draft-ietf-roll-dao-projection-15.txt   draft-ietf-roll-dao-projection-16.txt 
ROLL P. Thubert, Ed. ROLL P. Thubert, Ed.
Internet-Draft Cisco Systems Internet-Draft Cisco Systems
Intended status: Standards Track R.A. Jadhav Updates: 6554 (if approved) R.A. Jadhav
Expires: 31 May 2021 Huawei Tech Intended status: Standards Track Huawei Tech
M. Gillmore Expires: 19 July 2021 M. Gillmore
Itron Itron
27 November 2020 15 January 2021
Root initiated routing state in RPL Root initiated routing state in RPL
draft-ietf-roll-dao-projection-15 draft-ietf-roll-dao-projection-16
Abstract Abstract
This document extends RFC 6550 and RFC 6553 to enable a RPL Root to This document extends RFC 6550 and RFC 6553 to enable a RPL Root to
install and maintain Projected Routes within its DODAG, along a install and maintain Projected Routes within its DODAG, along a
selected set of nodes that may or may not include self, for a chosen selected set of nodes that may or may not include self, for a chosen
duration. This potentially enables routes that are more optimized or duration. This potentially enables routes that are more optimized or
resilient than those obtained with the classical distributed resilient than those obtained with the classical distributed
operation of RPL, either in terms of the size of a Routing Header or operation of RPL, either in terms of the size of a Routing Header or
in terms of path length, which impacts both the latency and the in terms of path length, which impacts both the latency and the
skipping to change at page 1, line 40 skipping to change at page 1, line 40
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on 31 May 2021. This Internet-Draft will expire on 19 July 2021.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2021 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 (https://trustee.ietf.org/ Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document. license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components and restrictions with respect to this document. Code Components
extracted from this document must include Simplified BSD License text extracted from this document must include Simplified BSD License text
as described in Section 4.e of the Trust Legal Provisions and are as described in Section 4.e of the Trust Legal Provisions and are
skipping to change at page 2, line 23 skipping to change at page 2, line 23
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 5 2.1. Requirements Language . . . . . . . . . . . . . . . . . . 5
2.2. Glossary . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2. Glossary . . . . . . . . . . . . . . . . . . . . . . . . 5
2.3. Other Terms . . . . . . . . . . . . . . . . . . . . . . . 6 2.3. Other Terms . . . . . . . . . . . . . . . . . . . . . . . 6
2.4. References . . . . . . . . . . . . . . . . . . . . . . . 6 2.4. References . . . . . . . . . . . . . . . . . . . . . . . 6
3. Extending RFC 6550 . . . . . . . . . . . . . . . . . . . . . 6 3. Extending RFC 6550 . . . . . . . . . . . . . . . . . . . . . 6
3.1. Projected DAO . . . . . . . . . . . . . . . . . . . . . . 6 3.1. Projected DAO . . . . . . . . . . . . . . . . . . . . . . 6
3.2. Sibling Information Option . . . . . . . . . . . . . . . 8 3.2. Sibling Information Option . . . . . . . . . . . . . . . 8
3.3. P-DAO Request . . . . . . . . . . . . . . . . . . . . . . 8 3.3. P-DAO Request . . . . . . . . . . . . . . . . . . . . . . 8
3.4. Extending the RPI . . . . . . . . . . . . . . . . . . . . 8 3.4. Extending the RPI . . . . . . . . . . . . . . . . . . . . 9
4. Extending RFC 6553 . . . . . . . . . . . . . . . . . . . . . 8 4. Extending RFC 6553 . . . . . . . . . . . . . . . . . . . . . 9
5. Extending RFC 8138 . . . . . . . . . . . . . . . . . . . . . 9 5. Extending RFC 8138 . . . . . . . . . . . . . . . . . . . . . 10
6. New RPL Control Messages and Options . . . . . . . . . . . . 10 6. New RPL Control Messages and Options . . . . . . . . . . . . 10
6.1. New P-DAO Request Control Message . . . . . . . . . . . . 10 6.1. New P-DAO Request Control Message . . . . . . . . . . . . 10
6.2. New PDR-ACK Control Message . . . . . . . . . . . . . . . 11 6.2. New PDR-ACK Control Message . . . . . . . . . . . . . . . 11
6.3. Via Information Options . . . . . . . . . . . . . . . . . 12 6.3. Via Information Options . . . . . . . . . . . . . . . . . 13
6.4. Sibling Information Option . . . . . . . . . . . . . . . 15 6.4. Sibling Information Option . . . . . . . . . . . . . . . 15
7. Projected DAO . . . . . . . . . . . . . . . . . . . . . . . . 16 7. Projected DAO . . . . . . . . . . . . . . . . . . . . . . . . 17
7.1. Requesting a Track . . . . . . . . . . . . . . . . . . . 18 7.1. Requesting a Track . . . . . . . . . . . . . . . . . . . 18
7.2. Identifying a Track . . . . . . . . . . . . . . . . . . . 18 7.2. Identifying a Track . . . . . . . . . . . . . . . . . . . 19
7.3. Installing a Track . . . . . . . . . . . . . . . . . . . 19 7.3. Installing a Track . . . . . . . . . . . . . . . . . . . 20
7.4. Forwarding Along a Track . . . . . . . . . . . . . . . . 20 7.3.1. Storing-Mode P-Route . . . . . . . . . . . . . . . . 21
7.5. Non-Storing Mode Projected Route . . . . . . . . . . . . 21 7.3.2. Non-Storing-Mode P-Route . . . . . . . . . . . . . . 23
7.6. Storing Mode Projected Route . . . . . . . . . . . . . . 23 7.4. Forwarding Along a Track . . . . . . . . . . . . . . . . 24
8. Security Considerations . . . . . . . . . . . . . . . . . . . 25 8. Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . 25
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25 9. Example Track Signaling . . . . . . . . . . . . . . . . . . . 26
9.1. New Elective 6LoWPAN Routing Header Type . . . . . . . . 25 9.1. Using Storing-Mode Segments . . . . . . . . . . . . . . . 27
9.2. New Critical 6LoWPAN Routing Header Type . . . . . . . . 25 9.1.1. Stitched Segments . . . . . . . . . . . . . . . . . . 27
9.3. New Subregistry For The RPL Option Flags . . . . . . . . 26 9.1.2. External routes . . . . . . . . . . . . . . . . . . . 29
9.4. New RPL Control Codes . . . . . . . . . . . . . . . . . . 26 9.1.3. Segment Routing . . . . . . . . . . . . . . . . . . . 30
9.5. New RPL Control Message Options . . . . . . . . . . . . . 27 9.2. Using Non-Storing-Mode joining Tracks . . . . . . . . . . 32
9.6. SubRegistry for the Projected DAO Request Flags . . . . . 27 9.2.1. Stitched Tracks . . . . . . . . . . . . . . . . . . . 32
9.7. SubRegistry for the PDR-ACK Flags . . . . . . . . . . . . 28 9.2.2. External routes . . . . . . . . . . . . . . . . . . . 34
9.8. Subregistry for the PDR-ACK Acceptance Status Values . . 28 9.2.3. Segment Routing . . . . . . . . . . . . . . . . . . . 36
9.9. Subregistry for the PDR-ACK Rejection Status Values . . . 28 10. Security Considerations . . . . . . . . . . . . . . . . . . . 39
9.10. SubRegistry for the Via Information Options Flags . . . . 29 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 39
9.11. SubRegistry for the Sibling Information Option Flags . . 29 11.1. New Elective 6LoWPAN Routing Header Type . . . . . . . . 39
9.12. Error in Projected Route ICMPv6 Code . . . . . . . . . . 30 11.2. New Critical 6LoWPAN Routing Header Type . . . . . . . . 39
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 30 11.3. New Subregistry For The RPL Option Flags . . . . . . . . 40
11. Normative References . . . . . . . . . . . . . . . . . . . . 30 11.4. New RPL Control Codes . . . . . . . . . . . . . . . . . 40
12. Informative References . . . . . . . . . . . . . . . . . . . 31 11.5. New RPL Control Message Options . . . . . . . . . . . . 41
Appendix A. Applications . . . . . . . . . . . . . . . . . . . . 32 11.6. SubRegistry for the Projected DAO Request Flags . . . . 41
A.1. Loose Source Routing . . . . . . . . . . . . . . . . . . 32 11.7. SubRegistry for the PDR-ACK Flags . . . . . . . . . . . 41
A.2. Transversal Routes . . . . . . . . . . . . . . . . . . . 34 11.8. Subregistry for the PDR-ACK Acceptance Status Values . . 42
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 36 11.9. Subregistry for the PDR-ACK Rejection Status Values . . 42
11.10. SubRegistry for the Via Information Options Flags . . . 43
11.11. SubRegistry for the Sibling Information Option Flags . . 43
11.12. New Destination Advertisement Object Flag . . . . . . . 43
11.13. Error in Projected Route ICMPv6 Code . . . . . . . . . . 44
12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 44
13. Normative References . . . . . . . . . . . . . . . . . . . . 44
14. Informative References . . . . . . . . . . . . . . . . . . . 45
Appendix A. Applications . . . . . . . . . . . . . . . . . . . . 46
A.1. Loose Source Routing . . . . . . . . . . . . . . . . . . 47
A.2. Transversal Routes . . . . . . . . . . . . . . . . . . . 48
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 50
1. Introduction 1. Introduction
RPL, the "Routing Protocol for Low Power and Lossy Networks" [RPL] RPL, the "Routing Protocol for Low Power and Lossy Networks" [RPL]
(LLNs), is a generic Distance Vector protocol that is well suited for (LLNs), is a generic Distance Vector protocol that is well suited for
application in a variety of low energy Internet of Things (IoT) application in a variety of low energy Internet of Things (IoT)
networks. RPL forms Destination Oriented Directed Acyclic Graphs networks. RPL forms Destination Oriented Directed Acyclic Graphs
(DODAGs) in which the Root often acts as the Border Router to connect (DODAGs) in which the Root often acts as the Border Router to connect
the RPL domain to the Internet. The Root is responsible to select the RPL domain to the Internet. The Root is responsible to select
the RPL Instance that is used to forward a packet coming from the the RPL Instance that is used to forward a packet coming from the
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2.2. Glossary 2.2. Glossary
This document often uses the following acronyms: This document often uses the following acronyms:
CMO: Control Message Option CMO: Control Message Option
DAO: Destination Advertisement Object DAO: Destination Advertisement Object
DAG: Directed Acyclic Graph DAG: Directed Acyclic Graph
DODAG: Destination-Oriented Directed Acyclic Graph; A DAG with only DODAG: Destination-Oriented Directed Acyclic Graph; A DAG with only
one vertex (i.e., node) that has no outgoing edge (i.e., link) one vertex (i.e., node) that has no outgoing edge (i.e., link)
LLN: Low-Power and Lossy Network LLN: Low-Power and Lossy Network
NMPR: Non-Storing Mode Projected Route
MOP: RPL Mode of Operation MOP: RPL Mode of Operation
P-DAO: Projected DAO P-DAO: Projected DAO
P-Route: Projected Route
PDR: P-DAO Request PDR: P-DAO Request
RAN: RPL-Aware Node (either a RPL Router or a RPL-Aware Leaf) RAN: RPL-Aware Node (either a RPL Router or a RPL-Aware Leaf)
RAL: RPL-Aware Leaf RAL: RPL-Aware Leaf
RH: Routing Header RH: Routing Header
RPI: RPL Packet Information RPI: RPL Packet Information
RTO: RPL Target Option RTO: RPL Target Option
RUL: RPL-Unaware Leaf RUL: RPL-Unaware Leaf
SIO: RPL Sibling Information Option SIO: RPL Sibling Information Option
SR-VIO: A Source-Routed Via Information Option, used in Non-Storing SR-VIO: A Source-Routed Via Information Option, used in Non-Storing-
Mode P-DAO messages. Mode P-DAO messages.
SMPR: Storing Mode Projected Route
TIO: RPL Transit Information Option TIO: RPL Transit Information Option
SF-VIO: A Via Information Option, used in Storing Mode P-DAO SF-VIO: A Via Information Option, used in Storing-Mode P-DAO
messages. messages.
VIO: A Via Information Option; it can be a SF-VIO or an SR-VIO. VIO: A Via Information Option; it can be a SF-VIO or an SR-VIO.
2.3. Other Terms 2.3. Other Terms
Projected Route: A RPL Projected Route is a RPL route that is Projected Route: A RPL Projected Route is a RPL route that is
computed remotely by a PCE, and installed and maintained by a RPL computed remotely by a PCE, and installed and maintained by a RPL
Root on behalf of the PCE. Root on behalf of the PCE.
Projected DAO: A DAO message used to install a Projected Route. Projected DAO: A DAO message used to install a Projected Route.
