draft-ietf-roll-useofrplinfo-23.txt   draft-ietf-roll-useofrplinfo-24.txt 
ROLL Working Group M. Robles ROLL Working Group M. Robles
Internet-Draft Ericsson Internet-Draft 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: November 2, 2018 P. Thubert Expires: July 27, 2019 P. Thubert
Cisco Cisco
May 1, 2018 January 23, 2019
When to use RFC 6553, 6554 and IPv6-in-IPv6 Using RPL Option Type, Routing Header for Source Routes and IPv6-in-
draft-ietf-roll-useofrplinfo-23 IPv6 encapsulation in the RPL Data Plane
draft-ietf-roll-useofrplinfo-24
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 RFC 6553, RFC 6554 and IPv6-in-IPv6 enumerates the cases where RFC 6553 (RPL Option Type), RFC 6554
encapsulation is required. This analysis provides the basis on which (Routing Header for Source Routes) and IPv6-in-IPv6 encapsulation is
to design efficient compression of these headers. This document required in data plane. This analysis provides the basis on which to
updates RFC 6553 adding a change to the RPL Option Type. design efficient compression of these headers. This document updates
Additionally, this document updates RFC 6550 to indicate about this RFC 6553 adding a change to the RPL Option Type. Additionally, this
change and updates RFC8138 as well to consider the new Option Type document updates RFC 6550 to indicate about this change and updates
when RPL Option is decompressed. RFC8138 as well to consider the new Option Type when 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 November 2, 2018. This Internet-Draft will expire on July 27, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology and Requirements Language . . . . . . . . . . . . 4 1.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. hop-by-hop IPv6-in-IPv6 headers . . . . . . . . . . . . . 5 2. Terminology and Requirements Language . . . . . . . . . . . . 5
3. Updates to RFC6553, RFC6550 and RFC 8138 . . . . . . . . . . 5 3. Updates to RFC6553, RFC6550 and RFC 8138 . . . . . . . . . . 5
3.1. Updates to RFC 6553 . . . . . . . . . . . . . . . . . . . 5 3.1. Updates to RFC 6553 . . . . . . . . . . . . . . . . . . . 5
3.2. Updates to RFC 8138 . . . . . . . . . . . . . . . . . . . 7 3.2. Updates to RFC 8138 . . . . . . . . . . . . . . . . . . . 8
3.3. Updates to RFC 6550: Indicating the new RPI in the DODAG 3.3. Updates to RFC 6550: Indicating the new RPI in the
Configuration Option Flag. . . . . . . . . . . . . . . . 7 DODAG Configuration Option Flag. . . . . . . . . . . . . 9
4. Sample/reference topology . . . . . . . . . . . . . . . . . . 8 4. Sample/reference topology . . . . . . . . . . . . . . . . . . 10
5. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 11 5. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 12
6. Storing mode . . . . . . . . . . . . . . . . . . . . . . . . 13 6. Storing mode . . . . . . . . . . . . . . . . . . . . . . . . 15
6.1. Storing Mode: Interaction between Leaf and Root . . . . . 14 6.1. Storing Mode: Interaction between Leaf and Root . . . . . 16
6.1.1. SM: Example of Flow from RPL-aware-leaf to root . . . 15 6.1.1. SM: Example of Flow from RPL-aware-leaf to root . . . 17
6.1.2. SM: Example of Flow from root to RPL-aware-leaf . . . 16 6.1.2. SM: Example of Flow from root to RPL-aware-leaf . . . 18
6.1.3. SM: Example of Flow from root to not-RPL-aware-leaf . 16 6.1.3. SM: Example of Flow from root to not-RPL-aware-leaf . 18
6.1.4. SM: Example of Flow from not-RPL-aware-leaf to root . 17 6.1.4. SM: Example of Flow from not-RPL-aware-leaf to root . 19
6.2. Storing Mode: Interaction between Leaf and Internet . . . 18 6.2. Storing Mode: Interaction between Leaf and Internet. . . 20
6.2.1. SM: Example of Flow from RPL-aware-leaf to Internet . 18 6.2.1. SM: Example of Flow from RPL-aware-leaf to Internet . 20
6.2.2. SM: Example of Flow from Internet to RPL-aware-leaf . 18 6.2.2. SM: Example of Flow from Internet to RPL-aware-leaf . 21
6.2.3. SM: Example of Flow from not-RPL-aware-leaf to 6.2.3. SM: Example of Flow from not-RPL-aware-leaf to
