draft-ietf-6lo-rfc6775-update-06.txt   draft-ietf-6lo-rfc6775-update-07.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: December 23, 2017 S. Chakrabarti Expires: January 29, 2018 S. Chakrabarti
June 21, 2017 July 28, 2017
An Update to 6LoWPAN ND An Update to 6LoWPAN ND
draft-ietf-6lo-rfc6775-update-06 draft-ietf-6lo-rfc6775-update-07
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 http://datatracker.ietf.org/drafts/current/. Drafts is at http://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 December 23, 2017. This Internet-Draft will expire on January 29, 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
(http://trustee.ietf.org/license-info) in effect on the date of (http://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 . . . . . . . . . . . . . . . . . . . . . . 5 4. Updating RFC 6775 . . . . . . . . . . . . . . . . . . . . . . 5
4.1. Extended Address Registration Option . . . . . . . . . . 6 4.1. Extended Address Registration Option . . . . . . . . . . 6
4.2. Transaction ID . . . . . . . . . . . . . . . . . . . . . 6 4.2. Transaction ID . . . . . . . . . . . . . . . . . . . . . 6
4.3. Owner Unique ID . . . . . . . . . . . . . . . . . . . . . 7 4.2.1. Comparing TID values . . . . . . . . . . . . . . . . 7
4.4. Registering the Target Address . . . . . . . . . . . . . 7 4.3. Owner Unique ID . . . . . . . . . . . . . . . . . . . . . 8
4.5. Link-Local Addresses and Registration . . . . . . . . . . 8 4.4. Registering the Target Address . . . . . . . . . . . . . 9
4.6. Maintaining the Registration States . . . . . . . . . . . 9 4.5. Link-Local Addresses and Registration . . . . . . . . . . 9
5. Detecting Enhanced ARO Capability Support . . . . . . . . . . 10 4.6. Maintaining the Registration States . . . . . . . . . . . 11
6. Updated ND Options . . . . . . . . . . . . . . . . . . . . . 11 5. Detecting Enhanced ARO Capability Support . . . . . . . . . . 12
6.1. The Enhanced Address Registration Option (EARO) . . . . . 11 6. Updated ND Options . . . . . . . . . . . . . . . . . . . . . 13
6.1. The Enhanced Address Registration Option (EARO) . . . . . 13
6.2. New 6LoWPAN capability Bits in the Capability Indication 6.2. New 6LoWPAN capability Bits in the Capability Indication
Option . . . . . . . . . . . . . . . . . . . . . . . . . 14 Option . . . . . . . . . . . . . . . . . . . . . . . . . 15
7. Backward Compatibility . . . . . . . . . . . . . . . . . . . 14 7. Backward Compatibility . . . . . . . . . . . . . . . . . . . 16
7.1. Discovering the capabilities of an ND peer . . . . . . . 14 7.1. Discovering the capabilities of an ND peer . . . . . . . 16
7.1.1. Using the E Flag in the CIO . . . . . . . . . . . . . 14 7.1.1. Using the E Flag in the CIO . . . . . . . . . . . . . 16
7.1.2. Using the T Flag in the EARO . . . . . . . . . . . . 15 7.1.2. Using the T Flag in the EARO . . . . . . . . . . . . 17
7.2. Legacy 6LoWPAN Node . . . . . . . . . . . . . . . . . . . 15 7.2. Legacy 6LoWPAN Node . . . . . . . . . . . . . . . . . . . 17
7.3. Legacy 6LoWPAN Router . . . . . . . . . . . . . . . . . . 16 7.3. Legacy 6LoWPAN Router . . . . . . . . . . . . . . . . . . 17
7.4. Legacy 6LoWPAN Border Router . . . . . . . . . . . . . . 16 7.4. Legacy 6LoWPAN Border Router . . . . . . . . . . . . . . 18
8. Security Considerations . . . . . . . . . . . . . . . . . . . 16 8. Security Considerations . . . . . . . . . . . . . . . . . . . 18
9. Privacy Considerations . . . . . . . . . . . . . . . . . . . 18 9. Privacy Considerations . . . . . . . . . . . . . . . . . . . 20
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 21
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 20 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 22
12.1. Normative References . . . . . . . . . . . . . . . . . . 20 12.1. Normative References . . . . . . . . . . . . . . . . . . 22
12.2. Informative References . . . . . . . . . . . . . . . . . 21 12.2. Informative References . . . . . . . . . . . . . . . . . 23
12.3. External Informative References . . . . . . . . . . . . 23 12.3. External Informative References . . . . . . . . . . . . 26
Appendix A. Applicability and Requirements Served . . . . . . . 24 Appendix A. Applicability and Requirements Served . . . . . . . 26
Appendix B. Requirements . . . . . . . . . . . . . . . . . . . . 24 Appendix B. Requirements . . . . . . . . . . . . . . . . . . . . 27
B.1. Requirements Related to Mobility . . . . . . . . . . . . 25 B.1. Requirements Related to Mobility . . . . . . . . . . . . 27