Track: A DODAG that provides a complex path from or to a Root that Track: A DODAG that provides a complex path from or to a Root that
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therein. This specification enables to combine one or more Projected therein. This specification enables to combine one or more Projected
Routes into a DODAG called a Track, that is traversed to reach the Routes into a DODAG called a Track, that is traversed to reach the
Targets. Targets.
The Track is assimilated with the DODAG formed for a Local RPL The Track is assimilated with the DODAG formed for a Local RPL
Instance. The local RPLInstanceID of the Track is called the Instance. The local RPLInstanceID of the Track is called the
TrackID, more in Section 7.2. A P-DAO message for a Track signals TrackID, more in Section 7.2. A P-DAO message for a Track signals
the TrackID in the RPLInstanceID field. The Track Ingress is the TrackID in the RPLInstanceID field. The Track Ingress is
signaled in the DODAGID field of the Projected DAO Base Object; that signaled in the DODAGID field of the Projected DAO Base Object; that
field is elided in the case of the main RPL Instance. The Track field is elided in the case of the main RPL Instance. The Track
Ingress is the Root of the Track, as shown in Figure 1. . Ingress is the Root of the Track, as shown in Figure 1.
This specification defines the new "Projected DAO" (P) flag. The 'P'
flag is encoded in bit position 2 (to be confirmed by IANA) of the
Flags field in the DAO Base Object. The Root MUST set it to 1 in a
Projected DAO message. Otherwise it MUST be set to 0. It is set to
0 in legacy implementations as specified respectively in Sections
20.11 and 6.4 of [RPL]. .
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TrackID |K|D| Flags | Reserved | DAOSequence | | TrackID |K|D|P| Flags | Reserved | DAOSequence |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
+ + + +
| | | |
+ IPv6 Address of the Track Ingress + + IPv6 Address of the Track Ingress +
| | | |
+ + + +
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Option(s)... | Option(s)...
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Figure 1: Projected DAO Format for a Track Figure 1: Projected DAO Base Object
New fields:
TrackID: In the case of a P-DAO, the RPLInstanceID field is called
TrackID. This is a naming convenience but does not change the
semantics and format of the RPLInstanceID that is used as TrackID.
P: 1-bit flag (position to be confirmed by IANA).
The 'P' flag is set to 1 by the Root to signal a Projected DAO,
and it is set to 0 otherwise.
In RPL Non-Storing Mode, the TIO and RTO are combined in a DAO In RPL Non-Storing Mode, the TIO and RTO are combined in a DAO
message to inform the DODAG Root of all the edges in the DODAG, which message to inform the DODAG Root of all the edges in the DODAG, which
are formed by the directed parent-child relationships. Options may are formed by the directed parent-child relationships. Options may
be factorized; multiple RTOs may be present to signal a collection of be factorized; multiple RTOs may be present to signal a collection of
children that can be reached via the parent(s) indicated in the children that can be reached via the parent(s) indicated in the
TIO(s) that follows the RTOs. This specification generalizes the TIO(s) that follows the RTOs. This specification generalizes the
case of a parent that can be used to reach a child with that of a case of a parent that can be used to reach a child with that of a
whole Track through which both children and siblings of the Track whole Track through which both children and siblings of the Track
Egress are reachable. Egress are reachable.
New CMOs called the Via Information Options (VIO) are introduced for New CMOs called the Via Information Options (VIO) are introduced for
use in P-DAO messages as a multihop alternative to the TIO. One VIO use in P-DAO messages as a multihop alternative to the TIO. One VIO
is the Stateful Via Information Option (SF-VIO); the SF-VIO installs is the Stateful VIO(SF-VIO); the SF-VIO installs Storing-Mode
Storing Mode Projected Route (SMPR) along a strict segment. The Projected Route along a strict segment. The other is the Source-
other is the Source-Routed SF-VIO (SR-VIO); the SR-VIO installs a Routed VIO (SR-VIO); the SR-VIO installs a Non-Storing-Mode Projected
Non-Storing Mode Projected Route (NMPR) at the Track Ingress, which Route at the Track Ingress, which uses that state to encapsulate a
uses that state to encapsulate a packet with a Routing Header (RH) to packet with a Routing Header (RH) to the Track Egress.
the Track Egress.
Like in a DAO message, the RTOs can be factorized in a P-DAO, but the Like in a DAO message, the RTOs can be factorized in a P-DAO, but the
Via Options cannot. A P-DAO contains one or more RTOs that indicate Via Information Options cannot. A P-DAO contains one or more RTOs
the destinations that can be reached via the Track, and exactly one that indicate the destinations that can be reached via the Track, and
Via Option that signals a sequence of nodes. In Non-Storing Mode, exactly one VIOthat signals a sequence of nodes. In Non-Storing
the Root sends the P-DAO to the Track Ingress where the source- Mode, the Root sends the P-DAO to the Track Ingress where the source-
routing state is stored. In Storing Mode, the P-DAO is sent to the routing state is stored. In Storing Mode, the P-DAO is sent to the
Track Egress and forwarded along the Segment in the reverse Track Egress and forwarded along the Segment in the reverse
direction, installing a Storing Mode state to the Track Egress at direction, installing a Storing Mode state to the Track Egress at
each hop. In both cases the Track Ingress is the owner of the Track, each hop. In both cases the Track Ingress is the owner of the Track,
and it generates the P-DAO-ACK when the installation is successful. and it generates the P-DAO-ACK when the installation is successful.
3.2. Sibling Information Option 3.2. Sibling Information Option
This specification adds another CMO called the Sibling Information This specification adds another CMO called the Sibling Information
Option (SIO) that is used by a RPL Aware Node (RAN) to advertise a Option (SIO) that is used by a RPL Aware Node (RAN) to advertise a
skipping to change at page 12, line 18 skipping to change at page 12, line 46
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Figure 6: PDR-ACK status Format Figure 6: PDR-ACK status Format
E: 1-bit flag. Set to indicate a rejection. When not set, the E: 1-bit flag. Set to indicate a rejection. When not set, the
value of 0 indicates Success/Unqualified acceptance and other value of 0 indicates Success/Unqualified acceptance and other
values indicate "not an outright rejection". values indicate "not an outright rejection".
R: 1-bit flag. Reserved, MUST be set to 0 by the sender and R: 1-bit flag. Reserved, MUST be set to 0 by the sender and
ignored by the receiver. ignored by the receiver.
Status Value: 6-bit unsigned integer. Values depending on the Status Value: 6-bit unsigned integer. Values depending on the
setting of the 'E' flag, see Table 7 and Table 8. setting of the 'E' flag, see Table 27 and Table 28.
Reserved: The Reserved field MUST initialized to zero by the sender Reserved: The Reserved field MUST initialized to zero by the sender
and MUST be ignored by the receiver and MUST be ignored by the receiver
6.3. Via Information Options 6.3. Via Information Options
An Via Option signals the ordered list of IPv6 Via Addresses that An VIOsignals the ordered list of IPv6 Via Addresses that constitutes
constitutes the hops of either a Serial Track or a Segment of a more the hops of either a Serial Track or a Segment of a more Complex
Complex Track. An Via Option MUST contain at least one Via Address, Track. An VIOMUST contain at least one Via Address, and a Via
and a Via Address MUST NOT be present more than once, otherwise the Address MUST NOT be present more than once, otherwise the VIOMUST be
Via Option MUST be ignored. The format of the Via Options is as ignored. The format of the Via Information Options is as follows:
follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Option Length | Flags | SegmentID | | Type | Option Length | Flags | SegmentID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Segm. Sequence | Seg. Lifetime | SRH-6LoRH header | |Segm. Sequence | Seg. Lifetime | SRH-6LoRH header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
+ + + +
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
+ + + +
. . . .
. Via Address n . . Via Address n .
. . . .
+ + + +
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: Via Information Option format (uncompressed form) Figure 7: VIOformat (uncompressed form)
Option Type: 0x0B for SF-VIO, 0x0C for SR-VIO (to be confirmed by Option Type: 0x0B for SF-VIO, 0x0C for SR-VIO (to be confirmed by
IANA) IANA)
Option Length: In bytes; variable, depending on the number of Via Option Length: In bytes; variable, depending on the number of Via
Addresses and the compression. Addresses and the compression.
SegmentID: 8-bit field that identifies a Segment within a Track or SegmentID: 8-bit field that identifies a Segment within a Track or
the main DODAG as indicated by the TrackID field. The value of 0 the main DODAG as indicated by the TrackID field. The value of 0
is used to signal a Serial Track, i.e., made of a single segment. is used to signal a Serial Track, i.e., made of a single segment.
Segment Sequence: 8-bit unsigned integer. The Segment Sequence Segment Sequence: 8-bit unsigned integer. The Segment Sequence
obeys the operation in section 7.2 of [RPL] and the lollipop obeys the operation in section 7.2 of [RPL] and the lollipop
starts at 255. starts at 255.
When the Root of the DODAG needs to refresh or update a Segment in When the Root of the DODAG needs to refresh or update a Segment in
a Track, it increments the Segment Sequence individually for that a Track, it increments the Segment Sequence individually for that
Segment. Segment.
The Segment information indicated in the Via Option deprecates any The Segment information indicated in the VIOdeprecates any state
state for the Segment indicated by the SegmentID within the for the Segment indicated by the SegmentID within the indicated
indicated Track and sets up the new information. Track and sets up the new information.
An Via Option with a Segment Sequence that is not as fresh as the An VIOwith a Segment Sequence that is not as fresh as the current
current one is ignored. one is ignored.
A VIO for a given DODAGID with the same (TrackID, SegmentID, A VIO for a given DODAGID with the same (TrackID, SegmentID,
Segment Sequence) indicates a retry; it MUST NOT change the Segment Sequence) indicates a retry; it MUST NOT change the
Segment and MUST be propagated or answered as the first copy. Segment and MUST be propagated or answered as the first copy.
Segment Lifetime: 8-bit unsigned integer. The length of time in Segment Lifetime: 8-bit unsigned integer. The length of time in
Lifetime Units (obtained from the Configuration option) that the Lifetime Units (obtained from the Configuration option) that the
Segment is usable. Segment is usable.
The period starts when a new Segment Sequence is seen. The value The period starts when a new Segment Sequence is seen. The value
of 255 (0xFF) represents infinity. The value of zero (0x00) of 255 (0xFF) represents infinity. The value of zero (0x00)
indicates a loss of reachability. indicates a loss of reachability.
A P-DAO message that contains a Via Information option with a A P-DAO message that contains a VIOwith a Segment Lifetime of zero
Segment Lifetime of zero is referred as a No-Path P-DAO in this is referred as a No-Path P-DAO in this document.
document.
SRH-6LoRH header: The first 2 bytes of the (first) SRH-6LoRH as SRH-6LoRH header: The first 2 bytes of the (first) SRH-6LoRH as
shown in Figure 6 of [RFC8138]. A 6LoRH Type of 4 means that the shown in Figure 6 of [RFC8138]. A 6LoRH Type of 4 means that the
VIA Addresses are provided in full with no compression. VIA Addresses are provided in full with no compression.
Via Address: An IPv6 addresse along the Segment. Via Address: An IPv6 addresse along the Segment.
In a SF-VIO, the list is a strict path between direct neighbors, In a SF-VIO, the list is a strict path between direct neighbors,
from the segment ingress to egress, both included. In an SR-VIO, from the segment ingress to egress, both included. In an SR-VIO,
the list starts at the first hop and ends at a Track Egress. The the list starts at the first hop and ends at a Track Egress. The
list in an SR-VIO may be loose, provided that each listed node has list in an SR-VIO may be loose, provided that each listed node has
a path to the next listed node, e.g., via a segment or another a path to the next listed node, e.g., via a segment or another
Track. Track.
In the case of a SF-VIO, or if [RFC8138] is not used in the data In the case of a SF-VIO, or if [RFC8138] is not used in the data
packets, then the Root MUST use only one SRH-6LoRH per Via Option, packets, then the Root MUST use only one SRH-6LoRH per Via
and the compression is the same for all the addresses, as shown in Information Option, and the compression is the same for all the
Figure 7. addresses, as shown in Figure 7.
In case of an SR-VIO, and if [RFC8138] is in use in the main In case of an SR-VIO, and if [RFC8138] is in use in the main
DODAG, then the Root SHOULD optimize the size of the SR-VIO; more DODAG, then the Root SHOULD optimize the size of the SR-VIO; more
than one SRH-6LoRH may be present, e.g., if the compression level than one SRH-6LoRH may be present, e.g., if the compression level
changes inside the Segment and different SRH-6LoRH Types are changes inside the Segment and different SRH-6LoRH Types are
required. The content of the SR-VIO starting at the first SRH- required. The content of the SR-VIO starting at the first SRH-
6LoRH header is thus verbatim the one that the Track Ingress 6LoRH header is thus verbatim the one that the Track Ingress
places in the packet encapsulation to reach the Track Ingress. places in the packet encapsulation to reach the Track Ingress.
