with sequence number called Transaction ID (TID) that is incremented with
each re-registration. The TID essentially obeys the same rules as each re-registration. The TID essentially obeys the same rules as
the Path Sequence field in the Transit Information Option (TIO) found the Path Sequence field in the Transit Information Option (TIO) found
in RPL's Destination Advertisement Object (DAO). This way, the LLN in RPL's Destination Advertisement Object (DAO). This way, the LLN
node can use the same counter for ND and RPL, and a 6LBR acting as node can use the same counter for ND and RPL, and a 6LBR acting as
RPL root may easily maintain the registration on behalf of a RPL node RPL root may easily maintain the registration on behalf of a RPL node
deep inside the mesh by simply using the RPL TIO Path Sequence as TID deep inside the mesh by simply using the RPL TIO Path Sequence as TID
for EARO. for EARO.
When a Registered Node is registered to multiple BBRs in parallel, it When a Registered Node is registered to multiple BBRs in parallel, it
is expected that the same TID is used, to enable the 6BBRs to is expected that the same TID is used, to enable the 6BBRs to
correlate the registrations as being a single one, and differentiate correlate the registrations as being a single one, and differentiate
that situation from a movement. that situation from a movement.
If the TIDs are different, the resolution inherited from RPL sorts If the TIDs are different, the resolution inherited from RPL sorts
out the most recent registration and other ones are removed. The out the most recent registration and other ones are removed. The
operation for computing and comparing the Path Sequence is detailed operation for computing and comparing the Path Sequence is detailed
in section 7 of [RFC6550] and applies to the TID in the exact same in section 7 of RFC 6550 [RFC6550] and applies to the TID in the
fashion. exact same fashion.
3.2. Owner Unique ID 5.2. Owner Unique ID
The Owner Unique ID (OUID) enables to differentiate a real duplicate The Owner Unique ID (OUID) enables to differentiate a real duplicate
address registration from a double registration or a movement. An ND address registration 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 and if they relate to a same target then represent different nodes and if they relate to a same target then
they reflect an address duplication. The Owner Unique ID can be as they reflect an address duplication. The Owner Unique ID can be as
simple as a EUI-64 burn-in address, if duplicate EUI-64 addresses are simple as a EUI-64 burn-in address, if duplicate EUI-64 addresses are
avoided. avoided.
Alternatively, the unique ID can be a cryptographic string that can Alternatively, the unique ID can be a cryptographic string that can
can be used to prove the ownership of the registration as discussed can be used to prove the ownership of the registration as discussed
in Address Protected Neighbor Discovery for Low-power and Lossy in "Address Protected Neighbor Discovery for Low-power and Lossy
Networks [I-D.ietf-6lo-ap-nd]. Networks" [I-D.ietf-6lo-ap-nd].
In any fashion, it is recommended that the node stores the unique Id In any fashion, it is recommended that the node stores the unique Id
or the keys used to generate that ID in persistent memory. or the keys used to generate that ID in persistent memory.
Otherwise, it will be prevented to re-register after a reboot that Otherwise, it will be prevented to re-register after a reboot that
would cause a loss of memory until the Backbone Router times out the would cause a loss of memory until the Backbone Router times out the
registration. registration.
3.3. Extended Address Registration Option 5.3. Extended Address Registration Option
This specification extends the Address Registration Option (ARO) used This specification extends the ARO option that is used for the
for the process of address registration. The new ARO is referred to process of address registration. The new ARO is referred to as
as Extended ARO (EARO), and its semantics are modified as follows: Extended ARO (EARO), and its semantics are modified as follows:
The address that is being registered with a Neighbor Solicitation The address that is being registered with a Neighbor Solicitation
(NS) with an EARO is now the Target Address, as opposed to the Source (NS) with an EARO is now the Target Address, as opposed to the Source
Address as specified in [RFC6775]. This change enables a 6LBR to use Address as specified in RFC 6775 [RFC6775]. This change enables a
an address of his as source to the proxy-registration of an address 6LBR to use an address of his as source to the proxy-registration of
that belongs to a LLN Node to a 6BBR. This also limits the use of an an address that belongs to a LLN Node to a 6BBR. This also limits
address as source address before it is registered and the associated the use of an address as source address before it is registered and
Duplicate Address Detection (DAD) is complete. the associated Duplicate Address Detection (DAD) is complete.
The Unique ID in the EARO option does no more have to be a MAC The Unique ID in the EARO option does no more have to be a MAC
address. A new TLV format is introduced and a IANA registry is address. A new TLV format is introduced and a IANA registry is
created for the type (TBD). This enables in particular the use of a created for the type (TBD). This enables in particular the use of a
Provable Temporary UID (PT-UID) as opposed to burn-in MAC address, Provable Temporary UID (PT-UID) as opposed to burn-in MAC address,
the PT-UID providing a trusted anchor by the 6LR and 6LBR to protect the PT-UID providing a trusted anchor by the 6LR and 6LBR to protect
the state associated to the node. the state associated to the node.
The specification introduces a Transaction ID (TID) field in the The specification introduces a Transaction ID (TID) field in the
EARO. The TID MUST be provided by a node that supports this EARO. The TID MUST be provided by a node that supports this
specification and a new T flag MUST be set to indicate so. The T bit specification and a new T flag MUST be set to indicate so. The T bit
can be used to determine whether the peer supports this can be used to determine whether the peer supports this
specification. specification.
3.4. Registering the Target Address 5.4. Registering the Target Address
One of the requirements that this specification serves is the This specification changes the behaviour of the 6LN and the 6LR so
capability by a router such as a RPL root to proxy-register an that the Registered Address is found in the Target Address field of
address to a 6BBR on behalf of a 6LN, as discussed in Appendix A.4. the NS and NA messages as opposed to the Source Address.
In order to serve that requirement, this specification changes the
behaviour 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
opposed to the Source Address.
With this convention, a TLLA option would indicate the link-layer The reason for this change is to enable proxy-registrations on behalf
address of the 6LN that owns the address, whereas the SLLA Option in of other nodes in Route-Over meshes, for instance to enable that a
a NS message indicates that of the Registering Node, which can be the RPL root registers addresses on behalf LLN nodes that are deeper in a
6TiSCH mesh, 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 get the packets and route them
down the mesh. But the Registered Address belongs to another node,
the Registered Node, and 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. owner device, or a proxy.