B.2. Requirements Related to Routing Protocols . . . . . . . . 25 B.2. Requirements Related to Routing Protocols . . . . . . . . 27
B.3. Requirements Related to the Variety of Low-Power Link B.3. Requirements Related to the Variety of Low-Power Link
types . . . . . . . . . . . . . . . . . . . . . . . . . . 26 types . . . . . . . . . . . . . . . . . . . . . . . . . . 28
B.4. Requirements Related to Proxy Operations . . . . . . . . 27 B.4. Requirements Related to Proxy Operations . . . . . . . . 29
B.5. Requirements Related to Security . . . . . . . . . . . . 27 B.5. Requirements Related to Security . . . . . . . . . . . . 29
B.6. Requirements Related to Scalability . . . . . . . . . . . 28 B.6. Requirements Related to Scalability . . . . . . . . . . . 31
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31
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 RFC 6775 "Neighbor Discovery behavior and protocol elements of RFC 6775 "Neighbor Discovery
Optimization for IPv6 over Low-Power Wireless Personal Area Networks Optimization for IPv6 over Low-Power Wireless Personal Area Networks
(6LoWPANs)" [RFC6775] to enable additional capabilities such as: (6LoWPANs)" [RFC6775] to enable additional capabilities such as:
* Support the indication of mobility vs retry (T-bit) * Support the indication of mobility vs retry (T-bit)
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each re-registration. The TID is used to detect the freshness of the each re-registration. The TID is used to detect the freshness of the
registration request and useful to detect one single registration by registration request and useful to detect one single registration by
multiple 6LOWPAN border routers supporting the same large 6LOWPAN, as multiple 6LOWPAN border routers supporting the same large 6LOWPAN, as
is the case for backbone routers (BBR). is the case for backbone routers (BBR).
For example, when a Registered Node is registered with multiple BBRs For example, when a Registered Node is registered with multiple BBRs
in parallel, it is expected that the same TID is used, to enable the in parallel, it is expected that the same TID is used, to enable the
6BBRs to correlate the registrations as being a single one, and 6BBRs to correlate the registrations as being a single one, and
differentiate that situation from a movement. differentiate that situation from a movement.
Thus TID could be tracked to follow the sequence of mobility of a Thus the TID could be tracked to follow the sequence of mobility of a
node. The details protocols of mobility verification by the border node. The details protocols of mobility verification by the border
routers is not part of this specification. routers is not part of this specification.
4.2.1. Comparing TID values
The TID is a sequence counter and by design, its operation is the
exact match of the path sequence specified in RPL, the IPv6 Routing
Protocol for Low-Power and Lossy Networks [RFC6550] specification.
In order to keep this document self-contained and yet compatible, the
text below is an exact copy from section 7.2. "Sequence Counter
Operation" of [RFC6550]. A TID is deemed to be fresher than another
when its value is greater per the operations detailed in this
section.
The TID range is subdivided in a 'lollipop' fashion ([Perlman83]),
where the values from 128 and greater are used as a linear sequence
to indicate a restart and bootstrap the counter, and the values less
than or equal to 127 used as a circular sequence number space of size
128 as in [RFC1982]. Consideration is given to the mode of operation
when transitioning from the linear region to the circular region.
Finally, when operating in the circular region, if sequence numbers
are detected to be too far apart then they are not comparable, as
detailed below.
A window of comparison, SEQUENCE_WINDOW = 16, is configured based on
a value of 2^N, where N is defined to be 4 in this specification.
For a given sequence counter,
1. The sequence counter SHOULD be initialized to an implementation
defined value which is 128 or greater prior to use. A
recommended value is 240 (256 - SEQUENCE_WINDOW).
2. When a sequence counter increment would cause the sequence
counter to increment beyond its maximum value, the sequence
counter MUST wrap back to zero. When incrementing a sequence
counter greater than or equal to 128, the maximum value is 255.
When incrementing a sequence counter less than 128, the maximum
value is 127.