6.4. Sibling Information Option 6.4. Sibling Information Option
skipping to change at page 16, line 51 skipping to change at page 17, line 12
that case the DAG Metric Container provides additional metrics for that case the DAG Metric Container provides additional metrics for
the hop from the Sibling to this node. the hop from the Sibling to this node.
7. Projected DAO 7. Projected DAO
This draft adds a capability to RPL whereby the Root of a main DODAG This draft adds a capability to RPL whereby the Root of a main DODAG
installs a Track as a collection of Projected Routes, using a installs a Track as a collection of Projected Routes, using a
Projected-DAO (P-DAO) message to maintain each individual route. The Projected-DAO (P-DAO) message to maintain each individual route. The
P-DAO signals a collection of Targets in the RPL Target Option(s) P-DAO signals a collection of Targets in the RPL Target Option(s)
(RTO). Those Targets can be reached via a sequence of routers (RTO). Those Targets can be reached via a sequence of routers
indicated in a Via Information Option (VIO). A P-DAO message MUST indicated in a VIO(VIO). A P-DAO message MUST contain exactly one
contain exactly one VIO, which is either a SF-VIO or an SR-VIO, and VIO, which is either a SF-VIO or an SR-VIO, and MUST follow one or
MUST follow one or more RTOs. There can be at most one such sequence more RTOs. There can be at most one such sequence of RTO(s) and an
of RTO(s) and an Via Option. A track is indentified by a tupple Via Information Option. A track is indentified by a tupple DODAGID,
DODAGID, TrackID and each route within a Track is indexed by a TrackID and each route within a Track is indexed by a SegmentID.
SegmentID.
A P-DAO MUST be sent from the address of the Root that serves as A P-DAO MUST be sent from the address of the Root that serves as
DODAGID for the main DODAG. It MUST be sent to a GUA or a ULA of DODAGID for the main DODAG. It MUST be sent to a GUA or a ULA of
either the ingress or the egress of the Segment, more below. If the either the ingress or the egress of the Segment, more below. If the
'K' Flag is present in the P-DAO, and unless the P-DAO does not reach 'K' Flag is present in the P-DAO, and unless the P-DAO does not reach
it, the ingress of the Segment is the node that acknowledges the it, the ingress of the Segment is the node that acknowledges the
message, using a DAO-ACK that MUST be sent back to the address that message, using a DAO-ACK that MUST be sent back to the address that
serves as DODAGID for the main DODAG. serves as DODAGID for the main DODAG.
Like a classical DAO message, a P-DAO causes a change of state only Like a classical DAO message, a P-DAO causes a change of state only
if it is "new" per section 9.2.2. "Generation of DAO Messages" of if it is "new" per section 9.2.2. "Generation of DAO Messages" of
the RPL specification [RPL]; this is determined using the Segment the RPL specification [RPL]; this is determined using the Segment
Sequence information from the Via Option as opposed to the Path Sequence information from the VIOas opposed to the Path Sequence from
Sequence from a TIO. Also, a Segment Lifetime of 0 in an Via Option a TIO. Also, a Segment Lifetime of 0 in an VIOindicates that the
indicates that the projected route associated to the Segment is to be projected route associated to the Segment is to be removed.
removed.
There are two kinds of operation for the Projected Routes, the There are two kinds of operation for the Projected Routes, the
Storing Mode and the Non-Storing Mode. Storing Mode and the Non-Storing Mode.
* The Non-Storing Mode is discussed in Section 7.5. A Non-Storing * The Non-Storing Mode is discussed in Section 7.3.2. A Non-Storing
Mode P-DAO carries an SR-VIO with the loose list of Via Addresses Mode P-DAO carries an SR-VIO with the loose list of Via Addresses
that forms a source-routed Segment to the Track Egress. The that forms a source-routed Segment to the Track Egress. The
recipient of the P-DAO is the Track Ingress; it MUST install a recipient of the P-DAO is the Track Ingress; it MUST install a
source-routed state to the Track Egress and reply to the Root source-routed state to the Track Egress and reply to the Root
directly using a DAO-ACK message if requested to. directly using a DAO-ACK message if requested to.
* The Storing Mode is discussed in Section 7.6. A Storing Mode * The Storing Mode is discussed in Section 7.3.1. A Storing Mode
P-DAO carries a SF-VIO with the strict list of Via Addresses from P-DAO carries a SF-VIO with the strict list of Via Addresses from
the ingress to the egress of the Segment in the data path order. the ingress to the egress of the Segment in the data path order.
The routers listed in the Via Addresses, except the egress, MUST The routers listed in the Via Addresses, except the egress, MUST
install a routing state to the Target(s) via the next Via Address install a routing state to the Target(s) via the next Via Address
in the SF-VIO. In normal operations, the P-DAO is propagated in the SF-VIO. In normal operations, the P-DAO is propagated
along the chain of Via Routers from the egress router of the path along the chain of Via Routers from the egress router of the path
till the ingress one, which confirms the installation to the Root till the ingress one, which confirms the installation to the Root
with a DAO-ACK message. with a DAO-ACK message.
In case of a forwarding error along a Projected Route, an ICMP error In case of a forwarding error along a Projected Route, an ICMP error
is sent to the Root with a new Code "Error in Projected Route" (See is sent to the Root with a new Code "Error in Projected Route" (See
Section 9.12). The Root can then modify or remove the Projected Section 11.13). The Root can then modify or remove the Projected
Route. The "Error in Projected Route" message has the same format as Route. The "Error in Projected Route" message has the same format as
the "Destination Unreachable Message", as specified in RFC 4443 the "Destination Unreachable Message", as specified in RFC 4443
[RFC4443]. [RFC4443].
The portion of the invoking packet that is sent back in the ICMP The portion of the invoking packet that is sent back in the ICMP
message SHOULD record at least up to the RH if one is present, and message SHOULD record at least up to the RH if one is present, and
this hop of the RH SHOULD be consumed by this node so that the this hop of the RH SHOULD be consumed by this node so that the
destination in the IPv6 header is the next hop that this node could destination in the IPv6 header is the next hop that this node could
not reach. if a 6LoWPAN Routing Header (6LoRH) [RFC8138] is used to not reach. if a 6LoWPAN Routing Header (6LoRH) [RFC8138] is used to
carry the IPv6 routing information in the outer header then that carry the IPv6 routing information in the outer header then that
whole 6LoRH information SHOULD be present in the ICMP message. whole 6LoRH information SHOULD be present in the ICMP message.
The sender and exact operation depend on the Mode and is described in The sender and exact operation depend on the Mode and is described in
Section 7.5 and Section 7.6 respectively. Section 7.3.2 and Section 7.3.1 respectively.
7.1. Requesting a Track 7.1. Requesting a Track
A Node is free to ask the Root for a new Track at any time. This is A Node is free to ask the Root for a new Track at any time. This is
done with a PDR message, that indicates in the Requested Lifetime done with a PDR message, that indicates in the Requested Lifetime
field the duration for which the Track should be established. Upon a field the duration for which the Track should be established. Upon a
PDR, the Root MAY install the necessary Segments, in which case it PDR, the Root MAY install the necessary Segments, in which case it
answers with a PDR-ACK indicating the granted Track Lifetime. All answers with a PDR-ACK indicating the granted Track Lifetime. All
the Segments MUST be of a same mode, either Storing or Non-Storing. the Segments MUST be of a same mode, either Storing or Non-Storing.
All the Segments MUST be created with the same TrackID and the same All the Segments MUST be created with the same TrackID and the same
skipping to change at page 19, line 9 skipping to change at page 19, line 17
RPL defines the concept of an Instance to signal an individual RPL defines the concept of an Instance to signal an individual
routing topology but does not have a concept of an administrative routing topology but does not have a concept of an administrative
distance, which exists in certain proprietary implementations to sort distance, which exists in certain proprietary implementations to sort
out conflicts between multiple sources of routing information within out conflicts between multiple sources of routing information within
one routing topology. one routing topology.
This draft leverages the RPL Instance model as follows: This draft leverages the RPL Instance model as follows:
* The Root MAY use P-DAO messages to add better routes in the main * The Root MAY use P-DAO messages to add better routes in the main
(Global) Instance in conformance with the routing objectives in (Global) Instance in conformance with the routing objectives in
that Instance. To achieve this, the Root MAY install an SMPR that Instance. To achieve this, the Root MAY install an Storing-
along a path down the main Non-Storing Mode DODAG. This enables a Mode P-Route along a path down the main Non-Storing Mode DODAG.
loose source routing and reduces the size of the Routing Header, This enables a loose source routing and reduces the size of the
see Appendix A.1. Routing Header, see Appendix A.1.
When adding an SMPR to the main RPL Instance, the Root MUST set When adding an Storing-Mode P-Route to the main RPL Instance, the
the RPLInstanceID field of the P-DAO message (see section 6.4.1. Root MUST set the RPLInstanceID field of the P-DAO message (see
of [RPL]) to the RPLInstanceID of the main DODAG, and MUST NOT use section 6.4.1. of [RPL]) to the RPLInstanceID of the main DODAG,
the DODAGID field. A Projected Route provides a longer match to and MUST NOT use the DODAGID field. A Projected Route provides a
the Target Address than the default route via the Root, so it is longer match to the Target Address than the default route via the
preferred. Root, so it is preferred.
Once the Projected Route is installed, the intermediate nodes Once the Projected Route is installed, the intermediate nodes
listed in the SF-VIO after first one (i.e. The ingress) can be listed in the SF-VIO after first one (i.e. The ingress) can be
elided from the RH in packets sent along the Segment signaled in elided from the RH in packets sent along the Segment signaled in
the P-DAO. The resulting loose source routing header indicates the P-DAO. The resulting loose source routing header indicates
(one of) the Target(s) as the next entry after the ingress. (one of) the Target(s) as the next entry after the ingress.
* The Root MAY also use P-DAO messages to install a specific (say, * The Root MAY also use P-DAO messages to install a specific (say,
Traffic Engineered) path as a Serial or as a Complex Track, to a Traffic Engineered) path as a Serial or as a Complex Track, to a
particular endpoint that is the Track Egress. In that case, the particular endpoint that is the Track Egress. In that case, the
skipping to change at page 19, line 43 skipping to change at page 20, line 7
IPv6 Address (GUA) or Unique-Local Address (ULA) of the Track IPv6 Address (GUA) or Unique-Local Address (ULA) of the Track
Ingress that serves as DODAGID for the Track. This way, a Track Ingress that serves as DODAGID for the Track. This way, a Track
is uniquely identified by the tuple (DODAGID, TrackID) where the is uniquely identified by the tuple (DODAGID, TrackID) where the
TrackID is always represented with the 'D' flag set to 0. TrackID is always represented with the 'D' flag set to 0.
The Track Egress Address and the TrackID MUST be signaled in the The Track Egress Address and the TrackID MUST be signaled in the
P-DAO message as shown in Figure 1. P-DAO message as shown in Figure 1.
7.3. Installing a Track 7.3. Installing a Track
A Storing Mode P-DAO contains an SF-VIO that signals the strict A Storing-Mode P-DAO contains an SF-VIO that signals the strict
sequence of consecutive nodes to form a segment between a segment sequence of consecutive nodes to form a segment between a segment
ingress and a segment egress (both included). It installs a route of ingress and a segment egress (both included). It installs a route of
a higher precedence along the segment towards the Targets indicated a higher precedence along the segment towards the Targets indicated
in the Target Options. The segment is included in a DODAG indicated in the Target Options. The segment is included in a DODAG indicated
by the P-DAO Base Object, that may be the one formed by the main RPL by the P-DAO Base Object, that may be the one formed by the main RPL
Instance, or a Track associated with a local RPL Instance. A Track Instance, or a Track associated with a local RPL Instance. A Track
Egress is signaled as a Target in the P-DAO, and as the last entry is Egress is signaled as a Target in the P-DAO, and as the last entry is
an SF-VIO of a last segment towards that Egress. an SF-VIO of a last segment towards that Egress.
A Non-Storing Mode P-DAO signals a strict or loose sequence of nodes A Non-Storing-Mode P-DAO signals a strict or loose sequence of nodes
between the Track Ingress (excluded) and a Track Egress (included). between the Track Ingress (excluded) and a Track Egress (included).
It installs a source-routed path of a higher precedence within the It installs a source-routed path of a higher precedence within the
Track indicated by the P-DAO Base Object, towards the Targets Track indicated by the P-DAO Base Object, towards the Targets
indicated in the Target Options. The source-routed path requires a indicated in the Target Options. The source-routed path requires a
Source-Routing header which implies an encapsulation to add the SRH Source-Routing header which implies an encapsulation to add the SRH
to an existing packet. to an existing packet.
