draft-ietf-roll-useofrplinfo-36.txt   draft-ietf-roll-useofrplinfo-37.txt 
ROLL Working Group M. Robles ROLL Working Group M. Robles
Internet-Draft UTN-FRM/Aalto Internet-Draft UTN-FRM/Aalto
Updates: 6553, 6550, 8138 (if approved) M. Richardson Updates: 6553, 6550, 8138 (if approved) M. Richardson
Intended status: Standards Track SSW Intended status: Standards Track SSW
Expires: August 29, 2020 P. Thubert Expires: September 15, 2020 P. Thubert
Cisco Cisco
February 26, 2020 March 14, 2020
Using RPI option Type, Routing Header for Source Routes and IPv6-in-IPv6 Using RPI Option Type, Routing Header for Source Routes and IPv6-in-IPv6
encapsulation in the RPL Data Plane encapsulation in the RPL Data Plane
draft-ietf-roll-useofrplinfo-36 draft-ietf-roll-useofrplinfo-37
Abstract Abstract
This document looks at different data flows through LLN (Low-Power This document looks at different data flows through LLN (Low-Power
and Lossy Networks) where RPL (IPv6 Routing Protocol for Low-Power and Lossy Networks) where RPL (IPv6 Routing Protocol for Low-Power
and Lossy Networks) is used to establish routing. The document and Lossy Networks) is used to establish routing. The document
enumerates the cases where RFC6553 (RPI option Type), RFC6554 enumerates the cases where RFC6553 (RPI Option Type), RFC6554
(Routing Header for Source Routes) and IPv6-in-IPv6 encapsulation is (Routing Header for Source Routes) and IPv6-in-IPv6 encapsulation is
required in data plane. This analysis provides the basis on which to required in data plane. This analysis provides the basis on which to
design efficient compression of these headers. This document updates design efficient compression of these headers. This document updates
RFC6553 adding a change to the RPI option Type. Additionally, this RFC6553 adding a change to the RPI Option Type. Additionally, this
document updates RFC6550 defining a flag in the DIO Configuration document updates RFC6550 defining a flag in the DIO Configuration
option to indicate about this change and updates RFC8138 as well to option to indicate about this change and updates [RFC8138] as well to
consider the new Option Type when the RPL Option is decompressed. consider the new Option Type when the RPL Option is decompressed.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
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 August 29, 2020. This Internet-Draft will expire on September 15, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 29 skipping to change at page 2, line 29
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology and Requirements Language . . . . . . . . . . . . 5 2. Terminology and Requirements Language . . . . . . . . . . . . 5
3. RPL Overview . . . . . . . . . . . . . . . . . . . . . . . . 6 3. RPL Overview . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Updates to RFC6553, RFC6550 and RFC8138 . . . . . . . . . . . 7 4. Updates to RFC6553, RFC6550 and RFC8138 . . . . . . . . . . . 7
4.1. Updates to RFC6550: Advertising External Routes with Non- 4.1. Updates to RFC6550: Advertising External Routes with Non-
Storing Mode Signaling. . . . . . . . . . . . . . . . . . 7 Storing Mode Signaling. . . . . . . . . . . . . . . . . . 7
4.2. Updates to RFC6553: Indicating the new RPI option Type. . 8 4.2. Updates to RFC6553: Indicating the new RPI Option Type. . 8
4.3. Updates to RFC6550: Indicating the new RPI in the 4.3. Updates to RFC6550: Indicating the new RPI in the
DODAG Configuration option Flag. . . . . . . . . . . . . 11 DODAG Configuration option Flag. . . . . . . . . . . . . 11
4.4. Updates to RFC8138: Indicating the way to decompress with 4.4. Updates to RFC8138: Indicating the way to decompress with
the new RPI option Type. . . . . . . . . . . . . . . . . 13 the new RPI Option Type. . . . . . . . . . . . . . . . . 13
5. Sample/reference topology . . . . . . . . . . . . . . . . . . 14 5. Sample/reference topology . . . . . . . . . . . . . . . . . . 14
6. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 16 6. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 16
7. Storing mode . . . . . . . . . . . . . . . . . . . . . . . . 19 7. Storing mode . . . . . . . . . . . . . . . . . . . . . . . . 19
7.1. Storing Mode: Interaction between Leaf and Root . . . . . 20 7.1. Storing Mode: Interaction between Leaf and Root . . . . . 20
7.1.1. SM: Example of Flow from RAL to root . . . . . . . . 20 7.1.1. SM: Example of Flow from RAL to root . . . . . . . . 21
7.1.2. SM: Example of Flow from root to RAL . . . . . . . . 21 7.1.2. SM: Example of Flow from root to RAL . . . . . . . . 21
7.1.3. SM: Example of Flow from root to RUL . . . . . . . . 22 7.1.3. SM: Example of Flow from root to RUL . . . . . . . . 22
7.1.4. SM: Example of Flow from RUL to root . . . . . . . . 22 7.1.4. SM: Example of Flow from RUL to root . . . . . . . . 23
7.2. SM: Interaction between Leaf and Internet. . . . . . . . 23 7.2. SM: Interaction between Leaf and Internet. . . . . . . . 24
7.2.1. SM: Example of Flow from RAL to Internet . . . . . . 23 7.2.1. SM: Example of Flow from RAL to Internet . . . . . . 24
7.2.2. SM: Example of Flow from Internet to RAL . . . . . . 24 7.2.2. SM: Example of Flow from Internet to RAL . . . . . . 26
7.2.3. SM: Example of Flow from RUL to Internet . . . . . . 25 7.2.3. SM: Example of Flow from RUL to Internet . . . . . . 26
7.2.4. SM: Example of Flow from Internet to RUL. . . . . . . 26 7.2.4. SM: Example of Flow from Internet to RUL. . . . . . . 27
7.3. SM: Interaction between Leaf and Leaf . . . . . . . . . . 27 7.3. SM: Interaction between Leaf and Leaf . . . . . . . . . . 28
7.3.1. SM: Example of Flow from RAL to RAL . . . . . . . . . 27 7.3.1. SM: Example of Flow from RAL to RAL . . . . . . . . . 28
7.3.2. SM: Example of Flow from RAL to RUL . . . . . . . . . 28 7.3.2. SM: Example of Flow from RAL to RUL . . . . . . . . . 30
7.3.3. SM: Example of Flow from RUL to RAL . . . . . . . . . 29 7.3.3. SM: Example of Flow from RUL to RAL . . . . . . . . . 31
7.3.4. SM: Example of Flow from RUL to RUL . . . . . . . . . 30 7.3.4. SM: Example of Flow from RUL to RUL . . . . . . . . . 32
8. Non Storing mode . . . . . . . . . . . . . . . . . . . . . . 31 8. Non Storing mode . . . . . . . . . . . . . . . . . . . . . . 33
8.1. Non-Storing Mode: Interaction between Leaf and Root . . . 33 8.1. Non-Storing Mode: Interaction between Leaf and Root . . . 35
8.1.1. Non-SM: Example of Flow from RAL to root . . . . . . 34 8.1.1. Non-SM: Example of Flow from RAL to root . . . . . . 36
8.1.2. Non-SM: Example of Flow from root to RAL . . . . . . 34 8.1.2. Non-SM: Example of Flow from root to RAL . . . . . . 36
8.1.3. Non-SM: Example of Flow from root to RUL . . . . . . 35 8.1.3. Non-SM: Example of Flow from root to RUL . . . . . . 37
8.1.4. Non-SM: Example of Flow from RUL to root . . . . . . 36 8.1.4. Non-SM: Example of Flow from RUL to root . . . . . . 38
8.2. Non-Storing Mode: Interaction between Leaf and Internet . 37 8.2. Non-Storing Mode: Interaction between Leaf and Internet . 39
8.2.1. Non-SM: Example of Flow from RAL to Internet . . . . 37 8.2.1. Non-SM: Example of Flow from RAL to Internet . . . . 39
8.2.2. Non-SM: Example of Flow from Internet to RAL . . . . 38 8.2.2. Non-SM: Example of Flow from Internet to RAL . . . . 40
8.2.3. Non-SM: Example of Flow from RUL to Internet . . . . 39 8.2.3. Non-SM: Example of Flow from RUL to Internet . . . . 41
8.2.4. Non-SM: Example of Flow from Internet to RUL . . . . 40 8.2.4. Non-SM: Example of Flow from Internet to RUL . . . . 42
8.3. Non-SM: Interaction between leaves . . . . . . . . . . . 41 8.3. Non-SM: Interaction between leaves . . . . . . . . . . . 43
8.3.1. Non-SM: Example of Flow from RAL to RAL . . . . . . . 41 8.3.1. Non-SM: Example of Flow from RAL to RAL . . . . . . . 43
8.3.2. Non-SM: Example of Flow from RAL to RUL . . . . . . . 44 8.3.2. Non-SM: Example of Flow from RAL to RUL . . . . . . . 46
8.3.3. Non-SM: Example of Flow from RUL to RAL . . . . . . . 46 8.3.3. Non-SM: Example of Flow from RUL to RAL . . . . . . . 48
8.3.4. Non-SM: Example of Flow from RUL to RUL . . . . . . . 47 8.3.4. Non-SM: Example of Flow from RUL to RUL . . . . . . . 49
9. Operational Considerations of supporting 9. Operational Considerations of supporting
RUL-leaves . . . . . . . . . . . . . . . . . . . . . . . . . 48 RUL-leaves . . . . . . . . . . . . . . . . . . . . . . . . . 50
10. Operational considerations of introducing 0x23 . . . . . . . 49 10. Operational considerations of introducing 0x23 . . . . . . . 51
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 49 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 51
12. Security Considerations . . . . . . . . . . . . . . . . . . . 50 12. Security Considerations . . . . . . . . . . . . . . . . . . . 52
13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 53 13. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 55
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 54 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 56
14.1. Normative References . . . . . . . . . . . . . . . . . . 54 14.1. Normative References . . . . . . . . . . . . . . . . . . 56
14.2. Informative References . . . . . . . . . . . . . . . . . 55 14.2. Informative References . . . . . . . . . . . . . . . . . 57
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 57 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 59
1. Introduction 1. Introduction
RPL (IPv6 Routing Protocol for Low-Power and Lossy Networks) RPL (IPv6 Routing Protocol for Low-Power and Lossy Networks)
[RFC6550] is a routing protocol for constrained networks. [RFC6553] [RFC6550] is a routing protocol for constrained networks. [RFC6553]
defines the RPL Option carried within the IPv6 Hop-by-Hop Header to defines the RPL Option carried within the IPv6 Hop-by-Hop Header to
carry the RPLInstanceID and quickly identify inconsistencies (loops) carry the RPLInstanceID and quickly identify inconsistencies (loops)
in the routing topology. The RPL Option is commonly referred to as in the routing topology. The RPL Option is commonly referred to as
the RPL Packet Information (RPI) though the RPI is really the the RPL Packet Information (RPI) though the RPI is really the
abstract information that is defined in [RFC6550] and transported in abstract information that is defined in [RFC6550] and transported in
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artifacts as possible that not all implementers agree when artifacts artifacts as possible that not all implementers agree when artifacts
are necessary, or when they can be safely omitted, or removed. are necessary, or when they can be safely omitted, or removed.
The ROLL WG analysized how [RFC2460] rules apply to storing and non- The ROLL WG analysized how [RFC2460] rules apply to storing and non-
storing use of RPL. The result was 24 data plane use cases. They storing use of RPL. The result was 24 data plane use cases. They
are exhaustively outlined here in order to be completely unambiguous. are exhaustively outlined here in order to be completely unambiguous.
During the processing of this document, new rules were published as During the processing of this document, new rules were published as
[RFC8200], and this document was updated to reflect the normative [RFC8200], and this document was updated to reflect the normative
changes in that document. changes in that document.
This document updates RFC6553, changing the value of the Option Type This document updates [RFC6553], changing the value of the Option
of the RPL Option to make RFC8200 routers ignore this option when not Type of the RPL Option to make [RFC8200] routers ignore this option
recognized. when not recognized.
A Routing Header Dispatch for 6LoWPAN (6LoRH)([RFC8138]) defines a A Routing Header Dispatch for 6LoWPAN (6LoRH)([RFC8138]) defines a
mechanism for compressing RPL Option information and Routing Header mechanism for compressing RPL Option information and Routing Header
type 3 (RH3) [RFC6554], as well as an efficient IPv6-in-IPv6 type 3 (RH3) [RFC6554], as well as an efficient IPv6-in-IPv6
technique. technique.
Since some of the uses cases here described, use IPv6-in-IPv6 Since some of the uses cases here described, use IPv6-in-IPv6
encapsulation. It MUST take in consideration, when encapsulation is encapsulation. It MUST take in consideration, when encapsulation is
applied, the RFC6040 [RFC6040], which defines how the explicit applied, the RFC6040 [RFC6040], which defines how the explicit
congestion notification (ECN) field of the IP header should be congestion notification (ECN) field of the IP header should be
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1.1. Overview 1.1. Overview
The rest of the document is organized as follows: Section 2 describes The rest of the document is organized as follows: Section 2 describes
the used terminology. Section 3 provides a RPL Overview. Section 4 the used terminology. Section 3 provides a RPL Overview. Section 4
describes the updates to RFC6553, RFC6550 and RFC 8138. Section 5 describes the updates to RFC6553, RFC6550 and RFC 8138. Section 5
provides the reference topology used for the uses cases. Section 6 provides the reference topology used for the uses cases. Section 6
describes the uses cases included. Section 7 describes the storing describes the uses cases included. Section 7 describes the storing
mode cases and section 8 the non-storing mode cases. Section 9 mode cases and section 8 the non-storing mode cases. Section 9
describes the operational considerations of supporting RPL-unaware- describes the operational considerations of supporting RPL-unaware-
leaves. Section 10 depicts operational considerations for the leaves. Section 10 depicts operational considerations for the
proposed change on RPI option Type, section 11 the IANA proposed change on RPI Option Type, section 11 the IANA
considerations and then section 12 describes the security aspects. considerations and then section 12 describes the security aspects.
2. Terminology and Requirements Language 2. Terminology and Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
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route-over topologies." route-over topologies."
6LoWPAN Border Router (6LBR): [RFC6775] defines it as:"A border 6LoWPAN Border Router (6LBR): [RFC6775] defines it as:"A border
router located at the junction of separate 6LoWPAN networks or router located at the junction of separate 6LoWPAN networks or
between a 6LoWPAN network and another IP network. There may be one between a 6LoWPAN network and another IP network. There may be one
or more 6LBRs at the 6LoWPAN network boundary. A 6LBR is the or more 6LBRs at the 6LoWPAN network boundary. A 6LBR is the
responsible authority for IPv6 prefix propagation for the 6LoWPAN responsible authority for IPv6 prefix propagation for the 6LoWPAN
network it is serving. An isolated LoWPAN also contains a 6LBR in network it is serving. An isolated LoWPAN also contains a 6LBR in
the network, which provides the prefix(es) for the isolated network." the network, which provides the prefix(es) for the isolated network."
Flag Day: A transition that involves having a network with different Flag Day: A transition that involves having a network with different
values of RPI option Type. Thus the network does not work correctly values of RPI Option Type. Thus the network does not work correctly
(Lack of interoperation). (Lack of interoperation).
Hop-by-Hop re-encapsulation: The term "Hop-by-Hop re-encapsulation" Hop-by-Hop re-encapsulation: The term "Hop-by-Hop re-encapsulation"
header refers to adding a header that originates from a node to an header refers to adding a header that originates from a node to an
adjacent node, using the addresses (usually the Global Unicast adjacent node, using the addresses (usually the Global Unicast
Address (GUA) or Unique Local Address (ULA) but could also use the Address (GUA) or Unique Local Address (ULA) but could also use the
link-local addresses) of each node. If the packet must traverse link-local addresses) of each node. If the packet must traverse
multiple hops, then it must be decapsulated at each hop, and then re- multiple hops, then it must be decapsulated at each hop, and then re-
encapsulated again in a similar fashion. encapsulated again in a similar fashion.
Non-Storing Mode (Non-SM): RPL mode of operation in which the RPL- Non-Storing Mode (Non-SM): RPL mode of operation in which the RPL-
aware-nodes send information to the root about its parents. Thus, aware-nodes send information to the root about their parents. Thus,
the root know the topology. Because the root knows the topology, the the root knows the topology. Because the root knows the topology,
intermediate 6LRs do not maintain routing state then source routing the intermediate 6LRs do not maintain routing state and source
is needed. routing is needed.
Storing Mode (SM): RPL mode of operation in which RPL-aware-nodes Storing Mode (SM): RPL mode of operation in which RPL-aware-nodes
(6LRs) maintain routing state (of the children) so that source (6LRs) maintain routing state (of the children) so that source
routing is not needed. routing is not needed.
Note: Due to lack of space in some figures (tables) we refers IPv6- Note: Due to lack of space in some figures (tables) we refer to IPv6-
in-IPv6 as IP6-IP6. in-IPv6 as IP6-IP6.
3. RPL Overview 3. RPL Overview
RPL defines the RPL Control messages (control plane), a new ICMPv6 RPL defines the RPL Control messages (control plane), a new ICMPv6
[RFC4443] message with Type 155. DIS (DODAG Information [RFC4443] message with Type 155. DIS (DODAG Information
Solicitation), DIO (DODAG Information Object) and DAO (Destination Solicitation), DIO (DODAG Information Object) and DAO (Destination
Advertisement Object) messages are all RPL Control messages but with Advertisement Object) messages are all RPL Control messages but with
different Code values. A RPL Stack is shown in Figure 1. different Code values. A RPL Stack is shown in Figure 1.
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by [RFC8504]. If the 6LN is a RUL, the Root that encapsulates a by [RFC8504]. If the 6LN is a RUL, the Root that encapsulates a
packet SHOULD terminate the tunnel at a parent 6LR unless it is aware packet SHOULD terminate the tunnel at a parent 6LR unless it is aware
that the RUL supports IP-in-IP decapsulation. that the RUL supports IP-in-IP decapsulation.
A node that is reachable over an external route is not expected to A node that is reachable over an external route is not expected to
support [RFC8138]. Whether a decapsulation took place or not and support [RFC8138]. Whether a decapsulation took place or not and
even when the 6LR is delivering the packet to a RUL, the 6LR that even when the 6LR is delivering the packet to a RUL, the 6LR that
injected an external route MUST uncompress the packet before injected an external route MUST uncompress the packet before
forwarding over that external route. forwarding over that external route.
4.2. Updates to RFC6553: Indicating the new RPI option Type. 4.2. Updates to RFC6553: Indicating the new RPI Option Type.
This modification is required in order to be able to send, for This modification is required in order to be able to send, for
example, IPv6 packets from a RPL-Aware-Leaf to a RPL-unaware node example, IPv6 packets from a RPL-Aware-Leaf to a RPL-unaware node
through Internet (see Section 7.2.1), without requiring IPv6-in-IPv6 through Internet (see Section 7.2.1), without requiring IPv6-in-IPv6
encapsulation. encapsulation.
[RFC6553] (Section 6, Page 7) states as shown in Figure 2, that in [RFC6553] (Section 6, Page 7) states as shown in Figure 2, that in
the Option Type field of the RPL Option, the two high order bits must the Option Type field of the RPL Option, the two high order bits must
be set to '01' and the third bit is equal to '1'. The first two bits be set to '01' and the third bit is equal to '1'. The first two bits
indicate that the IPv6 node must discard the packet if it doesn't indicate that the IPv6 node must discard the packet if it doesn't
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+-------+-------------------+----------------+-----------+ +-------+-------------------+----------------+-----------+
| Hex | Binary Value | Description | Reference | | Hex | Binary Value | Description | Reference |
+ Value +-------------------+ + + + Value +-------------------+ + +
| | act | chg | rest | | | | | act | chg | rest | | |
+-------+-----+-----+-------+----------------+-----------+ +-------+-----+-----+-------+----------------+-----------+
| 0x63 | 01 | 1 | 00011 | RPL Option | [RFC6553] | | 0x63 | 01 | 1 | 00011 | RPL Option | [RFC6553] |
+-------+-----+-----+-------+----------------+-----------+ +-------+-----+-----+-------+----------------+-----------+
Figure 2: Option Type in RPL Option. Figure 2: Option Type in RPL Option.