Since the Registering Node is the one that has reachability with the Since the Registering Node is the one that has reachability with the
6LR, and is the one expecting packets for the 6LN, it makes sense to 6LR, and is the one expecting packets for the 6LN, it makes sense to
maintain compatibility with [RFC6775], and it is REQUIRED that an maintain compatibility with RFC 6775 [RFC6775], and it is REQUIRED
SLLA Option is always placed in a registration NS(EARO) message. that an SLLA Option is always placed in a registration NS(EARO)
message.
3.5. Link-local Addresses and Registration 5.5. Link-local Addresses and Registration
Considering that LLN nodes are often not wired and may move, there is Considering that LLN nodes are often not wired and may move, there is
no guarantee that a link-local address stays unique between a no guarantee that a link-local address stays unique between a
potentially variable and unbounded set of neighboring nodes. potentially variable and unbounded set of neighboring nodes.
Compared to [RFC6775], this specification only requires that a link- Compared to RFC 6775 [RFC6775], this specification only requires that
local address is unique from the perspective of the peering nodes. a link-local address is unique from the perspective of the peering
This simplifies the Duplicate Address Detection (DAD) for link-local nodes. This simplifies the Duplicate Address Detection (DAD) for
addresses, and there is no DAR/DAC exchange between the 6LR and a link-local addresses, and there is no DAR/DAC exchange between the
6LBR for link-local addresses. 6LR and a 6LBR for link-local addresses.
Additionally, [RFC6775] requires that a 6LoWPAN Node (6LN) uses an Additionally, RFC 6775 [RFC6775] requires that a 6LoWPAN Node (6LN)
address being registered as the source of the registration message. uses an address being registered as the source of the registration
This generates complexities in the 6LR to be able to cope with a message. This generates complexities in the 6LR to be able to cope
potential duplication, in particular for global addresses. To with a potential duplication, in particular for global addresses. To
simplify this, a 6LN and a 6LR that conform this specification always simplify this, a 6LN and a 6LR that conform this specification always
use link-local addresses as source and destination addresses for the use link-local addresses as source and destination addresses for the
registration NS/NA exchange. As a result, the registration is registration NS/NA exchange. As a result, the registration is
globally faster, and some of the complexity is removed. 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. If there address to register other addresses, e.g. global addresses.
is no collision with an address previously registered to this 6LR by
another 6LN, then, from the standpoint of this 6LR, this link-local If there is no collision with an address previously registered to
address is unique and the registration is acceptable. Conversely, it this 6LR by another 6LN, then, from the standpoint of this 6LR, this
may possibly happen that two different 6LRs expose a same link-local link-local address is unique and the registration is acceptable.
address but different link-layer addresses. In that case, a 6LN may Conversely, it may possibly happen that two different 6LRs expose a
only interact with one of the 6LR so as to avoid confusion in the 6LN same link-local address but different link-layer addresses. In that
neighbor cache. case, a 6LN may only interact with one of the 6LR so as to avoid
confusion in the 6LN neighbor cache.
The DAD process between the 6LR and a 6LoWPAN Border Router (6LBR), The DAD process between the 6LR and a 6LoWPAN Border Router (6LBR),
which is based on a Duplicate Address Request (DAR) / Duplicate which is based on a Duplicate Address Request (DAR) / Duplicate
Address Confirmation (DAC) exchange as described in [RFC6775], does Address Confirmation (DAC) exchange as described in RFC 6775
not need to take place for link-local addresses. [RFC6775], does not need to take place for link-local addresses.
It is desired that a 6LR does not need to modify its state associated It is desired that a 6LR does not need to modify its state associated
to the Source Address of an NS(EARO) message. For that reason, when to the Source Address of an NS(EARO) message. For that reason, when
possible, it is RECOMMENDED to use an address that is already possible, it is RECOMMENDED to use an address that is already
registered with a 6LR registered with a 6LR
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
skipping to change at page 7, line 46 skipping to change at page 9, line 32
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 burn-in MAC address. An EARO
option in the response NA indicates that the 6LR supports this option in the response NA indicates that the 6LR supports this
specification. specification.
Since there is no DAR/DAC exchange for link-local addresses, the 6LR Since there is no DAR/DAC exchange for link-local addresses, the 6LR
may answer immediately to the registration of a link-local address, may answer immediately to the registration of a link-local address,
based solely on its existing state and the Source Link-Layer Option based solely on its existing state and the Source Link-Layer Option
that MUST be placed in the NS(EARO) message as required in [RFC6775]. that MUST be placed in the NS(EARO) message as required in RFC 6775
[RFC6775].
A node needs to register its IPv6 Global Unicast IPv6 Addresses (GUA) A node needs to register its IPv6 Global Unicast IPv6 Addresses (GUA)
to a 6LR in order to obtain a global reachability for these addresses to a 6LR in order to obtain a global reachability for these addresses
via that 6LR. As opposed to a node that complies to [RFC6775], a via that 6LR. As opposed to a node that complies to RFC 6775
Registering Node registering a GUA does not use that GUA as Source [RFC6775], a Registering Node registering a GUA does not use that GUA
Address for the registration to a 6LR that conforms this as Source Address for the registration to a 6LR that conforms this
specification. The DAR/DAC exchange MUST take place for non-link- specification. The DAR/DAC exchange MUST take place for non-link-
local addresses as prescribed by [RFC6775]. local addresses as prescribed by RFC 6775 [RFC6775].
4. Applicability and Requirements Served 6. Updated ND Options
This specification extends 6LoWPAN ND to sequence the registration This specification does not introduce new options, but it modifies
and serves the requirements expressed Appendix A.1 by enabling the existing ones and updates the associated behaviours as follow:
mobility of devices from one LLN to the next based on the
complementary work in [I-D.ietf-6lo-backbone-router].
In the context of the the TimeSlotted Channel Hopping (TSCH) mode of 6.1. New 6LoWPAN capability Bits in the Capability Indication Option
[IEEEstd802154], the 6TiSCH architecture
[I-D.ietf-6tisch-architecture] introduces how a 6LoWPAN ND host could
connect to the Internet via a RPL mesh Network, but this requires
additions to the 6LOWPAN ND protocol to support mobility and
reachability in a secured and manageable environment. This
specification details the new operations that are required to
implement the 6TiSCH architecture and serves the requirements listed
in Appendix A.2.
The term LLN is used loosely in this specification to cover multiple This specification defines a number of capability bits in the CIO
types of WLANs and WPANs, including Low-Power Wi-Fi, BLUETOOTH(R) Low that was introduced by RFC 7400 [RFC7400].