The next entry in the sequence must be either a neighbor of the The next entry in the sequence must be either a neighbor of the
previous entry, or reachable as a Target via another Projected Route, previous entry, or reachable as a Target via another Projected Route,
either Storing or Non-Storing. If it is reachable over a Storing either Storing or Non-Storing. If it is reachable over a Storing
skipping to change at page 20, line 39 skipping to change at page 21, line 5
A Complex Track can be installed as a collection of Projected Routes A Complex Track can be installed as a collection of Projected Routes
with the same DODAGID and Track ID. The Ingress of a Non-Storing with the same DODAGID and Track ID. The Ingress of a Non-Storing
Mode Projected Route must be the owner of the DODAGID. The Ingress Mode Projected Route must be the owner of the DODAGID. The Ingress
of a Storing Mode Projected Route must be either the owner of the of a Storing Mode Projected Route must be either the owner of the
DODAGID, or the egress of a preceding Storing Mode Projected Route in DODAGID, or the egress of a preceding Storing Mode Projected Route in
the same Track. In the latter case, the Targets of the Projected the same Track. In the latter case, the Targets of the Projected
Route must be Targets of the preceding Projected Route to ensure that Route must be Targets of the preceding Projected Route to ensure that
they are visible from the track Ingress. they are visible from the track Ingress.
7.4. Forwarding Along a Track 7.3.1. Storing-Mode P-Route
This draft leverages the RPL Forwarding model follows: Profile 1 extends RPL opertation in a Non-Storing Mode network with
Storing-Mode Projected Routes that install segments along the main
DODAG and enable to loose source routing between the Root and the
targets.
* In the data packets, the Track DODAGID and the TrackID MUST be As illustrated in Figure 9, a P-DAO that carries a SF-VIO enables the
respectively signaled as the IPv6 Source Address and the Root to install a stateful route towards a collection of Targets
RPLInstanceID field of the RPI that MUST be placed in the outer along a Segment between a Track Ingress and a Track Egress.
chain of IPv6 Headers.
The RPI carries a local RPLInstanceID called the TrackID, which, ------+---------
in association with the DODAGID, indicates the Track along which | Internet
the packet is forwarded. |
+-----+
| | Border Router
| | (RPL Root)
+-----+ | ^ |
| | DAO | ACK |
o o o o | | |
o o o o o o o o o | ^ | Projected .
o o o o o o o o o o | | DAO | Route .
o o o o o o o o o | ^ | .
o o o o o o o o v | DAO v .
o o LLN o o o |
o o o o o Loose Source Route Path |
o o o o From Root To Destination v
The 'D' flag in the RPLInstanceID MUST be set to 0 to indicate Figure 9: Projecting a route
that the source address in the IPv6 header is set ot the DODAGID,
more in Section 7.4.
* This draft conforms the principles of [USEofRPLinfo] with regards In order to install the relevant routing state along the Segment ,
to packet forwarding and encapsulation along a Track. the Root sends a unicast P-DAO message to the Track Egress router of
the routing Segment that is being installed. The P-DAO message
contains a SF-VIO with the direct sequence of Via Addresses. The SF-
VIO follows one or more RTOs indicating the Targets to which the
Track leads. The SF-VIO contains a Segment Lifetime for which the
state is to be maintained.
- In that case, the Track is the DODAG, the Track Ingress is the The Root sends the P-DAO directly to the egress node of the Segment.
Root, and the Track Egress is a RAL, and neighbors of the Track In that P-DAO, the destination IP address matches the last Via
Egress that can be reached via the Track are RULs. The Address in the SF-VIO. This is how the egress recognizes its role.
encapsulation rules in [USEofRPLinfo] apply. In a similar fashion, the ingress node recognizes its role as it
matches first Via Address in the SF-VIO.
- If the Track Ingress is the originator of the packet and the The Egress node of the Segment is the only node in the path that does
Track Egress is the destination of the packet, there is no need not install a route in response to the P-DAO; it is expected to be
for an encapsulation. already able to route to the Target(s) on its own. If one of the
Targets is not known, the node MUST answer to the Root with a
negative DAO-ACK listing the Target(s) that could not be located
(suggested status 10 to be confirmed by IANA).
- So the Track Ingress must encapsulate the traffic that it did If the egress node can reach all the Targets, then it forwards the
not originate, and add an RPI in any fashion. P-DAO with unchanged content to its loose predecessor in the Segment
as indicated in the list of Via Information options, and recursively
the message is propagated unchanged along the sequence of routers
indicated in the P-DAO, but in the reverse order, from egress to
ingress.
A packet that is being routed over the RPL Instance associated to The address of the predecessor to be used as destination of the
a first Non-Storing Mode Track MAY be placed (encapsulated) in a propagated DAO message is found in the Via Address the precedes the
second Track to cover one loose hop of the first Track. On the one that contain the address of the propagating node, which is used
other hand, a Storing Mode Track must be strict and a packet that as source of the message.
it placed in a Storing Mode Track MUST follow that Track till the
Track Egress.
When a Track Egress extracts a packet from a Track (decapsulates Upon receiving a propagated DAO, all except the Egress Router MUST
the packet), the Destination of the inner packet MUST be either install a route towards the DAO Target(s) via their successor in the
this node or a direct neighbor, or a Target of another Segment of SF-VIO. The router MAY install additional routes towards the VIA
the same Track for which this node is ingress, otherwise the Addresses that are the SF-VIO after the next one, if any, but in case
packet MUST be dropped. of a conflict or a lack of resource, the route(s) to the Target(s)
have precedence.
All properties of a Track operations are inherited form the main RPL If a router cannot reach its predecessor in the SF-VIO, the router
Instance that is used to install the Track. For instance, the use of MUST answer to the Root with a negative DAO-ACK indicating the
compression per [RFC8138] is determined by whether it is used in the successor that is unreachable (suggested status 11 to be confirmed by
main instance, e.g., by setting the "T" flag [TURN-ON_RFC8138] in the IANA).
RPL configuration option.
7.5. Non-Storing Mode Projected Route The process continues till the P-DAO is propagated to ingress router
of the Segment, which answers with a DAO-ACK to the Root.
As illustrated in Figure 9, a P-DAO that carries an SR-VIO enables A Segment Lifetime of 0 in a VIOis used to clean up the state. The
the Root to install a source-routed path towards a Track Egress in P-DAO is forwarded as described above, but the DAO is interpreted as
any particular router. a No-Path DAO and results in cleaning up existing state as opposed to
refreshing an existing one or installing a new one.
In case of a forwarding error along an Storing-Mode P-Route, the node
that fails to forward SHOULD send an ICMP error with a code "Error in
Projected Route" to the Root. Failure to do so may result in packet
loss and wasted resources along the Projected Route that is broken.
7.3.2. Non-Storing-Mode P-Route
As illustrated in Figure 10, a P-DAO that carries an SR-VIO enables
the Root to install a source-routed path from a Track Ingress towards
a Target along the main DODAG.
------+--------- ------+---------
| Internet | Internet
| |
+-----+ +-----+
| | Border Router | | Border Router
| | (RPL Root) | | (RPL Root)
+-----+ | P ^ ACK +-----+ | P ^ ACK
| Track | DAO | | Track | DAO |
o o o o Ingress X V | X o o o o Ingress X V | X
skipping to change at page 22, line 26 skipping to change at page 23, line 32
o o ° o o o o X o X Segment o o ° o o o o X o X Segment
o o o o o o o o X Track X o o o o o o o o X Track X
o o o o o Egress o o o o o Egress
o o o o o o o o
o o o o o o o o
destination destination
LLN LLN
Figure 9: Projecting a Non-Storing Route Figure 10: Projecting a Non-Storing Route
A route indicated by an SR-VIO may be loose, meaning that the node
that owns the next listed Via Address is not necessarily a neighbor.
Without proper loop avoidance mechanisms, the interaction of loose
source routing and other mechanisms may effectively cause loops.
When forwarding a packet to a destination for which the router When forwarding a packet to a destination for which the router
determines that routing happens via the Track Egress, the router determines that routing happens via a Track Target, the router
inserts the source routing header in the packet with the destination inserts the Source Routing Header in the packet with the final
set to the Track Egress. destination at the Track Egress.
In order to signal the Segment, the router encapsulates the packet In order to signal the Segment, the router encapsulates the packet
with an IP-in-IP header and a Routing Header as follows: with an IP-in-IP header and a Routing Header as follows:
* In the uncompressed form the source of the packet is this router, * In the uncompressed form the source of the packet is this router,
the destination is the first Via Address in the SR-VIO, and the RH the destination is the first Via Address in the SR-VIO, and the RH
is a Source Routing Header (SRH) [RFC6554] that contains the list is a Source Routing Header (SRH) [RFC6554] that contains the list
of the remaining Via Addresses terminating by the Track Egress. of the remaining Via Addresses terminating by the Track Egress.
* The preferred alternate in a network where 6LoWPAN Header * The preferred alternate in a network where 6LoWPAN Header
skipping to change at page 23, line 28 skipping to change at page 24, line 28
In case of a forwarding error along a Source Route path, the node In case of a forwarding error along a Source Route path, the node
that fails to forward SHOULD send an ICMP error with a code "Error in that fails to forward SHOULD send an ICMP error with a code "Error in
Source Routing Header" back to the source of the packet, as described Source Routing Header" back to the source of the packet, as described
in section 11.2.2.3. of [RPL]. Upon this message, the encapsulating in section 11.2.2.3. of [RPL]. Upon this message, the encapsulating
node SHOULD stop using the source route path for a period of time and node SHOULD stop using the source route path for a period of time and
it SHOULD send an ICMP message with a Code "Error in Projected Route" it SHOULD send an ICMP message with a Code "Error in Projected Route"
to the Root. Failure to follow these steps may result in packet loss to the Root. Failure to follow these steps may result in packet loss
and wasted resources along the source route path that is broken. and wasted resources along the source route path that is broken.
7.6. Storing Mode Projected Route 7.4. Forwarding Along a Track
As illustrated in Figure 10, a P-DAO that carries a SF-VIO enables This draft leverages the RPL Forwarding model follows:
the Root to install a stateful route towards a collection of Targets
along a Segment between a Track Ingress and a Track Egress.
------+--------- * In the data packets, the Track DODAGID and the TrackID MUST be
| Internet respectively signaled as the IPv6 Source Address and the
| RPLInstanceID field of the RPI that MUST be placed in the outer
+-----+ chain of IPv6 Headers.
| | Border Router
| | (RPL Root)
+-----+ | ^ |
| | DAO | ACK |
o o o o | | |
o o o o o o o o o | ^ | Projected .
o o o o o o o o o o | | DAO | Route .
o o o o o o o o o | ^ | .
o o o o o o o o v | DAO v .
o o LLN o o o |
o o o o o Loose Source Route Path |
o o o o From Root To Destination v
Figure 10: Projecting a route The RPI carries a local RPLInstanceID called the TrackID, which,
in association with the DODAGID, indicates the Track along which
the packet is forwarded.
In order to install the relevant routing state along the Segment , The 'D' flag in the RPLInstanceID MUST be set to 0 to indicate
the Root sends a unicast P-DAO message to the Track Egress router of that the source address in the IPv6 header is set ot the DODAGID,
the routing Segment that is being installed. The P-DAO message more in Section 7.4.
contains a SF-VIO with the direct sequence of Via Addresses. The SF-
VIO follows one or more RTOs indicating the Targets to which the
Track leads. The SF-VIO contains a Segment Lifetime for which the
state is to be maintained.
The Root sends the P-DAO directly to the egress node of the Segment. * This draft conforms the principles of [USEofRPLinfo] with regards
In that P-DAO, the destination IP address matches the last Via to packet forwarding and encapsulation along a Track.
Address in the SF-VIO. This is how the egress recognizes its role.
In a similar fashion, the ingress node recognizes its role as it
matches first Via Address in the SF-VIO.
The Egress node of the Segment is the only node in the path that does - In that case, the Track is the DODAG, the Track Ingress is the
not install a route in response to the P-DAO; it is expected to be Root, and the Track Egress is a RAL, and neighbors of the Track
already able to route to the Target(s) on its own. If one of the Egress that can be reached via the Track are RULs. The
Targets is not known, the node MUST answer to the Root with a encapsulation rules in [USEofRPLinfo] apply.
negative DAO-ACK listing the Target(s) that could not be located
(suggested status 10 to be confirmed by IANA).
If the egress node can reach all the Targets, then it forwards the - If the Track Ingress is the originator of the packet and the
P-DAO with unchanged content to its loose predecessor in the Segment Track Egress is the destination of the packet, there is no need
as indicated in the list of Via Information options, and recursively for an encapsulation.
the message is propagated unchanged along the sequence of routers
indicated in the P-DAO, but in the reverse order, from egress to
ingress.
The address of the predecessor to be used as destination of the - So the Track Ingress must encapsulate the traffic that it did
propagated DAO message is found in the Via Address the precedes the not originate, and add an RPI in any fashion.
one that contain the address of the propagating node, which is used
as source of the message.