3. When comparing two sequence counters, the following rules MUST be
applied:
1. When a first sequence counter A is in the interval [128..255]
and a second sequence counter B is in [0..127]:
1. If (256 + B - A) is less than or equal to
SEQUENCE_WINDOW, then B is greater than A, A is less than
B, and the two are not equal.
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
equal.
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
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
(16), thus 250 is less than 5.
2. In the case where both sequence counters to be compared are
less than or equal to 127, and in the case where both
sequence counters to be compared are greater than or equal to
128:
1. If the absolute magnitude of difference between the two
sequence counters is less than or equal to
SEQUENCE_WINDOW, then a comparison as described in
[RFC1982] is used to determine the relationships greater
than, less than, and equal.
2. If the absolute magnitude of difference of the two
sequence counters is greater than SEQUENCE_WINDOW, then a
desynchronization has occurred and the two sequence
numbers are not comparable.
4. If two sequence numbers are determined to be not comparable, i.e.
the results of the comparison are not defined, then a node should
consider the comparison as if it has evaluated in such a way so
as to give precedence to the sequence number that has most
recently been observed to increment. Failing this, the node
should consider the comparison as if it has evaluated in such a
way so as to minimize the resulting changes to its own state.
4.3. Owner Unique ID 4.3. 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
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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, from the standpoint of this 6LR, this
Link-Local address is unique and the registration is acceptable. Link-Local address is unique and the registration is acceptable.
Conversely, it may possibly happen that two different 6LRs expose a Conversely, it may possibly happen that two different 6LRs expose the
same Link-Local address but different link-layer addresses. In that same Link-Local address but different link-layer addresses. In that
case, a 6LN may only interact with one of the 6LR so as to avoid case, a 6LN may only interact with one of the 6LR so as to avoid
confusion in the 6LN neighbor cache. 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 RFC 6775 Address Confirmation (DAC) exchange as described in RFC 6775
[RFC6775], does 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
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messages for the Registered Address. In order to refresh the messages for the Registered Address. In order to refresh the
registration state in the 6LBR, these registrations MUST be reported registration state in the 6LBR, these registrations MUST be reported
to the 6LBR. to 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. deregister all of its addresses registered to that 6LR and register
to a new 6LR with an incremented TID.
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 DAR/DAC to the 6LBR, then the 6LR MUST report to the 6LBR, through a DAR/DAC
exchange with the 6LBR, or an alternate protocol, indicating the null exchange with the 6LBR, or an alternate protocol, indicating the null
Registration Lifetime and the latest TID that this 6LR is aware of. Registration Lifetime and the latest TID that this 6LR is aware of.
Upon the DAR message, the 6LBR evaluates if this is the freshest EARO Upon the DAR message, the 6LBR evaluates if this is the freshest EARO
it has received for that particular registry entry. If it is, then it has received for that particular registry entry. If it is, then
the entry is scheduled to be removed, and the DAR is answered with a the entry is scheduled to be removed, and the DAR is answered with a
DAC message bearing a Status of 0 "Success". If it is not the DAC message bearing a Status of 0 "Success". If it is not the
freshest, then a Status 2 "Moved" is returned instead, and the freshest, then a Status 2 "Moved" is returned instead, and the
existing entry is conserved. The 6LBR SHOULD conserve the address in existing entry is conserved.
a DELAY state for a configurable period of time, so as to protect a
mobile node that deregistered from one 6LR and did not register yet Upon timing out a registration, a 6LR removes silently its binding
to a new one. cache entry, and a 6LBR schedules its entry to be removed.
When an address is scheduled to be removed, the 6LBR SHOULD conserve
its 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
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
time is passed, the 6LBR removes silently its entry.
5. Detecting Enhanced ARO Capability Support 5. Detecting Enhanced ARO Capability Support
The nodes and routers in a network may be mixed and if a node wants The nodes and routers in a network may be mixed and if a node wants
to use EARO feature for address registration, it has to find a router to use EARO feature for address registration, it has to find a router
which supports it. Thus all implementations with EARO option MUST which supports it. Thus all implementations with EARO option MUST
provide the capability detection method using 6CIO option to support provide the capability detection method using 6CIO option to support
both types of registrations (ARO and EARO) as described in later both types of registrations (ARO and EARO) as described in later
sections. Moreover, any new implementation of 6LOWPAN is also sections. Moreover, any new implementation of 6LOWPAN is also
RECOMMENDED to support 6LoWPAN Capability Indication option(6CIO)in RECOMMENDED to support 6LoWPAN Capability Indication option(6CIO)in
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6.1. The Enhanced Address Registration Option (EARO) 6.1. 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 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, 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 "T" flag set.