Energy, IEEE std 802.11AH and IEEE std 802.15.4 wireless meshes, so
as to address the requirements discussed in Appendix A.3
This specification can be used by any wireless node to associate at Support for this specification is indicated by setting the "E" flag
Layer-3 with a 6BBR and register its IPv6 addresses to obtain routing in a CIO option. Routers that are capable of acting as 6LR, 6LBR and
services including proxy-ND operations over the backbone, effectively 6BBR SHOULD set the L, B andP flags, respectively.
providing a solution to the requirements expressed in Appendix A.4.
Efficiency aware IPv6 Neighbor Discovery Optimizations Those flags are not mutually exclusive and if a router is capable of
[I-D.chakrabarti-nordmark-6man-efficient-nd] suggests that 6LoWPAN ND multiple roles, it SHOULD set all the related flags.
[RFC6775] can be extended to other types of links beyond IEEE std
802.15.4 for which it was defined. The registration technique is
beneficial when the Link-Layer technique used to carry IPv6 multicast
packets is not sufficiently efficient in terms of delivery ratio or
energy consumption in the end devices, in particular to enable
energy-constrained sleeping nodes. The value of such extension is
especially apparent in the case of mobile wireless nodes, to reduce
the multicast operations that are related to classical ND ([RFC4861],
[RFC4862]) and plague the wireless medium. This serves scalability
requirements listed in Appendix A.6.
5. The Enhanced Address Registration Option (EARO) 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length = 1 |_____________________|L|B|P|E|G|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|_______________________________________________________________|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
With the ARO option defined in 6LoWPAN ND [RFC6775], the address Figure 1: New capability Bits L, B, P, E in the CIO
being registered and its owner can be uniquely identified and matched
with the Binding Table entries of each Backbone Router. Option Fields
Type: 36
L: Node is a 6LR, it can take registrations.
B: Node is a 6LBR.
P: Node is a 6BBR, proxying for nodes on this link.
E: This specification is supported and applied.
6.2. The Enhanced Address Registration Option (EARO)
The Enhanced Address Registration Option (EARO) is intended to be The Enhanced Address Registration Option (EARO) is intended to be
used as a replacement to the ARO option within Neighbor Discovery NS used as a replacement to the ARO option within Neighbor Discovery NS
and NA messages between a LLN node and its 6LoWPAN Router (6LR), as and NA messages between a LLN node and its 6LoWPAN Router (6LR), as
well as in Duplicate Address Request (DAR) and the Duplicate Address well as in Duplicate Address Request (DAR) and the Duplicate Address
Confirmation (DAC) messages between 6LRs and 6LBRs in LLNs meshes Confirmation (DAC) messages between 6LRs and 6LBRs in LLNs meshes
such as 6TiSCH networks. such as 6TiSCH 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 AERO option also used in NS and NA also carries an SLLAO option. The AERO 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, and in that case, it does not the distributed registration state, and in that case, it does not
carry the SLLAO option and is not confused with a registration. carry the SLLAO option and is not confused with a registration.
The EARO extends the ARO and is recognized by the setting of the TID The EARO extends the ARO and is recognized by the "T" flag set.
bit. 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
harmless since the TID bit and fields are reserved in [RFC6775] are
ignored by a legacy router. A router that supports this
specification answers to an ARO with an ARO and to an EARO with an
EARO.
This specification changes the behavior of the peers in a
registration flows. To enable backward compatibility, a node that
registers to a router that is not known to support this specification
MUST behave as prescribed by [RFC6775]. Once the router is known to
support this specification, the node MUST obey this specification.
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. This differs
from 6LoWPAN ND [RFC6775] which specifies that the address being from 6LoWPAN ND RFC 6775 [RFC6775] which specifies that the address
registered is the source of the NS. being registered is the source of the NS.
The reason for this change is to enable proxy-registrations on behalf
of other nodes in Route-Over meshes, for instance to enable that a
RPL root registers addresses on behalf LLN nodes that are deeper in a
6TiSCH mesh. 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
get the packets and route them down the mesh. But the Registered
Address belongs to another node, the Registered Node, and that
address is indicated in the Target Address field of the NS message.
One way of achieving all the above is for a node to first register an
address that it owns in order to validate that the router supports
this specification, placing the same address in the Source and Target
Address fields of the NS message. The node may for instance register
an address that is based on EUI-64. For such address, DAD is not
required and using the SLLAO option in the NS is actually more
amenable with older ND specifications such as ODAD [RFC4429].
Once that first registration is complete, the node knows from the
setting of the TID in the response whether the router supports this
specification. If this is verified, the node may register other
addresses that it owns, or proxy-register addresses on behalf some
another node, indicating those addresses being registered in the
Target Address field of the NS messages, while using one of its own,
already registered, addresses as source.
The format of the EARO option is as follows: The 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
+ Owner Unique ID (EUI-64 or equivalent) + + Owner Unique ID (EUI-64 or equivalent) +
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: EARO Figure 2: EARO
Option Fields Option Fields
Type: Type: 33
Length: 2 Length: 8-bit unsigned integer.
Status: Status: 8-bit unsigned integer. Indicates the status of a
registration in the NA response. MUST be set to 0 in NS messages.
See Table 1 below.
Reserved: This field is unused. It MUST be initialized to zero by
the sender and MUST be ignored by the receiver.
T: One bit flag. Set if the next octet is a used as a TID.
TID: 1-byte integer; a transaction id that is maintained by the node
and incremented with each transaction. it is recommended that the
node maintains the TID in a persistent storage.
Registration Lifetime: 16-bit integer; expressed in minutes. 0
means that the registration has ended and the state should be
removed.
Owner Unique Identifier (OUI): A globally unique identifier for the
node associated. This can be the EUI-64 derived IID of an
interface, or some provable ID obtained cryptographically.