This document illustrates that is is not always possible to know for This document illustrates that it is not always possible to know for
sure at the source that a packet will only travel within the RPL sure at the source that a packet will only travel within the RPL
domain or may leave it. domain or may leave it.
At the time [RFC6553] was published, leaking a Hop-by-Hop header in At the time [RFC6553] was published, leaking a Hop-by-Hop header in
the outer IPv6 header chain could potentially impact core routers in the outer IPv6 header chain could potentially impact core routers in
the internet. So at that time, it was decided to encapsulate any the internet. So at that time, it was decided to encapsulate any
packet with a RPL Option using IPv6-in-IPv6 in all cases where it was packet with a RPL Option using IPv6-in-IPv6 in all cases where it was
unclear whether the packet would remain within the RPL domain. In unclear whether the packet would remain within the RPL domain. In
the exception case where a packet would still leak, the Option Type the exception case where a packet would still leak, the Option Type
would ensure that the first router in the Internet that does not would ensure that the first router in the Internet that does not
recognize the option would drop the packet and protect the rest of recognize the option would drop the packet and protect the rest of
the network. the network.
Even with [RFC8138], where the IPv6-in-IPv6 header is compressed, Even with [RFC8138], where the IPv6-in-IPv6 header is compressed,
this approach yields extra bytes in a packet which means consuming this approach yields extra bytes in a packet; this means consuming
more energy, more bandwidth, incurring higher chances of loss and more energy, more bandwidth, incurring higher chances of loss and
possibly causing a fragmentation at the 6LoWPAN level. This impacts possibly causing a fragmentation at the 6LoWPAN level. This impacts
the daily operation of constrained devices for a case that generally the daily operation of constrained devices for a case that generally
does not happen and would not heavily impact the core anyway. does not happen and would not heavily impact the core anyway.
While intention was and remains that the Hop-by-Hop header with a RPL While intention was and remains that the Hop-by-Hop header with a RPL
Option should be confined within the RPL domain, this specification Option should be confined within the RPL domain, this specification
modifies this behavior in order to reduce the dependency on IPv6-in- modifies this behavior in order to reduce the dependency on IPv6-in-
IPv6 and protect the constrained devices. Section 4 of [RFC8200] IPv6 and protect the constrained devices. Section 4 of [RFC8200]
clarifies the behaviour of routers in the Internet as follows: "it is clarifies the behaviour of routers in the Internet as follows: "it is
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leave the RPL domain on its way to its destination. In that event, leave the RPL domain on its way to its destination. In that event,
the packet should reach its destination and should not be discarded the packet should reach its destination and should not be discarded
by the first node that does not recognize the RPL Option. But with by the first node that does not recognize the RPL Option. But with
the current value of the Option Type, if a node in the Internet is the current value of the Option Type, if a node in the Internet is
configured to process the Hop-by-Hop header, and if such node configured to process the Hop-by-Hop header, and if such node
encounters an option with the first two bits set to 01 and conforms encounters an option with the first two bits set to 01 and conforms
to [RFC8200], it will drop the packet. Host systems should do the to [RFC8200], it will drop the packet. Host systems should do the
same, irrespective of the configuration. same, irrespective of the configuration.
Thus, this document updates the Option Type of the RPL Option Thus, this document updates the Option Type of the RPL Option
[RFC6553], abusively naming it RPI option Type for simplicity, to [RFC6553], abusively naming it RPI Option Type for simplicity, to
(Figure 3): the two high order bits MUST be set to '00' and the third (Figure 3): the two high order bits MUST be set to '00' and the third
bit is equal to '1'. The first two bits indicate that the IPv6 node bit is equal to '1'. The first two bits indicate that the IPv6 node
MUST skip over this option and continue processing the header MUST skip over this option and continue processing the header
([RFC8200] Section 4.2) if it doesn't recognize the Option Type, and ([RFC8200] Section 4.2) if it doesn't recognize the Option Type, and
the third bit continues to be set to indicate that the Option Data the third bit continues to be set to indicate that the Option Data
may change en route. The five rightmost bits remain at 0x3(00011). may change en route. The rightmost five bits remain at 0x3(00011).
This ensures that a packet that leaves the RPL domain of an LLN (or This ensures that a packet that leaves the RPL domain of an LLN (or
that leaves the LLN entirely) will not be discarded when it contains that leaves the LLN entirely) will not be discarded when it contains
the RPL Option. the RPL Option.
With the new Option Type, if an IPv6 (intermediate) node (RPL-not- With the new Option Type, if an IPv6 (intermediate) node (RPL-not-
capable) receives a packet with an RPL Option, it should ignore the capable) receives a packet with an RPL Option, it should ignore the
Hop-by-Hop RPL Option (skip over this option and continue processing Hop-by-Hop RPL Option (skip over this option and continue processing
the header). This is relevant, as it was mentioned previously, in the header). This is relevant, as it was mentioned previously, in
the case that there is a flow from RAL to Internet (see the case that there is a flow from RAL to Internet (see
Section 7.2.1). Section 7.2.1).
skipping to change at page 10, line 44 skipping to change at page 10, line 44
| | act | chg | rest | | | | | act | chg | rest | | |
+-------+-----+-----+-------+-------------+------------+ +-------+-----+-----+-------+-------------+------------+
| 0x23 | 00 | 1 | 00011 | RPL Option |[RFCXXXX](*)| | 0x23 | 00 | 1 | 00011 | RPL Option |[RFCXXXX](*)|
+-------+-----+-----+-------+-------------+------------+ +-------+-----+-----+-------+-------------+------------+
Figure 3: Revised Option Type in RPL Option. (*)represents this Figure 3: Revised Option Type in RPL Option. (*)represents this
document document
Without the signaling described below, this change would otherwise Without the signaling described below, this change would otherwise
create a lack of interoperation (flag day) for existing networks create a lack of interoperation (flag day) for existing networks
which are currently using 0x63 as the RPI option Type value. A move which are currently using 0x63 as the RPI Option Type value. A move
to 0x23 will not be understood by those networks. It is suggested to 0x23 will not be understood by those networks. It is suggested
that RPL implementations accept both 0x63 and 0x23 when processing that RPL implementations accept both 0x63 and 0x23 when processing
the header. the header.
When forwarding packets, implementations SHOULD use the same value of When forwarding packets, implementations SHOULD use the same value of
RPI Type as it was received. This is required because the RPI option RPI Type as was received. This is required because the RPI Option
Type does not change en route ([RFC8200] - Section 4.2). It allows Type does not change en route ([RFC8200] - Section 4.2). It allows
the network to be incrementally upgraded and allows the DODAG root to the network to be incrementally upgraded and allows the DODAG root to
know which parts of the network have been upgraded. know which parts of the network have been upgraded.
When originating new packets, implementations SHOULD have an option When originating new packets, implementations SHOULD have an option
to determine which value to originate with, this option is controlled to determine which value to originate with, this option is controlled
by the DIO option described below. by the DIO option described below.
The change of RPI option Type from 0x63 to 0x23, makes all [RFC8200] The change of RPI Option Type from 0x63 to 0x23, makes all [RFC8200]
Section 4.2 compliant nodes tolerant of the RPL artifacts. There is Section 4.2 compliant nodes tolerant of the RPL artifacts. There is
therefore no longer a necessity to remove the artifacts when sending therefore no longer a necessity to remove the artifacts when sending
traffic to the Internet. This change clarifies when to use IPv6-in- traffic to the Internet. This change clarifies when to use IPv6-in-
IPv6 headers, and how to address them: The Hop-by-Hop Options header IPv6 headers, and how to address them: The Hop-by-Hop Options header
containing the RPI MUST always be added when 6LRs originate packets containing the RPI MUST always be added when 6LRs originate packets
(without IPv6-in-IPv6 headers), and IPv6-in-IPv6 headers MUST always (without IPv6-in-IPv6 headers), and IPv6-in-IPv6 headers MUST always
be added when a 6LR find that it needs to insert a Hop-by-Hop Options be added when a 6LR finds that it needs to insert a Hop-by-Hop
header containing the RPL Option. The IPv6-in-IPv6 header is to be Options header containing the RPL Option. The IPv6-in-IPv6 header is
addressed to the RPL root when on the way up, and to the end-host to be addressed to the RPL root when on the way up, and to the end-
when on the way down. host when on the way down.
In the non-storing case, dealing with not-RPL aware leaf nodes is In the non-storing case, dealing with not-RPL aware leaf nodes is
much easier as the 6LBR (DODAG root) has complete knowledge about the much easier as the 6LBR (DODAG root) has complete knowledge about the
connectivity of all DODAG nodes, and all traffic flows through the connectivity of all DODAG nodes, and all traffic flows through the
root node. root node.
The 6LBR can recognize not-RPL aware leaf nodes because it will The 6LBR can recognize not-RPL aware leaf nodes because it will
receive a DAO about that node from the 6LR immediately above that receive a DAO about that node from the 6LR immediately above that
not-RPL aware node. This means that the non-storing mode case can not-RPL aware node. This means that the non-storing mode case can
avoid ever using Hop-by-Hop re-encapsulation headers for traffic avoid ever using Hop-by-Hop re-encapsulation headers for traffic
originating from the root to the leaves. originating from the root to the leaves.
The non-storing mode case does not require the type change from 0x63 The non-storing mode case does not require the type change from 0x63
to 0x23, as the root can always create the right packet. The type to 0x23, as the root can always create the right packet. The type
change does not adversely affect the non-storing case. change does not adversely affect the non-storing case.
4.3. Updates to RFC6550: Indicating the new RPI in the DODAG 4.3. Updates to RFC6550: Indicating the new RPI in the DODAG
Configuration option Flag. Configuration option Flag.
In order to avoid a Flag Day caused by lack of interoperation between In order to avoid a Flag Day caused by lack of interoperation between
new RPI option Type (0x23) and old RPI option Type (0x63) nodes, this new RPI Option Type (0x23) and old RPI Option Type (0x63) nodes, this
section defines a flag in the DIO Configuration option, to indicate section defines a flag in the DIO Configuration option, to indicate
when then new RPI option Type can be safely used. This means, the when the new RPI Option Type can be safely used. This means, the
flag is going to indicate the value of Option Type that the network flag is going to indicate the value of Option Type that the network
is using for the RPL Option. Thus, when a node join to a network will be using for the RPL Option. Thus, when a node joins to a
will know which value to use. With this, RPL-capable nodes know if network will know which value to use. With this, RPL-capable nodes
it is safe to use 0x23 when creating a new RPL Option. A node that know if it is safe to use 0x23 when creating a new RPL Option. A
forwards a packet with a RPI MUST NOT modify the Option Type of the node that forwards a packet with an RPI MUST NOT modify the Option
RPL Option. Type of the RPL Option.
This is done using a DODAG Configuration option flag which will This is done using a DODAG Configuration option flag which will
signal "RPI 0x23 enable" and propagate through the network. signal "RPI 0x23 enable" and propagate through the network.
Section 6.3.1. of [RFC6550] defines a 3-bit Mode of Operation (MOP) Section 6.3.1. of [RFC6550] defines a 3-bit Mode of Operation (MOP)
in the DIO Base Object. The flag is defined only for MOP value in the DIO Base Object. The flag is defined only for MOP value
between 0 to 6. For a MOP value of 7 or above, the flag MAY indicate between 0 to 6. For a MOP value of 7 or above, the flag MAY indicate
something different and MUST NOT be interpreted as "RPI 0x23 enable" something different and MUST NOT be interpreted as "RPI 0x23 enable"
unless the specification of the MOP indicates to do so. unless the specification of the MOP indicates to do so.
As stated in [RFC6550] the DODAG Configuration option is present in As stated in [RFC6550] the DODAG Configuration option is present in
skipping to change at page 12, line 25 skipping to change at page 12, line 25
configuration information. It is generally static, and does not configuration information. It is generally static, and does not
change within the DODAG. This information is configured at the DODAG change within the DODAG. This information is configured at the DODAG
root and distributed throughout the DODAG with the DODAG root and distributed throughout the DODAG with the DODAG
Configuration option. Nodes other than the DODAG root do not modify Configuration option. Nodes other than the DODAG root do not modify
this information when propagating the DODAG Configuration option. this information when propagating the DODAG Configuration option.
Currently, the DODAG Configuration option in [RFC6550] states: "the Currently, the DODAG Configuration option in [RFC6550] states: "the
unused bits MUST be initialize to zero by the sender and MUST be unused bits MUST be initialize to zero by the sender and MUST be
ignored by the receiver". If the flag is received with a value zero ignored by the receiver". If the flag is received with a value zero
(which is the default), then new nodes will remain in RFC6553 (which is the default), then new nodes will remain in RFC6553
Compatible Mode; originating traffic with the old-RPI option Type Compatible Mode; originating traffic with the old-RPI Option Type
(0x63) value. If the flag is received with a value of 1, then the (0x63) value. If the flag is received with a value of 1, then the
option value for the RPL Option MUST be set to 0x23. value for the RPL Option MUST be set to 0x23.
Bit number three of the flag field in the DODAG Configuration option Bit number three of the flag field in the DODAG Configuration option
is to be used as shown in Figure 4 (which is the same as Figure 26 in is to be used as shown in Figure 4 (which is the same as Figure 29 in
Section 11 and is shown here for convenience): Section 11 and is shown here for convenience):
+------------+-----------------+---------------+ +------------+-----------------+---------------+
| Bit number | Description | Reference | | Bit number | Description | Reference |
+------------+-----------------+---------------+ +------------+-----------------+---------------+
| 3 | RPI 0x23 enable | This document | | 3 | RPI 0x23 enable | This document |
+------------+-----------------+---------------+ +------------+-----------------+---------------+
Figure 4: DODAG Configuration option Flag to indicate the RPI-flag- Figure 4: DODAG Configuration option Flag to indicate the RPI-flag-
day. day.
In the case of rebooting, the node (6LN or 6LR) does not remember the In the case of reboot, the node (6LN or 6LR) does not remember the
RPL Option Type (i.e., whether or not the flag is set), so DIO RPI Option Type (i.e., whether or not the flag is set), so the node
messages sent by the node would be sent with the flag unset until a will not trigger DIO messages until a DIO message is received
DIO message is received with the flag set, indicating the new RPI indicating the RPI value to be used. The node will use the value
value. The node will use the value 0x23 if it supports this feature. 0x23 if the network supports this feature
4.4. Updates to RFC8138: Indicating the way to decompress with the new 4.4. Updates to RFC8138: Indicating the way to decompress with the new
RPI option Type. RPI Option Type.
This modification is required in order to be able to decompress the This modification is required in order to be able to decompress the
RPL Option with the new Option Type of 0x23. RPL Option with the new Option Type of 0x23.
RPI-6LoRH header provides a compressed form for the RPL RPI; see RPI-6LoRH header provides a compressed form for the RPL RPI; see
[RFC8138], Section 6. A node that is decompressing this header MUST [RFC8138], Section 6. A node that is decompressing this header MUST
decompress using the RPI option Type that is currently active: that decompress using the RPI Option Type that is currently active: that
is, a choice between 0x23 (new) and 0x63 (old). The node will know is, a choice between 0x23 (new) and 0x63 (old). The node will know
which to use based upon the presence of the flag in the DODAG which to use based upon the presence of the flag in the DODAG
Configuration option defined in Section 4.3. E.g. If the network is Configuration option defined in Section 4.3. E.g. If the network is
in 0x23 mode (by DIO option), then it should be decompressed to 0x23. in 0x23 mode (by DIO option), then it should be decompressed to 0x23.
[RFC8138] section 7 documents how to compress the IPv6-in-IPv6 [RFC8138] section 7 documents how to compress the IPv6-in-IPv6
header. header.
There are potential significant advantages to having a single code There are potential significant advantages to having a single code
path that always processes IPv6-in-IPv6 headers with no conditional path that always processes IPv6-in-IPv6 headers with no conditional
skipping to change at page 14, line 13 skipping to change at page 14, line 13
Follows the RPI-6LoRH and then the IP-in-IP 6LoRH. When the IP-in-IP Follows the RPI-6LoRH and then the IP-in-IP 6LoRH. When the IP-in-IP
6LoRH is removed, all the router headers that precede it are also 6LoRH is removed, all the router headers that precede it are also
removed. The Paging Dispatch [RFC8025] may also be removed if there removed. The Paging Dispatch [RFC8025] may also be removed if there
was no previous Page change to a Page other than 0 or 1, since the was no previous Page change to a Page other than 0 or 1, since the
LOWPAN_IPHC is encoded in the same fashion in the default Page 0 and LOWPAN_IPHC is encoded in the same fashion in the default Page 0 and
in Page 1. The resulting packet to the destination is the inner in Page 1. The resulting packet to the destination is the inner
packet compressed with [RFC6282]. packet compressed with [RFC6282].
5. Sample/reference topology 5. Sample/reference topology
A RPL network in general is composed of a 6LBR, Backbone Router A RPL network in general is composed of a 6LBR, a Backbone Router
(6BBR), 6LR and 6LN as a leaf logically organized in a DODAG (6BBR), a 6LR and a 6LN as a leaf logically organized in a DODAG
structure. structure.
Figure 6 shows the reference RPL Topology for this document. The Figure 6 shows the reference RPL Topology for this document. The
letters above the nodes are there so that they may be referenced in letters above the nodes are there so that they may be referenced in
subsequent sections. In the figure, 6LR represents a full router subsequent sections. In the figure, 6LR represents a full router
node. The 6LN is a RPL aware router, or host (as a leaf). node. The 6LN is a RPL aware router, or host (as a leaf).
Additionally, for simplification purposes, it is supposed that the Additionally, for simplification purposes, it is supposed that the
6LBR has direct access to Internet and is the root of the DODAG, thus 6LBR has direct access to Internet and is the root of the DODAG, thus
the 6BBR is not present in the figure. the 6BBR is not present in the figure.
skipping to change at page 16, line 11 skipping to change at page 16, line 11
+-------+ +-------+ +------+ +-------+ +-------+ +-------+ +-------+ +------+ +-------+ +-------+
Figure 6: A reference RPL Topology. Figure 6: A reference RPL Topology.
6. Use cases 6. Use cases
In the data plane a combination of RFC6553, RFC6554 and IPv6-in-IPv6 In the data plane a combination of RFC6553, RFC6554 and IPv6-in-IPv6
encapsulation are going to be analyzed for a number of representative encapsulation are going to be analyzed for a number of representative
traffic flows. traffic flows.
This document assumes that the LLN is using the no-drop RPI option This document assumes that the LLN is using the no-drop RPI Option
Type of 0x23. Type of 0x23.
The use cases describe the communication in the following cases: - The use cases describe the communication in the following cases: -
Between RPL-aware-nodes with the root (6LBR) - Between RPL-aware- Between RPL-aware-nodes with the root (6LBR) - Between RPL-aware-
nodes with the Internet - Between RUL nodes within the LLN (e.g. see nodes with the Internet - Between RUL nodes within the LLN (e.g. see
Section 7.1.4) - Inside of the LLN when the final destination address Section 7.1.4) - Inside of the LLN when the final destination address
resides outside of the LLN (e.g. see Section 7.2.3). resides outside of the LLN (e.g. see Section 7.2.3).
The uses cases are as follows: The uses cases are as follows:
skipping to change at page 17, line 22 skipping to change at page 17, line 22
DODAG root MUST force it to zero when passing the packet out to the DODAG root MUST force it to zero when passing the packet out to the
Internet. The Internet will therefore not see any SenderRank Internet. The Internet will therefore not see any SenderRank
information. information.
Despite being legal to leave the RPI artifact in place, an Despite being legal to leave the RPI artifact in place, an
intermediate router that needs to add an extension header (e.g. RH3 intermediate router that needs to add an extension header (e.g. RH3
or RPL Option) MUST still encapsulate the packet in an (additional) or RPL Option) MUST still encapsulate the packet in an (additional)
outer IP header. The new header is placed after this new outer IP outer IP header. The new header is placed after this new outer IP
header. header.
A corollary is that a RH3 or RPL Option can only be removed by an A corollary is that an RH3 or RPL Option can only be removed by an
intermediate router if it is placed in an encapsulating IPv6 Header, intermediate router if it is placed in an encapsulating IPv6 Header,
which is addressed TO the intermediate router. When it does so, the which is addressed TO the intermediate router. When it does so, the
whole encapsulating header must be removed. (A replacement may be whole encapsulating header must be removed. (A replacement may be
added). This sometimes can result in outer IP headers being added). This sometimes can result in outer IP headers being
addressed to the next hop router using link-local address. addressed to the next hop router using link-local address.