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 RFC 6775 [RFC6775] which specifies that the address from 6LoWPAN ND RFC 6775 [RFC6775] which specifies that the address
being registered is the source of the NS. being registered is the source of the NS.
The format of the EARO option is as follows: The EARO extends the ARO and is recognized by the "T" flag set. 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 1: EARO
Option Fields Option Fields
Type: 33 Type: 33
Length: 8-bit unsigned integer.
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 Length: 8-bit unsigned integer.
means that the registration has ended and the associated state
should be removed.
Owner Unique Identifier (OUI): A globally unique identifier for the Status: 8-bit unsigned integer. Indicates the status of a
node associated. This can be the EUI-64 derived IID of an registration in the NA response. MUST be set to 0 in
interface, or some provable ID obtained cryptographically. NS messages. See Table 1 below.
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
| Value | Description | | Value | Description |
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
| 0..2 | See RFC 6775 [RFC6775]. Note that a Status of 1 | | 0..2 | See RFC 6775 [RFC6775]. Note that a Status of 1 |
| | "Duplicate Address" applies to the Registered Address. If | | | "Duplicate Address" applies to the Registered Address. If |
| | the Source Address conflicts with an existing | | | the Source Address conflicts with an existing |
| | registration, "Duplicate Source Address" should be used. | | | registration, "Duplicate 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 |
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| | | | | |
| 9 | 6LBR Registry saturated: A new registration cannot be | | 9 | 6LBR Registry saturated: A new registration cannot be |
| | accepted because the 6LBR Registry is saturated. | | | accepted because the 6LBR Registry is saturated. |
| | | | | |
| 10 | Incorrect proof: The proof of ownership of the registered | | 10 | Incorrect proof: The proof of ownership of the registered |
| | address is not correct. | | | address is not correct. |
+-------+-----------------------------------------------------------+ +-------+-----------------------------------------------------------+
Table 1: EARO Status Table 1: EARO Status
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
associated 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.
Note: the code "6LBR Registry saturated" is used by 6LBRs instead of Note: the code "6LBR Registry saturated" is used by 6LBRs instead of
Status 2 when responding to a DAR/DAC exchange and passed on to the Status 2 when responding to a DAR/DAC exchange and passed on to the
Registering Node by the 6LR. There is no point for the node to retry Registering Node by the 6LR. There is no point for the node to retry
this registration immediately via another 6LR, since the problem is this registration immediately via another 6LR, since the problem is
global to the network. The node may either abandon that address, global to the network. The node may either abandon that address,
deregister other addresses first to make room, or keep the address in deregister other addresses first to make room, or keep the address in
TENTATIVE state and retry later. TENTATIVE state and retry later.
6.2. New 6LoWPAN capability Bits in the Capability Indication Option 6.2. New 6LoWPAN capability Bits in the Capability Indication Option
skipping to change at page 16, line 13 skipping to change at page 17, line 50
[RFC6775] specification, and manage the binding cache accordingly. [RFC6775] specification, and manage the binding cache accordingly.
The main difference with RFC 6775 is that DAR/DAC exchange for DAD The main difference with RFC 6775 is that DAR/DAC exchange for DAD
may be avoided for Link-Local addresses. Additionally, the 6LR may be avoided for Link-Local addresses. Additionally, 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 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 6LR will
not makes a difference and accept -or reject- that registration as if not make 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 6LR will always reply with an ARO option in
in the NA message. So from that first registration, the updated 6LN the NA message. So from that first registration, the updated 6LN can
can figure whether the 6LR supports this specification or not. 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 behavior and source the packet with the Registered fallback to legacy behavior and source the packet with the Registered
Address. 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 6LR, legacy or updated
7.4. 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, 6LBR
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 behavior. all the associated behavior. A legacy 6LBR will accept and process
an EARO option as if it was an ARO option, so the legacy support of
DAD will function. But considering that there are a lot fewer 6LBR
than 6LR, the expectation is that they are upgraded as soon as
devices that implement this specification are deployed.