Upon receiving a propagated DAO, all except the Egress Router MUST A packet that is being routed over the RPL Instance associated to
install a route towards the DAO Target(s) via their successor in the a first Non-Storing Mode Track MAY be placed (encapsulated) in a
SF-VIO. The router MAY install additional routes towards the VIA second Track to cover one loose hop of the first Track. On the
Addresses that are the SF-VIO after the next one, if any, but in case other hand, a Storing Mode Track must be strict and a packet that
of a conflict or a lack of resource, the route(s) to the Target(s) it placed in a Storing Mode Track MUST follow that Track till the
have precedence. Track Egress.
If a router cannot reach its predecessor in the SF-VIO, the router When a Track Egress extracts a packet from a Track (decapsulates
MUST answer to the Root with a negative DAO-ACK indicating the the packet), the Destination of the inner packet MUST be either
successor that is unreachable (suggested status 11 to be confirmed by this node or a direct neighbor, or a Target of another Segment of
IANA). the same Track for which this node is ingress, otherwise the
packet MUST be dropped.
The process continues till the P-DAO is propagated to ingress router All properties of a Track operations are inherited form the main RPL
of the Segment, which answers with a DAO-ACK to the Root. Instance that is used to install the Track. For instance, the use of
compression per [RFC8138] is determined by whether it is used in the
main instance, e.g., by setting the "T" flag [TURN-ON_RFC8138] in the
RPL configuration option.
A Segment Lifetime of 0 in a Via Information option is used to clean 8. Profiles
up the state. The P-DAO is forwarded as described above, but the DAO
is interpreted as a No-Path DAO and results in cleaning up existing
state as opposed to refreshing an existing one or installing a new
one.
In case of a forwarding error along an SMPR, the node that fails to This document provides a set of tools that may or may not be needed
forward SHOULD send an ICMP error with a code "Error in Projected by an implementation depending on the type of application it serves.
Route" to the Root. Failure to do so may result in packet loss and This sections described profiles that can be implemented separately
wasted resources along the Projected Route that is broken. and can be used to discriminate what an implementation can and cannot
do.
8. Security Considerations Profile 0 Profile 0 is the legacy support of [RPL] Non-Storing Mode.
It provides the minimal common functionality that must be
implemented as a prerequisite to all the Track-supporting
profiles. The other Profiles extend Profile 0 with selected
capabilities that this specification introduces on top.
Profile 1 (Storing-Mode P-Route Segments along the main DODAG) Profi
le 1 does not create new paths; it combines Storing and Non-
Storing Modes to balance the size of the routing header in the
packet and the amount of state in the intermediate routers in a
Non-Storing Mode RPL DODAG.
Profile 2 (Non-Storing-Mode P-Route Segments along the main DODAG) P
rofile 2 extends Profile 0 with Strict Source-Routing Non-Storing-
Mode Projected Routes along the main DODAG. Profile 2 provides
the same capability to compress the SRH in packets down the main
DODAG as Profile 1, but it require an encapsulation, in order to
insert an additional SRH between the loose source routing hops.
Profile 3 Profile 3 and above build Tracks that do not necessarily
follow the main DODAG. In order to form the best path possible,
those Profiles require the support of Sibling Information Option
to inform the Root of additional possible hops. Profile 3 extends
Profile 1 with additional Storing-Mode Projected Routes that
install segments that do not follow the main DODAG. Segments can
be associated in a Track rooted at an Ingress node, but there is
no explicit Egress node, and no source routing operation.
Profile 4 Profile 4 extends Profile 2 with Strict Source-Routing
Non-Storing-Mode Projected Routes to form Tracks inside the main
DODAG. A Track is formed as one or more strict source source
routed paths between the Root that is the Track Ingress, and the
Track Egress that is the last node
Profile 5 Profile 5 Combines Profile 4 with Profile 1 and enables to
loose source routing between the Ingress and the Egress of the
Track. As in Profile 1, Storing-Mode Projected Routes connect the
dots in the loose source route.
Profile 6 Profile 6 Combines Profile 4 with Profile 2 and also
enables to loose source routing between the Ingress and the Egress
of the Track.
9. Example Track Signaling
The remainder of the section provides an example of how a Track can
be signaled
===> F
A ===> B ===> C ===> D===> E <
===> G
Figure 11: Reference Track
A is Track ingress, E is track Egress. C is stitching point. F and
G are E's neighbors, "external" to the Track, and reachable from A
over the Track A->E.
In a general manner we want:
* P-DAO 1 signals C==>B==>E
* P-DAO 2 signals A==>B==>C
* P-DAO 3 signals F and G via the A==>E Track
P-DAO 3 being loose, it can only be non-storing. Note that since the
Root is always the ingress of a Track, and all SR-VIOs are now Track,
the Root being signaled in the DAO base object can now be elided in
the VIA list in SR-VIO. This enables the construction by the main
root of the RFC 8138 optimized SRH-6LoRH in the SR-VIO, to be placed
as is in the packet by the Root.
9.1. Using Storing-Mode Segments
A==>B==>C and C==>D==>E are segments of a same Track. Note that the
storing mode signaling imposes strict continuity in a segment. One
benefit of strict routing is that loops are avoided along the Track.
9.1.1. Stitched Segments
Storing-Mode P-DAO 1 and 2 are sent to E and C, as follows:
+===============+==============+==============+
| Field | P-DAO 1 to E | P-DAO 2 to C |
+===============+==============+==============+
| Mode | Storing | Storing |
+---------------+--------------+--------------+
| Track Ingress | A | A |
+---------------+--------------+--------------+
| TrackID | (A, 129) | (A, 129) |
+---------------+--------------+--------------+
| VIO | C, D, E | A, B, C |
+---------------+--------------+--------------+
| Targets | E, F, G | E, F, G |
+---------------+--------------+--------------+
Table 1: P-DAO Messages
As a result the RIBs are set as follows:
+======+=============+=========+=============+==========+
| Node | Destination | Origin | Next Hop(s) | TrackID |
+======+=============+=========+=============+==========+
| E | F, G | P-DAO 1 | Neighbor | (A, 129) |
+------+-------------+---------+-------------+----------+
| D | E | P-DAO 1 | Neighbor | (A, 129) |
+------+-------------+---------+-------------+----------+
| " | F, G | P-DAO 1 | E | (A, 129) |
+------+-------------+---------+-------------+----------+
| C | D | P-DAO 1 | Neighbor | (A, 129) |
+------+-------------+---------+-------------+----------+
| " | E, F, G | P-DAO 1 | D | (A, 129) |
+------+-------------+---------+-------------+----------+
| B | C | P-DAO 2 | Neighbor | (A, 129) |
+------+-------------+---------+-------------+----------+
| " | E, F, G | P-DAO 2 | C | (A, 129) |
+------+-------------+---------+-------------+----------+
| A | B | P-DAO 2 | Neighbor | (A, 129) |
+------+-------------+---------+-------------+----------+
| A | E, F, G | P-DAO 2 | B | (A, 129) |
+------+-------------+---------+-------------+----------+
Table 2: RIB setting
E recognizes that it is the Track Egress because it is both a Target
and a Segment Endpoint.
Packets originated by A to E, F, or G, do not require an
encapsulation. In any fashion, the outer headers of the packets that
are forwarded along the Track have the following settings:
+========+===================+===================+================+
| Header | IPv6 Source Addr. | IPv6 Dest. Addr. | TrackID in RPI |
+========+===================+===================+================+
| Outer | A | E, F or G | (A, 129) |
+--------+-------------------+-------------------+----------------+
| Inner | X != A | E, F or G | N/A |
+--------+-------------------+-------------------+----------------+
Table 3: Packet header settings
As an example, say that A has a packet for F. Using the RIB above:
* From P-DAO 2: A forwards to B and B forwards to C.
* From P-DAO 1: C forwards to D and D forwards to E.
* From Neighbor Cache Entry: C delivers the packet to F.
9.1.2. External routes
Storing-Mode P-DAO 1 and 2, and Non-Storing-Mode P-DAO 3, are sent to
E, C and A, respectively, as follows:
+===============+==============+==============+==============+
| | P-DAO 1 to E | P-DAO 2 to C | P-DAO 3 to A |
+===============+==============+==============+==============+
| Mode | Storing | Storing | Non-Storing |
+---------------+--------------+--------------+--------------+
| Track Ingress | A | A | A |
+---------------+--------------+--------------+--------------+
| TrackID | (A, 129) | (A, 129) | (A, 129) |
+---------------+--------------+--------------+--------------+
| VIO | C, D, E | A, B, C | E |
+---------------+--------------+--------------+--------------+
| Targets | E | E | F, G |
+---------------+--------------+--------------+--------------+
Table 4: P-DAO Messages
As a result the RIBs are set as follows:
+======+=============+=========+=============+==========+
| Node | Destination | Origin | Next Hop(s) | TrackID |
+======+=============+=========+=============+==========+
| E | F, G | P-DAO 1 | Neighbor | (A, 129) |
+------+-------------+---------+-------------+----------+
| D | E | P-DAO 1 | Neighbor | (A, 129) |
+------+-------------+---------+-------------+----------+
| C | D | P-DAO 1 | Neighbor | (A, 129) |
+------+-------------+---------+-------------+----------+
| " | E | P-DAO 1 | D | (A, 129) |
+------+-------------+---------+-------------+----------+
| B | C | P-DAO 2 | Neighbor | (A, 129) |
+------+-------------+---------+-------------+----------+
| " | E | P-DAO 2 | C | (A, 129) |
+------+-------------+---------+-------------+----------+
| A | B | P-DAO 2 | Neighbor | (A, 129) |
+------+-------------+---------+-------------+----------+
| A | E | P-DAO 2 | B | (A, 129) |
+------+-------------+---------+-------------+----------+
| A | F, G | P-DAO 3 | E | (A, 129) |
+------+-------------+---------+-------------+----------+
Table 5: RIB setting
Packets from A to E do not require an encapsulation. In any fashion,
the outer headers of the packets that are forwarded along the Track
have the following settings:
+========+===================+====================+================+
| Header | IPv6 Source Addr. | IPv6 Dest. Addr. | TrackID in RPI |
+========+===================+====================+================+
| Outer | A | E | (A, 129) |
+--------+-------------------+--------------------+----------------+
| Inner | X | E (X != A), F or G | N/A |
+--------+-------------------+--------------------+----------------+
Table 6: Packet header settings
As an example, say that A has a packet for F. Using the RIB above:
* From P-DAO 3: A encapsulates the packet the Track signaled by
P-DAO 3, with the outer header above. Now the packet destination
is E.
* From P-DAO 2: A forwards to B and B forwards to C.
* From P-DAO 1: C forwards to D and D forwards to E; E decapsulates
the packet.
* From Neighbor Cache Entry: C delivers packets to F or G.
9.1.3. Segment Routing
Storing-Mode P-DAO 1 and 2, and Non-Storing-Mode P-DAO 3, are sent to
E, B and A, respectively, as follows:
+===============+==============+==============+==============+
| | P-DAO 1 to E | P-DAO 2 to B | P-DAO 3 to A |
+===============+==============+==============+==============+
| Mode | Storing | Storing | Non-Storing |
+---------------+--------------+--------------+--------------+
| Track Ingress | A | A | A |
+---------------+--------------+--------------+--------------+
| TrackID | (A, 129) | (A, 129) | (A, 129) |
+---------------+--------------+--------------+--------------+
| VIO | C, D, E | A, B | C, E |
+---------------+--------------+--------------+--------------+
| Targets | E | B, C | F, G |
+---------------+--------------+--------------+--------------+
Table 7: P-DAO Messages
As a result the RIBs are set as follows:
+======+=============+=========+=============+==========+
| Node | Destination | Origin | Next Hop(s) | TrackID |
+======+=============+=========+=============+==========+
| E | F, G | P-DAO 1 | Neighbor | (A, 129) |
+------+-------------+---------+-------------+----------+
| D | E | P-DAO 1 | Neighbor | (A, 129) |
+------+-------------+---------+-------------+----------+
| C | D | P-DAO 1 | Neighbor | (A, 129) |
+------+-------------+---------+-------------+----------+
| " | E | P-DAO 1 | D | (A, 129) |
+------+-------------+---------+-------------+----------+
| B | C | P-DAO 2 | Neighbor | (A, 129) |
+------+-------------+---------+-------------+----------+
| A | B | P-DAO 2 | Neighbor | (A, 129) |
+------+-------------+---------+-------------+----------+
| " | C | P-DAO 2 | B | (A, 129) |
+------+-------------+---------+-------------+----------+
| " | E, F, G | P-DAO 3 | C, E | (A, 129) |
+------+-------------+---------+-------------+----------+
Table 8: RIB setting
Packets from A to E do not require an encapsulation, but carry a SRH
via C. In any fashion, the outer headers of the packets that are
forwarded along the Track have the following settings:
+========+===================+====================+================+
| Header | IPv6 Source Addr. | IPv6 Dest. Addr. | TrackID in RPI |
+========+===================+====================+================+
| Outer | A | C till C then E | (A, 129) |
+--------+-------------------+--------------------+----------------+
| Inner | X | E (X != A), F or G | N/A |
+--------+-------------------+--------------------+----------------+
Table 9: Packet header settings
As an example, say that A has a packet for F. Using the RIB above:
* From P-DAO 3: A encapsulates the packet the Track signaled by
P-DAO 3, with the outer header above. Now the destination in the
IPv6 Header is C, and a SRH signals the final destination is E.