Internet . . . . . . . . . . . . . . . . . . . . . . 19 Internet . . . . . . . . . . . . . . . . . . . . . . 22
6.2.4. SM: Example of Flow from Internet to non-RPL-aware- 6.2.4. SM: Example of Flow from Internet to non-RPL-aware-
leaf . . . . . . . . . . . . . . . . . . . . . . . . 20 leaf. . . . . . . . . . . . . . . . . . . . . . . . . 23
6.3. Storing Mode: Interaction between Leaf and Leaf . . . . . 21 6.3. Storing Mode: Interaction between Leaf and Leaf . . . . . 24
6.3.1. SM: Example of Flow from RPL-aware-leaf to RPL-aware- 6.3.1. SM: Example of Flow from RPL-aware-leaf to RPL-aware-
leaf . . . . . . . . . . . . . . . . . . . . . . . . 21 leaf . . . . . . . . . . . . . . . . . . . . . . . . 25
6.3.2. SM: Example of Flow from RPL-aware-leaf to non-RPL- 6.3.2. SM: Example of Flow from RPL-aware-leaf to non-RPL-
aware-leaf . . . . . . . . . . . . . . . . . . . . . 22 aware-leaf . . . . . . . . . . . . . . . . . . . . . 26
6.3.3. SM: Example of Flow from not-RPL-aware-leaf to RPL- 6.3.3. SM: Example of Flow from not-RPL-aware-leaf to RPL-
aware-leaf . . . . . . . . . . . . . . . . . . . . . 23 aware-leaf . . . . . . . . . . . . . . . . . . . . . 27
6.3.4. SM: Example of Flow from not-RPL-aware-leaf to not- 6.3.4. SM: Example of Flow from not-RPL-aware-leaf to not-
RPL-aware-leaf . . . . . . . . . . . . . . . . . . . 24 RPL-aware-leaf . . . . . . . . . . . . . . . . . . . 28
7. Non Storing mode . . . . . . . . . . . . . . . . . . . . . . 25 7. Non Storing mode . . . . . . . . . . . . . . . . . . . . . . 29
7.1. Non-Storing Mode: Interaction between Leaf and Root . . . 27 7.1. Non-Storing Mode: Interaction between Leaf and Root . . . 31
7.1.1. Non-SM: Example of Flow from RPL-aware-leaf to root . 27 7.1.1. Non-SM: Example of Flow from RPL-aware-leaf to root . 32
7.1.2. Non-SM: Example of Flow from root to RPL-aware-leaf . 27 7.1.2. Non-SM: Example of Flow from root to RPL-aware-leaf . 32
7.1.3. Non-SM: Example of Flow from root to not-RPL-aware- 7.1.3. Non-SM: Example of Flow from root to not-RPL-aware-
leaf . . . . . . . . . . . . . . . . . . . . . . . . 28 leaf . . . . . . . . . . . . . . . . . . . . . . . . 33
7.1.4. Non-SM: Example of Flow from not-RPL-aware-leaf to 7.1.4. Non-SM: Example of Flow from not-RPL-aware-leaf to
root . . . . . . . . . . . . . . . . . . . . . . . . 29 root . . . . . . . . . . . . . . . . . . . . . . . . 34
7.2. Non-Storing Mode: Interaction between Leaf and Internet . 30 7.2. Non-Storing Mode: Interaction between Leaf and Internet . 35
7.2.1. Non-SM: Example of Flow from RPL-aware-leaf to 7.2.1. Non-SM: Example of Flow from RPL-aware-leaf to
Internet . . . . . . . . . . . . . . . . . . . . . . 30 Internet . . . . . . . . . . . . . . . . . . . . . . 35
7.2.2. Non-SM: Example of Flow from Internet to RPL-aware- 7.2.2. Non-SM: Example of Flow from Internet to RPL-aware-
leaf . . . . . . . . . . . . . . . . . . . . . . . . 31 leaf . . . . . . . . . . . . . . . . . . . . . . . . 36
7.2.3. Non-SM: Example of Flow from not-RPL-aware-leaf to 7.2.3. Non-SM: Example of Flow from not-RPL-aware-leaf to
Internet . . . . . . . . . . . . . . . . . . . . . . 32 Internet . . . . . . . . . . . . . . . . . . . . . . 37
7.2.4. Non-SM: Example of Flow from Internet to not-RPL- 7.2.4. Non-SM: Example of Flow from Internet to not-RPL-
aware-leaf . . . . . . . . . . . . . . . . . . . . . 33 aware-leaf . . . . . . . . . . . . . . . . . . . . . 38
7.3. Non-Storing Mode: Interaction between Leafs . . . . . . . 34 7.3. Non-Storing Mode: Interaction between Leafs . . . . . . . 39
7.3.1. Non-SM: Example of Flow from RPL-aware-leaf to RPL- 7.3.1. Non-SM: Example of Flow from RPL-aware-leaf to RPL-
aware-leaf . . . . . . . . . . . . . . . . . . . . . 34 aware-leaf . . . . . . . . . . . . . . . . . . . . . 39
7.3.2. Non-SM: Example of Flow from RPL-aware-leaf to not- 7.3.2. Non-SM: Example of Flow from RPL-aware-leaf to not-
RPL-aware-leaf . . . . . . . . . . . . . . . . . . . 36 RPL-aware-leaf . . . . . . . . . . . . . . . . . . . 41