Both the RPL Option and the RH3 headers may be modified in very Both the RPL Option and the RH3 headers may be modified in very
specific ways by routers on the path of the packet without the need specific ways by routers on the path of the packet without the need
to add and remove an encapsulating header. Both headers were to add and remove an encapsulating header. Both headers were
designed with this modification in mind, and both the RPL RH3 and the designed with this modification in mind, and both the RPL RH3 and the
RPL Option are marked mutable but recoverable: so an IPsec AH RPL Option are marked mutable but recoverable: so an IPsec AH
security header can be applied across these headers, but it can not security header can be applied across these headers, but it can not
secure the values which mutate. secure the values which mutate.
The RPI MUST be present in every single RPL data packet. The RPI MUST be present in every single RPL data packet.
Prior to [RFC8138], there was significant interest in removing the Prior to [RFC8138], there was significant interest in creating an
RPI for downward flows in non-storing mode. The exception covered a exception to this rule and removing the RPI for downward flows in
very small number of cases, and causes significant interoperability non-storing mode. This exception covered a very small number of
challenges, yet costed significant code and testing complexity. The cases, and caused significant interoperability challenges while
ability to compress the RPI down to three bytes or less removes much adding significant in the code and tests. The ability to compress
of the pressure to optimize this any further the RPI down to three bytes or less removes much of the pressure to
[I-D.ietf-anima-autonomic-control-plane]. optimize this any further [I-D.ietf-anima-autonomic-control-plane].
The earlier examples are more extensive to make sure that the process The earlier examples are more extensive to make sure that the process
is clear, while later examples are more concise. is clear, while later examples are more concise.
The uses cases are delineated based on the following requirements: The uses cases are delineated based on the following requirements:
The RPIhas to be in every packet that traverses the LLN. The RPI has to be in every packet that traverses the LLN.
- Because of the previous requirement, packets from the Internet - Because of the above requirement, packets from the Internet have
have to be encapsulated. to be encapsulated.
- A Header cannot be inserted or removed on the fly inside an IPv6 - A Header cannot be inserted or removed on the fly inside an IPv6
packet that is being routed. packet that is being routed.
- Extension headers may not be added or removed except by the - Extension headers may not be added or removed except by the
sender or the receiver. sender or the receiver.
- RPI and RH3 headers may be modified by routers on the path of - RPI and RH3 headers may be modified by routers on the path of
the packet without the need to add and remove an encapsulating the packet without the need to add and remove an encapsulating
header. header.
- a RH3 or RPL Option can only be removed by an intermediate - an RH3 or RPL Option can only be removed by an intermediate
router if it is placed in an encapsulating IPv6 Header, which is router if it is placed in an encapsulating IPv6 Header, which is
addressed to the intermediate router. addressed to the intermediate router.
- Non-storing mode requires downstream encapsulation by root for - Non-storing mode requires downstream encapsulation by root for
RH3. RH3.
The uses cases are delineated based on the following assumptions: The uses cases are delineated based on the following assumptions:
This document assumes that the LLN is using the no-drop RPI option This document assumes that the LLN is using the no-drop RPI Option
Type (0x23). Type (0x23).
- Each IPv6 node (including Internet routers) obeys [RFC8200] RFC - Each IPv6 node (including Internet routers) obeys [RFC8200], so
8200, so that 0x23 RPI option Type can be safely inserted. that 0x23 RPI Option Type can be safely inserted.
- All 6LRs obey RFC 8200 [RFC8200]. - All 6LRs obey [RFC8200].
- The RPI is ignored at the IPv6 dst node (RUL). - The RPI is ignored at the IPv6 dst node (RUL).
- In the uses cases, we assume that the RAL supports IP-in-IP - In the uses cases, we assume that the RAL supports IP-in-IP
encapsulation. encapsulation.
- In the uses cases, we dont assume that the RUL supports IP-in-IP - In the uses cases, we dont assume that the RUL supports IP-in-IP
encapsulation. encapsulation.
- For traffic leaving a RUL, if the RUL adds an opaque RPI then
the description of the RAL applies.
- The description for RALs applies to RAN in general.
- Non-constrained uses of RPL are not in scope of this document. - Non-constrained uses of RPL are not in scope of this document.
- Compression is based on [RFC8138]. - Compression is based on [RFC8138].
- The flow label [RFC6437] is not needed in RPL. - The flow label [RFC6437] is not needed in RPL.
7. Storing mode 7. Storing mode
In storing mode (SM) (fully stateful), the sender can determine if In storing mode (SM) (fully stateful), the sender can determine if
the destination is inside the LLN by looking if the destination the destination is inside the LLN by looking if the destination
address is matched by the DIO's Prefix Information Option (PIO) address is matched by the DIO's Prefix Information Option (PIO)
option. option.
The following table (Figure 7) itemizes which headers are needed in The following table (Figure 7) itemizes which headers are needed in
each of the following scenarios. It indicates whether (1) the IPv6- each of the following scenarios. It indicates whether an IPv6-in-
in-IPv6 header that is added must be addressed to the final IPv6 header must be added and what destination it must be addressed
destination (the RAL node that is the target (tgt)), (2) the IPv6-in- to: (1) the final destination (the RAL node that is the target
IPv6 header that is added must be addressed to the "root", or (3) the (tgt)), (2) the "root", or (3) the 6LR parent of a RUL.
6LR parent of a RUL.
In cases where no IPv6-in-IPv6 header is needed, the column states as In cases where no IPv6-in-IPv6 header is needed, the column states as
"No". If the IPv6-in-IPv6 header is needed is a "must". "No". If the IPv6-in-IPv6 header is needed, the column shows "must".
In all cases the RPI is needed, since it identifies inconsistencies In all cases, the RPI is needed, since it identifies inconsistencies
(loops) in the routing topology. In all cases the RH3 is not needed (loops) in the routing topology. In all cases, the RH3 is not needed
because it is not used in storing mode. because it is not used in storing mode.
In each case, 6LR_i represents the intermediate routers from source
to destination. "1 <= i <= n", n is the number of routers (6LR) that
the packet goes through from source (6LN) to destination.
The leaf can be a router 6LR or a host, both indicated as 6LN. The The leaf can be a router 6LR or a host, both indicated as 6LN. The
root refers to the 6LBR (see Figure 6). root refers to the 6LBR (see Figure 6).
+---------------------+--------------+------------+----------------+ +---------------------+--------------+------------+----------------+
| Interaction between | Use Case |IPv6-in-IPv6|IPv6-in-IPv6 dst| | Interaction between | Use Case |IPv6-in-IPv6|IPv6-in-IPv6 dst|
+---------------------+--------------+------------+----------------+ +---------------------+--------------+------------+----------------+
| | RAL to root | No | No | | | RAL to root | No | No |
+ +--------------+------------+----------------+ + +--------------+------------+----------------+
| Leaf - Root | root to RAL | No | No | | Leaf - Root | root to RAL | No | No |
+ +--------------+------------+----------------+ + +--------------+------------+----------------+
| | root to RUL | No | No | | | root to RUL | must | 6LR |
+ +--------------+------------+----------------+ + +--------------+------------+----------------+
| | RUL to root | must | root | | | RUL to root | must | root |
+---------------------+--------------+------------+----------------+ +---------------------+--------------+------------+----------------+
| | RAL to Int | No | No | | | RAL to Int | may | root |
+ +--------------+------------+----------------+ + +--------------+------------+----------------+
| Leaf - Internet | Int to RAL | must | RAL (tgt) | | Leaf - Internet | Int to RAL | must | RAL (tgt) |
+ +--------------+------------+----------------+ + +--------------+------------+----------------+
| | RUL to Int | must | root | | | RUL to Int | must | root |
+ +--------------+------------+----------------+ + +--------------+------------+----------------+
| | Int to RUL | must | 6LR | | | Int to RUL | must | 6LR |
+---------------------+--------------+------------+----------------+ +---------------------+--------------+------------+----------------+
| | RAL to RAL | No | No | | | RAL to RAL | No | No |
+ +--------------+------------+----------------+ | Leaf - Leaf +--------------+------------+----------------+
| | RAL to RUL | No | No | | | RAL to RUL | must(down) | 6LR |
+ Leaf - Leaf +--------------+------------+----------------+ | +--------------+------------+----------------+
| | RUL to RAL | must | root | | | RUL to RAL | must(up) | root |
+ +--------------+------------+----------------+ | | +------------+----------------+
| | RUL to RUL | must | root | | | | must(down) | RAL |
+---------------------+--------------+------------+----------------+ | +--------------+------------+----------------+
| | RUL to RUL | must(up) | root |
| | +------------+----------------+
| | | must(down) | 6LR |
|---------------------+--------------+------------+----------------+
Figure 7: Table of IPv6-in-IPv6 encapsulation in Storing mode. Figure 7: Table of IPv6-in-IPv6 encapsulation in Storing mode.
7.1. Storing Mode: Interaction between Leaf and Root 7.1. Storing Mode: Interaction between Leaf and Root
In this section is described the communication flow in storing mode In this section is described the communication flow in storing mode
(SM) between, (SM) between,
RAL to root RAL to root
skipping to change at page 22, line 25 skipping to change at page 22, line 31
Table 2: SM: Summary of the use of headers from root to RAL Table 2: SM: Summary of the use of headers from root to RAL
7.1.3. SM: Example of Flow from root to RUL 7.1.3. SM: Example of Flow from root to RUL
In this case the flow comprises: In this case the flow comprises:
root (6LBR) --> 6LR_i --> RUL (IPv6 dst node) root (6LBR) --> 6LR_i --> RUL (IPv6 dst node)
For example, a communication flow could be: Node A (6LBR) --> Node B For example, a communication flow could be: Node A (6LBR) --> Node B
(6LR_i) --> Node E (6LR_i) --> Node G (RUL) (6LR_i) --> Node E (6LR_n) --> Node G (RUL)
As the RPI extension can be ignored by the RUL, this situation is 6LR_i (Node B) represents the intermediate routers from the source
identical to the previous scenario. (6LBR) to the destination (RUL), 1 <= i <= n, where n is the total
number of routers (6LR) that the packet goes through from the 6LBR
(Node A) to the RUL (Node G).
The Table 3 summarizes what headers are needed for this use case. The 6LBR will insert an RPI, encapsulated in a IPv6-in-IPv6 header.
The IPv6-in-IPv6 header is addressed to the 6LR parent of the RUL
(6LR_n). The 6LR parent of the RUL removes the header and sends the
packet to the RUL.
+-------------------+----------+-------+----------------------+ The Figure 8 summarizes what headers are needed for this use case.
| Header | 6LBR src | 6LR_i | RUL (IPv6 dst node) |
+-------------------+----------+-------+----------------------+
| Added headers | RPI | -- | -- |
| Modified headers | -- | RPI | -- |
| Removed headers | -- | -- | -- |
| Untouched headers | -- | -- | RPI (Ignored) |
+-------------------+----------+-------+----------------------+
Table 3: SM: Summary of the use of headers from root to RUL +-----------+---------+---------+---------+-----+
| Header | 6LBR | 6LR_i | 6LR_n | RUL |
| | src | | | dst |
+-----------+---------+---------+---------+-----+
| Added | IP6-IP6 | -- | -- | -- |
| headers | (RPI) | | | |
+-----------+---------+---------+---------+-----+
| Modified | -- | IP6-IP6 | -- | -- |
| headers | | (RPI) | | |
+-----------+---------+---------+---------+-----+
| Removed | -- | -- | IP6-IP6 | -- |
| headers | | | (RPI) | |
+-----------+---------+---------+---------+-----+
| Untouched | -- | -- | -- | -- |
| headers | | | | |
+-----------+---------+---------+---------+-----+
Figure 8: SM: Summary of the use of headers from root to RUL
7.1.4. SM: Example of Flow from RUL to root 7.1.4. SM: Example of Flow from RUL to root
In this case the flow comprises: In this case the flow comprises:
RUL (IPv6 src node) --> 6LR_1 --> 6LR_i --> root (6LBR) RUL (IPv6 src node) --> 6LR_1 --> 6LR_i --> root (6LBR)
For example, a communication flow could be: Node G (RUL) --> Node E For example, a communication flow could be: Node G (RUL) --> Node E
(6LR_1)--> Node B (6LR_i)--> Node A root(6LBR) (6LR_1)--> Node B (6LR_i)--> Node A root(6LBR)
6LR_i represents the intermediate routers from the source (RUL) to
the destination (6LBR), 1 <= i <= n, where n is the total number of
routers (6LR) that the packet goes through from the RUL to the 6LBR.
When the packet arrives from IPv6 node (Node G) to 6LR_1 (Node E), When the packet arrives from IPv6 node (Node G) to 6LR_1 (Node E),
the 6LR_1 will insert a RPI, encapsulated in a IPv6-in-IPv6 header. the 6LR_1 will insert an RPI, encapsulated in a IPv6-in-IPv6 header.
The IPv6-in-IPv6 header is addressed to the root (Node A). The root The IPv6-in-IPv6 header is addressed to the root (Node A). The root
removes the header and processes the packet. removes the header and processes the packet.
The Figure 8 shows the table that summarizes what headers are needed The Figure 9 shows the table that summarizes what headers are needed
for this use case where the IPv6-in-IPv6 header is addressed to the for this use case where the IPv6-in-IPv6 header is addressed to the
root (Node A). root (Node A).
+-----------+------+--------------+----------------+-----------------+ +-----------+------+--------------+----------------+-----------------+
| Header | RUL | 6LR_1 | 6LR_i | 6LBR dst | | Header | RUL | 6LR_1 | 6LR_i | 6LBR dst |
| | src | | | | | | src | | | |
| | node | | | | | | node | | | |
+-----------+------+--------------+----------------+-----------------+ +-----------+------+--------------+----------------+-----------------+
| Added | -- | IP6-IP6(RPI) | | -- | | Added | -- | IP6-IP6(RPI) | | -- |
| headers | | | -- | | | headers | | | -- | |
skipping to change at page 23, line 31 skipping to change at page 24, line 23
| Modified | -- | -- | IP6-IP6(RPI) | -- | | Modified | -- | -- | IP6-IP6(RPI) | -- |
| headers | | | | | | headers | | | | |
+-----------+------+--------------+----------------+-----------------+ +-----------+------+--------------+----------------+-----------------+
| Removed | -- | -- | --- | IP6-IP6(RPI) | | Removed | -- | -- | --- | IP6-IP6(RPI) |
| headers | | | | | | headers | | | | |
+-----------+------+--------------+----------------+-----------------+ +-----------+------+--------------+----------------+-----------------+
| Untouched | -- | -- | -- | -- | | Untouched | -- | -- | -- | -- |
| headers | | | | | | headers | | | | |
+-----------+------+--------------+----------------+-----------------+ +-----------+------+--------------+----------------+-----------------+
Figure 8: SM: Summary of the use of headers from RUL to root. Figure 9: SM: Summary of the use of headers from RUL to root.
7.2. SM: Interaction between Leaf and Internet. 7.2. SM: Interaction between Leaf and Internet.
In this section is described the communication flow in storing mode In this section is described the communication flow in storing mode
(SM) between, (SM) between,
RAL to Internet RAL to Internet
Internet to RAL Internet to RAL
RUL to Internet RUL to Internet
Internet to RUL Internet to RUL
7.2.1. SM: Example of Flow from RAL to Internet 7.2.1. SM: Example of Flow from RAL to Internet
RPL information from RFC 6553 may go out to Internet as it will be
ignored by nodes which have not been configured to be RPI aware.
In this case the flow comprises: In this case the flow comprises:
RAL (6LN) --> 6LR_i --> root (6LBR) --> Internet RAL (6LN) --> 6LR_i --> root (6LBR) --> Internet
For example, the communication flow could be: Node F (RAL) --> Node D For example, the communication flow could be: Node F (RAL) --> Node D
(6LR_i)--> Node B (6LR_i)--> Node A root(6LBR) --> Internet (6LR_i)--> Node B (6LR_i)--> Node A root(6LBR) --> Internet
6LR_i represents the intermediate routers from the source (RAL) to
the root (6LBR), 1 <= i <= n, where n is the total number of routers
(6LR) that the packet goes through from the RAL to the 6LBR.
RPL information from RFC 6553 may go out to Internet as it will be
ignored by nodes which have not been configured to be RPI aware. No
IPv6-in-IPv6 header is required.
On the other hand, the RAL may insert the RPI encapsulated in a IPv6-
in-IPv6 header to the root. Thus, the root removes the RPI and send
the packet to the Internet.
No IPv6-in-IPv6 header is required. No IPv6-in-IPv6 header is required.
Note: In this use case, it is used a node as a leaf, but this use Note: In this use case, it is used a node as a leaf, but this use
case can be also applicable to any RPL-aware-node type (e.g. 6LR) case can be also applicable to any RPL-aware-node type (e.g. 6LR)
The Table 4 summarizes what headers are needed for this use case. The Table 3 summarizes what headers are needed for this use case when
there is no encapsulation. The Figure 10 summarizes what headers are
needed when encapsulation to the root takes place.
+-------------------+---------+-------+------+----------------+ +-------------------+---------+-------+------+----------------+
| Header | RAL src | 6LR_i | 6LBR | Internet dst | | Header | RAL src | 6LR_i | 6LBR | Internet dst |
+-------------------+---------+-------+------+----------------+ +-------------------+---------+-------+------+----------------+
| Added headers | RPI | -- | -- | -- | | Added headers | RPI | -- | -- | -- |
| Modified headers | -- | RPI | -- | -- | | Modified headers | -- | RPI | -- | -- |
| Removed headers | -- | -- | -- | -- | | Removed headers | -- | -- | -- | -- |
| Untouched headers | -- | -- | RPI | RPI (Ignored) | | Untouched headers | -- | -- | RPI | RPI (Ignored) |
+-------------------+---------+-------+------+----------------+ +-------------------+---------+-------+------+----------------+
Table 4: SM: Summary of the use of headers from RAL to Internet Table 3: SM: Summary of the use of headers from RAL to Internet with
no encapsulation
+-----------+----------+--------------+--------------+--------------+
| Header | RAL | 6LR_i | 6LBR | Internet dst |
| | src | | | |
+-----------+----------+--------------+--------------+--------------+
| Added |IP6-IP6 | -- | -- | -- |
| headers | (RPI) | | | |
+-----------+----------+--------------+--------------+--------------+
| Modified | -- |IP6-IP6(RPI) | -- | -- |
| headers | | | | |
+-----------+----------+--------------+--------------+--------------+
| Removed | -- | -- |IP6-IP6(RPI) | -- |
| headers | | | | |
+-----------+----------+--------------+--------------+--------------+
| Untouched | -- | -- | -- | -- |
| headers | | | | |
+-----------+----------+--------------+--------------+--------------+
Figure 10: SM: Summary of the use of headers from RAL to Internet
with encapsulation to the root (6LBR).
7.2.2. SM: Example of Flow from Internet to RAL 7.2.2. SM: Example of Flow from Internet to RAL
In this case the flow comprises: In this case the flow comprises:
Internet --> root (6LBR) --> 6LR_i --> RAL (6LN) Internet --> root (6LBR) --> 6LR_i --> RAL (6LN)
For example, a communication flow could be: Internet --> Node A For example, a communication flow could be: Internet --> Node A
root(6LBR) --> Node B (6LR_1) --> Node D (6LR_n) --> Node F (RAL) root(6LBR) --> Node B (6LR_1) --> Node D (6LR_n) --> Node F (RAL)
When the packet arrives from Internet to 6LBR the RPI is added in a When the packet arrives from Internet to 6LBR the RPI is added in a
outer IPv6-in-IPv6 header (with the IPv6-in-IPv6 destination address outer IPv6-in-IPv6 header (with the IPv6-in-IPv6 destination address
set to the RAL) and sent to 6LR, which modifies the rank in the RPI. set to the RAL) and sent to 6LR, which modifies the rank in the RPI.
When the packet arrives at the RAL the RPI is removed and the packet When the packet arrives at the RAL the RPI is removed and the packet
processed. processed.
The Figure 9 shows the table that summarizes what headers are needed The Figure 11 shows the table that summarizes what headers are needed
for this use case. for this use case.