8. Security Considerations 8. Security Considerations
This specification extends RFC 6775 [RFC6775], and the security This specification extends RFC 6775 [RFC6775], and the security
section of that draft also applies to this as well. In particular, section of that draft also applies to this as well. In particular,
it is expected that the link layer is sufficiently protected to it is expected that the link layer is sufficiently protected to
prevent a rogue access, either by means of physical or IP security on prevent a rogue access, either by means of physical or IP security on
the Backbone Link and link layer cryptography on the LLN. This the Backbone Link and link layer cryptography on the LLN. This
specification also expects that the LLN MAC provides secure unicast specification also expects that the LLN MAC provides secure unicast
to/from the Backbone Router and secure Broadcast from the Backbone to/from the Backbone Router and secure Broadcast from the Backbone
skipping to change at page 18, line 38 skipping to change at page 20, line 32
specifications involving 6LOWPAN Neighbor Discovery should consult specifications involving 6LOWPAN Neighbor Discovery should consult
"Recommendation on Stable IPv6 Interface Identifiers" [RFC8064] for "Recommendation on Stable IPv6 Interface Identifiers" [RFC8064] for
default interface identifaction. default interface identifaction.
10. IANA Considerations 10. IANA Considerations
IANA is requested to create a new subregistry for "ARO Flags" under IANA is requested to create a new subregistry for "ARO Flags" under
the "Internet Control Message Protocol version 6 (ICMPv6) the "Internet Control Message Protocol version 6 (ICMPv6)
Parameters". This specification defines 8 positions, bit 0 to bit 7, Parameters". This specification defines 8 positions, bit 0 to bit 7,
and assigns bit 7 for the "T" flag in Section 6.1. The policy is and assigns bit 7 for the "T" flag in Section 6.1. The policy is
"IETF Review" or "IESG Approval" [RFC5226]. The initial content of "IETF Review" or "IESG Approval" [RFC8126]. The initial content of
the registry is as shown in Table 2. the registry is as 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) Parameters" Protocol version 6 (ICMPv6) Parameters"
+------------+--------------+-----------+ +------------+--------------+-----------+
| ARO Status | Description | Document | | ARO Status | Description | Document |
+------------+--------------+-----------+ +------------+--------------+-----------+
| 0..6 | Unassigned | | | 0..6 | Unassigned | |
| | | | | | | |
skipping to change at page 20, line 8 skipping to change at page 21, line 50
| 13 | 6BBR capable (P bit) | RFC This | | 13 | 6BBR capable (P bit) | RFC This |
| | | | | | | |
| 14 | EARO support (E bit) | RFC This | | 14 | EARO support (E bit) | RFC This |
+----------------+----------------------+-----------+ +----------------+----------------------+-----------+
Table 4: New 6LoWPAN capability Bits Table 4: 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 at Cisco. infrastructure at Cisco, upon which the first backbone router wsa
implemented; many thanks to Sedat Gormus, Rahul Jadhav, Charlie
Perkins for their various contributions and reviews. Also many
thanks to Thomas Watteyne for his early implementation of a 6LN that
was instrumental to test 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,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
skipping to change at page 20, line 33 skipping to change at page 22, line 30
[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>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", 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 [RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6
Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
DOI 10.17487/RFC6282, September 2011, DOI 10.17487/RFC6282, September 2011,
<http://www.rfc-editor.org/info/rfc6282>. <http://www.rfc-editor.org/info/rfc6282>.
[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>.
[RFC7400] Bormann, C., "6LoWPAN-GHC: Generic Header Compression for [RFC7400] Bormann, C., "6LoWPAN-GHC: Generic Header Compression for
IPv6 over Low-Power Wireless Personal Area Networks IPv6 over Low-Power Wireless Personal Area Networks
(6LoWPANs)", RFC 7400, DOI 10.17487/RFC7400, November (6LoWPANs)", RFC 7400, DOI 10.17487/RFC7400, November
2014, <http://www.rfc-editor.org/info/rfc7400>. 2014, <http://www.rfc-editor.org/info/rfc7400>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<http://www.rfc-editor.org/info/rfc8126>.
12.2. Informative References 12.2. Informative References
[I-D.chakrabarti-nordmark-6man-efficient-nd] [I-D.chakrabarti-nordmark-6man-efficient-nd]
Chakrabarti, S., Nordmark, E., Thubert, P., and M. Chakrabarti, S., Nordmark, E., Thubert, P., and M.
Wasserman, "IPv6 Neighbor Discovery Optimizations for Wasserman, "IPv6 Neighbor Discovery Optimizations for
Wired and Wireless Networks", draft-chakrabarti-nordmark- Wired and Wireless Networks", draft-chakrabarti-nordmark-
6man-efficient-nd-07 (work in progress), February 2015. 6man-efficient-nd-07 (work in progress), February 2015.