7.3.3. Non-SM: Example of Flow from not-RPL-aware-leaf to 7.3.3. Non-SM: Example of Flow from not-RPL-aware-leaf to
RPL-aware-leaf . . . . . . . . . . . . . . . . . . . 37 RPL-aware-leaf . . . . . . . . . . . . . . . . . . . 42
7.3.4. Non-SM: Example of Flow from not-RPL-aware-leaf to 7.3.4. Non-SM: Example of Flow from not-RPL-aware-leaf to
not-RPL-aware-leaf . . . . . . . . . . . . . . . . . 38 not-RPL-aware-leaf . . . . . . . . . . . . . . . . . 43
8. Observations about the cases . . . . . . . . . . . . . . . . 38 8. Operational Considerations of supporting
8.1. Storing mode . . . . . . . . . . . . . . . . . . . . . . 38 not-RPL-aware-leaves . . . . . . . . . . . . . . . . . . . . 43
8.2. Non-Storing mode . . . . . . . . . . . . . . . . . . . . 39 9. Operational considerations of introducing 0x23 . . . . . . . 44
9. 6LoRH Compression cases . . . . . . . . . . . . . . . . . . . 39 9.1. Has deployment been discussed? . . . . . . . . . . . . . 45
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 40 9.2. Has installation and initial setup been discussed?? . . . 45
11. Security Considerations . . . . . . . . . . . . . . . . . . . 40 9.3. Has the migration path been discussed? . . . . . . . . . 45
12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 43 9.4. Have the Requirements on other protocols and
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 43 functional components been discussed? . . . . . . . . . . 45
13.1. Normative References . . . . . . . . . . . . . . . . . . 43 9.5. Has the impact on network operation been discussed? . . . 45
13.2. Informative References . . . . . . . . . . . . . . . . . 44 9.6. Have suggestions for verifying correct operation been
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 46 discussed? . . . . . . . . . . . . . . . . . . . . . . . 45
9.7. Has management interoperability been discussed? . . . . . 45
9.8. Are there fault or threshold conditions that should be
reported? . . . . . . . . . . . . . . . . . . . . . . . . 46
9.9. Is configuration discussed? . . . . . . . . . . . . . . . 46
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 46
11. Security Considerations . . . . . . . . . . . . . . . . . . . 46
12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 49
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 49
13.1. Normative References . . . . . . . . . . . . . . . . . . 49
13.2. Informative References . . . . . . . . . . . . . . . . . 50
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 52
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. RFC 6553 [RFC6550] is a routing protocol for constrained networks. RFC 6553
[RFC6553] defines the "RPL option" (RPI), carried within the IPv6 [RFC6553] defines the "RPL option" (RPI), carried within the IPv6
Hop-by-Hop header to quickly identify inconsistencies (loops) in the Hop-by-Hop header to quickly identify inconsistencies (loops) in the
routing topology. RFC 6554 [RFC6554] defines the "RPL Source Route routing topology. RFC 6554 [RFC6554] defines the "RPL Source Route
Header" (RH3), an IPv6 Extension Header to deliver datagrams within a Header" (RH3), an IPv6 Extension Header to deliver datagrams within a
RPL routing domain, particularly in non-storing mode. RPL routing domain, particularly in non-storing mode.
skipping to change at page 4, line 14 skipping to change at page 4, line 30
traffic at all which is mostly hop-by-hop traffic (one exception traffic at all which is mostly hop-by-hop traffic (one exception
being DAO messages in non-storing mode). being DAO messages in non-storing mode).
It has become clear from attempts to do multi-vendor It has become clear from attempts to do multi-vendor
interoperability, and from a desire to compress as many of the above interoperability, and from a desire to compress as many of the above
artifacts as possible that not all implementors agree when artifacts artifacts as possible that not all implementors 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.