+-----------+----------+--------------+--------------+--------------+ +-----------+----------+--------------+--------------+--------------+
| Header | Internet | 6LBR | 6LR_i | RAL dst | | Header | Internet | 6LBR | 6LR_i | RAL dst |
| | src | | | | | | src | | | |
+-----------+----------+--------------+--------------+--------------+ +-----------+----------+--------------+--------------+--------------+
| Added | -- | IP6-IP6(RPI) | -- | -- | | Added | -- | IP6-IP6(RPI) | -- | -- |
| headers | | | | | | headers | | | | |
+-----------+----------+--------------+--------------+--------------+ +-----------+----------+--------------+--------------+--------------+
| Modified | -- | -- | IP6-IP6(RPI) | -- | | Modified | -- | -- | IP6-IP6(RPI) | -- |
| headers | | | | | | headers | | | | |
+-----------+----------+--------------+--------------+--------------+ +-----------+----------+--------------+--------------+--------------+
| Removed | -- | -- | -- | IP6-IP6(RPI) | | Removed | -- | -- | -- | IP6-IP6(RPI) |
| headers | | | | | | headers | | | | |
+-----------+----------+--------------+--------------+--------------+ +-----------+----------+--------------+--------------+--------------+
| Untouched | -- | -- | -- | -- | | Untouched | -- | -- | -- | -- |
| headers | | | | | | headers | | | | |
+-----------+----------+--------------+--------------+--------------+ +-----------+----------+--------------+--------------+--------------+
Figure 9: SM: Summary of the use of headers from Internet to RAL. Figure 11: SM: Summary of the use of headers from Internet to RAL.
7.2.3. SM: Example of Flow from RUL to Internet 7.2.3. SM: Example of Flow from RUL to Internet
In this case the flow comprises: In this case the flow comprises:
RUL (IPv6 src node) --> 6LR_1 --> 6LR_i -->root (6LBR) --> Internet RUL (IPv6 src node) --> 6LR_1 --> 6LR_i -->root (6LBR) --> Internet
For example, a communication flow could be: Node G (RUL)--> Node E For example, a communication flow could be: Node G (RUL)--> Node E
(6LR_1)--> Node B (6lR_i) --> Node A root(6LBR) --> Internet (6LR_1)--> Node B (6lR_i) --> Node A root(6LBR) --> Internet
The node 6LR_1 (i=1) will add an IPv6-in-IPv6(RPI) header addressed The node 6LR_1 (i=1) will add an IPv6-in-IPv6(RPI) header addressed
to the root such that the root can remove the RPI before passing to the root such that the root can remove the RPI before passing
upwards. The IPv6-in-IPv6 addressed to the root cause less upwards. In the intermediate 6LR, the rank in the RPI is modified.
processing overhead. In the intermindiate 6LR the rank in the RPI is
modified.
The originating node will ideally leave the IPv6 flow label as zero The originating node will ideally leave the IPv6 flow label as zero
so that the packet can be better compressed through the LLN. The so that the packet can be better compressed through the LLN. The
6LBR will set the flow label of the packet to a non-zero value when 6LBR will set the flow label of the packet to a non-zero value when
sending to the Internet, for details check [RFC6437]. sending to the Internet, for details check [RFC6437].
The Figure 10 shows the table that summarizes what headers are needed The Figure 12 shows the table that summarizes what headers are needed
for this use case. for this use case.
+---------+-------+------------+-------------+-------------+--------+ +---------+-------+------------+-------------+-------------+--------+
| Header | IPv6 | 6LR_1 | 6LR_i | 6LBR |Internet| | Header | IPv6 | 6LR_1 | 6LR_i | 6LBR |Internet|
| | src | | [i=2,...,n] | | dst | | | src | | [i=2,...,n] | | dst |
| | node | | | | | | | node | | | | |
| | (RUL) | | | | | | | (RUL) | | | | |
+---------+-------+------------+-------------+-------------+--------+ +---------+-------+------------+-------------+-------------+--------+
| Added | -- |IP6-IP6(RPI)| -- | -- | -- | | Added | -- |IP6-IP6(RPI)| -- | -- | -- |
| headers | | | | | | | headers | | | | | |
skipping to change at page 26, line 24 skipping to change at page 27, line 35
| Modified| -- | -- |IP6-IP6(RPI) | -- | -- | | Modified| -- | -- |IP6-IP6(RPI) | -- | -- |
| headers | | | | | | | headers | | | | | |
+---------+-------+------------+-------------+-------------+--------+ +---------+-------+------------+-------------+-------------+--------+
| Removed | -- | -- | -- | IP6-IP6(RPI)| -- | | Removed | -- | -- | -- | IP6-IP6(RPI)| -- |
| headers | | | | | | | headers | | | | | |
+---------+-------+------------+-------------+-------------+--------+ +---------+-------+------------+-------------+-------------+--------+
|Untouched| -- | -- | -- | -- | -- | |Untouched| -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
+---------+-------+------------+-------------+-------------+--------+ +---------+-------+------------+-------------+-------------+--------+
Figure 10: SM: Summary of the use of headers from RUL to Internet. Figure 12: SM: Summary of the use of headers from RUL to Internet.
7.2.4. SM: Example of Flow from Internet to RUL. 7.2.4. SM: Example of Flow from Internet to RUL.
In this case the flow comprises: In this case the flow comprises:
Internet --> root (6LBR) --> 6LR_i --> RUL (IPv6 dst node) Internet --> root (6LBR) --> 6LR_i --> RUL (IPv6 dst node)
For example, a communication flow could be: Internet --> Node A For example, a communication flow could be: Internet --> Node A
root(6LBR) --> Node B (6LR_i)--> Node E (6LR_n) --> Node G (RUL) root(6LBR) --> Node B (6LR_i)--> Node E (6LR_n) --> Node G (RUL)
The 6LBR will have to add a RPI within an IPv6-in-IPv6 header. The The 6LBR will have to add an RPI within an IPv6-in-IPv6 header. The
IPv6-in-IPv6 is addressed to the 6LR parent of the RUL. IPv6-in-IPv6 is addressed to the 6LR parent of the RUL.
Further details about this are mentioned in Further details about this are mentioned in
[I-D.ietf-roll-unaware-leaves], which specifies RPL routing for a 6LN [I-D.ietf-roll-unaware-leaves], which specifies RPL routing for a 6LN
acting as a plain host and not being aware of RPL. acting as a plain host and not being aware of RPL.
The 6LBR may set the flow label on the inner IPv6-in-IPv6 header to The 6LBR may set the flow label on the inner IPv6-in-IPv6 header to
zero in order to aid in compression [RFC8138][RFC6437]. zero in order to aid in compression [RFC8138][RFC6437].
The Figure 11 shows the table that summarizes what headers are needed The Figure 13 shows the table that summarizes what headers are needed
for this use case. for this use case.
+---------+-------+------------+--------------+-------------+-------+ +---------+-------+------------+--------------+-------------+-------+
| Header |Inter- | 6LBR | 6LR_i | 6LR_n | RUL | | Header |Inter- | 6LBR | 6LR_i | 6LR_n | RUL |
| | net | |[i=1,..,n-1] | | dst | | | net | |[i=1,..,n-1] | | dst |
| | src | | | | | | | src | | | | |
| | | | | | | | | | | | | |
+---------+-------+------------+--------------+-------------+-------+ +---------+-------+------------+--------------+-------------+-------+
| Inserted| -- |IP6-IP6(RPI)| -- | -- | -- | | Inserted| -- |IP6-IP6(RPI)| -- | -- | -- |
| headers | | | | | | | headers | | | | | |
skipping to change at page 27, line 24 skipping to change at page 28, line 30
| Modified| -- | -- | IP6-IP6(RPI) | -- | -- | | Modified| -- | -- | IP6-IP6(RPI) | -- | -- |
| headers | | | | | | | headers | | | | | |
+---------+-------+------------+--------------+-------------+-------+ +---------+-------+------------+--------------+-------------+-------+
| Removed | -- | -- | -- | IP6-IP6(RPI)| -- | | Removed | -- | -- | -- | IP6-IP6(RPI)| -- |
| headers | | | | | | | headers | | | | | |
+---------+-------+------------+--------------+-------------+-------+ +---------+-------+------------+--------------+-------------+-------+
|Untouched| -- | -- | -- | -- | -- | |Untouched| -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
+---------+-------+------------+--------------+-------------+-------+ +---------+-------+------------+--------------+-------------+-------+
Figure 11: SM: Summary of the use of headers from Internet to RUL. Figure 13: SM: Summary of the use of headers from Internet to RUL.
7.3. SM: Interaction between Leaf and Leaf 7.3. SM: Interaction between Leaf and Leaf
In this section is described the communication flow in storing mode In this section is described the communication flow in storing mode
(SM) between, (SM) between,
RAL to RAL RAL to RAL
RAL to RUL RAL to RUL
skipping to change at page 28, line 4 skipping to change at page 29, line 10
In [RFC6550] RPL allows a simple one-hop optimization for both In [RFC6550] RPL allows a simple one-hop optimization for both
storing and non-storing networks. A node may send a packet destined storing and non-storing networks. A node may send a packet destined
to a one-hop neighbor directly to that node. See section 9 in to a one-hop neighbor directly to that node. See section 9 in
[RFC6550]. [RFC6550].
When the nodes are not directly connected, then in storing mode, the When the nodes are not directly connected, then in storing mode, the
flow comprises: flow comprises:
RAL src (6LN) --> 6LR_ia --> common parent (6LR_x) --> 6LR_id --> RAL RAL src (6LN) --> 6LR_ia --> common parent (6LR_x) --> 6LR_id --> RAL
dst (6LN) dst (6LN)
For example, a communication flow could be: Node F (RAL src)--> Node For example, a communication flow could be: Node F (RAL src)--> Node
D (6LR_ia)--> Node B (6LR_x) --> Node E (6LR_id) --> Node H (RAL dst) D (6LR_ia)--> Node B (6LR_x) --> Node E (6LR_id) --> Node H (RAL dst)
6LR_ia (Node D) represents the intermediate routers from source to 6LR_ia (Node D) represents the intermediate routers from source to
the common parent (6LR_x) (Node B). In this case, 1 <= ia <= n, n is the common parent (6LR_x) (Node B), 1 <= ia <= n, where n is the
the number of routers (6LR) that the packet goes through from RAL total number of routers (6LR) that the packet goes through from RAL
(Node F) to the common parent 6LR_x (Node B). (Node F) to the common parent 6LR_x (Node B).
6LR_id (Node E) represents the intermediate routers from the common 6LR_id (Node E) represents the intermediate routers from the common
parent (6LR_x) (Node B) to destination RAL (Node H). In this case, 1 parent (6LR_x) (Node B) to destination RAL (Node H), 1 <= id <= m,
<= id <= m, m is the number of routers (6LR) that the packet goes where m is the total number of routers (6LR) that the packet goes
through from the common parent (6LR_x) to destination RAL (Node H). through from the common parent (6LR_x) to destination RAL (Node H).
It is assumed that the two nodes are in the same RPL domain (that It is assumed that the two nodes are in the same RPL domain (that
they share the same DODAG root). At the common parent (Node B), the they share the same DODAG root). At the common parent (Node B), the
direction of RPI is changed (from decreasing to increasing the rank). direction flag ('O' flag) of the RPI is changed (from decreasing
ranks to increasing ranks).
While the 6LR nodes will update the RPI, no node needs to add or While the 6LR nodes will update the RPI, no node needs to add or
remove the RPI, so no IPv6-in-IPv6 headers are necessary. remove the RPI, so no IPv6-in-IPv6 headers are necessary.
The Table 5 summarizes what headers are needed for this use case. The Table 4 summarizes what headers are needed for this use case.
+---------------+--------+--------+---------------+--------+--------+ +---------------+--------+--------+---------------+--------+--------+
| Header | RAL | 6LR_ia | 6LR_x (common | 6LR_id | RAL | | Header | RAL | 6LR_ia | 6LR_x (common | 6LR_id | RAL |
| | src | | parent) | | dst | | | src | | parent) | | dst |
+---------------+--------+--------+---------------+--------+--------+ +---------------+--------+--------+---------------+--------+--------+
| Added headers | RPI | -- | -- | -- | -- | | Added headers | RPI | -- | -- | -- | -- |
| Modified | -- | RPI | RPI | RPI | -- | | Modified | -- | RPI | RPI | RPI | -- |
| headers | | | | | | | headers | | | | | |
| Removed | -- | -- | -- | -- | RPI | | Removed | -- | -- | -- | -- | RPI |
| headers | | | | | | | headers | | | | | |
| Untouched | -- | -- | -- | -- | -- | | Untouched | -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
+---------------+--------+--------+---------------+--------+--------+ +---------------+--------+--------+---------------+--------+--------+
Table 5: SM: Summary of the Use of Headers from RAL to RAL Table 4: SM: Summary of the Use of Headers from RAL to RAL
7.3.2. SM: Example of Flow from RAL to RUL 7.3.2. SM: Example of Flow from RAL to RUL
In this case the flow comprises: In this case the flow comprises:
RAL src (6LN) --> 6LR_ia --> common parent (6LR_x) --> 6LR_id --> RUL RAL src (6LN) --> 6LR_ia --> common parent (6LR_x) --> 6LR_id --> RUL
(IPv6 dst node) (IPv6 dst node)
For example, a communication flow could be: Node F (RAL)--> Node D For example, a communication flow could be: Node F (RAL)--> Node D
--> Node B --> Node E --> Node G (RUL) --> Node B --> Node E --> Node G (RUL)
skipping to change at page 29, line 4 skipping to change at page 30, line 14
7.3.2. SM: Example of Flow from RAL to RUL 7.3.2. SM: Example of Flow from RAL to RUL
In this case the flow comprises: In this case the flow comprises:
RAL src (6LN) --> 6LR_ia --> common parent (6LR_x) --> 6LR_id --> RUL RAL src (6LN) --> 6LR_ia --> common parent (6LR_x) --> 6LR_id --> RUL
(IPv6 dst node) (IPv6 dst node)
For example, a communication flow could be: Node F (RAL)--> Node D For example, a communication flow could be: Node F (RAL)--> Node D
--> Node B --> Node E --> Node G (RUL) --> Node B --> Node E --> Node G (RUL)
6LR_ia represents the intermediate routers from source (RAL) to the 6LR_ia represents the intermediate routers from source (RAL) to the
common parent (6LR_x) In this case, 1 <= ia <= n, n is the number of common parent (6LR_x), 1 <= ia <= n, where n is the total number of
routers (6LR) that the packet goes through from RAL to the common routers (6LR) that the packet goes through from RAL to the common
parent (6LR_x). parent (6LR_x).
6LR_id (Node E) represents the intermediate routers from the common 6LR_id (Node E) represents the intermediate routers from the common
parent (6LR_x) (Node B) to destination RUL (Node G). In this case, 1 parent (6LR_x) (Node B) to destination RUL (Node G). In this case, 1
<= id <= m, m is the number of routers (6LR) that the packet goes <= id <= m, where m is the total number of routers (6LR) that the
through from the common parent (6LR_x) to destination RUL. The packet goes through from the common parent (6LR_x) to destination
packet from the RAL goes to 6LBR because the route to the RUL is not RUL.
injected into the RPL-SM.
The Table 6 summarizes what headers are needed for this use case. In this case, the packet from the RAL goes to 6LBR because the route
to the RUL is not injected into the RPL-SM. Thus, the RAL inserts an
RPI (RPI1) addressed to the root(6LBR). The root removes the RPI1
and inserts an RPI2 encapsulated to the 6LR parent of the RUL, which
removes the RPI2 before pasing the packet to the RUL.
+-----------------+---------+--------+------+--------+--------------+ The Figure 14 summarizes what headers are needed for this use case.
| Header | RAL src | 6LR_ia | 6LBR | 6LR_id | RUL dst |
+-----------------+---------+--------+------+--------+--------------+
| Added headers | RPI | -- | -- | -- | -- |
| Modified | -- | RPI | RPI | RPI | -- |
| headers | | | | | |
| Removed headers | -- | -- | -- | -- | -- |
| Untouched | -- | -- | -- | -- | RPI(Ignored) |
| headers | | | | | |
+-----------------+---------+--------+------+--------+--------------+
Table 6: SM: Summary of the Use of Headers from RAL to RUL +-----------+---------+---------+---------+---------+---------+------+
| Header | RAL | 6LR_ia | 6LBR | 6LR_id | 6LR_m | RUL |
| | src | | | | | dst |
| | node | | | | | node |
+-----------+---------+---------+---------+---------+---------+------+
| Added | | | IP6-IP6 | -- | -- | -- |
| headers | RPI1 | -- | (RPI2) | | | |
| | | | | | | |
+-----------+---------+---------+---------+---------+---------+------+
| Modified | -- | | -- | IP6-IP6 | | -- |
| headers | | RPI1 | | (RPI2) | -- | |
| | | | | | | |
+-----------+---------+---------+---------+---------+---------+------+
| Removed | -- | -- | | -- | IP6-IP6 | -- |
| headers | | | RPI1 | | (RPI2) | |
| | | | | | | |
+-----------+---------+---------+---------+---------+---------+------+
| Untouched | -- | -- | -- | -- | -- | -- |
| headers | | | | | | |
+-----------+---------+---------+---------+---------+---------+------+
Figure 14: SM: Summary of the Use of Headers from RAL to RUL
7.3.3. SM: Example of Flow from RUL to RAL 7.3.3. SM: Example of Flow from RUL to RAL
In this case the flow comprises: In this case the flow comprises:
RUL (IPv6 src node) --> 6LR_ia --> 6LBR --> 6LR_id --> RAL dst (6LN) RUL (IPv6 src node) --> 6LR_ia --> 6LBR --> 6LR_id --> RAL dst (6LN)
For example, a communication flow could be: Node G (RUL)--> Node E For example, a communication flow could be: Node G (RUL)--> Node E
--> Node B --> Node A --> Node B --> Node D --> Node F (RAL) --> Node B --> Node A --> Node B --> Node D --> Node F (RAL)
6LR_ia (Node E) represents the intermediate routers from source (RUL) 6LR_ia (Node E) represents the intermediate routers from source (RUL)
(Node G) to the root (Node A). In this case, 1 <= ia <= n, n is the (Node G) to the root (Node A). In this case, 1 <= ia <= n, where n
number of routers (6LR) that the packet goes through from source to is the total number of routers (6LR) that the packet goes through
the root. from source to the root.
6LR_id represents the intermediate routers from the root (Node A) to 6LR_id represents the intermediate routers from the root (Node A) to
destination RAL (Node F). In this case, 1 <= id <= m, m is the destination RAL (Node F). In this case, 1 <= id <= m, where m is the
number of routers (6LR) that the packet goes through from the root to total number of routers (6LR) that the packet goes through from the
the destination RAL. root to the destination RAL.
The 6LR_ia (ia=1) (Node E) receives the packet from the RUL (Node G) The 6LR_ia (ia=1) (Node E) receives the packet from the RUL (Node G)
and inserts the RPI (RPI1) encapsulated in a IPv6-in-IPv6 header to and inserts the RPI (RPI1) encapsulated in a IPv6-in-IPv6 header to
the root. The root removes the outer header including the RPI (RPI1) the root. The root removes the outer header including the RPI (RPI1)
and inserts a new RPI (RPI2) addressed to the destination RAL (Node and inserts a new RPI (RPI2) addressed to the destination RAL (Node
F). F).
The Figure 12 shows the table that summarizes what headers are needed The Figure 15 shows the table that summarizes what headers are needed
for this use case. for this use case.