[I-D.delcarpio-6lo-wlanah] [I-D.delcarpio-6lo-wlanah]
Vega, L., Robles, I., and R. Morabito, "IPv6 over Vega, L., Robles, I., and R. Morabito, "IPv6 over
skipping to change at page 21, line 26 skipping to change at page 23, line 26
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-02 (work in progress), May
2017. 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-03 (work in progress), January 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.
[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-11 (work of IEEE 802.15.4", draft-ietf-6tisch-architecture-11 (work
skipping to change at page 22, line 11 skipping to change at page 24, line 11
Thaler, D. and C. Huitema, "Multi-link Subnet Support in Thaler, D. and C. Huitema, "Multi-link Subnet Support in
IPv6", draft-ietf-ipv6-multilink-subnets-00 (work in IPv6", draft-ietf-ipv6-multilink-subnets-00 (work in
progress), July 2002. progress), July 2002.
[I-D.popa-6lo-6loplc-ipv6-over-ieee19012-networks] [I-D.popa-6lo-6loplc-ipv6-over-ieee19012-networks]
Popa, D. and J. Hui, "6LoPLC: Transmission of IPv6 Packets Popa, D. and J. Hui, "6LoPLC: Transmission of IPv6 Packets
over IEEE 1901.2 Narrowband Powerline Communication over IEEE 1901.2 Narrowband Powerline Communication
Networks", draft-popa-6lo-6loplc-ipv6-over- Networks", draft-popa-6lo-6loplc-ipv6-over-
ieee19012-networks-00 (work in progress), March 2014. ieee19012-networks-00 (work in progress), March 2014.
[RFC1982] Elz, R. and R. Bush, "Serial Number Arithmetic", RFC 1982,
DOI 10.17487/RFC1982, August 1996,
<http://www.rfc-editor.org/info/rfc1982>.
[RFC3610] Whiting, D., Housley, R., and N. Ferguson, "Counter with [RFC3610] Whiting, D., Housley, R., and N. Ferguson, "Counter with
CBC-MAC (CCM)", RFC 3610, DOI 10.17487/RFC3610, September CBC-MAC (CCM)", RFC 3610, DOI 10.17487/RFC3610, September
2003, <http://www.rfc-editor.org/info/rfc3610>. 2003, <http://www.rfc-editor.org/info/rfc3610>.
[RFC3810] Vida, R., Ed. and L. Costa, Ed., "Multicast Listener [RFC3810] Vida, R., Ed. and L. Costa, Ed., "Multicast Listener
Discovery Version 2 (MLDv2) for IPv6", RFC 3810, Discovery Version 2 (MLDv2) for IPv6", RFC 3810,
DOI 10.17487/RFC3810, June 2004, DOI 10.17487/RFC3810, June 2004,
<http://www.rfc-editor.org/info/rfc3810>. <http://www.rfc-editor.org/info/rfc3810>.
[RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander,
skipping to change at page 24, line 5 skipping to change at page 26, line 12
Passing (MS/TP) Networks", RFC 8163, DOI 10.17487/RFC8163, Passing (MS/TP) Networks", RFC 8163, DOI 10.17487/RFC8163,
May 2017, <http://www.rfc-editor.org/info/rfc8163>. May 2017, <http://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/IEEESTD.2016.7460875,
<http://ieeexplore.ieee.org/document/7460875/>. <http://ieeexplore.ieee.org/document/7460875/>.
[Perlman83]
Perlman, R., "Fault-Tolerant Broadcast of Routing
Information", North-Holland Computer Networks 7: 395-405,
1983, <http://www.cs.illinois.edu/~pbg/courses/cs598fa09/
readings/p83.pdf>.
Appendix A. Applicability and Requirements Served Appendix A. Applicability and Requirements Served
This specification extends 6LoWPAN ND to sequence the registration This specification extends 6LoWPAN ND to sequence the registration
and serves the requirements expressed Appendix B.1 by enabling the and serves the requirements expressed Appendix B.1 by enabling the
mobility of devices from one LLN to the next based on the mobility of devices from one LLN to the next based on the
complementary work in the "IPv6 Backbone Router" complementary work in the "IPv6 Backbone Router"
[I-D.ietf-6lo-backbone-router] specification. [I-D.ietf-6lo-backbone-router] specification.
In the context of the the TimeSlotted Channel Hopping (TSCH) mode of In the context of the the TimeSlotted Channel Hopping (TSCH) mode of
IEEE Std. 802.15.4 [IEEEstd802154], the "6TiSCH architecture" IEEE Std. 802.15.4 [IEEEstd802154], the "6TiSCH architecture"
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