An interim meeting went through the 24 cases defined here to discover An interim meeting went through the 24 cases defined here to discover
if there were any shortcuts, and this document is the result of that if there were any shortcuts, and this document is the result of that
discussion. This document clarifies what is the correct and the discussion. This document clarifies examples that intend to
incorrect behaviour. illustrate the result of the normative language in RFC8200 and
RFC6553. In other words, the examples are intended to be normative
explanation of the results of executing that language.
The related document A Routing Header Dispatch for 6LoWPAN (6LoRH) A Routing Header Dispatch for 6LoWPAN (6LoRH)([RFC8138]) defines a
[RFC8138] defines a method to compress RPL Option information and mechanism for compressing RPL Option information and Routing Header
Routing Header type 3 [RFC6554], an efficient IP-in-IP technique, and type 3 [RFC6554], as well as an efficient IPv6-in-IPv6 technique.
use cases proposed for the [Second6TischPlugtest] involving 6loRH.
1.1. Overview
The rest of the document is organized as follows: Section 2 describes
the used terminology. Section 3 describes the updates to RFC6553,
RFC6550 and RFC 8138. Section 4 provides the reference topology used
for the uses cases. Section 5 describes the uses cases included.
Section 6 describes the storing mode cases and section 7 the non-
storing mode cases. Section 8 describes the operational
considerations for the proposed change on RPL Option type. Section 9
depicts the 6LoRH Compression cases, section 10 the IANA
considerations and then section 11 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", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
document are to be interpreted as described in RFC 2119 [RFC2119]. "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119], [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Terminology defined in [RFC7102] applies to this document: LBR, LLN, Terminology defined in [RFC7102] applies to this document: LBR, LLN,
RPL, RPL Domain and ROLL. RPL, RPL Domain and ROLL.
RPL-node: A device which implements RPL, thus we can say that the RPL-node: A device which implements RPL, thus the device is RPL-
device is RPL-capable or RPL-aware. Please note that the device can aware. Please note that the device can be found inside the LLN or
be found inside the LLN or outside LLN. In this document a RPL-node outside LLN. In this document a RPL-node which is a leaf of a
which is a leaf of a DODAG is called RPL-aware-leaf. (Destination Oriented Directed Acyclic Graph) DODAG is called RPL-
aware-leaf (Raf).
RPL-not-capable: A device which does not implement RPL, thus we can
say that the device is not-RPL-aware. Please note that the device
can be found inside the LLN. In this document a not-RPL-aware node
which is a leaf of a DODAG is called not-RPL-aware-leaf.
pledge: a new device which seeks admission to a network. (from RPL-not-capable: A device which does not implement RPL, thus the
[I-D.ietf-anima-bootstrapping-keyinfra]) device is not-RPL-aware. Please note that the device can be found
inside the LLN. In this document a not-RPL-aware node which is a
leaf of a DODAG is called not-RPL-aware-leaf (~Raf).
Join Registrar and Coordinator (JRC): a device which brings new nodes 6LN: [RFC6775] defines it as: "A 6LoWPAN node is any host or router
(pledges) into a network. (from participating in a LoWPAN. This term is used when referring to
[I-D.ietf-anima-bootstrapping-keyinfra]) situations in which either a host or router can play the role
described.". In this document, a 6LN acts as a leaf.
Flag day: A "flag day" is a procedure in which the network, or a part 6LR, 6LBR are defined in [RFC6775].
of it, is changed during a planned outage, or suddenly, causing an
outage while the network recovers [RFC4192]
2.1. hop-by-hop IPv6-in-IPv6 headers Flag Day: A transition that involves have a network with different
values of RPL Option Type. Thus the network do not work correctly.
The term "hop-by-hop IPv6-in-IPv6" header refers to: adding a header Hop-by-hop IPv6-in-IPv6 headers: The term "hop-by-hop IPv6-in-IPv6"
that originates from a node to an adjacent node, using the addresses header refers to: adding a header that originates from a node to an
(usually the GUA or ULA, but could use the link-local addresses) of adjacent node, using the addresses (usually the GUA or ULA, but could
each node. If the packet must traverse multiple hops, then it must use the link-local addresses) of each node. If the packet must
be decapsulated at each hop, and then re-encapsulated again in a traverse multiple hops, then it must be decapsulated at each hop, and
similar fashion. then re-encapsulated again in a similar fashion.