+-----------+------+---------+---------+---------+---------+---------+ +-----------+------+---------+---------+---------+---------+---------+
| Header | RUL | 6LR_1 | 6LR_ia | 6LBR | 6LR_id | RAL | | Header | RUL | 6LR_1 | 6LR_ia | 6LBR | 6LR_id | RAL |
| | src | | | | | dst | | | src | | | | | dst |
| | node | | | | | node | | | node | | | | | node |
+-----------+------+---------+---------+---------+---------+---------+ +-----------+------+---------+---------+---------+---------+---------+
| Added | -- | IP6-IP6 | -- | IP6-IP6 | -- | -- | | Added | -- | IP6-IP6 | -- | IP6-IP6 | -- | -- |
| headers | | (RPI1) | | (RPI2) | | | | headers | | (RPI1) | | (RPI2) | | |
| | | | | | | | | | | | | | | |
skipping to change at page 30, line 32 skipping to change at page 32, line 29
| | | | | | | | | | | | | | | |
+-----------+------+---------+---------+---------+---------+---------+ +-----------+------+---------+---------+---------+---------+---------+
| Removed | -- | | -- | IP6-IP6 | -- | IP6-IP6 | | Removed | -- | | -- | IP6-IP6 | -- | IP6-IP6 |
| headers | | -- | | (RPI1) | | (RPI2) | | headers | | -- | | (RPI1) | | (RPI2) |
| | | | | | | | | | | | | | | |
+-----------+------+---------+---------+---------+---------+---------+ +-----------+------+---------+---------+---------+---------+---------+
| Untouched | -- | -- | -- | -- | -- | -- | | Untouched | -- | -- | -- | -- | -- | -- |
| headers | | | | | | | | headers | | | | | | |
+-----------+------+---------+---------+---------+---------+---------+ +-----------+------+---------+---------+---------+---------+---------+
Figure 12: SM: Summary of the use of headers from RUL to RAL. Figure 15: SM: Summary of the use of headers from RUL to RAL.
7.3.4. SM: Example of Flow from RUL to RUL 7.3.4. SM: Example of Flow from RUL to RUL
In this case the flow comprises: In this case the flow comprises:
RUL (IPv6 src node)--> 6LR_1--> 6LR_ia --> 6LBR --> 6LR_id --> RUL RUL (IPv6 src node)--> 6LR_1--> 6LR_ia --> 6LBR --> 6LR_id --> RUL
(IPv6 dst node) (IPv6 dst node)
For example, a communication flow could be: Node G (RUL src)--> Node For example, a communication flow could be: Node G (RUL src)--> Node
E --> Node B --> Node A (root) --> Node C --> Node J (RUL dst) E --> Node B --> Node A (root) --> Node C --> Node J (RUL dst)
Internal nodes 6LR_ia (e.g: Node E or Node B) is the intermediate Internal nodes 6LR_ia (e.g: Node E or Node B) is the intermediate
router from the RUL source (Node G) to the root (6LBR) (Node A). In router from the RUL source (Node G) to the root (6LBR) (Node A). In
this case, 1 <= ia <= n, n is the number of routers (6LR) that the this case, 1 <= ia <= n, where n is the total number of routers (6LR)
packet goes through from the RUL to the root. 6LR_1 refers when ia=1. that the packet goes through from the RUL to the root. 6LR_1 refers
when ia=1.
6LR_id (Node C) represents the intermediate routers from the root 6LR_id (Node C) represents the intermediate routers from the root
(Node A) to the destination RUL dst node (Node J). In this case, 1 (Node A) to the destination RUL dst node (Node J). In this case, 1
<= id <= m, m is the number of routers (6LR) that the packet goes <= id <= m, where m is the total number of routers (6LR) that the
through from the root to destination RUL. packet goes through from the root to destination RUL.
The RPI is ignored at the RUL dst node. The RPI is ignored at the RUL dst node.
The 6LR_1 (Node E) receives the packet from the RUL (Node G) and The 6LR_1 (Node E) receives the packet from the RUL (Node G) and
inserts the RPI (RPI), encapsulated in an IPv6-in-IPv6 header inserts the RPI (RPI), encapsulated in an IPv6-in-IPv6 header
directed to the root. The root removes the outer header including directed to the root. The root removes the outer header including
the RPI (RPI1) and inserts a new RPI (RPI2) addressed to the 6LR the RPI (RPI1) and inserts a new RPI (RPI2) addressed to the 6LR
father of the RUL. father of the RUL.
The Figure 13 shows the table that summarizes what headers are needed The Figure 16 shows the table that summarizes what headers are needed
for this use case. for this use case.
+---------+----+-------------+--------+---------+--------+-------+---+ +---------+----+-------------+--------+---------+--------+-------+---+
| Header |RUL | 6LR_1 | 6LR_ia | 6LBR | 6LR_id |6LR_n |RUL| | Header |RUL | 6LR_1 | 6LR_ia | 6LBR | 6LR_id |6LR_n |RUL|
| |src | | | | | |dst| | |src | | | | | |dst|
| | | | | | | | | | | | | | | | | |
+---------+----+-------------+--------+---------+--------+-------+---+ +---------+----+-------------+--------+---------+--------+-------+---+
| Added | -- |IP6-IP6(RPI1)| -- | IP6-IP6 | -- | -- | --| | Added | -- |IP6-IP6(RPI1)| -- | IP6-IP6 | -- | -- | --|
| Headers | | | | (RPI2) | | | | | Headers | | | | (RPI2) | | | |
+---------+----+-------------+--------+---------+--------+-------+---+ +---------+----+-------------+--------+---------+--------+-------+---+
|Modified | -- | -- |IP6-IP6 | -- |IP6-IP6 | -- | --| |Modified | -- | -- |IP6-IP6 | -- |IP6-IP6 | -- | --|
|headers | | | (RPI1) | | (RPI2) | | | |headers | | | (RPI1) | | (RPI2) | | |
+---------+----+-------------+--------+---------+--------+-------+---+ +---------+----+-------------+--------+---------+--------+-------+---+
| Removed | -- | -- | -- | IP6-IP6 | -- |IP6-IP6| --| | Removed | -- | -- | -- | IP6-IP6 | -- |IP6-IP6| --|
| headers | | | | (RPI1) | | (RPI2)| | | headers | | | | (RPI1) | | (RPI2)| |
+---------+----+-------------+--------+---------+--------+-------+---+ +---------+----+-------------+--------+---------+--------+-------+---+
|Untouched| -- | -- | -- | -- | -- | -- | --| |Untouched| -- | -- | -- | -- | -- | -- | --|
| headers | | | | | | | | | headers | | | | | | | |
+---------+----+-------------+--------+---------+--------+-------+---+ +---------+----+-------------+--------+---------+--------+-------+---+
Figure 13: SM: Summary of the use of headers from RUL to RUL Figure 16: SM: Summary of the use of headers from RUL to RUL
8. Non Storing mode 8. Non Storing mode
In Non Storing Mode (Non-SM) (fully source routed), the 6LBR (DODAG In Non Storing Mode (Non-SM) (fully source routed), the 6LBR (DODAG
root) has complete knowledge about the connectivity of all DODAG root) has complete knowledge about the connectivity of all DODAG
nodes, and all traffic flows through the root node. Thus, there is nodes, and all traffic flows through the root node. Thus, there is
no need for all nodes to know about the existence of RPL-unaware no need for all nodes to know about the existence of RPL-unaware
nodes. Only the 6LBR needs to act if compensation is necessary for nodes. Only the 6LBR needs to act if compensation is necessary for
not-RPL aware receivers. not-RPL aware receivers.
The table (Figure 14) summarizes what headers are needed in the The table (Figure 17) summarizes what headers are needed in the
following scenarios, and indicates when the RPI, RH3 and IPv6-in-IPv6 following scenarios, and indicates when the RPI, RH3 and IPv6-in-IPv6
header are to be inserted. It depicts the target destination address header are to be inserted. The last column depicts the target
possible to a 6LN (indicated by "RAL"), to a 6LR (parent of a RUL) or destination of the IPv6-in-IPv6 header: 6LN (indicated by "RAL"), 6LR
to the root. In cases where no IPv6-in-IPv6 header is needed, the (parent of a RUL) or the root. In cases where no IPv6-in-IPv6 header
column states as "No". There is no expectation on RPL that RPI can is needed, the column indicates "No". There is no expectation on RPL
be omitted, because it is needed for routing, quality of service and that RPI can be omitted, because it is needed for routing, quality of
compression. This specification expects that is always a RPI service and compression. This specification expects that an RPI is
Present. The term "may(up)" refers that the IPv6-in-IPv6 header may always present. The term "may(up)" means that the IPv6-in-IPv6
be necessary in the upwards direction. The term "must(up)" refers header may be necessary in the upwards direction. The term
that the IPv6-in-IPv6 header must be present in the upwards "must(up)" means that the IPv6-in-IPv6 header must be present in the
direction. The term "must(down)" refers that the IPv6-in-IPv6 header upwards direction. The term "must(down)" means that the IPv6-in-IPv6
must be present in the downward direction. header must be present in the downward direction.
The leaf can be a router 6LR or a host, both indicated as 6LN The leaf can be a router 6LR or a host, both indicated as 6LN
(Figure 6). In the table (Figure 14) the (1) indicates a 6tisch case (Figure 6). In the table (Figure 17) the (1) indicates a 6tisch case
[RFC8180], where the RPI may still be needed for the RPLInstanceID to [RFC8180], where the RPI may still be needed for the RPLInstanceID to
be available for priority/channel selection at each hop. be available for priority/channel selection at each hop.
The root always have to encapuslate on the way down The root always have to encapuslate on the way down
+--- ------------+-------------+-----+-----+--------------+----------+ +--- ------------+-------------+-----+-----+--------------+----------+
| Interaction | Use Case | RPI | RH3 | IPv6-in-IPv6 | IP-in-IP | | Interaction | Use Case | RPI | RH3 | IPv6-in-IPv6 | IP-in-IP |
| between | | | | | dst | | between | | | | | dst |
+----------------+-------------+-----+-----+--------------+----------+ +----------------+-------------+-----+-----+--------------+----------+
| | RAL to root | Yes | No | No | No | | | RAL to root | Yes | No | No | No |
skipping to change at page 33, line 43 skipping to change at page 35, line 43
| +-------------+-----+-----+--------------+----------+ | +-------------+-----+-----+--------------+----------+
| | RUL to RAL | Yes | Yes | must(up) | root | | | RUL to RAL | Yes | Yes | must(up) | root |
| | | | +--------------+----------+ | | | | +--------------+----------+
| | | | | must(down) | RAL | | | | | | must(down) | RAL |
| +-------------+-----+-----+--------------+----------+ | +-------------+-----+-----+--------------+----------+
| | RUL to RUL | Yes | Yes | must(up) | root | | | RUL to RUL | Yes | Yes | must(up) | root |
| | | | +--------------+----------+ | | | | +--------------+----------+
| | | | | must(down) | 6LR | | | | | | must(down) | 6LR |
+----------------+-------------+-----+-----+--------------+----------+ +----------------+-------------+-----+-----+--------------+----------+
Figure 14: Table that shows headers needed in Non-Storing mode: RPI, Figure 17: Table that shows headers needed in Non-Storing mode: RPI,
RH3, IPv6-in-IPv6 encapsulation. RH3, IPv6-in-IPv6 encapsulation.
8.1. Non-Storing Mode: Interaction between Leaf and Root 8.1. Non-Storing Mode: Interaction between Leaf and Root
In this section is described the communication flow in Non Storing In this section is described the communication flow in Non Storing
Mode (Non-SM) between, Mode (Non-SM) between,
RAL to root RAL to root
root to RAL root to RAL
skipping to change at page 34, line 22 skipping to change at page 36, line 22
In non-storing mode the leaf node uses default routing to send In non-storing mode the leaf node uses default routing to send
traffic to the root. The RPI must be included since it contains the traffic to the root. The RPI must be included since it contains the
rank information, which is used to avoid/detect loops. rank information, which is used to avoid/detect loops.
RAL (6LN) --> 6LR_i --> root(6LBR) RAL (6LN) --> 6LR_i --> root(6LBR)
For example, a communication flow could be: Node F --> Node D --> For example, a communication flow could be: Node F --> Node D -->
Node B --> Node A (root) Node B --> Node A (root)
6LR_i represents the intermediate routers from source to destination. 6LR_i represents the intermediate routers from source to destination.
In this case, 1 <= i <= n, n is the number of routers (6LR) that the In this case, 1 <= i <= n, where n is the total number of routers
packet goes through from source (RAL) to destination (6LBR). (6LR) that the packet goes through from source (RAL) to destination
(6LBR).
This situation is the same case as storing mode. This situation is the same case as storing mode.
The Table 7 summarizes what headers are needed for this use case. The Table 5 summarizes what headers are needed for this use case.
+-------------------+---------+-------+----------+ +-------------------+---------+-------+----------+
| Header | RAL src | 6LR_i | 6LBR dst | | Header | RAL src | 6LR_i | 6LBR dst |
+-------------------+---------+-------+----------+ +-------------------+---------+-------+----------+
| Added headers | RPI | -- | -- | | Added headers | RPI | -- | -- |
| Modified headers | -- | RPI | -- | | Modified headers | -- | RPI | -- |
| Removed headers | -- | -- | RPI | | Removed headers | -- | -- | RPI |
| Untouched headers | -- | -- | -- | | Untouched headers | -- | -- | -- |
+-------------------+---------+-------+----------+ +-------------------+---------+-------+----------+
Table 7: Non-SM: Summary of the use of headers from RAL to root Table 5: Non-SM: Summary of the use of headers from RAL to root
8.1.2. Non-SM: Example of Flow from root to RAL 8.1.2. Non-SM: Example of Flow from root to RAL
In this case the flow comprises: In this case the flow comprises:
root (6LBR) --> 6LR_i --> RAL (6LN) root (6LBR) --> 6LR_i --> RAL (6LN)
For example, a communication flow could be: Node A (root) --> Node B For example, a communication flow could be: Node A (root) --> Node B
--> Node D --> Node F --> Node D --> Node F
6LR_i represents the intermediate routers from source to destination. 6LR_i represents the intermediate routers from source to destination.
In this case, 1 <= i <= n, n is the number of routers (6LR) that the In this case, 1 <= i <= n, where n is the total number of routers
packet goes through from source (6LBR) to destination (RAL). (6LR) that the packet goes through from source (6LBR) to destination
(RAL).
The 6LBR inserts a RH3, and a RPI. No IPv6-in-IPv6 header is The 6LBR inserts an RH3, and an RPI. No IPv6-in-IPv6 header is
necessary as the traffic originates with a RPL aware node, the 6LBR. necessary as the traffic originates with a RPL aware node, the 6LBR.
The destination is known to be RPL-aware because the root knows the The destination is known to be RPL-aware because the root knows the
whole topology in non-storing mode. whole topology in non-storing mode.
The Table 8 summarizes what headers are needed for this use case. The Table 6 summarizes what headers are needed for this use case.
+-------------------+----------+-----------+-----------+ +-------------------+----------+-----------+-----------+
| Header | 6LBR src | 6LR_i | RAL dst | | Header | 6LBR src | 6LR_i | RAL dst |
+-------------------+----------+-----------+-----------+ +-------------------+----------+-----------+-----------+
| Added headers | RPI, RH3 | -- | -- | | Added headers | RPI, RH3 | -- | -- |
| Modified headers | -- | RPI, RH3 | -- | | Modified headers | -- | RPI, RH3 | -- |
| Removed headers | -- | -- | RH3, RPI | | Removed headers | -- | -- | RH3, RPI |
| Untouched headers | -- | -- | -- | | Untouched headers | -- | -- | -- |
+-------------------+----------+-----------+-----------+ +-------------------+----------+-----------+-----------+
Table 8: Non-SM: Summary of the use of headers from root to RAL Table 6: Non-SM: Summary of the use of headers from root to RAL
8.1.3. Non-SM: Example of Flow from root to RUL 8.1.3. Non-SM: Example of Flow from root to RUL
In this case the flow comprises: In this case the flow comprises:
root (6LBR) --> 6LR_i --> RUL (IPv6 dst node) root (6LBR) --> 6LR_i --> RUL (IPv6 dst node)
For example, a communication flow could be: Node A (root) --> Node B For example, a communication flow could be: Node A (root) --> Node B
--> Node E --> Node G (RUL) --> Node E --> Node G (RUL)
6LR_i represents the intermediate routers from source to destination. 6LR_i represents the intermediate routers from source to destination.
In this case, 1 <= i <= n, n is the number of routers (6LR) that the In this case, 1 <= i <= n, where n is the total number of routers
packet goes through from source (6LBR) to destination (RUL). (6LR) that the packet goes through from source (6LBR) to destination
(RUL).
In the 6LBR, the RH3 is added; it is then modified at each In the 6LBR, the RH3 is added; it is then modified at each
intermediate 6LR (6LR_1 and so on), and it is fully consumed in the intermediate 6LR (6LR_1 and so on), and it is fully consumed in the
last 6LR (6LR_n) but is left in place. When the RPI is added, the last 6LR (6LR_n) but is left in place. When the RPI is added, the
IPv6 node, which does not understand the RPI, will ignore it (per IPv6 node, which does not understand the RPI, will ignore it (per
RFC8200); thus, encapsulation is not necessary. [RFC8200]); thus, encapsulation is not necessary.
The Figure 15 depicts the table that summarizes what headers are The Figure 18 depicts the table that summarizes what headers are
needed for this use case. needed for this use case.
+-----------+----------+--------------+----------------+----------+ +-----------+----------+--------------+----------------+----------+
| Header | 6LBR | 6LR_i | 6LR_n | RUL | | Header | 6LBR | 6LR_i | 6LR_n | RUL |
| | src | i=(1,..,n-1) | | dst | | | src | i=(1,..,n-1) | | dst |
| | | | | | | | | | | |
+-----------+----------+--------------+----------------+----------+ +-----------+----------+--------------+----------------+----------+
| Added | RPI, RH3 | -- | -- | -- | | Added | RPI, RH3 | -- | -- | -- |
| headers | | | | | | headers | | | | |
+-----------+----------+--------------+----------------+----------+ +-----------+----------+--------------+----------------+----------+
skipping to change at page 36, line 24 skipping to change at page 38, line 24
| headers | | | RH3(consumed) | | | headers | | | RH3(consumed) | |
+-----------+----------+--------------+----------------+----------+ +-----------+----------+--------------+----------------+----------+
| Removed | -- | -- | -- | -- | | Removed | -- | -- | -- | -- |
| headers | | | | | | headers | | | | |
+-----------+----------+--------------+----------------+----------+ +-----------+----------+--------------+----------------+----------+
| Untouched | -- | -- | -- | RPI, RH3 | | Untouched | -- | -- | -- | RPI, RH3 |
| headers | | | | (both | | headers | | | | (both |
| | | | | ignored) | | | | | | ignored) |
+-----------+----------+--------------+----------------+----------+ +-----------+----------+--------------+----------------+----------+
Figure 15: Non-SM: Summary of the use of headers from root to RUL Figure 18: Non-SM: Summary of the use of headers from root to RUL
8.1.4. Non-SM: Example of Flow from RUL to root 8.1.4. Non-SM: Example of Flow from RUL to root
In this case the flow comprises: In this case the flow comprises:
RUL (IPv6 src node) --> 6LR_1 --> 6LR_i --> root (6LBR) dst RUL (IPv6 src node) --> 6LR_1 --> 6LR_i --> root (6LBR) dst
For example, a communication flow could be: Node G --> Node E --> For example, a communication flow could be: Node G --> Node E -->
Node B --> Node A (root) Node B --> Node A (root)
6LR_i represents the intermediate routers from source to destination. 6LR_i represents the intermediate routers from source to destination.
In this case, 1 <= i <= n, n is the number of routers (6LR) that the In this case, 1 <= i <= n, where n is the total number of routers
packet goes through from source (RUL) to destination (6LBR). For (6LR) that the packet goes through from source (RUL) to destination
example, 6LR_1 (i=1) is the router that receives the packets from the (6LBR). For example, 6LR_1 (i=1) is the router that receives the
IPv6 node. packets from the IPv6 node.
In this case, the RPI is added by the first 6LR (6LR_1) (Node E), In this case, the RPI is added by the first 6LR (6LR_1) (Node E),
encapsulated in an IPv6-in-IPv6 header, and modified in the encapsulated in an IPv6-in-IPv6 header, and modified in the
subsequent 6LRs in the flow. The RPI and the entire packet is subsequent 6LRs in the flow. The RPI and the entire packet are
consumed by the root. consumed by the root.
The Figure 16 shows the table that summarizes what headers are needed The Figure 19 shows the table that summarizes what headers are needed
for this use case. for this use case.