* From P-DAO 2: A forwards to B and B forwards to C.
* From P-DAO 3: C processes the SRH and sets the destination in the
IPv6 Header to E.
* From P-DAO 1: C forwards to D and D forwards to E; E decapsulates
the packet.
* From the Neighbor Cache Entry: C delivers packets to F or G.
9.2. Using Non-Storing-Mode joining Tracks
A==>B==>C and C==>D==>E are Tracks expressed as non-storing P-DAOs.
9.2.1. Stitched Tracks
Non-Storing Mode P-DAO 1 and 2 are sent to C and A respectively, as
follows:
+===============+==============+==============+
| | P-DAO 1 to C | P-DAO 2 to A |
+===============+==============+==============+
| Mode | Non-Storing | Non-Storing |
+---------------+--------------+--------------+
| Track Ingress | C | A |
+---------------+--------------+--------------+
| TrackID | (C, 131) | (A, 129) |
+---------------+--------------+--------------+
| VIO | D, E | B, C |
+---------------+--------------+--------------+
| Targets | F, G | E, F, G |
+---------------+--------------+--------------+
Table 10: P-DAO Messages
As a result the RIBs are set as follows:
+======+=============+=========+=============+==========+
| Node | Destination | Origin | Next Hop(s) | TrackID |
+======+=============+=========+=============+==========+
| E | F, G | ND | Neighbor | Any |
+------+-------------+---------+-------------+----------+
| D | E | ND | Neighbor | Any |
+------+-------------+---------+-------------+----------+
| C | D | ND | Neighbor | Any |
+------+-------------+---------+-------------+----------+
| " | E, F, G | P-DAO 1 | D, E | (C, 131) |
+------+-------------+---------+-------------+----------+
| B | C | ND | Neighbor | Any |
+------+-------------+---------+-------------+----------+
| A | B | ND | Neighbor | Any |
+------+-------------+---------+-------------+----------+
| " | C, E, F, G | P-DAO 2 | B, C | (A, 129) |
+------+-------------+---------+-------------+----------+
Table 11: RIB setting
Packets from A to E, F and G do not require an encapsulation, though
it is preferred that A encapsulates and C decapsulates. Either way,
they carry a SRH via B and C, and C needs to encapsulate to E, F, or
G to add an SRH via D and E. The encapsulating headers of packets
that are forwarded along the Track between C and E have the following
settings:
+========+===================+===================+================+
| Header | IPv6 Source Addr. | IPv6 Dest. Addr. | TrackID in RPI |
+========+===================+===================+================+
| Outer | C | D till D then E | (C, 131) |
+--------+-------------------+-------------------+----------------+
| Inner | X | E, F, or G | N/A |
+--------+-------------------+-------------------+----------------+
Table 12: Packet header settings
As an example, say that A has a packet for F. Using the RIB above:
* From P-DAO 2: A encapsulates the packet with destination of F in
the Track signaled by P-DAO 2. The outer header has source A,
destination B, an SRH that indicates C as the next loose hop, and
a RPI indicating a TrackId of 129 from A's namespace.
* From the SRH: Packets forwarded by B have source A, destination C
, a consumed SRH, and a RPI indicating a TrackId of 129 from A's
namespace. C decapsulates.
* From P-DAO 1: C encapsulates the packet with destination of F in
the Track signaled by P-DAO 1. The outer header has source C,
destination D, an SRH that indicates E as the next loose hop, and
a RPI indicating a TrackId of 131 from C's namespace. E
decapsulates.
9.2.2. External routes
Non-Storing Mode P-DAO 1 is sent to C and Non-Storing Mode P-DAO 2
and 3 are sent A, as follows:
+===============+==============+==============+==============+
| | P-DAO 1 to C | P-DAO 2 to A | P-DAO 3 to A |
+===============+==============+==============+==============+
| Mode | Non-Storing | Non-Storing | Non-Storing |
+---------------+--------------+--------------+--------------+
| Track Ingress | C | A | A |
+---------------+--------------+--------------+--------------+
| TrackID | (C, 131) | (A, 129) | (A, 141) |
+---------------+--------------+--------------+--------------+
| VIO | D, E | B, C | E |
+---------------+--------------+--------------+--------------+
| Targets | E | E | F, G |
+---------------+--------------+--------------+--------------+
Table 13: P-DAO Messages
As a result the RIBs are set as follows:
+======+=============+=========+=============+==========+
| Node | Destination | Origin | Next Hop(s) | TrackID |
+======+=============+=========+=============+==========+
| E | F, G | ND | Neighbor | Any |
+------+-------------+---------+-------------+----------+
| D | E | ND | Neighbor | Any |
+------+-------------+---------+-------------+----------+
| C | D | ND | Neighbor | Any |
+------+-------------+---------+-------------+----------+
| " | E | P-DAO 1 | D, E | (C, 131) |
+------+-------------+---------+-------------+----------+
| B | C | ND | Neighbor | Any |
+------+-------------+---------+-------------+----------+
| A | B | ND | Neighbor | Any |
+------+-------------+---------+-------------+----------+
| " | C, E | P-DAO 2 | B, C | (A, 129) |
+------+-------------+---------+-------------+----------+
| " | F, G | P-DAO 3 | E | (A, 141) |
+------+-------------+---------+-------------+----------+
Table 14: RIB setting
The encapsulating headers of packets that are forwarded along the
Track between C and E have the following settings:
+========+===================+===================+================+
| Header | IPv6 Source Addr. | IPv6 Dest. Addr. | TrackID in RPI |
+========+===================+===================+================+
| Outer | C | D till D then E | (C, 131) |
+--------+-------------------+-------------------+----------------+
| Middle | A | E | (A, 141) |
+--------+-------------------+-------------------+----------------+
| Inner | X | E, F or G | N/A |
+--------+-------------------+-------------------+----------------+
Table 15: Packet header settings
As an example, say that A has a packet for F. Using the RIB above:
* From P-DAO 3: A encapsulates the packet with destination of F in
the Track signaled by P-DAO 3. The outer header has source A,
destination E, and a RPI indicating a TrackId of 141 from A's
namespace. This recurses with:
* From P-DAO 2: A encapsulates the packet with destination of E in
the Track signaled by P-DAO 2. The outer header has source A,
destination B, an SRH that indicates C as the next loose hop, and
a RPI indicating a TrackId of 129 from A's namespace.
* From the SRH: Packets forwarded by B have source A, destination C
, a consumed SRH, and a RPI indicating a TrackId of 129 from A's
namespace. C decapsulates.
* From P-DAO 1: C encapsulates the packet with destination of E in
the Track signaled by P-DAO 1. The outer header has source C,
destination D, an SRH that indicates E as the next loose hop, and
a RPI indicating a TrackId of 131 from C's namespace. E
decapsulates.
9.2.3. Segment Routing
Non-Storing Mode P-DAO 1 is sent to C and Non-Storing Mode P-DAO 2
and 3 are sent A, as follows:
+===============+==============+==============+==============+
| | P-DAO 1 to C | P-DAO 2 to A | P-DAO 3 to A |
+===============+==============+==============+==============+
| Mode | Non-Storing | Non-Storing | Non-Storing |
+---------------+--------------+--------------+--------------+
| Track Ingress | C | A | A |
+---------------+--------------+--------------+--------------+
| TrackID | (C, 131) | (A, 129) | (A, 141) |
+---------------+--------------+--------------+--------------+
| VIO | D, E | B | C, E |
+---------------+--------------+--------------+--------------+
| Targets | | C | F, G |
+---------------+--------------+--------------+--------------+
Table 16: P-DAO Messages
As a result the RIBs are set as follows:
+======+=============+=========+=============+==========+
| Node | Destination | Origin | Next Hop(s) | TrackID |
+======+=============+=========+=============+==========+
| E | F, G | ND | Neighbor | Any |
+------+-------------+---------+-------------+----------+
| D | E | ND | Neighbor | Any |
+------+-------------+---------+-------------+----------+
| C | D | ND | Neighbor | Any |
+------+-------------+---------+-------------+----------+
| " | E | P-DAO 1 | D, E | (C, 131) |
+------+-------------+---------+-------------+----------+
| B | C | ND | Neighbor | Any |
+------+-------------+---------+-------------+----------+
| A | B | ND | Neighbor | Any |
+------+-------------+---------+-------------+----------+
| " | C | P-DAO 2 | B, C | (A, 129) |
+------+-------------+---------+-------------+----------+
| " | E, F, G | P-DAO 3 | C, E | (A, 141) |
+------+-------------+---------+-------------+----------+
Table 17: RIB setting
The encapsulating headers of packets that are forwarded along the
Track between A and B have the following settings:
+========+===================+===================+================+
| Header | IPv6 Source Addr. | IPv6 Dest. Addr. | TrackID in RPI |
+========+===================+===================+================+
| Outer | A | B till D then E | (A, 129) |
+--------+-------------------+-------------------+----------------+
| Middle | A | C | (A, 141) |
+--------+-------------------+-------------------+----------------+
| Inner | X | E, F or G | N/A |
+--------+-------------------+-------------------+----------------+
Table 18: Packet header settings
The encapsulating headers of packets that are forwarded along the
Track between B and C have the following settings:
+========+===================+===================+================+
| Header | IPv6 Source Addr. | IPv6 Dest. Addr. | TrackID in RPI |
+========+===================+===================+================+
| Outer | A | C | (A, 141) |
+--------+-------------------+-------------------+----------------+
| Inner | X | E, F or G | N/A |
+--------+-------------------+-------------------+----------------+
Table 19: Packet header settings
The encapsulating headers of packets that are forwarded along the
Track between C and E have the following settings:
+========+===================+===================+================+
| Header | IPv6 Source Addr. | IPv6 Dest. Addr. | TrackID in RPI |
+========+===================+===================+================+
| Outer | C | D till D then E | (C, 131) |
+--------+-------------------+-------------------+----------------+
| Middle | A | E | (A, 141) |
+--------+-------------------+-------------------+----------------+
| Inner | X | E, F or G | N/A |
+--------+-------------------+-------------------+----------------+
Table 20: Packet header settings
As an example, say that A has a packet for F. Using the RIB above:
* From P-DAO 3: A encapsulates the packet with destination of F in
the Track signaled by P-DAO 3. The outer header has source A,
destination C, an SRH that indicates E as the next loose hop, and
a RPI indicating a TrackId of 141 from A's namespace. This
recurses with:
* From P-DAO 2: A encapsulates the packet with destination of C in
the Track signaled by P-DAO 2. The outer header has source A,
destination B, and a RPI indicating a TrackId of 129 from A's
namespace. B decapsulates forwards to C based on a sibling
connected route.
* From the SRH: C consumes the SRH and makes the destination E.
* From P-DAO 1: C encapsulates the packet with destination of E in
the Track signaled by P-DAO 1. The outer header has source C,
destination D, an SRH that indicates E as the next loose hop, and
a RPI indicating a TrackId of 131 from C's namespace. E
decapsulates.
10. Security Considerations
This draft uses messages that are already present in RPL [RPL] with This draft uses messages that are already present in RPL [RPL] with
optional secured versions. The same secured versions may be used optional secured versions. The same secured versions may be used
with this draft, and whatever security is deployed for a given with this draft, and whatever security is deployed for a given
network also applies to the flows in this draft. network also applies to the flows in this draft.
TODO: should probably consider how P-DAO messages could be abused by TODO: should probably consider how P-DAO messages could be abused by
a) rogue nodes b) via replay of messages c) if use of P-DAO messages a) rogue nodes b) via replay of messages c) if use of P-DAO messages
could in fact deal with any threats? could in fact deal with any threats?