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
| Value | Description | | Value | Description |
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
| 0..2 | See [RFC6775]. Note that a Status of 1 "Duplicate | | 0..2 | See RFC 6775 [RFC6775]. Note that a Status of 1 |
| | Address" applies to the Registered Address. If the Source | | | "Duplicate Address" applies to the Registered Address. If |
| | Address conflicts with an existing registration, | | | the Source Address conflicts with an existing |
| | "Duplicate Source Address" should be used instead | | | registration, "Duplicate Source Address" should be used |
| | instead |
| | | | | |
| 3 | Moved: The registration fails because it is not the | | 3 | Moved: The registration fails because it is not the |
| | freshest | | | freshest. This status indicates that the registration is |
| | rejected because another more recent registration was |
| | done, as indicated by a same OUI and a more recent TID. |
| | One possible cause is a stale registration that has |
| | progressed slowly in the network and was passed by a more |
| | 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 |
| | placed in an asynchronous NS(ARO) message, or as the | | | placed in an asynchronous NS(ARO) message, or as the |
| | rejection of a proxy registration to a Backbone Router | | | rejection of a proxy registration to a Backbone Router |
| | | | | |
| 5 | Proof requested: The registering node is challenged for | | 5 | Proof requested: The registering node is challenged for |
| | owning the registered address or for being an acceptable | | | owning the registered address or for being an acceptable |
| | proxy for the registration | | | proxy for the registration. This status is expected in |
| | asynchronous messages from a registrar (6LR, 6LBR, 6BBR) |
| | to indicate that the registration state is removed, for |
| | instance due to time out of a lifetime, or a movement. It |
| | is used for instance by a 6BBR in a NA(ARO) message to |
| | indicate that the ownership of the proxy state on the |
| | backbone was transfered to another 6BBR, which is |
| | indicative of a movement of the device. The receiver of |
| | the NA is the device that has performed a registration |
| | that is now stale and it should clean up its state. |
| | | | | |
| 6 | Duplicate Source Address: The address used as source of | | 6 | Duplicate Source Address: The address used as source of |
| | the NS(ARO) conflicts with an existing registration. | | | the NS(ARO) conflicts with an existing registration. |
| | | | | |
| 7 | Administrative Rejection: The address being registered is | | 7 | Invalid Source Address: The address used as source of the |
| | reserved for another use by an administrative decision | | | NS(ARO) is not usable on this link, e.g. it is not |
| | (e.g. placed in a DHCPv6 pool); The Registering Node is | | | topologically correct |
| | requested to form a different address and retry |
| | | | | |
| 8 | Invalid Registered Address: The address being registered | | 8 | Invalid Registered Address: The address being registered |
| | is not usable on this link, e.g. it is not topologically | | | is not usable on this link, e.g. it is not topologically |
| | correct | | | correct |
| | |
| 9 | Invalid Source Address: The address used as source of the |
| | NS(ARO) is not usable on this link, e.g. it is not |
| | topologically correct |
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
Table 1 Table 1: EARO Status
Reserved: This field is unused. It MUST be initialized to zero by 7. Backward Compatibility
the sender and MUST be ignored by the receiver.
T: One bit flag. Set if the next octet is a used as a TID. 7.1. Discovering the capabilities of an ND peer
TID: 1-byte integer; a transaction id that is maintained by the node 7.1.1. Using the E Flag in the CIO
and incremented with each transaction. it is recommended that the
node maintains the TID in a persistent storage.
Registration Lifetime: 16-bit integer; expressed in minutes. 0 If the CIO is used in an ND message, then the "E" Flag MUST be set by
means that the registration has ended and the state should be the sending node if supports this specification.
removed.
Owner Unique Identifier (OUI): A globally unique identifier for the It is RECOMMENDED that a router that supports this specification
node associated. This can be the EUI-64 derived IID of an indicates so with a CIO option, but this might not be practical if
interface, or some provable ID obtained cryptographically. the link-layer MTU is too small.
New status values are introduced, their values to be confirmed by If the registering node receives a CIO in a RA, then the setting of
IANA: the E" Flag indicates whether or not this specification is supported.
Moved: This status indicates that the registration is rejected 7.1.2. Using the T Flag in the EARO
because another more recent registration was done, as indicated by
a same OUI and a more recent TID. One possible cause is a stale
registration that has progressed slowly in the network and was
passed by a more recent one. It could also indicate a OUI
collision.
Removed: This status is expected in asynchronous messages from a One alternate way for a 6LN to discover the router's capabilities to
registrar (6LR, 6LBR, 6BBR) to indicate that the registration first register a Link Local address, placing the same address in the
state is removed, for instance due to time out of a lifetime, or a Source and Target Address fields of the NS message, and setting the
movement. It is used for instance by a 6BBR in a NA(ARO) message "T" Flag. The node may for instance register an address that is
to indicate that the ownership of the proxy state on the backbone based on EUI-64. For such address, DAD is not required and using the
was transfered to another 6BBR, which is indicative of a movement SLLAO option in the NS is actually more amenable with existing ND
of the device. The receiver of the NA is the device that has specifications such as the "Optimistic Duplicate Address Detection
performed a registration that is now stale and it should clean up (DAD) for IPv6" [RFC4429]. Once that first registration is complete,
its state. the node knows from the setting of the "T" Flag in the response
whether the router supports this specification. If this is verified,
the node may register other addresses that it owns, or proxy-register
addresses on behalf some another node, indicating those addresses
being registered in the Target Address field of the NS messages,
while using one of its own, already registered, addresses as source.
6. Backward Compatibility 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
harmless since the "T" flag and TID field are reserved in RFC 6775
[RFC6775] are ignored by a legacy router. A router that supports
this specification answers to an ARO with an ARO and to an EARO with
an EARO.
6.1. Legacy 6LoWPAN Node This specification changes the behavior of the peers in a
registration flows. To enable backward compatibility, a node that
registers to a router that is not known to support this specification
MUST behave as prescribed by RFC 6775 [RFC6775]. Once the router is
known to support this specification, the node MUST obey this
specification.
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. In order to be backward compatible, an updated use an EARO option. In order to be backward compatible, an updated
6LR needs to accept that registration if it is valid per [RFC3972], 6LR needs to accept that registration if it is valid per the
and manage the binding cache accordingly. "Cryptographically Generated Addresses (CGA)" [RFC3972]
specification, and manage the binding cache accordingly.
The main difference with [RFC3972] is that DAR/DAC exchange for DAD The main difference with RFC 3972 [RFC3972] is that DAR/DAC exchange
may be avoided for link-local addresses. Additionally, the 6LR for DAD may be avoided for link-local addresses. Additionally, the
SHOULD use an EARO in the reply, and may use all the status codes 6LR SHOULD use an EARO in the reply, and may use any of the status
defined in this specification. codes defined in this specification.
6.2. Legacy 6LoWPAN Router 7.3. Legacy 6LoWPAN Router
The first registration by a an updated 6LN is for a link-local The first registration by a an updated 6LN is for a link-local
address, using that link-local address as source. A legacy 6LN will address, using that link-local address as source. A legacy 6LN will
not makes a difference and accept -or reject- that registration as if not makes a difference and accept -or reject- that registration as if
the 6LN was a legacy node. the 6LN was a 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 6LN will always areply with an ARO option message, whereas a legacy 6LN will always areply with an ARO option
in the NA message. So from that first registration, the updated 6LN in the NA message. So from that first registration, the updated 6LN
can figure whether the 6LR supports this specification or not. can figure whether the 6LR supports this specification or not.