+---------+----+-----------------+-----------------+-----------------+ +---------+----+-----------------+-----------------+-----------------+
| |RUL | | | | | |RUL | | | |
| Header |src | 6LR_1 | 6LR_i | 6LBR dst | | Header |src | 6LR_1 | 6LR_i | 6LBR dst |
| |node| | | | | |node| | | |
+---------+----+-----------------+-----------------+-----------------+ +---------+----+-----------------+-----------------+-----------------+
| Added | -- |IPv6-in-IPv6(RPI)| -- | -- | | Added | -- |IPv6-in-IPv6(RPI)| -- | -- |
| headers | | | | | | headers | | | | |
+---------+----+-----------------+-----------------+-----------------+ +---------+----+-----------------+-----------------+-----------------+
| Modified| -- | -- |IPv6-in-IPv6(RPI)| -- | | Modified| -- | -- |IPv6-in-IPv6(RPI)| -- |
| headers | | | | | | headers | | | | |
+---------+----+-----------------+-----------------+-----------------+ +---------+----+-----------------+-----------------+-----------------+
| Removed | -- | -- | -- |IPv6-in-IPv6(RPI)| | Removed | -- | -- | -- |IPv6-in-IPv6(RPI)|
| headers | | | | | | headers | | | | |
+---------+----+-----------------+-----------------+-----------------+ +---------+----+-----------------+-----------------+-----------------+
|Untouched| -- | -- | -- | -- | |Untouched| -- | -- | -- | -- |
| headers | | | | | | headers | | | | |
+---------+----+-----------------+-----------------+-----------------+ +---------+----+-----------------+-----------------+-----------------+
Figure 16: Non-SM: Summary of the use of headers from RUL to root Figure 19: Non-SM: Summary of the use of headers from RUL to root
8.2. Non-Storing Mode: Interaction between Leaf and Internet 8.2. Non-Storing Mode: Interaction between Leaf and Internet
This section will describe the communication flow in Non Storing Mode This section will describe the communication flow in Non Storing Mode
(Non-SM) between: (Non-SM) between:
RAL to Internet RAL to Internet
Internet to RAL Internet to RAL
skipping to change at page 37, line 47 skipping to change at page 39, line 47
8.2.1. Non-SM: Example of Flow from RAL to Internet 8.2.1. Non-SM: Example of Flow from RAL to Internet
In this case the flow comprises: In this case the flow comprises:
RAL (6LN) src --> 6LR_i --> root (6LBR) --> Internet dst RAL (6LN) src --> 6LR_i --> root (6LBR) --> Internet dst
For example, a communication flow could be: Node F (RAL) --> Node D For example, a communication flow could be: Node F (RAL) --> Node D
--> Node B --> Node A --> Internet --> Node B --> Node A --> Internet
6LR_i represents the intermediate routers from source to destination. 6LR_i represents the intermediate routers from source to destination,
In this case, 1 <= i <= n, n is the number of routers (6LR) that the 1 <= i <= n, where n is the total number of routers (6LR) that the
packet goes through from source (RAL) to 6LBR. packet goes through from source (RAL) to 6LBR.
In this case, the encapsulation from the RAL to the root is optional. In this case, the encapsulation from the RAL to the root is optional.
The simplest case is when the RPI gets to the Internet (as the table The simplest case is when the RPI gets to the Internet (as the
show it), knowing that the Internet is going to ignore it. Table 7 shows it), knowing that the Internet is going to ignore it.
The IPv6 flow label should be set to zero to aid in compression The IPv6 flow label should be set to zero to aid in compression
[RFC8138], and the 6LBR will set it to a non-zero value when sending [RFC8138], and the 6LBR will set it to a non-zero value when sending
towards the Internet [RFC6437]. towards the Internet [RFC6437].
The Table 9 summarizes what headers are needed for this use case when The Table 7 summarizes what headers are needed for this use case when
no encapsulation is used. The Table 10 summarizes what headers are no encapsulation is used. The Table 8 summarizes what headers are
needed for this use case when encapsulation to the root is used. needed for this use case when encapsulation to the root is used.
+-------------------+---------+-------+------+----------------+ +-------------------+---------+-------+------+----------------+
| Header | RAL src | 6LR_i | 6LBR | Internet dst | | Header | RAL src | 6LR_i | 6LBR | Internet dst |
+-------------------+---------+-------+------+----------------+ +-------------------+---------+-------+------+----------------+
| Added headers | RPI | -- | -- | -- | | Added headers | RPI | -- | -- | -- |
| Modified headers | -- | RPI | -- | -- | | Modified headers | -- | RPI | -- | -- |
| Removed headers | -- | -- | -- | -- | | Removed headers | -- | -- | -- | -- |
| Untouched headers | -- | -- | RPI | RPI (Ignored) | | Untouched headers | -- | -- | RPI | RPI (Ignored) |
+-------------------+---------+-------+------+----------------+ +-------------------+---------+-------+------+----------------+
Table 9: Non-SM: Summary of the use of headers from RAL to Internet Table 7: Non-SM: Summary of the use of headers from RAL to Internet
with no encapsulation with no encapsulation
+-----------+--------------+--------------+--------------+----------+ +-----------+--------------+--------------+--------------+----------+
| Header | RAL src | 6LR_i | 6LBR | Internet | | Header | RAL src | 6LR_i | 6LBR | Internet |
| | | | | dst | | | | | | dst |
+-----------+--------------+--------------+--------------+----------+ +-----------+--------------+--------------+--------------+----------+
| Added | IPv6-in-IPv6 | -- | -- | -- | | Added | IPv6-in-IPv6 | -- | -- | -- |
| headers | (RPI) | | | | | headers | (RPI) | | | |
| Modified | -- | IPv6-in-IPv6 | -- | -- | | Modified | -- | IPv6-in-IPv6 | -- | -- |
| headers | | (RPI) | | | | headers | | (RPI) | | |
| Removed | -- | -- | IPv6-in-IPv6 | -- | | Removed | -- | -- | IPv6-in-IPv6 | -- |
| headers | | | (RPI) | | | headers | | | (RPI) | |
| Untouched | -- | -- | -- | -- | | Untouched | -- | -- | -- | -- |
| headers | | | | | | headers | | | | |
+-----------+--------------+--------------+--------------+----------+ +-----------+--------------+--------------+--------------+----------+
Table 10: Non-SM: Summary of the use of headers from RAL to Internet Table 8: Non-SM: Summary of the use of headers from RAL to Internet
with encapsulation to the root with encapsulation to the root
8.2.2. Non-SM: Example of Flow from Internet to RAL 8.2.2. Non-SM: Example of Flow from Internet to RAL
In this case the flow comprises: In this case the flow comprises:
Internet --> root (6LBR) --> 6LR_i --> RAL dst (6LN) Internet --> root (6LBR) --> 6LR_i --> RAL dst (6LN)
For example, a communication flow could be: Internet --> Node A For example, a communication flow could be: Internet --> Node A
(root) --> Node B --> Node D --> Node F (RAL) (root) --> Node B --> Node D --> Node F (RAL)
6LR_i represents the intermediate routers from source to destination. 6LR_i represents the intermediate routers from source to destination,
In this case, 1 <= i <= n, n is the number of routers (6LR) that the 1 <= i <= n, where n is the total number of routers (6LR) that the
packet goes through from 6LBR to destination (RAL). packet goes through from 6LBR to destination (RAL).
The 6LBR must add a RH3 header. As the 6LBR will know the path and The 6LBR must add an RH3 header. As the 6LBR will know the path and
address of the target node, it can address the IPv6-in-IPv6 header to address of the target node, it can address the IPv6-in-IPv6 header to
that node. The 6LBR will zero the flow label upon entry in order to that node. The 6LBR will zero the flow label upon entry in order to
aid compression [RFC8138]. aid compression [RFC8138].
The Table 11 summarizes what headers are needed for this use case. The Table 9 summarizes what headers are needed for this use case.
+-----------+----------+--------------+--------------+--------------+ +-----------+----------+--------------+--------------+--------------+
| Header | Internet | 6LBR | 6LR_i | RAL dst | | Header | Internet | 6LBR | 6LR_i | RAL dst |
| | src | | | | | | src | | | |
+-----------+----------+--------------+--------------+--------------+ +-----------+----------+--------------+--------------+--------------+
| Added | -- | IPv6-in-IPv6 | -- | -- | | Added | -- | IPv6-in-IPv6 | -- | -- |
| headers | | (RH3,RPI) | | | | headers | | (RH3,RPI) | | |
| Modified | -- | -- | IPv6-in-IPv6 | -- | | Modified | -- | -- | IPv6-in-IPv6 | -- |
| headers | | | (RH3,RPI) | | | headers | | | (RH3,RPI) | |
| Removed | -- | -- | -- | IPv6-in-IPv6 | | Removed | -- | -- | -- | IPv6-in-IPv6 |
| headers | | | | (RH3,RPI) | | headers | | | | (RH3,RPI) |
| Untouched | -- | -- | -- | -- | | Untouched | -- | -- | -- | -- |
| headers | | | | | | headers | | | | |
+-----------+----------+--------------+--------------+--------------+ +-----------+----------+--------------+--------------+--------------+
Table 11: Non-SM: Summary of the use of headers from Internet to RAL Table 9: Non-SM: Summary of the use of headers from Internet to RAL
8.2.3. Non-SM: Example of Flow from RUL to Internet 8.2.3. Non-SM: Example of Flow from RUL to Internet
In this case the flow comprises: In this case the flow comprises:
RUL (IPv6 src node) --> 6LR_1 --> 6LR_i -->root (6LBR) --> Internet RUL (IPv6 src node) --> 6LR_1 --> 6LR_i -->root (6LBR) --> Internet
dst dst
For example, a communication flow could be: Node G --> Node E --> For example, a communication flow could be: Node G --> Node E -->
Node B --> Node A --> Internet Node B --> Node A --> Internet
6LR_i are the intermediate routers from source to destination. In 6LR_i are the intermediate routers from source to destination, 1 <= i
this case, "1 <= i <= n", where n is the number of routers (6LRs) <= n, where n is the total number of routers (6LRs) that the packet
that the packet goes through from the source (RUL) to the 6LBR, e.g., goes through from the source (RUL) to the 6LBR, e.g., 6LR_1 (i=1).
6LR_1 (i=1).
In this case the flow label is recommended to be zero in the IPv6 In this case the flow label is recommended to be zero in the IPv6
node. As RPL headers are added in the IPv6 node packet, the first node. As RPL headers are added in the IPv6 node packet, the first
6LR (6LR_1) will add a RPI inside a new IPv6-in-IPv6 header. The 6LR (6LR_1) will add an RPI inside a new IPv6-in-IPv6 header. The
IPv6-in-IPv6 header will be addressed to the root. This case is IPv6-in-IPv6 header will be addressed to the root. This case is
identical to the storing-mode case (see Section 7.2.3). identical to the storing-mode case (see Section 7.2.3).
The Figure 17 shows the table that summarizes what headers are needed The Figure 20 shows the table that summarizes what headers are needed
for this use case. for this use case.
+---------+----+-------------+--------------+--------------+--------+ +---------+----+-------------+--------------+--------------+--------+
| Header |RUL | 6LR_1 | 6LR_i | 6LBR |Internet| | Header |RUL | 6LR_1 | 6LR_i | 6LBR |Internet|
| |src | | [i=2,..,n] | | dst | | |src | | [i=2,..,n] | | dst |
| |node| | | | | | |node| | | | |
+---------+----+-------------+--------------+--------------+--------+ +---------+----+-------------+--------------+--------------+--------+
| Added | -- |IP6-IP6(RPI) | -- | -- | -- | | Added | -- |IP6-IP6(RPI) | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
+---------+----+-------------+--------------+--------------+--------+ +---------+----+-------------+--------------+--------------+--------+
| Modified| -- | -- | IP6-IP6(RPI) | -- | -- | | Modified| -- | -- | IP6-IP6(RPI) | -- | -- |
| headers | | | | | | | headers | | | | | |
+---------+----+-------------+--------------+--------------+--------+ +---------+----+-------------+--------------+--------------+--------+
| Removed | -- | -- | -- | IP6-IP6(RPI) | -- | | Removed | -- | -- | -- | IP6-IP6(RPI) | -- |
| headers | | | | | | | headers | | | | | |
+---------+----+-------------+--------------+--------------+--------+ +---------+----+-------------+--------------+--------------+--------+
|Untouched| -- | -- | -- | -- | -- | |Untouched| -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
+---------+----+-------------+--------------+--------------+--------+ +---------+----+-------------+--------------+--------------+--------+
Figure 17: Non-SM: Summary of the use of headers from RUL to Internet Figure 20: Non-SM: Summary of the use of headers from RUL to Internet
8.2.4. Non-SM: Example of Flow from Internet to RUL 8.2.4. Non-SM: Example of Flow from Internet to RUL
In this case the flow comprises: In this case the flow comprises:
Internet src --> root (6LBR) --> 6LR_i --> RUL (IPv6 dst node) Internet src --> root (6LBR) --> 6LR_i --> RUL (IPv6 dst node)
For example, a communication flow could be: Internet --> Node A For example, a communication flow could be: Internet --> Node A
(root) --> Node B --> Node E --> Node G (root) --> Node B --> Node E --> Node G
6LR_i represents the intermediate routers from source to destination. 6LR_i represents the intermediate routers from source to destination,
In this case, 1 <= i <= n, n is the number of routers (6LR) that the 1 <= i <= n, where n is the total number of routers (6LR) that the
packet goes through from 6LBR to RUL. packet goes through from 6LBR to RUL.
The 6LBR must add a RH3 header inside an IPv6-in-IPv6 header. The The 6LBR must add an RH3 header inside an IPv6-in-IPv6 header. The
6LBR will know the path, and will recognize that the final node is 6LBR will know the path, and will recognize that the final node is
not a RPL capable node as it will have received the connectivity DAO not a RPL capable node as it will have received the connectivity DAO
from the nearest 6LR. The 6LBR can therefore make the IPv6-in-IPv6 from the nearest 6LR. The 6LBR can therefore make the IPv6-in-IPv6
header destination be the last 6LR. The 6LBR will set to zero the header destination be the last 6LR. The 6LBR will set to zero the
flow label upon entry in order to aid compression [RFC8138]. flow label upon entry in order to aid compression [RFC8138].
The Figure 18 shows the table that summarizes what headers are needed The Figure 21 shows the table that summarizes what headers are needed
for this use case. for this use case.
+----------+--------+------------------+-----------+-----------+-----+ +----------+--------+------------------+-----------+-----------+-----+
| Header |Internet| 6LBR | 6LR_i | 6LR_n | RUL | | Header |Internet| 6LBR | 6LR_i | 6LR_n | RUL |
| | src | | | | dst | | | src | | | | dst |
+----------+--------+------------------+-----------+-----------+-----+ +----------+--------+------------------+-----------+-----------+-----+
| Added | -- | IP6-IP6(RH3,RPI) | -- | -- | -- | | Added | -- | IP6-IP6(RH3,RPI) | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
+----------+--------+------------------+-----------+-----------+-----+ +----------+--------+------------------+-----------+-----------+-----+
| Modified | -- | -- | IP6-IP6 | -- | -- | | Modified | -- | -- | IP6-IP6 | -- | -- |
| headers | | | (RH3,RPI) | | | | headers | | | (RH3,RPI) | | |
+----------+--------+------------------+-----------+-----------+-----+ +----------+--------+------------------+-----------+-----------+-----+
| Removed | -- | -- | -- | IP6-IP6 | -- | | Removed | -- | -- | -- | IP6-IP6 | -- |
| headers | | | | (RH3,RPI) | | | headers | | | | (RH3,RPI) | |
+----------+--------+------------------+-----------+-----------+-----+ +----------+--------+------------------+-----------+-----------+-----+
|Untouched | -- | -- | -- | -- | -- | |Untouched | -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
+----------+--------+------------------+-----------+-----------+-----+ +----------+--------+------------------+-----------+-----------+-----+
Figure 18: Non-SM: Summary of the use of headers from Internet to Figure 21: Non-SM: Summary of the use of headers from Internet to
RUL. RUL.
8.3. Non-SM: Interaction between leaves 8.3. Non-SM: Interaction between leaves
In this section is described the communication flow in Non Storing In this section is described the communication flow in Non Storing
Mode (Non-SM) between, Mode (Non-SM) between,
RAL to RAL RAL to RAL
RAL to RUL RAL to RUL
skipping to change at page 41, line 48 skipping to change at page 43, line 48
8.3.1. Non-SM: Example of Flow from RAL to RAL 8.3.1. Non-SM: Example of Flow from RAL to RAL
In this case the flow comprises: In this case the flow comprises:
RAL src --> 6LR_ia --> root (6LBR) --> 6LR_id --> RAL dst RAL src --> 6LR_ia --> root (6LBR) --> 6LR_id --> RAL dst
For example, a communication flow could be: Node F (RAL src)--> Node For example, a communication flow could be: Node F (RAL src)--> Node
D --> Node B --> Node A (root) --> Node B --> Node E --> Node H (RAL D --> Node B --> Node A (root) --> Node B --> Node E --> Node H (RAL
dst) dst)
6LR_ia represents the intermediate routers from source to the root In 6LR_ia represents the intermediate routers from source to the root, 1
this case, 1 <= ia <= n, n is the number of routers (6LR) that the <= ia <= n, where n is the total number of routers (6LR) that the
packet goes through from RAL to the root. packet goes through from RAL to the root.
6LR_id represents the intermediate routers from the root to the 6LR_id represents the intermediate routers from the root to the
destination. In this case, 1 <= id <= m, m is the number of the destination, 1 <= id <= m, where m is the total number of the
intermediate routers (6LR). intermediate routers (6LR).
This case involves only nodes in same RPL domain. The originating This case involves only nodes in same RPL domain. The originating
node will add a RPI to the original packet, and send the packet node will add an RPI to the original packet, and send the packet
upwards. upwards.
The originating node may put the RPI (RPI1) into an IPv6-in-IPv6 The originating node may put the RPI (RPI1) into an IPv6-in-IPv6
header addressed to the root, so that the 6LBR can remove that header addressed to the root, so that the 6LBR can remove that
header. If it does not, then the RPI1 is forwarded down from the header. If it does not, then the RPI1 is forwarded down from the
root in the inner header to no avail. root in the inner header to no avail.
The 6LBR will need to insert a RH3 header, which requires that it add The 6LBR will need to insert an RH3 header, which requires that it
an IPv6-in-IPv6 header. It should be able to remove the RPI(RPI1), add an IPv6-in-IPv6 header. It should be able to remove the
as it was contained in an IPv6-in-IPv6 header addressed to it. RPI(RPI1), as it was contained in an IPv6-in-IPv6 header addressed to
Otherwise, there may be a RPI buried inside the inner IP header, it. Otherwise, there may be an RPI buried inside the inner IP
which should get ignored. The root inserts a RPI (RPI2) alongside header, which should get ignored. The root inserts an RPI (RPI2)
the RH3. alongside the RH3.
Networks that use the RPL P2P extension [RFC6997] are essentially Networks that use the RPL P2P extension [RFC6997] are essentially
non-storing DODAGs and fall into this scenario or scenario non-storing DODAGs and fall into this scenario or scenario
Section 8.1.2, with the originating node acting as 6LBR. Section 8.1.2, with the originating node acting as 6LBR.
The Figure 19 shows the table that summarizes what headers are needed The Figure 22 shows the table that summarizes what headers are needed
for this use case when encapsulation to the root takes place. for this use case when encapsulation to the root takes place.
The Figure 20 shows the table that summarizes what headers are needed The Figure 23 shows the table that summarizes what headers are needed
for this use case when there is no encapsulation to the root. for this use case when there is no encapsulation to the root.