9. IANA Considerations 11. IANA Considerations
9.1. New Elective 6LoWPAN Routing Header Type 11.1. New Elective 6LoWPAN Routing Header Type
This document updates the IANA registry titled "Elective 6LoWPAN This document updates the IANA registry titled "Elective 6LoWPAN
Routing Header Type" that was created for [RFC8138] and assigns the Routing Header Type" that was created for [RFC8138] and assigns the
following value: following value:
+=======+=============+===============+ +=======+=============+===============+
| Value | Description | Reference | | Value | Description | Reference |
+=======+=============+===============+ +=======+=============+===============+
| 7 | P-RPI-6LoRH | This document | | 7 | P-RPI-6LoRH | This document |
+-------+-------------+---------------+ +-------+-------------+---------------+
Table 1: New Elective 6LoWPAN Table 21: New Elective 6LoWPAN
Routing Header Type Routing Header Type
9.2. New Critical 6LoWPAN Routing Header Type 11.2. New Critical 6LoWPAN Routing Header Type
This document updates the IANA registry titled "Critical 6LoWPAN This document updates the IANA registry titled "Critical 6LoWPAN
Routing Header Type" that was created for [RFC8138] and assigns the Routing Header Type" that was created for [RFC8138] and assigns the
following value: following value:
+=======+=============+===============+ +=======+=============+===============+
| Value | Description | Reference | | Value | Description | Reference |
+=======+=============+===============+ +=======+=============+===============+
| 7 | P-RPI-6LoRH | This document | | 7 | P-RPI-6LoRH | This document |
+-------+-------------+---------------+ +-------+-------------+---------------+
Table 2: New Critical 6LoWPAN Table 22: New Critical 6LoWPAN
Routing Header Type Routing Header Type
9.3. New Subregistry For The RPL Option Flags 11.3. New Subregistry For The RPL Option Flags
IANA is required to create a subregistry for the 8-bit RPL Option IANA is required to create a subregistry for the 8-bit RPL Option
Flags field, as detailed in Figure 2, under the "Routing Protocol for Flags field, as detailed in Figure 2, under the "Routing Protocol for
Low Power and Lossy Networks (RPL)" registry. The bits are indexed Low Power and Lossy Networks (RPL)" registry. The bits are indexed
from 0 (leftmost) to 7. Each bit is tracked with the following from 0 (leftmost) to 7. Each bit is tracked with the following
qualities: qualities:
* Bit number (counting from bit 0 as the most significant bit) * Bit number (counting from bit 0 as the most significant bit)
* Indication When Set * Indication When Set
* Reference * Reference
Registration procedure is "Standards Action" [RFC8126]. The initial Registration procedure is "Standards Action" [RFC8126]. The initial
allocation is as indicated in Table 6: allocation is as indicated in Table 26:
+============+======================+===============+ +============+======================+===============+
| Bit number | Indication When Set | Reference | | Bit number | Indication When Set | Reference |
+============+======================+===============+ +============+======================+===============+
| 0 | Down 'O' | [RFC6553] | | 0 | Down 'O' | [RFC6553] |
+------------+----------------------+---------------+ +------------+----------------------+---------------+
| 1 | Rank-Error (R) | [RFC6553] | | 1 | Rank-Error (R) | [RFC6553] |
+------------+----------------------+---------------+ +------------+----------------------+---------------+
| 2 | Forwarding-Error (F) | [RFC6553] | | 2 | Forwarding-Error (F) | [RFC6553] |
+------------+----------------------+---------------+ +------------+----------------------+---------------+
| 3 | Projected-Route (P) | This document | | 3 | Projected-Route (P) | This document |
+------------+----------------------+---------------+ +------------+----------------------+---------------+
Table 3: Initial PDR Flags Table 23: Initial PDR Flags
9.4. New RPL Control Codes 11.4. New RPL Control Codes
This document extends the IANA Subregistry created by RFC 6550 for This document extends the IANA Subregistry created by RFC 6550 for
RPL Control Codes as indicated in Table 4: RPL Control Codes as indicated in Table 24:
+======+=============================+===============+ +======+=============================+===============+
| Code | Description | Reference | | Code | Description | Reference |
+======+=============================+===============+ +======+=============================+===============+
| 0x09 | Projected DAO Request (PDR) | This document | | 0x09 | Projected DAO Request (PDR) | This document |
+------+-----------------------------+---------------+ +------+-----------------------------+---------------+
| 0x0A | PDR-ACK | This document | | 0x0A | PDR-ACK | This document |
+------+-----------------------------+---------------+ +------+-----------------------------+---------------+
Table 4: New RPL Control Codes Table 24: New RPL Control Codes
9.5. New RPL Control Message Options 11.5. New RPL Control Message Options
This document extends the IANA Subregistry created by RFC 6550 for This document extends the IANA Subregistry created by RFC 6550 for
RPL Control Message Options as indicated in Table 5: RPL Control Message Options as indicated in Table 25:
+=======+==========================================+===============+ +=======+============================+===============+
| Value | Meaning | Reference | | Value | Meaning | Reference |
+=======+==========================================+===============+ +=======+============================+===============+
| 0x0B | Stateful Via Information option (SF-VIO) | This document | | 0x0B | Stateful VIO(SF-VIO) | This document |
+-------+------------------------------------------+---------------+ +-------+----------------------------+---------------+
| 0x0C | Source-Routed Via Information option | This document | | 0x0C | Source-Routed VIO(SR-VIO) | This document |
| | (SR-VIO) | | +-------+----------------------------+---------------+
+-------+------------------------------------------+---------------+ | 0x0D | Sibling Information option | This document |
| 0x0D | Sibling Information option | This document | +-------+----------------------------+---------------+
+-------+------------------------------------------+---------------+
Table 5: RPL Control Message Options Table 25: RPL Control Message Options
9.6. SubRegistry for the Projected DAO Request Flags 11.6. SubRegistry for the Projected DAO Request Flags
IANA is required to create a registry for the 8-bit Projected DAO IANA is required to create a registry for the 8-bit Projected DAO
Request (PDR) Flags field. Each bit is tracked with the following Request (PDR) Flags field. Each bit is tracked with the following
qualities: qualities:
* Bit number (counting from bit 0 as the most significant bit) * Bit number (counting from bit 0 as the most significant bit)
* Capability description * Capability description
* Reference * Reference
Registration procedure is "Standards Action" [RFC8126]. The initial Registration procedure is "Standards Action" [RFC8126]. The initial
allocation is as indicated in Table 6: allocation is as indicated in Table 26:
+============+========================+===============+ +============+========================+===============+
| Bit number | Capability description | Reference | | Bit number | Capability description | Reference |
+============+========================+===============+ +============+========================+===============+
| 0 | PDR-ACK request (K) | This document | | 0 | PDR-ACK request (K) | This document |
+------------+------------------------+---------------+ +------------+------------------------+---------------+
| 1 | Requested path should | This document | | 1 | Requested path should | This document |
| | be redundant (R) | | | | be redundant (R) | |
+------------+------------------------+---------------+ +------------+------------------------+---------------+
Table 6: Initial PDR Flags Table 26: Initial PDR Flags
9.7. SubRegistry for the PDR-ACK Flags 11.7. SubRegistry for the PDR-ACK Flags
IANA is required to create an subregistry for the 8-bit PDR-ACK Flags IANA is required to create an subregistry for the 8-bit PDR-ACK Flags
field. Each bit is tracked with the following qualities: field. Each bit is tracked with the following qualities:
* Bit number (counting from bit 0 as the most significant bit) * Bit number (counting from bit 0 as the most significant bit)
* Capability description * Capability description
* Reference * Reference
Registration procedure is "Standards Action" [RFC8126]. No bit is Registration procedure is "Standards Action" [RFC8126]. No bit is
currently defined for the PDR-ACK Flags. currently defined for the PDR-ACK Flags.
9.8. Subregistry for the PDR-ACK Acceptance Status Values 11.8. Subregistry for the PDR-ACK Acceptance Status Values
IANA is requested to create a Subregistry for the PDR-ACK Acceptance IANA is requested to create a Subregistry for the PDR-ACK Acceptance
Status values. Status values.
* Possible values are 6-bit unsigned integers (0..63). * Possible values are 6-bit unsigned integers (0..63).
* Registration procedure is "Standards Action" [RFC8126]. * Registration procedure is "Standards Action" [RFC8126].
* Initial allocation is as indicated in Table 7: * Initial allocation is as indicated in Table 27:
+-------+------------------------+---------------+ +-------+------------------------+---------------+
| Value | Meaning | Reference | | Value | Meaning | Reference |
+-------+------------------------+---------------+ +-------+------------------------+---------------+
| 0 | Unqualified acceptance | This document | | 0 | Unqualified acceptance | This document |
+-------+------------------------+---------------+ +-------+------------------------+---------------+
Table 7: Acceptance values of the PDR-ACK Status Table 27: Acceptance values of the PDR-ACK Status
9.9. Subregistry for the PDR-ACK Rejection Status Values 11.9. Subregistry for the PDR-ACK Rejection Status Values
IANA is requested to create a Subregistry for the PDR-ACK Rejection IANA is requested to create a Subregistry for the PDR-ACK Rejection
Status values. Status values.
* Possible values are 6-bit unsigned integers (0..63). * Possible values are 6-bit unsigned integers (0..63).
* Registration procedure is "Standards Action" [RFC8126]. * Registration procedure is "Standards Action" [RFC8126].
* Initial allocation is as indicated in Table 8: * Initial allocation is as indicated in Table 28:
+-------+-----------------------+---------------+ +-------+-----------------------+---------------+
| Value | Meaning | Reference | | Value | Meaning | Reference |
+-------+-----------------------+---------------+ +-------+-----------------------+---------------+
| 0 | Unqualified rejection | This document | | 0 | Unqualified rejection | This document |
+-------+-----------------------+---------------+ +-------+-----------------------+---------------+
Table 8: Rejection values of the PDR-ACK Status Table 28: Rejection values of the PDR-ACK Status
9.10. SubRegistry for the Via Information Options Flags 11.10. SubRegistry for the Via Information Options Flags
IANA is requested to create a Subregistry for the 5-bit Via IANA is requested to create a Subregistry for the 5-bit Via
Information Options (Via Option) Flags field. Each bit is tracked Information Options (Via Information Option) Flags field. Each bit
with the following qualities: is tracked with the following qualities:
* Bit number (counting from bit 0 as the most significant bit) * Bit number (counting from bit 0 as the most significant bit)
* Capability description * Capability description
* Reference * Reference
Registration procedure is "Standards Action" [RFC8126]. No bit is Registration procedure is "Standards Action" [RFC8126]. No bit is
currently defined for the Via Information Options (Via Option) Flags. currently defined for the Via Information Options (Via Information
Option) Flags.
9.11. SubRegistry for the Sibling Information Option Flags 11.11. SubRegistry for the Sibling Information Option Flags
IANA is required to create a registry for the 5-bit Sibling IANA is required to create a registry for the 5-bit Sibling
Information Option (SIO) Flags field. Each bit is tracked with the Information Option (SIO) Flags field. Each bit is tracked with the
following qualities: following qualities:
* Bit number (counting from bit 0 as the most significant bit) * Bit number (counting from bit 0 as the most significant bit)
* Capability description * Capability description
* Reference * Reference
Registration procedure is "Standards Action" [RFC8126]. The initial Registration procedure is "Standards Action" [RFC8126]. The initial
allocation is as indicated in Table 9: allocation is as indicated in Table 29:
+============+===================================+===============+ +============+===================================+===============+
| Bit number | Capability description | Reference | | Bit number | Capability description | Reference |
+============+===================================+===============+ +============+===================================+===============+
| 0 | Connectivity is bidirectional (B) | This document | | 0 | Connectivity is bidirectional (B) | This document |
+------------+-----------------------------------+---------------+ +------------+-----------------------------------+---------------+
Table 9: Initial SIO Flags Table 29: Initial SIO Flags
9.12. Error in Projected Route ICMPv6 Code 11.12. New Destination Advertisement Object Flag
This document modifies the "Destination Advertisement Object (DAO)
Flags" registry initially created in Section 20.11 of [RPL] .
Section 3.1 also defines one new entry in the Registry as follows:
+---------------+------------------------+-----------+
| Bit Number | Capability Description | Reference |
+---------------+------------------------+-----------+
| 2 (suggested) | Projected DAO (P) | THIS RFC |
+---------------+------------------------+-----------+
Table 30: New Destination Advertisement Object
(DAO) Flag
11.13. Error in Projected Route ICMPv6 Code
In some cases RPL will return an ICMPv6 error message when a message In some cases RPL will return an ICMPv6 error message when a message
cannot be forwarded along a Projected Route. This ICMPv6 error cannot be forwarded along a Projected Route. This ICMPv6 error
message is "Error in Projected Route". message is "Error in Projected Route".
IANA has defined an ICMPv6 "Code" Fields Registry for ICMPv6 Message IANA has defined an ICMPv6 "Code" Fields Registry for ICMPv6 Message
Types. ICMPv6 Message Type 1 describes "Destination Unreachable" Types. ICMPv6 Message Type 1 describes "Destination Unreachable"
codes. This specification requires that a new code is allocated from codes. This specification requires that a new code is allocated from
the ICMPv6 Code Fields Registry for ICMPv6 Message Type 1, for "Error the ICMPv6 Code Fields Registry for ICMPv6 Message Type 1, for "Error
in Projected Route", with a suggested code value of 8, to be in Projected Route", with a suggested code value of 8, to be
confirmed by IANA. confirmed by IANA.