When facing a legacy 6LR, an updated 6LN may attempt to find an When facing 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. In order to be backward compatible,
based on the discovery that a 6LR is legacy, the 6LN needs to based on the discovery that a 6LR is legacy, the 6LN needs to
fallback to legacy behaviour and source the packet with the fallback to legacy behaviour and source the packet with the
registrered address. registrered address.
The main difference is that the updated 6LN SHOULD use an EARO in the The main difference is that the updated 6LN SHOULD use an EARO in the
request regardless of the type of 6LN, legacy or updated request regardless of the type of 6LN, legacy or updated
6.3. Legacy 6LoWPAN Border Router 7.4. Legacy 6LoWPAN Border Router
With this specification, the DAR/DAC transports an EARO option as With this specification, the DAR/DAC transports an EARO option as
opposed to an ARO option. As described for the NS/NA exchange, opposed to an ARO option. As described for the NS/NA exchange,
devices that support this specification always use an EARO option and devices that support this specification always use an EARO option and
all the associated behaviour. all the associated behaviour.
7. Security Considerations 8. Security Considerations
This specification expects that the link layer is sufficiently This specification expects that the link layer is sufficiently
protected, either by means of physical or IP security for the protected, either by means of physical or IP security for the
Backbone Link or MAC sublayer cryptography. In particular, it is Backbone Link or MAC sublayer cryptography. In particular, it is
expected that the LLN MAC provides secure unicast to/from the expected that the LLN MAC provides secure unicast to/from the
Backbone Router and secure Broadcast from the Backbone Router in a Backbone Router and secure Broadcast from the Backbone Router in a
way that prevents tempering with or replaying the RA messages. way that prevents tempering with or replaying the RA messages.
The use of EUI-64 for forming the Interface ID in the link-local The use of EUI-64 for forming the Interface ID in the link-local
address prevents the usage of Secure ND ([RFC3971] and [RFC3972]) and address prevents the usage of "SEcure Neighbor Discovery (SEND)"
address privacy techniques. This specification RECOMMENDS the use of [RFC3971] and CGA [RFC3972], and that of address privacy techniques.
additional protection against address theft such as provided by This specification RECOMMENDS the use of additional protection
[I-D.ietf-6lo-ap-nd], which guarantees the ownership of the OUID. against address theft such as provided by "Address Protected Neighbor
Discovery for Low-power and Lossy Networks" [I-D.ietf-6lo-ap-nd],
which guarantees the ownership of the OUID.
When the ownership of the OUID cannot be assessed, this specification When the ownership of the OUID cannot be assessed, this specification
limits the cases where the OUID and the TID are multicasted, and limits the cases where the OUID and the TID are multicasted, and
obfuscates them in responses to attempts to take over an address. obfuscates them in responses to attempts to take over an address.
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.
8. IANA Considerations 9. IANA Considerations
This document requires the following additions: IANA is requested to create a new subregistry for "ARO Flags" under
the "Internet Control Message Protocol version 6 (ICMPv6)
Parameters". This specification defines 8 positions, bit 0 to bit 7,
and assigns bit 7 for the "T" flag in Section 6.2. The policy is
"IETF Review" or "IESG Approval" [RFC5226]. The initial content of
the registry is as shown in Table 2.
New subregistry for ARO Flags under the "Internet Control Message
Protocol version 6 (ICMPv6) Parameters"
+------------+--------------+-----------+
| ARO Status | Description | Document |
+------------+--------------+-----------+
| 0..6 | Unassigned | |
| | | |
| 7 | "T" Flag | RFC This |
+------------+--------------+-----------+
Table 2: new ARO Flags
IANA is requested to make additions to existing registries as
follows:
Address Registration Option Status Values Registry Address Registration Option Status Values Registry
+--------+--------------------------+ +------------+----------------------------+-----------+
| Status | Description | | ARO Status | Description | Document |
+--------+--------------------------+ +------------+----------------------------+-----------+
| 3 | Moved | | 3 | Moved | RFC This |
| | | | | | |
| 4 | Removed | | 4 | Removed | RFC This |
| | | | | | |
| 5 | Proof requested | | 5 | Proof requested | RFC This |
| | | | | | |
| 6 | Invalid Source Address | | 6 | Duplicate Source Address | RFC This |
| | | | | | |
| 7 | Administrative Rejection | | 7 | Invalid Source Address | RFC This |
+--------+--------------------------+ | | | |
| 8 | Invalid Registered Address | RFC This |
+------------+----------------------------+-----------+
IANA is required to change the registry accordingly Table 3: New ARO Status values
Table 2: New ARO Status values Subregistry for "6LoWPAN capability Bits" under the "Internet Control
Message Protocol version 6 (ICMPv6) Parameters"
9. Acknowledgments +----------------+----------------------+-----------+
| capability Bit | Description | Document |
+----------------+----------------------+-----------+
| 11 | 6LR capable (L bit) | RFC This |
| | | |
| 12 | 6LBR capable (B bit) | RFC This |
| | | |
| 13 | 6BBR capable (P bit) | RFC This |
| | | |
| 14 | EARO support (E bit) | RFC This |
+----------------+----------------------+-----------+
Table 4: New 6LoWPAN capability Bits
10. Acknowledgments
Kudos to Eric Levy-Abegnoli who designed the First Hop Security Kudos to Eric Levy-Abegnoli who designed the First Hop Security
infrastructure at Cisco. infrastructure at Cisco.
10. References 11. References
11.1. Normative References
10.1. Normative References [I-D.ietf-6lo-backbone-router]
Thubert, P., "IPv6 Backbone Router", draft-ietf-6lo-
backbone-router-03 (work in progress), January 2017.
[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,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, DOI 10.17487/RFC4291, February
2006, <http://www.rfc-editor.org/info/rfc4291>.
[RFC4429] Moore, N., "Optimistic Duplicate Address Detection (DAD) [RFC4429] Moore, N., "Optimistic Duplicate Address Detection (DAD)
for IPv6", RFC 4429, DOI 10.17487/RFC4429, April 2006, for IPv6", RFC 4429, DOI 10.17487/RFC4429, April 2006,
<http://www.rfc-editor.org/info/rfc4429>. <http://www.rfc-editor.org/info/rfc4429>.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007, DOI 10.17487/RFC4861, September 2007,
<http://www.rfc-editor.org/info/rfc4861>. <http://www.rfc-editor.org/info/rfc4861>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007, DOI 10.17487/RFC4862, September 2007,
<http://www.rfc-editor.org/info/rfc4862>. <http://www.rfc-editor.org/info/rfc4862>.
[RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in
IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007,
<http://www.rfc-editor.org/info/rfc4941>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.
[RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6
Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
DOI 10.17487/RFC6282, September 2011,
<http://www.rfc-editor.org/info/rfc6282>.
[RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J., [RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J.,
Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur, Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur,
JP., and R. Alexander, "RPL: IPv6 Routing Protocol for JP., and R. Alexander, "RPL: IPv6 Routing Protocol for
Low-Power and Lossy Networks", RFC 6550, Low-Power and Lossy Networks", RFC 6550,
DOI 10.17487/RFC6550, March 2012, DOI 10.17487/RFC6550, March 2012,
<http://www.rfc-editor.org/info/rfc6550>. <http://www.rfc-editor.org/info/rfc6550>.
[RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
Bormann, "Neighbor Discovery Optimization for IPv6 over Bormann, "Neighbor Discovery Optimization for IPv6 over
Low-Power Wireless Personal Area Networks (6LoWPANs)", Low-Power Wireless Personal Area Networks (6LoWPANs)",
RFC 6775, DOI 10.17487/RFC6775, November 2012, RFC 6775, DOI 10.17487/RFC6775, November 2012,
<http://www.rfc-editor.org/info/rfc6775>. <http://www.rfc-editor.org/info/rfc6775>.
10.2. Informative References [RFC7400] Bormann, C., "6LoWPAN-GHC: Generic Header Compression for
IPv6 over Low-Power Wireless Personal Area Networks
(6LoWPANs)", RFC 7400, DOI 10.17487/RFC7400, November
2014, <http://www.rfc-editor.org/info/rfc7400>.
[RFC7934] Colitti, L., Cerf, V., Cheshire, S., and D. Schinazi,
"Host Address Availability Recommendations", BCP 204,
RFC 7934, DOI 10.17487/RFC7934, July 2016,
<http://www.rfc-editor.org/info/rfc7934>.
11.2. Informative References
[I-D.chakrabarti-nordmark-6man-efficient-nd] [I-D.chakrabarti-nordmark-6man-efficient-nd]
Chakrabarti, S., Nordmark, E., Thubert, P., and M. Chakrabarti, S., Nordmark, E., Thubert, P., and M.
Wasserman, "IPv6 Neighbor Discovery Optimizations for Wasserman, "IPv6 Neighbor Discovery Optimizations for
Wired and Wireless Networks", draft-chakrabarti-nordmark- Wired and Wireless Networks", draft-chakrabarti-nordmark-
6man-efficient-nd-07 (work in progress), February 2015. 6man-efficient-nd-07 (work in progress), February 2015.
[I-D.delcarpio-6lo-wlanah] [I-D.delcarpio-6lo-wlanah]
Vega, L., Robles, I., and R. Morabito, "IPv6 over Vega, L., Robles, I., and R. Morabito, "IPv6 over
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-6lobac] [I-D.ietf-6lo-6lobac]
Lynn, K., Martocci, J., Neilson, C., and S. Donaldson, Lynn, K., Martocci, J., Neilson, C., and S. Donaldson,
"Transmission of IPv6 over MS/TP Networks", draft-ietf- "Transmission of IPv6 over MS/TP Networks", draft-ietf-
6lo-6lobac-06 (work in progress), October 2016. 6lo-6lobac-08 (work in progress), March 2017.
[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-00 (work in progress), Networks", draft-ietf-6lo-ap-nd-00 (work in progress),
November 2016. November 2016.
[I-D.ietf-6lo-backbone-router]
Thubert, P., "IPv6 Backbone Router", draft-ietf-6lo-
backbone-router-02 (work in progress), September 2016.
[I-D.ietf-6lo-dect-ule] [I-D.ietf-6lo-dect-ule]
Mariager, P., Petersen, J., Shelby, Z., Logt, M., and D. Mariager, P., Petersen, J., Shelby, Z., Logt, M., and D.
Barthel, "Transmission of IPv6 Packets over DECT Ultra Low Barthel, "Transmission of IPv6 Packets over DECT Ultra Low
Energy", draft-ietf-6lo-dect-ule-09 (work in progress), Energy", draft-ietf-6lo-dect-ule-09 (work in progress),
December 2016. December 2016.
[I-D.ietf-6lo-nfc] [I-D.ietf-6lo-nfc]
Choi, Y., Youn, J., and Y. Hong, "Transmission of IPv6 Choi, Y., Hong, Y., Youn, J., Kim, D., and J. Choi,
Packets over Near Field Communication", draft-ietf-6lo- "Transmission of IPv6 Packets over Near Field
nfc-05 (work in progress), October 2016. Communication", draft-ietf-6lo-nfc-06 (work in progress),
March 2017.
[I-D.ietf-6tisch-architecture] [I-D.ietf-6tisch-architecture]
Thubert, P., "An Architecture for IPv6 over the TSCH mode Thubert, P., "An Architecture for IPv6 over the TSCH mode
of IEEE 802.15.4", draft-ietf-6tisch-architecture-10 (work of IEEE 802.15.4", draft-ietf-6tisch-architecture-11 (work
in progress), June 2016. in progress), January 2017.
[I-D.ietf-6tisch-terminology] [I-D.ietf-6tisch-terminology]
Palattella, M., Thubert, P., Watteyne, T., and Q. Wang, Palattella, M., Thubert, P., Watteyne, T., and Q. Wang,
"Terminology in IPv6 over the TSCH mode of IEEE "Terminology in IPv6 over the TSCH mode of IEEE
802.15.4e", draft-ietf-6tisch-terminology-08 (work in 802.15.4e", draft-ietf-6tisch-terminology-08 (work in
progress), December 2016. progress), December 2016.
[I-D.ietf-bier-architecture] [I-D.ietf-bier-architecture]
Wijnands, I., Rosen, E., Dolganow, A., Przygienda, T., and Wijnands, I., Rosen, E., Dolganow, A., Przygienda, T., and
S. Aldrin, "Multicast using Bit Index Explicit S. Aldrin, "Multicast using Bit Index Explicit
skipping to change at page 17, line 20 skipping to change at page 20, line 20
[RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)", [RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)",
RFC 3972, DOI 10.17487/RFC3972, March 2005, RFC 3972, DOI 10.17487/RFC3972, March 2005,
<http://www.rfc-editor.org/info/rfc3972>. <http://www.rfc-editor.org/info/rfc3972>.
[RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6 [RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6
over Low-Power Wireless Personal Area Networks (6LoWPANs): over Low-Power Wireless Personal Area Networks (6LoWPANs):
Overview, Assumptions, Problem Statement, and Goals", Overview, Assumptions, Problem Statement, and Goals",
RFC 4919, DOI 10.17487/RFC4919, August 2007, RFC 4919, DOI 10.17487/RFC4919, August 2007,
<http://www.rfc-editor.org/info/rfc4919>. <http://www.rfc-editor.org/info/rfc4919>.
[RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6
Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
DOI 10.17487/RFC6282, September 2011,
<http://www.rfc-editor.org/info/rfc6282>.
[RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and [RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and
Lossy Networks", RFC 7102, DOI 10.17487/RFC7102, January Lossy Networks", RFC 7102, DOI 10.17487/RFC7102, January
2014, <http://www.rfc-editor.org/info/rfc7102>. 2014, <http://www.rfc-editor.org/info/rfc7102>.
[RFC7217] Gont, F., "A Method for Generating Semantically Opaque [RFC7217] Gont, F., "A Method for Generating Semantically Opaque
Interface Identifiers with IPv6 Stateless Address Interface Identifiers with IPv6 Stateless Address
Autoconfiguration (SLAAC)", RFC 7217, Autoconfiguration (SLAAC)", RFC 7217,
DOI 10.17487/RFC7217, April 2014, DOI 10.17487/RFC7217, April 2014,
<http://www.rfc-editor.org/info/rfc7217>. <http://www.rfc-editor.org/info/rfc7217>.
[RFC7428] Brandt, A. and J. Buron, "Transmission of IPv6 Packets [RFC7428] Brandt, A. and J. Buron, "Transmission of IPv6 Packets
over ITU-T G.9959 Networks", RFC 7428, over ITU-T G.9959 Networks", RFC 7428,
DOI 10.17487/RFC7428, February 2015, DOI 10.17487/RFC7428, February 2015,
<http://www.rfc-editor.org/info/rfc7428>. <http://www.rfc-editor.org/info/rfc7428>.
[RFC7668] Nieminen, J., Savolainen, T., Isomaki, M., Patil, B., [RFC7668] Nieminen, J., Savolainen, T., Isomaki, M., Patil, B.,
Shelby, Z., and C. Gomez, "IPv6 over BLUETOOTH(R) Low Shelby, Z., and C. Gomez, "IPv6 over BLUETOOTH(R) Low
Energy", RFC 7668, DOI 10.17487/RFC7668, October 2015, Energy", RFC 7668, DOI 10.17487/RFC7668, October 2015,
<http://www.rfc-editor.org/info/rfc7668>. <http://www.rfc-editor.org/info/rfc7668>.
10.3. External Informative References 11.3. External Informative References
[IEEEstd802154] [IEEEstd802154]
IEEE standard for Information Technology, "IEEE Standard IEEE, "IEEE Standard for Low-Rate Wireless Networks",
for Local and metropolitan area networks-- Part 15.4: Low- IEEE Standard 802.15.4,
Rate Wireless Personal Area Networks (LR-WPANs)". <http://ieeexplore.ieee.org/document/7460875/>.
Appendix A. Requirements Appendix A. Applicability and Requirements Served
This specification extends 6LoWPAN ND to sequence the registration
and serves the requirements expressed Appendix B.1 by enabling the
mobility of devices from one LLN to the next based on the
complementary work in the "IPv6 Backbone Router"
[I-D.ietf-6lo-backbone-router] specification.
In the context of the the TimeSlotted Channel Hopping (TSCH) mode of
IEEE Std. 802.15.4 [IEEEstd802154], the "6TiSCH architecture"
[I-D.ietf-6tisch-architecture] introduces how a 6LoWPAN ND host could
connect to the Internet via a RPL mesh Network, but this requires
additions to the 6LOWPAN ND protocol to support mobility and
reachability in a secured and manageable environment. This
specification details the new operations that are required to
implement the 6TiSCH architecture and serves the requirements listed
in Appendix B.2.
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
Energy, IEEE std 802.11AH and IEEE std 802.15.4 wireless meshes, so
as to address the requirements discussed in Appendix B.3
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
services including proxy-ND operations over the backbone, effectively
providing a solution to the requirements expressed in Appendix B.4.
"Efficiency aware IPv6 Neighbor Discovery Optimizations"
[I-D.chakrabarti-nordmark-6man-efficient-nd] suggests that 6LoWPAN ND
[RFC6775] can be extended to other types of links beyond IEEE Std.
802.15.4 for which it was defined. The registration technique is
beneficial when the Link-Layer technique used to carry IPv6 multicast
packets is not sufficiently efficient in terms of delivery ratio or
energy consumption in the end devices, in particular to enable
energy-constrained sleeping nodes. The value of such extension is
especially apparent in the case of mobile wireless nodes, to reduce
the multicast operations that are related to classical ND ([RFC4861],
[RFC4862]) and plague the wireless medium. This serves scalability
requirements listed in Appendix B.6.
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 A.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]. specification such as [I-D.ietf-6lo-ap-nd], and those related to
multicast.
A.1. Requirements Related to Mobility B.1. Requirements Related to Mobility
Due to the unstable nature of LLN links, even in a LLN of immobile Due to the unstable nature of LLN links, even in a LLN of immobile
nodes a 6LN may change its point of attachment to a 6LR, say 6LR-a, nodes a 6LN may change its point of attachment to a 6LR, say 6LR-a,
and may not be able to notify 6LR-a. Consequently, 6LR-a may still and may not be able to notify 6LR-a. Consequently, 6LR-a may still
attract traffic that it cannot deliver any more. When links to a 6LR attract traffic that it cannot deliver any more. When links to a 6LR
change state, there is thus a need to identify stale states in a 6LR change state, there is thus a need to identify stale states in a 6LR
and restore reachability in a timely fashion. and restore reachability in a timely fashion.
Req1.1: Upon a change of point of attachment, connectivity via a new Req1.1: Upon a change of point of attachment, connectivity via a new
6LR MUST be restored timely without the need to de-register from the 6LR MUST be restored timely without the need to de-register from the
skipping to change at page 18, line 34 skipping to change at page 22, line 27
Req1.2: For that purpose, the protocol MUST enable to differentiate Req1.2: For that purpose, the protocol MUST enable to differentiate
between multiple registrations from one 6LoWPAN Node and between multiple registrations from one 6LoWPAN Node and
registrations from different 6LoWPAN Nodes claiming the same address. registrations from different 6LoWPAN Nodes claiming the same address.