+---------+-------+----------+------------+----------+------------+ +---------+-------+----------+------------+----------+------------+
| Header | RAL | 6LR_ia | 6LBR | 6LR_id | RAL | | Header | RAL | 6LR_ia | 6LBR | 6LR_id | RAL |
| | src | | | | dst | | | src | | | | dst |
+---------+-------+----------+------------+----------+------------+ +---------+-------+----------+------------+----------+------------+
| Added |IP6-IP6| | IP6-IP6 | -- | -- | | Added |IP6-IP6| | IP6-IP6 | -- | -- |
| headers |(RPI1) | -- |(RH3-> RAL, | | | | headers |(RPI1) | -- |(RH3-> RAL, | | |
| | | | RPI2) | | | | | | | RPI2) | | |
+---------+-------+----------+------------+----------+------------+ +---------+-------+----------+------------+----------+------------+
skipping to change at page 43, line 24 skipping to change at page 45, line 24
| headers | | (RPI1) | |(RH3,RPI) | | | headers | | (RPI1) | |(RH3,RPI) | |
+---------+-------+----------+------------+----------+------------+ +---------+-------+----------+------------+----------+------------+
| Removed | -- | -- | IP6-IP6 | -- | IP6-IP6 | | Removed | -- | -- | IP6-IP6 | -- | IP6-IP6 |
| headers | | | (RPI1) | | (RH3, | | headers | | | (RPI1) | | (RH3, |
| | | | | | RPI2) | | | | | | | RPI2) |
+---------+-------+----------+------------+----------+------------+ +---------+-------+----------+------------+----------+------------+
|Untouched| -- | -- | -- | -- | -- | |Untouched| -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
+---------+-------+----------+------------+----------+------------+ +---------+-------+----------+------------+----------+------------+
Figure 19: Non-SM: Summary of the Use of Headers from RAL to RAL with Figure 22: Non-SM: Summary of the Use of Headers from RAL to RAL with
encapsulation to the root. encapsulation to the root.
+-----------+------+--------+---------+---------+---------+ +-----------+------+--------+---------+---------+---------+
| Header | RAL | 6LR_ia | 6LBR | 6LR_id | RAL | | Header | RAL | 6LR_ia | 6LBR | 6LR_id | RAL |
+-----------+------+--------+---------+---------+---------+ +-----------+------+--------+---------+---------+---------+
| Inserted | RPI1 | -- | IP6-IP6 | -- | -- | | Inserted | RPI1 | -- | IP6-IP6 | -- | -- |
| headers | | | (RH3, | | | | headers | | | (RH3, | | |
| | | | RPI2) | | | | | | | RPI2) | | |
+-----------+------+--------+---------+---------+---------+ +-----------+------+--------+---------+---------+---------+
| Modified | -- | RPI1 | -- | IP6-IP6 | -- | | Modified | -- | RPI1 | -- | IP6-IP6 | -- |
skipping to change at page 43, line 47 skipping to change at page 45, line 47
+-----------+------+--------+---------+---------+---------+ +-----------+------+--------+---------+---------+---------+
| Removed | -- | -- | -- | -- | IP6-IP6 | | Removed | -- | -- | -- | -- | IP6-IP6 |
| headers | | | | | (RH3, | | headers | | | | | (RH3, |
| | | | | | RPI2) | | | | | | | RPI2) |
| | | | | | RPI1 | | | | | | | RPI1 |
+-----------+------+--------+---------+---------+---------+ +-----------+------+--------+---------+---------+---------+
| Untouched | -- | -- | RPI1 | RPI1 | -- | | Untouched | -- | -- | RPI1 | RPI1 | -- |
| headers | | | | | | | headers | | | | | |
+-----------+------+--------+---------+---------+---------+ +-----------+------+--------+---------+---------+---------+
Figure 20: Non-SM: Summary of the Use of Headers from RAL to RAL Figure 23: Non-SM: Summary of the Use of Headers from RAL to RAL
without encapsulation to the root. without encapsulation to the root.
8.3.2. Non-SM: Example of Flow from RAL to RUL 8.3.2. Non-SM: Example of Flow from RAL to RUL
In this case the flow comprises: In this case the flow comprises:
RAL --> 6LR_ia --> root (6LBR) --> 6LR_id --> RUL (IPv6 dst node) RAL --> 6LR_ia --> root (6LBR) --> 6LR_id --> RUL (IPv6 dst node)
For example, a communication flow could be: Node F (RAL) --> Node D For example, a communication flow could be: Node F (RAL) --> Node D
--> Node B --> Node A (root) --> Node B --> Node E --> Node G (RUL) --> Node B --> Node A (root) --> Node B --> Node E --> Node G (RUL)
6LR_ia represents the intermediate routers from source to the root In 6LR_ia represents the intermediate routers from source to the root, 1
this case, 1 <= ia <= n, n is the number of intermediate routers <= ia <= n, where n is the total number of intermediate routers (6LR)
(6LR)
6LR_id represents the intermediate routers from the root to the 6LR_id represents the intermediate routers from the root to the
destination. In this case, 1 <= id <= m, m is the number of the destination, 1 <= id <= m, where m is the total number of the
intermediate routers (6LRs). intermediate routers (6LRs).
As in the previous case, the RAL (6LN) may insert a RPI (RPI1) header As in the previous case, the RAL (6LN) may insert an RPI (RPI1)
which must be in an IPv6-in-IPv6 header addressed to the root so that header which must be in an IPv6-in-IPv6 header addressed to the root
the 6LBR can remove this RPI. The 6LBR will then insert a RH3 inside so that the 6LBR can remove this RPI. The 6LBR will then insert an
a new IPv6-in-IPv6 header addressed to the last 6LR_id (6LR_id = m) RH3 inside a new IPv6-in-IPv6 header addressed to the last 6LR_id
alongside the insertion of RPI2. (6LR_id = m) alongside the insertion of RPI2.
If the originating node does not not put the RPI (RPI1) into an IPv6- If the originating node does not not put the RPI (RPI1) into an IPv6-
in-IPv6 header addressed to the root. Then, the RPI1 is forwarded in-IPv6 header addressed to the root. Then, the RPI1 is forwarded
down from the root in the inner header to no avail. down from the root in the inner header to no avail.
The Figure 21 shows the table that summarizes what headers are needed The Figure 24 shows the table that summarizes what headers are needed
for this use case when encapsulation to the root takes place. The for this use case when encapsulation to the root takes place. The
Figure 22 shows the table that summarizes what headers are needed for Figure 25 shows the table that summarizes what headers are needed for
this use case when no encapsulation to the root takes place. this use case when no encapsulation to the root takes place.
+-----------+---------+---------+---------+---------+---------+------+ +-----------+---------+---------+---------+---------+---------+------+
| Header | RAL | 6LR_ia | 6LBR | 6LR_id | 6LR_m | RUL | | Header | RAL | 6LR_ia | 6LBR | 6LR_id | 6LR_m | RUL |
| | src | | | | | dst | | | src | | | | | dst |
| | node | | | | | node | | | node | | | | | node |
+-----------+---------+---------+---------+---------+---------+------+ +-----------+---------+---------+---------+---------+---------+------+
| Added | IP6-IP6 | | IP6-IP6 | -- | -- | -- | | Added | IP6-IP6 | | IP6-IP6 | -- | -- | -- |
| headers | (RPI1) | -- | (RH3, | | | | | headers | (RPI1) | -- | (RH3, | | | |
| | | | RPI2) | | | | | | | | RPI2) | | | |
skipping to change at page 45, line 26 skipping to change at page 47, line 26
| | | | | RPI2) | | | | | | | | RPI2) | | |
+-----------+---------+---------+---------+---------+---------+------+ +-----------+---------+---------+---------+---------+---------+------+
| Removed | -- | -- | IP6-IP6 | -- | IP6-IP6 | -- | | Removed | -- | -- | IP6-IP6 | -- | IP6-IP6 | -- |
| headers | | | (RPI1) | | (RH3, | | | headers | | | (RPI1) | | (RH3, | |
| | | | | | RPI2) | | | | | | | | RPI2) | |
+-----------+---------+---------+---------+---------+---------+------+ +-----------+---------+---------+---------+---------+---------+------+
| Untouched | -- | -- | -- | -- | -- | -- | | Untouched | -- | -- | -- | -- | -- | -- |
| headers | | | | | | | | headers | | | | | | |
+-----------+---------+---------+---------+---------+---------+------+ +-----------+---------+---------+---------+---------+---------+------+
Figure 21: Non-SM: Summary of the use of headers from RAL to RUL with Figure 24: Non-SM: Summary of the use of headers from RAL to RUL with
encapsulation to the root. encapsulation to the root.
+-----------+------+--------+---------+---------+---------+---------+ +-----------+------+--------+---------+---------+---------+---------+
| Header | RAL | 6LR_ia | 6LBR | 6LR_id | 6LR_n | RUL | | Header | RAL | 6LR_ia | 6LBR | 6LR_id | 6LR_n | RUL |
| | src | | | | | dst | | | src | | | | | dst |
| | node | | | | | node | | | node | | | | | node |
+-----------+------+--------+---------+---------+---------+---------+ +-----------+------+--------+---------+---------+---------+---------+
| Inserted | RPI1 | -- | IP6-IP6 | -- | -- | -- | | Inserted | RPI1 | -- | IP6-IP6 | -- | -- | -- |
| headers | | | (RH3, | | | | | headers | | | (RH3, | | | |
| | | | RPI2) | | | | | | | | RPI2) | | | |
skipping to change at page 45, line 50 skipping to change at page 47, line 50
| | | | | RPI2) | | | | | | | | RPI2) | | |
+-----------+------+--------+---------+---------+---------+---------+ +-----------+------+--------+---------+---------+---------+---------+
| Removed | -- | -- | -- | -- | IP6-IP6 | -- | | Removed | -- | -- | -- | -- | IP6-IP6 | -- |
| headers | | | | | (RH3, | | | headers | | | | | (RH3, | |
| | | | | | RPI2) | | | | | | | | RPI2) | |
+-----------+------+--------+---------+---------+---------+---------+ +-----------+------+--------+---------+---------+---------+---------+
| Untouched | -- | -- | RPI1 | RPI1 | RPI1 | RPI1 | | Untouched | -- | -- | RPI1 | RPI1 | RPI1 | RPI1 |
| headers | | | | | |(Ignored)| | headers | | | | | |(Ignored)|
+-----------+------+--------+---------+---------+---------+---------+ +-----------+------+--------+---------+---------+---------+---------+
Figure 22: Non-SM: Summary of the use of headers from RAL to RUL Figure 25: Non-SM: Summary of the use of headers from RAL to RUL
without encapsulation to the root. without encapsulation to the root.
8.3.3. Non-SM: Example of Flow from RUL to RAL 8.3.3. Non-SM: Example of Flow from RUL to RAL
In this case the flow comprises: In this case the flow comprises:
RUL (IPv6 src node) --> 6LR_1 --> 6LR_ia --> root (6LBR) --> 6LR_id RUL (IPv6 src node) --> 6LR_1 --> 6LR_ia --> root (6LBR) --> 6LR_id
--> RAL dst (6LN) --> RAL dst (6LN)
For example, a communication flow could be: Node G (RUL)--> Node E For example, a communication flow could be: Node G (RUL)--> Node E
--> Node B --> Node A (root) --> Node B --> Node E --> Node H (RAL) --> Node B --> Node A (root) --> Node B --> Node E --> Node H (RAL)
6LR_ia represents the intermediate routers from source to the root. 6LR_ia represents the intermediate routers from source to the root, 1
In this case, 1 <= ia <= n, n is the number of intermediate routers <= ia <= n, where n is the total number of intermediate routers (6LR)
(6LR)
6LR_id represents the intermediate routers from the root to the 6LR_id represents the intermediate routers from the root to the
destination. In this case, 1 <= id <= m, m is the number of the destination, 1 <= id <= m, where m is the total number of the
intermediate routers (6LR). intermediate routers (6LR).
In this scenario the RPI (RPI1) is added by the first 6LR (6LR_1) In this scenario the RPI (RPI1) is added by the first 6LR (6LR_1)
inside an IPv6-in-IPv6 header addressed to the root. The 6LBR will inside an IPv6-in-IPv6 header addressed to the root. The 6LBR will
remove this RPI, and add it's own IPv6-in-IPv6 header containing a remove this RPI, and add it's own IPv6-in-IPv6 header containing an
RH3 header and a RPI (RPI2). RH3 header and an RPI (RPI2).
The Figure 23 shows the table that summarizes what headers are needed The Figure 26 shows the table that summarizes what headers are needed
for this use case. for this use case.
+----------+------+---------+---------+---------+---------+---------+ +----------+------+---------+---------+---------+---------+---------+
| Header | RUL | 6LR_1 | 6LR_ia | 6LBR | 6LR_id | RAL | | Header | RUL | 6LR_1 | 6LR_ia | 6LBR | 6LR_id | RAL |
| | src | | | | | dst | | | src | | | | | dst |
| | node | | | | | node | | | node | | | | | node |
+----------+------+---------+---------+---------+---------+---------+ +----------+------+---------+---------+---------+---------+---------+
| Added | -- | IP6-IP6 | -- | IP6-IP6 | -- | -- | | Added | -- | IP6-IP6 | -- | IP6-IP6 | -- | -- |
| headers | | (RPI1) | | (RH3, | | | | headers | | (RPI1) | | (RH3, | | |
| | | | | RPI2) | | | | | | | | RPI2) | | |
skipping to change at page 46, line 52 skipping to change at page 48, line 51
| | | | | | RPI2) | | | | | | | | RPI2) | |
+----------+------+---------+---------+---------+---------+---------+ +----------+------+---------+---------+---------+---------+---------+
| Removed | -- | | -- | IP6-IP6 | -- | IP6-IP6 | | Removed | -- | | -- | IP6-IP6 | -- | IP6-IP6 |
| headers | | -- | | (RPI1) | | (RH3, | | headers | | -- | | (RPI1) | | (RH3, |
| | | | | | | RPI2) | | | | | | | | RPI2) |
+----------+------+---------+---------+---------+---------+---------+ +----------+------+---------+---------+---------+---------+---------+
|Untouched | -- | -- | -- | -- | -- | -- | |Untouched | -- | -- | -- | -- | -- | -- |
| headers | | | | | | | | headers | | | | | | |
+----------+------+---------+---------+---------+---------+---------+ +----------+------+---------+---------+---------+---------+---------+
Figure 23: Non-SM: Summary of the use of headers from RUL to RAL. Figure 26: Non-SM: Summary of the use of headers from RUL to RAL.
8.3.4. Non-SM: Example of Flow from RUL to RUL 8.3.4. Non-SM: Example of Flow from RUL to RUL
In this case the flow comprises: In this case the flow comprises:
RUL (IPv6 src node) --> 6LR_1 --> 6LR_ia --> root (6LBR) --> 6LR_id RUL (IPv6 src node) --> 6LR_1 --> 6LR_ia --> root (6LBR) --> 6LR_id
--> RUL (IPv6 dst node) --> RUL (IPv6 dst node)
For example, a communication flow could be: Node G --> Node E --> For example, a communication flow could be: Node G --> Node E -->
Node B --> Node A (root) --> Node C --> Node J Node B --> Node A (root) --> Node C --> Node J
6LR_ia represents the intermediate routers from source to the root. 6LR_ia represents the intermediate routers from source to the root, 1
In this case, 1 <= ia <= n, n is the number of intermediate routers <= ia <= n, where n is the total number of intermediate routers (6LR)
(6LR)
6LR_id represents the intermediate routers from the root to the 6LR_id represents the intermediate routers from the root to the
destination. In this case, 1 <= id <= m, m is the number of the destination, 1 <= id <= m, where m is the total number of the
intermediate routers (6LR). intermediate routers (6LR).
This scenario is the combination of the previous two cases. This scenario is the combination of the previous two cases.
The Figure 24 shows the table that summarizes what headers are needed The Figure 27 shows the table that summarizes what headers are needed
for this use case. for this use case.
+---------+------+-------+-------+---------+-------+---------+------+ +---------+------+-------+-------+---------+-------+---------+------+
| Header | RUL | 6LR_1 | 6LR_ia| 6LBR |6LR_id | 6LR_m | RUL | | Header | RUL | 6LR_1 | 6LR_ia| 6LBR |6LR_id | 6LR_m | RUL |
| | src | | | | | | dst | | | src | | | | | | dst |
| | node | | | | | | node | | | node | | | | | | node |
+---------+------+-------+-------+---------+-------+---------+------+ +---------+------+-------+-------+---------+-------+---------+------+
| Added | -- |IP6-IP6| -- | IP6-IP6 | -- | -- | -- | | Added | -- |IP6-IP6| -- | IP6-IP6 | -- | -- | -- |
| headers | | (RPI1)| | (RH3, | | | | | headers | | (RPI1)| | (RH3, | | | |
| | | | | RPI2) | | | | | | | | | RPI2) | | | |
skipping to change at page 47, line 49 skipping to change at page 49, line 48
| | | | | | RPI2)| | | | | | | | | RPI2)| | |
+---------+------+-------+-------+---------+-------+---------+------+ +---------+------+-------+-------+---------+-------+---------+------+
| Removed | -- | -- | -- | IP6-IP6 | -- | IP6-IP6 | -- | | Removed | -- | -- | -- | IP6-IP6 | -- | IP6-IP6 | -- |
| headers | | | | (RPI1) | | (RH3, | | | headers | | | | (RPI1) | | (RH3, | |
| | | | | | | RPI2) | | | | | | | | | RPI2) | |
+---------+------+-------+-------+---------+-------+---------+------+ +---------+------+-------+-------+---------+-------+---------+------+
|Untouched| -- | -- | -- | -- | -- | -- | -- | |Untouched| -- | -- | -- | -- | -- | -- | -- |
| headers | | | | | | | | | headers | | | | | | | |
+---------+------+-------+-------+---------+-------+---------+------+ +---------+------+-------+-------+---------+-------+---------+------+
Figure 24: Non-SM: Summary of the use of headers from RUL to RUL Figure 27: Non-SM: Summary of the use of headers from RUL to RUL
9. Operational Considerations of supporting RUL-leaves 9. Operational Considerations of supporting RUL-leaves
Roughly half of the situations described in this document involve Roughly half of the situations described in this document involve
leaf ("host") nodes that do not speak RPL. These nodes fall into two leaf ("host") nodes that do not speak RPL. These nodes fall into two
further categories: ones that drop a packet that have RPI or RH3 further categories: ones that drop a packet that have RPI or RH3
headers, and ones that continue to process a packet that has RPI and/ headers, and ones that continue to process a packet that has RPI and/
or RH3 headers. or RH3 headers.
[RFC8200] provides for new rules that suggest that nodes that have [RFC8200] provides for new rules that suggest that nodes that have
skipping to change at page 49, line 8 skipping to change at page 51, line 8
could otherwise omit this unnecessary header if it was certain of the could otherwise omit this unnecessary header if it was certain of the
properties of the leaf. properties of the leaf.
As storing mode can not know the final path of the traffic, As storing mode can not know the final path of the traffic,
intolerant (that drop packets with RPL artifacts) leaf nodes can not intolerant (that drop packets with RPL artifacts) leaf nodes can not
be supported. be supported.
10. Operational considerations of introducing 0x23 10. Operational considerations of introducing 0x23
This section describes the operational considerations of introducing This section describes the operational considerations of introducing
the new RPI option Type of 0x23. the new RPI Option Type of 0x23.
During bootstrapping the node gets the DIO with the information of During bootstrapping the node gets the DIO with the information of
RPI option Type, indicating the new RPI in the DODAG Configuration RPI Option Type, indicating the new RPI in the DODAG Configuration
option Flag. The DODAG root is in charge to configure the current option Flag. The DODAG root is in charge to configure the current
network to the new value, through DIO messages and when all the nodes network to the new value, through DIO messages and when all the nodes
are set with the new value. The DODAG should change to a new DODAG are set with the new value. The DODAG should change to a new DODAG
version. In case of rebooting, the node does not remember the RPI version. In case of rebooting, the node does not remember the RPI
option Type. Thus, the DIO is sent with a flag indicating the new Option Type. Thus, the DIO is sent with a flag indicating the new
RPI option Type. RPI Option Type.
The DODAG Configuration option is contained in a RPL DIO message, The DODAG Configuration option is contained in a RPL DIO message,
which contains a unique DTSN counter. The leaf nodes respond to this which contains a unique DTSN counter. The leaf nodes respond to this
message with DAO messages containing the same DTSN. This is a normal message with DAO messages containing the same DTSN. This is a normal
part of RPL routing; the RPL root therefore knows when the updated part of RPL routing; the RPL root therefore knows when the updated
DODAG Configuration option has been seen by all nodes. DODAG Configuration option has been seen by all nodes.
Before the migration happens, all the RPL-aware nodes should support Before the migration happens, all the RPL-aware nodes should support
both values . The migration procedure it is triggered when the DIO both values . The migration procedure it is triggered when the DIO
is sent with the flag indicating the new RPI option Type. Namely, it is sent with the flag indicating the new RPI Option Type. Namely, it
remains at 0x63 until it is sure that the network is capable of 0x23, remains at 0x63 until it is sure that the network is capable of 0x23,
then it abruptly change to 0x23. This options allows to send packets then it abruptly change to 0x23. This options allows to send packets
to not-RPL nodes, which should ignore the option and continue to not-RPL nodes, which should ignore the option and continue
processing the packets. processing the packets.