10. Acknowledgments 12. Acknowledgments
The authors wish to acknowledge JP Vasseur, Remy Liubing, James The authors wish to acknowledge JP Vasseur, Remy Liubing, James
Pylakutty and Patrick Wetterwald for their contributions to the ideas Pylakutty and Patrick Wetterwald for their contributions to the ideas
developed here. developed here.
11. Normative References 13. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet [RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet
Control Message Protocol (ICMPv6) for the Internet Control Message Protocol (ICMPv6) for the Internet
Protocol Version 6 (IPv6) Specification", STD 89, Protocol Version 6 (IPv6) Specification", STD 89,
RFC 4443, DOI 10.17487/RFC4443, March 2006, RFC 4443, DOI 10.17487/RFC4443, March 2006,
skipping to change at page 31, line 29 skipping to change at page 45, line 33
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26, Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>. <https://www.rfc-editor.org/info/rfc8126>.
12. Informative References 14. Informative References
[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, <https://www.rfc-editor.org/info/rfc7102>. 2014, <https://www.rfc-editor.org/info/rfc7102>.
[RFC6997] Goyal, M., Ed., Baccelli, E., Philipp, M., Brandt, A., and [RFC6997] Goyal, M., Ed., Baccelli, E., Philipp, M., Brandt, A., and
J. Martocci, "Reactive Discovery of Point-to-Point Routes J. Martocci, "Reactive Discovery of Point-to-Point Routes
in Low-Power and Lossy Networks", RFC 6997, in Low-Power and Lossy Networks", RFC 6997,
DOI 10.17487/RFC6997, August 2013, DOI 10.17487/RFC6997, August 2013,
<https://www.rfc-editor.org/info/rfc6997>. <https://www.rfc-editor.org/info/rfc6997>.
[6TiSCH-ARCHI] [6TiSCH-ARCHI]
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", Work in Progress, Internet-Draft, of IEEE 802.15.4", Work in Progress, Internet-Draft,
draft-ietf-6tisch-architecture-29, 27 August 2020, draft-ietf-6tisch-architecture-30, 26 November 2020,
<https://tools.ietf.org/html/draft-ietf-6tisch- <https://tools.ietf.org/html/draft-ietf-6tisch-
architecture-29>. architecture-30>.
[RAW-ARCHI] [RAW-ARCHI]
Thubert, P., Papadopoulos, G., and R. Buddenberg, Thubert, P., Papadopoulos, G., and R. Buddenberg,
"Reliable and Available Wireless Architecture/Framework", "Reliable and Available Wireless Architecture/Framework",
Work in Progress, Internet-Draft, draft-pthubert-raw- Work in Progress, Internet-Draft, draft-pthubert-raw-
architecture-05, 15 November 2020, architecture-05, 15 November 2020,
<https://tools.ietf.org/html/draft-pthubert-raw- <https://tools.ietf.org/html/draft-pthubert-raw-
architecture-05>. architecture-05>.
[TURN-ON_RFC8138] [TURN-ON_RFC8138]
Thubert, P. and L. Zhao, "A RPL DODAG Configuration Option Thubert, P. and L. Zhao, "A RPL DODAG Configuration Option
for the 6LoWPAN Routing Header", Work in Progress, for the 6LoWPAN Routing Header", Work in Progress,
Internet-Draft, draft-ietf-roll-turnon-rfc8138-17, 30 Internet-Draft, draft-ietf-roll-turnon-rfc8138-18, 18
September 2020, <https://tools.ietf.org/html/draft-ietf- December 2020, <https://tools.ietf.org/html/draft-ietf-
roll-turnon-rfc8138-17>. roll-turnon-rfc8138-18>.
[RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas, [RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas,
"Deterministic Networking Architecture", RFC 8655, "Deterministic Networking Architecture", RFC 8655,
DOI 10.17487/RFC8655, October 2019, DOI 10.17487/RFC8655, October 2019,
<https://www.rfc-editor.org/info/rfc8655>. <https://www.rfc-editor.org/info/rfc8655>.
[RFC8025] Thubert, P., Ed. and R. Cragie, "IPv6 over Low-Power [RFC8025] Thubert, P., Ed. and R. Cragie, "IPv6 over Low-Power
Wireless Personal Area Network (6LoWPAN) Paging Dispatch", Wireless Personal Area Network (6LoWPAN) Paging Dispatch",
RFC 8025, DOI 10.17487/RFC8025, November 2016, RFC 8025, DOI 10.17487/RFC8025, November 2016,
<https://www.rfc-editor.org/info/rfc8025>. <https://www.rfc-editor.org/info/rfc8025>.
[RFC8138] Thubert, P., Ed., Bormann, C., Toutain, L., and R. Cragie, [RFC8138] Thubert, P., Ed., Bormann, C., Toutain, L., and R. Cragie,
"IPv6 over Low-Power Wireless Personal Area Network "IPv6 over Low-Power Wireless Personal Area Network
(6LoWPAN) Routing Header", RFC 8138, DOI 10.17487/RFC8138, (6LoWPAN) Routing Header", RFC 8138, DOI 10.17487/RFC8138,
April 2017, <https://www.rfc-editor.org/info/rfc8138>. April 2017, <https://www.rfc-editor.org/info/rfc8138>.
[USEofRPLinfo] [USEofRPLinfo]
Robles, I., Richardson, M., and P. Thubert, "Using RPI Robles, I., Richardson, M., and P. Thubert, "Using RPI
Option Type, Routing Header for Source Routes and IPv6-in- Option Type, Routing Header for Source Routes and IPv6-in-
IPv6 encapsulation in the RPL Data Plane", Work in IPv6 encapsulation in the RPL Data Plane", Work in
Progress, Internet-Draft, draft-ietf-roll-useofrplinfo-42, Progress, Internet-Draft, draft-ietf-roll-useofrplinfo-43,
12 November 2020, <https://tools.ietf.org/html/draft-ietf- 10 January 2021, <https://tools.ietf.org/html/draft-ietf-
roll-useofrplinfo-42>. roll-useofrplinfo-43>.
[PCE] IETF, "Path Computation Element", [PCE] IETF, "Path Computation Element",
<https://datatracker.ietf.org/doc/charter-ietf-pce/>. <https://datatracker.ietf.org/doc/charter-ietf-pce/>.
Appendix A. Applications Appendix A. Applications
A.1. Loose Source Routing A.1. Loose Source Routing
A RPL implementation operating in a very constrained LLN typically A RPL implementation operating in a very constrained LLN typically
uses the Non-Storing Mode of Operation as represented in Figure 11. uses the Non-Storing Mode of Operation as represented in Figure 12.
In that mode, a RPL node indicates a parent-child relationship to the In that mode, a RPL node indicates a parent-child relationship to the
Root, using a Destination Advertisement Object (DAO) that is unicast Root, using a Destination Advertisement Object (DAO) that is unicast
from the node directly to the Root, and the Root typically builds a from the node directly to the Root, and the Root typically builds a
source routed path to a destination down the DODAG by recursively source routed path to a destination down the DODAG by recursively
concatenating this information. concatenating this information.
------+--------- ------+---------
| Internet | Internet
| |
+-----+ +-----+
skipping to change at page 33, line 21 skipping to change at page 47, line 30
+-----+ ^ | | +-----+ ^ | |
| | DAO | ACK | | | DAO | ACK |
o o o o | | | Strict o o o o | | | Strict
o o o o o o o o o | | | Source o o o o o o o o o | | | Source
o o o o o o o o o o | | | Route o o o o o o o o o o | | | Route
o o o o o o o o o | | | o o o o o o o o o | | |
o o o o o o o o | v v o o o o o o o o | v v
o o o o o o o o
LLN LLN
Figure 11: RPL Non-Storing Mode of operation Figure 12: RPL Non-Storing Mode of operation
Based on the parent-children relationships expressed in the non- Based on the parent-children relationships expressed in the non-
storing DAO messages,the Root possesses topological information about storing DAO messages,the Root possesses topological information about
the whole network, though this information is limited to the the whole network, though this information is limited to the
structure of the DODAG for which it is the destination. A packet structure of the DODAG for which it is the destination. A packet
that is generated within the domain will always reach the Root, which that is generated within the domain will always reach the Root, which
can then apply a source routing information to reach the destination can then apply a source routing information to reach the destination
if the destination is also in the DODAG. Similarly, a packet coming if the destination is also in the DODAG. Similarly, a packet coming
from the outside of the domain for a destination that is expected to from the outside of the domain for a destination that is expected to
be in a RPL domain reaches the Root. be in a RPL domain reaches the Root.
skipping to change at page 34, line 36 skipping to change at page 48, line 36
become loose. become loose.
A.2. Transversal Routes A.2. Transversal Routes
RPL is optimized for Point-to-Multipoint (P2MP) and Multipoint-to- RPL is optimized for Point-to-Multipoint (P2MP) and Multipoint-to-
Point (MP2P), whereby routes are always installed along the RPL DODAG Point (MP2P), whereby routes are always installed along the RPL DODAG
respectively from and towards the DODAG Root. Transversal Peer to respectively from and towards the DODAG Root. Transversal Peer to
Peer (P2P) routes in a RPL network will generally suffer from some Peer (P2P) routes in a RPL network will generally suffer from some
elongated (stretched) path versus the best possible path, since elongated (stretched) path versus the best possible path, since
routing between 2 nodes always happens via a common parent, as routing between 2 nodes always happens via a common parent, as
illustrated in Figure 12: illustrated in Figure 13:
* In Storing Mode, unless the destination is a child of the source, * In Storing Mode, unless the destination is a child of the source,
the packets will follow the default route up the DODAG as well. the packets will follow the default route up the DODAG as well.
If the destination is in the same DODAG, they will eventually If the destination is in the same DODAG, they will eventually
reach a common parent that has a route to the destination; at reach a common parent that has a route to the destination; at
worse, the common parent may also be the Root. From that common worse, the common parent may also be the Root. From that common
parent, the packet will follow a path down the DODAG that is parent, the packet will follow a path down the DODAG that is
optimized for the Objective Function that was used to build the optimized for the Objective Function that was used to build the
DODAG. DODAG.
skipping to change at page 35, line 21 skipping to change at page 49, line 21
+-----+ +-----+
X X
^ v o o ^ v o o
^ o o v o o o o o ^ o o v o o o o o
^ o o o v o o o o o ^ o o o v o o o o o
^ o o v o o o o o ^ o o v o o o o o
S o o o D o o o S o o o D o o o
o o o o o o o o
LLN LLN
Figure 12: Routing Stretch between S and D via common parent X Figure 13: Routing Stretch between S and D via common parent X
It results that it is often beneficial to enable transversal P2P It results that it is often beneficial to enable transversal P2P
routes, either if the RPL route presents a stretch from shortest routes, either if the RPL route presents a stretch from shortest
path, or if the new route is engineered with a different objective, path, or if the new route is engineered with a different objective,
and that it is even more critical in Non-Storing Mode than it is in and that it is even more critical in Non-Storing Mode than it is in
Storing Mode, because the routing stretch is wider. For that reason, Storing Mode, because the routing stretch is wider. For that reason,
earlier work at the IETF introduced the "Reactive Discovery of earlier work at the IETF introduced the "Reactive Discovery of
Point-to-Point Routes in Low Power and Lossy Networks" [RFC6997], Point-to-Point Routes in Low Power and Lossy Networks" [RFC6997],
which specifies a distributed method for establishing optimized P2P which specifies a distributed method for establishing optimized P2P
routes. This draft proposes an alternate based on a centralized routes. This draft proposes an alternate based on a centralized
skipping to change at page 35, line 50 skipping to change at page 49, line 50
+-----+ +-----+
| |
o o o o o o o o
o o o o o o o o o o o o o o o o o o
o o o o o o o o o o o o o o o o o o o o
o o o o o o o o o o o o o o o o o o
S>>A>>>B>>C>>>D o o o S>>A>>>B>>C>>>D o o o
o o o o o o o o
LLN LLN
Figure 13: Projected Transversal Route Figure 14: Projected Transversal Route
This specification enables to store source-routed or Storing Mode This specification enables to store source-routed or Storing Mode
state in intermediate routers, which enables to limit the stretch of state in intermediate routers, which enables to limit the stretch of
a P2P route and maintain the characteristics within a given SLA. An a P2P route and maintain the characteristics within a given SLA. An
example of service using this mechanism oculd be a control loop that example of service using this mechanism oculd be a control loop that
would be installed in a network that uses classical RPL for would be installed in a network that uses classical RPL for
asynchronous data collection. In that case, the P2P path may be asynchronous data collection. In that case, the P2P path may be
installed in a different RPL Instance, with a different objective installed in a different RPL Instance, with a different objective
function. function.
 End of changes. 112 change blocks. 
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