Req1.3: Stale states MUST be cleaned up in 6LRs. Req1.3: Stale states MUST be cleaned up in 6LRs.
Req1.4: A 6LoWPAN Node SHOULD also be capable to register its Address Req1.4: A 6LoWPAN Node SHOULD also be capable to register its Address
to multiple 6LRs, and this, concurrently. to multiple 6LRs, and this, concurrently.
A.2. Requirements Related to Routing Protocols B.2. Requirements Related to Routing Protocols
The point of attachment of a 6LN may be a 6LR in an LLN mesh. IPv6 The point of attachment of a 6LN may be a 6LR in an LLN mesh. IPv6
routing in a LLN can be based on RPL, which is the routing protocol routing in a LLN can be based on RPL, which is the routing protocol
that was defined at the IETF for this particular purpose. Other that was defined at the IETF for this particular purpose. Other
routing protocols than RPL are also considered by Standard Defining routing protocols than RPL are also considered by Standard Defining
Organizations (SDO) on the basis of the expected network Organizations (SDO) on the basis of the expected network
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.
skipping to change at page 19, line 33 skipping to change at page 23, line 24
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
burden of supporting the Multicast Listener Discovery Version 2 burden of supporting the Multicast Listener Discovery Version 2
[RFC3810] (MLDv2) for IPv6. [RFC3810] (MLDv2) for IPv6.
A.3. Requirements Related to the Variety of Low-Power Link types B.3. Requirements Related to the Variety of Low-Power Link types
6LoWPAN ND [RFC6775] was defined with a focus on IEEE std 802.15.4 6LoWPAN ND [RFC6775] was defined with a focus on IEEE std 802.15.4
and in particular the capability to derive a unique Identifier from a and in particular the capability to derive a unique Identifier from a
globally unique MAC-64 address. At this point, the 6lo Working Group globally unique MAC-64 address. At this point, the 6lo Working Group
is extending the 6LoWPAN Header Compression (HC) [RFC6282] technique is extending the 6LoWPAN Header Compression (HC) [RFC6282] technique
to other link types ITU-T G.9959 [RFC7428], Master-Slave/Token- to other link types ITU-T G.9959 [RFC7428], Master-Slave/Token-
Passing [I-D.ietf-6lo-6lobac], DECT Ultra Low Energy Passing [I-D.ietf-6lo-6lobac], DECT Ultra Low Energy
[I-D.ietf-6lo-dect-ule], Near Field Communication [I-D.ietf-6lo-nfc], [I-D.ietf-6lo-dect-ule], Near Field Communication [I-D.ietf-6lo-nfc],
IEEE std 802.11ah [I-D.delcarpio-6lo-wlanah], as well as IEEE1901.2 IEEE std 802.11ah [I-D.delcarpio-6lo-wlanah], as well as IEEE1901.2
Narrowband Powerline Communication Networks Narrowband Powerline Communication Networks
skipping to change at page 20, line 17 skipping to change at page 24, line 9
Local Address that SHOULD be unique at least within the LLN connected Local Address that SHOULD be unique at least within the LLN connected
to a 6LBR discovered by ND in each node within the LLN. to a 6LBR discovered by ND in each node within the LLN.
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].
A.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 classical ND on a backbone and may need a
proxy. Additionally, the duty-cycled device may need to rely on the proxy. Additionally, the duty-cycled device may need to rely on the
6LBR to perform registration to the 6BBR. 6LBR to 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.
skipping to change at page 20, line 41 skipping to change at page 24, line 33
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.
Req4.2: The registration mechanism SHOULD be applicable to a duty- Req4.2: The registration mechanism SHOULD be applicable to a duty-
cycled device regardless of the link type, and enable a 6BBR to cycled device regardless of the link type, and enable a 6BBR to
operate as a proxy to defend the registered Addresses on its behalf. operate as a proxy to defend the registered Addresses on its behalf.
Req4.3: The registration mechanism SHOULD enable long sleep Req4.3: The registration mechanism SHOULD enable long sleep
durations, in the order of multiple days to a month. durations, in the order of multiple days to a month.
A.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.
skipping to change at page 22, line 7 skipping to change at page 25, line 48
Req5.8: Routing of packets should continue when links pass from the Req5.8: Routing of packets should continue when links pass from the
unsecured to the secured state. unsecured to the secured state.
Req5.9: 6LoWPAN ND security mechanisms SHOULD provide a mechanism for Req5.9: 6LoWPAN ND security mechanisms SHOULD provide a mechanism for
the 6LR and the 6LBR to validate whether a new registration for a the 6LR and the 6LBR to validate whether a new registration for a
given address corresponds to the same 6LoWPAN Node that registered it given address corresponds to the same 6LoWPAN Node that registered it
initially, and, if not, determine the rightful owner, and deny or initially, and, if not, determine the rightful owner, and deny or
clean-up the registration that is duplicate. clean-up the registration that is duplicate.
A.6. Requirements Related to Scalability B.6. Requirements Related to Scalability
Use cases from Automatic Meter Reading (AMR, collection tree Use cases from Automatic Meter Reading (AMR, collection tree
operations) and Advanced Metering Infrastructure (AMI, bi-directional operations) and Advanced Metering Infrastructure (AMI, bi-directional
communication to the meters) indicate the needs for a large number of communication to the meters) indicate the needs for a large number of
LLN nodes pertaining to a single RPL DODAG (e.g. 5000) and connected LLN nodes pertaining to a single RPL DODAG (e.g. 5000) and connected
to the 6LBR over a large number of LLN hops (e.g. 15). to the 6LBR over a large number of LLN hops (e.g. 15).
Related requirements are: Related requirements are:
Req6.1: The registration mechanism SHOULD enable a single 6LBR to Req6.1: The registration mechanism SHOULD enable a single 6LBR to
register multiple thousands of devices. register multiple thousands of devices.
Req6.2: The timing of the registration operation should allow for a Req6.2: The timing of the registration operation should allow for a
large latency such as found in LLNs with ten and more hops. large latency such as found in LLNs with ten and more hops.
Authors' Addresses Authors' Addresses
Pascal Thubert (editor) Pascal Thubert (editor)
Cisco Systems, Inc Cisco Systems, Inc
Building D Sophia Antipolis
45 Allee des Ormes - BP1200
MOUGINS - Sophia Antipolis 06254
FRANCE FRANCE
Phone: +33 497 23 26 34
Email: pthubert@cisco.com Email: pthubert@cisco.com
Erik Nordmark Erik Nordmark
Arista Networks
Santa Clara, CA Santa Clara, CA
USA USA
Email: nordmark@arista.com 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
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