In case that a node join to a network that only process 0x63, it In case that a node join to a network that only process 0x63, it
would produce a flag day as was mentioned previously. Indicating the would produce a flag day as was mentioned previously. Indicating the
new RPI in the DODAG Configuration option Flag is a way to avoid the new RPI in the DODAG Configuration option Flag is a way to avoid the
flag day in a network. It is recommended that a network process both flag day in a network. It is recommended that a network process both
options to enable interoperability. options to enable interoperability.
11. IANA Considerations 11. IANA Considerations
This document updates the registration made in [RFC6553] Destination This document updates the registration made in [RFC6553] Destination
Options and Hop-by-Hop Options registry from 0x63 to 0x23 as shown in Options and Hop-by-Hop Options registry from 0x63 to 0x23 as shown in
Figure 25. Figure 28.
+-------+-------------------+------------------------+---------- -+ +-------+-------------------+------------------------+---------- -+
| Hex | Binary Value | Description | Reference | | Hex | Binary Value | Description | Reference |
+ Value +-------------------+ + + + Value +-------------------+ + +
| | act | chg | rest | | | | | act | chg | rest | | |
+-------+-----+-----+-------+------------------------+------------+ +-------+-----+-----+-------+------------------------+------------+
| 0x23 | 00 | 1 | 00011 | RPL Option |[RFCXXXX](*)| | 0x23 | 00 | 1 | 00011 | RPL Option |[RFCXXXX](*)|
+-------+-----+-----+-------+------------------------+------------+ +-------+-----+-----+-------+------------------------+------------+
| 0x63 | 01 | 1 | 00011 | RPL Option(DEPRECATED) | [RFC6553] | | 0x63 | 01 | 1 | 00011 | RPL Option(DEPRECATED) | [RFC6553] |
| | | | | |[RFCXXXX](*)| | | | | | |[RFCXXXX](*)|
+-------+-----+-----+-------+------------------------+------------+ +-------+-----+-----+-------+------------------------+------------+
Figure 25: Option Type in RPL Option.(*)represents this document Figure 28: Option Type in RPL Option.(*)represents this document
DODAG Configuration option is updated as follows (Figure 26): DODAG Configuration option is updated as follows (Figure 29):
+------------+-----------------+---------------+ +------------+-----------------+---------------+
| Bit number | Description | Reference | | Bit number | Description | Reference |
+------------+-----------------+---------------+ +------------+-----------------+---------------+
| 3 | RPI 0x23 enable | This document | | 3 | RPI 0x23 enable | This document |
+------------+-----------------+---------------+ +------------+-----------------+---------------+
Figure 26: DODAG Configuration option Flag to indicate the RPI-flag- Figure 29: DODAG Configuration option Flag to indicate the RPI-flag-
day. day.
12. Security Considerations 12. Security Considerations
The security considerations covered in [RFC6553] and [RFC6554] apply The security considerations covered in [RFC6553] and [RFC6554] apply
when the packets are in the RPL Domain. when the packets are in the RPL Domain.
The IPv6-in-IPv6 mechanism described in this document is much more The IPv6-in-IPv6 mechanism described in this document is much more
limited than the general mechanism described in [RFC2473]. The limited than the general mechanism described in [RFC2473]. The
willingness of each node in the LLN to decapsulate packets and willingness of each node in the LLN to decapsulate packets and
forward them could be exploited by nodes to disguise the origin of an forward them could be exploited by nodes to disguise the origin of an
attack. attack.
While a typical LLN may be a very poor origin for attack traffic (as While a typical LLN may be a very poor origin for attack traffic (as
the networks tend to be very slow, and the nodes often have very low the networks tend to be very slow, and the nodes often have very low
duty cycles) given enough nodes, they could still have a significant duty cycles), given enough nodes, LLNs could still have a significant
impact, particularly if attack is targeting another LLN. impact, particularly if attack is targeting another LLN.
Additionally, some uses of RPL involve large backbone ISP scale Additionally, some uses of RPL involve large backbone ISP scale
equipment [I-D.ietf-anima-autonomic-control-plane], which may be equipment [I-D.ietf-anima-autonomic-control-plane], which may be
equipped with multiple 100Gb/s interfaces. equipped with multiple 100Gb/s interfaces.
Blocking or careful filtering of IPv6-in-IPv6 traffic entering the Blocking or careful filtering of IPv6-in-IPv6 traffic entering the
LLN as described above will make sure that any attack that is mounted LLN as described above will make sure that any attack that is mounted
must originate from compromised nodes within the LLN. The use of must originate from compromised nodes within the LLN. The use of
BCP38 [BCP38] filtering at the RPL root on egress traffic will both BCP38 [BCP38] filtering at the RPL root on egress traffic will both
alert the operator to the existence of the attack, as well as drop alert the operator to the existence of the attack, as well as drop
skipping to change at page 51, line 34 skipping to change at page 53, line 34
be done without the use of IPv6-in-IPv6 headers using forged source be done without the use of IPv6-in-IPv6 headers using forged source
addresses. If the attack requires bi-directional communication, then addresses. If the attack requires bi-directional communication, then
IPv6-in-IPv6 provides no advantages. IPv6-in-IPv6 provides no advantages.
Whenever IPv6-in-IPv6 headers are being proposed, there is a concern Whenever IPv6-in-IPv6 headers are being proposed, there is a concern
about creating security issues. In the Security Considerations about creating security issues. In the Security Considerations
section of [RFC2473], it was suggested that tunnel entry and exit section of [RFC2473], it was suggested that tunnel entry and exit
points can be secured by securing the IPv6 path between them. This points can be secured by securing the IPv6 path between them. This
recommendation is not practical for RPL networks. [RFC5406] goes recommendation is not practical for RPL networks. [RFC5406] goes
into some detail on what additional details would be needed in order into some detail on what additional details would be needed in order
to "Use IPsec". Use of ESP would prevent RFC8138 compression to "Use IPsec". Use of ESP would prevent [RFC8138] compression
(compression must occur before encryption), and RFC8138 compression (compression must occur before encryption), and [RFC8138] compression
is lossy in a way that prevents use of AH. These are minor issues. is lossy in a way that prevents use of AH. These are minor issues.
The major issue is how to establish trust enough such that IKEv2 The major issue is how to establish trust enough such that IKEv2
could be used. This would require a system of certificates to be could be used. This would require a system of certificates to be
present in every single node, including any Internet nodes that might present in every single node, including any Internet nodes that might
need to communicate with the LLN. Thus, using IPsec requires a need to communicate with the LLN. Thus, using IPsec requires a
global PKI in the general case. global PKI in the general case.
More significantly, the use of IPsec tunnels to protect the IPv6-in- More significantly, the use of IPsec tunnels to protect the IPv6-in-
IPv6 headers would in the general case scale with the square of the IPv6 headers would in the general case scale with the square of the
number of nodes. This is a lot of resource for a constrained nodes number of nodes. This is a lot of resource for a constrained nodes
skipping to change at page 52, line 15 skipping to change at page 54, line 15
recommended. recommended.
An LLN with hostile nodes within it would not be protected against An LLN with hostile nodes within it would not be protected against
impersonation with the LLN by entry/exit filtering. impersonation with the LLN by entry/exit filtering.
The RH3 header usage described here can be abused in equivalent ways The RH3 header usage described here can be abused in equivalent ways
(to disguise the origin of traffic and attack other nodes) with an (to disguise the origin of traffic and attack other nodes) with an
IPv6-in-IPv6 header to add the needed RH3 header. As such, the IPv6-in-IPv6 header to add the needed RH3 header. As such, the
attacker's RH3 header will not be seen by the network until it attacker's RH3 header will not be seen by the network until it
reaches the end host, which will decapsulate it. An end-host should reaches the end host, which will decapsulate it. An end-host should
be suspicious about a RH3 header which has additional hops which have be suspicious about an RH3 header which has additional hops which
not yet been processed, and SHOULD ignore such a second RH3 header. have not yet been processed, and SHOULD ignore such a second RH3
header.
In addition, the LLN will likely use [RFC8138] to compress the IPv6- In addition, the LLN will likely use [RFC8138] to compress the IPv6-
in-IPv6 and RH3 headers. As such, the compressor at the RPL-root in-IPv6 and RH3 headers. As such, the compressor at the RPL-root
will see the second RH3 header and MAY choose to discard the packet will see the second RH3 header and MAY choose to discard the packet
if the RH3 header has not been completely consumed. A consumed if the RH3 header has not been completely consumed. A consumed
(inert) RH3 header could be present in a packet that flows from one (inert) RH3 header could be present in a packet that flows from one
LLN, crosses the Internet, and enters another LLN. As per the LLN, crosses the Internet, and enters another LLN. As per the
discussion in this document, such headers do not need to be removed. discussion in this document, such headers do not need to be removed.
However, there is no case described in this document where a RH3 is However, there is no case described in this document where an RH3 is
inserted in a non-storing network on traffic that is leaving the LLN, inserted in a non-storing network on traffic that is leaving the LLN,
but this document should not preclude such a future innovation. It but this document should not preclude such a future innovation. It
should just be noted that an incoming RH3 must be fully consumed, or should just be noted that an incoming RH3 must be fully consumed, or
very carefully inspected. very carefully inspected.
The RPI, if permitted to enter the LLN, could be used by an attacker The RPI, if permitted to enter the LLN, could be used by an attacker
to change the priority of a packet by selecting a different to change the priority of a packet by selecting a different
RPLInstanceID, perhaps one with a higher energy cost, for instance. RPLInstanceID, perhaps one with a higher energy cost, for instance.
It could also be that not all nodes are reachable in an LLN using the It could also be that not all nodes are reachable in an LLN using the
default RPLInstanceID, but a change of RPLInstanceID would permit an default RPLInstanceID, but a change of RPLInstanceID would permit an
attacker to bypass such filtering. Like the RH3, a RPI is to be attacker to bypass such filtering. Like the RH3, an RPI is to be
inserted by the RPL root on traffic entering the LLN by first inserted by the RPL root on traffic entering the LLN by first
inserting an IPv6-in-IPv6 header. The attacker's RPI therefore will inserting an IPv6-in-IPv6 header. The attacker's RPI therefore will
not be seen by the network. Upon reaching the destination node the not be seen by the network. Upon reaching the destination node the
RPI has no further meaning and is just skipped; the presence of a RPI has no further meaning and is just skipped; the presence of a
second RPI will have no meaning to the end node as the packet has second RPI will have no meaning to the end node as the packet has
already been identified as being at it's final destination. already been identified as being at it's final destination.
The RH3 and RPIs could be abused by an attacker inside of the network The RH3 and RPIs could be abused by an attacker inside of the network
to route packets on non-obvious ways, perhaps eluding observation. to route packets on non-obvious ways, perhaps eluding observation.
This usage is in fact part of [RFC6997] and can not be restricted at This usage appears consistent with a normal operation of [RFC6997]
all. This is a feature, not a bug. and can not be restricted at all. This is a feature, not a bug.
[RFC7416] deals with many other threats to LLNs not directly related [RFC7416] deals with many other threats to LLNs not directly related
to the use of IPv6-in-IPv6 headers, and this document does not change to the use of IPv6-in-IPv6 headers, and this document does not change
that analysis. that analysis.
Nodes within the LLN can use the IPv6-in-IPv6 mechanism to mount an Nodes within the LLN can use the IPv6-in-IPv6 mechanism to mount an
attack on another part of the LLN, while disguising the origin of the attack on another part of the LLN, while disguising the origin of the
attack. The mechanism can even be abused to make it appear that the attack. The mechanism can even be abused to make it appear that the
attack is coming from outside the LLN, and unless countered, this attack is coming from outside the LLN, and unless countered, this
could be used to mount a Distributed Denial Of Service attack upon could be used to mount a Distributed Denial Of Service attack upon
skipping to change at page 53, line 21 skipping to change at page 55, line 25
such attacks already seen in the real world. such attacks already seen in the real world.
If an attack comes from inside of LLN, it can be alleviated with SAVI If an attack comes from inside of LLN, it can be alleviated with SAVI
(Source Address Validation Improvement) using [RFC8505] with (Source Address Validation Improvement) using [RFC8505] with
[I-D.ietf-6lo-ap-nd]. The attacker will not be able to source [I-D.ietf-6lo-ap-nd]. The attacker will not be able to source
traffic with an address that is not registered, and the registration traffic with an address that is not registered, and the registration
process checks for topological correctness. Notice that there is an process checks for topological correctness. Notice that there is an
L2 authentication in most of the cases. If an attack comes from L2 authentication in most of the cases. If an attack comes from
outside LLN IPv6-in- IPv6 can be used to hide inner routing headers, outside LLN IPv6-in- IPv6 can be used to hide inner routing headers,
but by construction, the RH3 can typically only address nodes within but by construction, the RH3 can typically only address nodes within
the LLN. That is, a RH3 with a CmprI less than 8 , should be the LLN. That is, an RH3 with a CmprI less than 8 , should be
considered an attack (see RFC6554, section 3). considered an attack (see RFC6554, section 3).
Nodes outside of the LLN will need to pass IPv6-in-IPv6 traffic Nodes outside of the LLN will need to pass IPv6-in-IPv6 traffic
through the RPL root to perform this attack. To counter, the RPL through the RPL root to perform this attack. To counter, the RPL
root SHOULD either restrict ingress of IPv6-in-IPv6 packets (the root SHOULD either restrict ingress of IPv6-in-IPv6 packets (the
simpler solution), or it SHOULD walk the IP header extension chain simpler solution), or it SHOULD walk the IP header extension chain
until it can inspect the upper-layer-payload as described in until it can inspect the upper-layer-payload as described in
[RFC7045]. In particular, the RPL root SHOULD do [BCP38] processing [RFC7045]. In particular, the RPL root SHOULD do [BCP38] processing
on the source addresses of all IP headers that it examines in both on the source addresses of all IP headers that it examines in both
directions. directions.
skipping to change at page 53, line 51 skipping to change at page 56, line 6
13. Acknowledgments 13. Acknowledgments
This work is done thanks to the grant given by the StandICT.eu This work is done thanks to the grant given by the StandICT.eu
project. project.
A special BIG thanks to C. M. Heard for the help with the A special BIG thanks to C. M. Heard for the help with the
Section 4. Much of the redaction in that section is based on his Section 4. Much of the redaction in that section is based on his
comments. comments.
Additionally, the authors would like to acknowledge the review, Additionally, the authors would like to acknowledge the review,
feedback, and comments of (alphabetical order): Robert Cragie, Simon feedback, and comments of (alphabetical order): Dominique Barthel,
Duquennoy, Ralph Droms, Cenk Guendogan, Rahul Jadhav, Benjamin Kaduk, Robert Cragie, Simon Duquennoy, Ralph Droms, Cenk Guendogan, Rahul
Matthias Kovatsch, Charlie Perkins, Alvaro Retana, Peter van der Jadhav, Benjamin Kaduk, Matthias Kovatsch, Charlie Perkins, Alvaro
Stok, Xavier Vilajosana, Eric Vyncke and Thomas Watteyne. Retana, Peter van der Stok, Xavier Vilajosana, Eric Vyncke and Thomas
Watteyne.
14. References 14. References
14.1. Normative References 14.1. Normative References
[BCP38] Ferguson, P. and D. Senie, "Network Ingress Filtering: [BCP38] Ferguson, P. and D. Senie, "Network Ingress Filtering:
Defeating Denial of Service Attacks which employ IP Source Defeating Denial of Service Attacks which employ IP Source
Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827, Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827,
May 2000, <https://www.rfc-editor.org/info/bcp38>. May 2000, <https://www.rfc-editor.org/info/bcp38>.
skipping to change at page 55, line 44 skipping to change at page 57, line 44
[DDOS-KREBS] [DDOS-KREBS]
Goodin, D., "Record-breaking DDoS reportedly delivered by Goodin, D., "Record-breaking DDoS reportedly delivered by
>145k hacked cameras", September 2016, >145k hacked cameras", September 2016,
<http://arstechnica.com/security/2016/09/botnet-of-145k- <http://arstechnica.com/security/2016/09/botnet-of-145k-
cameras-reportedly-deliver-internets-biggest-ddos-ever/>. cameras-reportedly-deliver-internets-biggest-ddos-ever/>.
[I-D.ietf-6lo-ap-nd] [I-D.ietf-6lo-ap-nd]
Thubert, P., Sarikaya, B., Sethi, M., and R. Struik, Thubert, P., Sarikaya, B., Sethi, M., and R. Struik,
"Address Protected Neighbor Discovery for Low-power and "Address Protected Neighbor Discovery for Low-power and
Lossy Networks", draft-ietf-6lo-ap-nd-19 (work in Lossy Networks", draft-ietf-6lo-ap-nd-20 (work in
progress), February 2020. progress), March 2020.
[I-D.ietf-6lo-backbone-router] [I-D.ietf-6lo-backbone-router]
Thubert, P., Perkins, C., and E. Levy-Abegnoli, "IPv6 Thubert, P., Perkins, C., and E. Levy-Abegnoli, "IPv6
Backbone Router", draft-ietf-6lo-backbone-router-17 (work Backbone Router", draft-ietf-6lo-backbone-router-19 (work
in progress), February 2020. in progress), March 2020.
[I-D.ietf-6tisch-dtsecurity-zerotouch-join] [I-D.ietf-6tisch-dtsecurity-zerotouch-join]
Richardson, M., "6tisch Zero-Touch Secure Join protocol", Richardson, M., "6tisch Zero-Touch Secure Join protocol",
draft-ietf-6tisch-dtsecurity-zerotouch-join-04 (work in draft-ietf-6tisch-dtsecurity-zerotouch-join-04 (work in
progress), July 2019. progress), July 2019.
[I-D.ietf-anima-autonomic-control-plane] [I-D.ietf-anima-autonomic-control-plane]
Eckert, T., Behringer, M., and S. Bjarnason, "An Autonomic Eckert, T., Behringer, M., and S. Bjarnason, "An Autonomic
Control Plane (ACP)", draft-ietf-anima-autonomic-control- Control Plane (ACP)", draft-ietf-anima-autonomic-control-
plane-22 (work in progress), February 2020. plane-24 (work in progress), March 2020.
[I-D.ietf-anima-bootstrapping-keyinfra] [I-D.ietf-anima-bootstrapping-keyinfra]
Pritikin, M., Richardson, M., Eckert, T., Behringer, M., Pritikin, M., Richardson, M., Eckert, T., Behringer, M.,
and K. Watsen, "Bootstrapping Remote Secure Key and K. Watsen, "Bootstrapping Remote Secure Key
Infrastructures (BRSKI)", draft-ietf-anima-bootstrapping- Infrastructures (BRSKI)", draft-ietf-anima-bootstrapping-
keyinfra-35 (work in progress), February 2020. keyinfra-38 (work in progress), March 2020.
[I-D.ietf-intarea-tunnels] [I-D.ietf-intarea-tunnels]
Touch, J. and M. Townsley, "IP Tunnels in the Internet Touch, J. and M. Townsley, "IP Tunnels in the Internet
Architecture", draft-ietf-intarea-tunnels-10 (work in Architecture", draft-ietf-intarea-tunnels-10 (work in
progress), September 2019. progress), September 2019.
[I-D.ietf-roll-unaware-leaves] [I-D.ietf-roll-unaware-leaves]
Thubert, P. and M. Richardson, "Routing for RPL Leaves", Thubert, P. and M. Richardson, "Routing for RPL Leaves",
draft-ietf-roll-unaware-leaves-09 (work in progress), draft-ietf-roll-unaware-leaves-11 (work in progress),
January 2020. March 2020.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460, (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
December 1998, <https://www.rfc-editor.org/info/rfc2460>. December 1998, <https://www.rfc-editor.org/info/rfc2460>.
[RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in [RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in
IPv6 Specification", RFC 2473, DOI 10.17487/RFC2473, IPv6 Specification", RFC 2473, DOI 10.17487/RFC2473,
December 1998, <https://www.rfc-editor.org/info/rfc2473>. December 1998, <https://www.rfc-editor.org/info/rfc2473>.
[RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet [RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet
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