3. Updates to RFC6553, RFC6550 and RFC 8138 3. Updates to RFC6553, RFC6550 and RFC 8138
3.1. Updates to RFC 6553 3.1. Updates to RFC 6553
This modification is required to be able to send, for example, IPv6 This modification is required to be able to send, for example, IPv6
packets from a RPL-aware-leaf to a not-RPL-aware node through packets from a RPL-aware-leaf to a not-RPL-aware node through
Internet (see Section 6.2.1), without requiring IP-in-IP Internet (see Section 6.2.1), without requiring IPv6-in-IPv6
encapsulation. encapsulation.
[RFC6553] states as showed below, that in the Option Type field of [RFC6553] states as shown below, that in the Option Type field of the
the RPL Option header, the two high order bits MUST be set to '01' RPL Option header, the two high order bits must be set to '01' and
and the third bit is equal to '1'. The first two bits indicate that the third bit is equal to '1'. The first two bits indicate that the
the IPv6 node MUST discard the packet if it doesn't recognize the IPv6 node must discard the packet if it doesn't recognize the option
option type, and the third bit indicates that the Option Data may type, and the third bit indicates that the Option Data may change in
change en route. The remaining bits serve as the option type. route. The remaining bits serve as the option type.
Hex Value Binary Value Hex Value Binary Value
act chg rest Description Reference act chg rest Description Reference
--------- --- --- ------- ----------------- ---------- --------- --- --- ------- ----------------- ----------
0x63 01 1 00011 RPL Option [RFC6553] 0x63 01 1 00011 RPL Option [RFC6553]
Figure 1: Option Type in RPL Option. Figure 1: Option Type in RPL Option.
Recent changes in [RFC8200] (section 4, page 8), states: "it is now Recent changes in [RFC8200] (section 4, page 8), states: "it is now
expected that nodes along a packet's delivery path only examine and expected that nodes along a packet's delivery path only examine and
process the Hop-by-Hop Options header if explicitly configured to do process the Hop-by-Hop Options header if explicitly configured to do
so". Processing of the Hop-by-Hop Options header (by IPv6 so". Processing of the Hop-by-Hop Options header (by IPv6
intermediate nodes) is now optional, but if they are configured to intermediate nodes) is now optional, but if they are configured to
process the header, and if such nodes encounter an option with the process the header, and if such nodes encounter an option with the
first two bits set to 01, they will drop the packet (if they conform first two bits set to 01, they will drop the packet (if they conform
to [RFC8200]). Host systems should do the same, irrespective of the to [RFC8200]). Host systems should do the same, irrespective of the
configuration. configuration.
Based on That, if an IPv6 (intermediate) node (RPL-not-capable) Based on that, if an IPv6 (intermediate) node (RPL-not-capable)
receives a packet with an RPL Option, it should ignore the HBH RPL receives a packet with an RPL Option, it should ignore the HBH RPL
option (skip over this option and continue processing the header). option (skip over this option and continue processing the header).
This is relevant, as it was mentioned previously, in the case that
This is relevant, as we mentioned previously, in the case that we there is a flow from RPL-aware-leaf to Internet (see Section 6.2.1).
have a flow from RPL-aware-leaf to Internet (see Section 6.2.1).
Thus, this document updates the Option Type field to: the two high Thus, this document updates the Option Type field to: the two high
order bits MUST be set to '00' and the third bit is equal to '1'. order bits MUST be set to '00' and the third bit is equal to '1'.
The first two bits indicate that the IPv6 node MUST skip over this The first two bits indicate that the IPv6 node MUST skip over this
option and continue processing the header ([RFC8200] Section 4.2) if option and continue processing the header ([RFC8200] Section 4.2) if
it doesn't recognize the option type, and the third bit continues to it doesn't recognize the option type, and the third bit continues to
be set to indicate that the Option Data may change en route. The be set to indicate that the Option Data may change en route. The
remaining bits serve as the option type and remain as 0x3. This remaining bits serve as the option type and remain as 0x3. This
ensures that a packet that leaves the RPL domain of an LLN (or that 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 the leaves the LLN entirely) will not be discarded when it contains the
skipping to change at page 6, line 34 skipping to change at page 7, line 17
--------- --- --- ------- ----------------- ---------- --------- --- --- ------- ----------------- ----------
0x23 00 1 00011 RPL Option [RFCXXXX] 0x23 00 1 00011 RPL Option [RFCXXXX]
Figure 2: Revised Option Type in RPL Option. Figure 2: Revised Option Type in RPL Option.
This change creates a flag day for existing networks which are This change creates a flag day for existing networks which are
currently using 0x63 as the RPI value. A move to 0x23 will not be currently using 0x63 as the RPI value. A move to 0x23 will not be
understood by those networks. It is suggested that implementations understood by those networks. It is suggested that implementations
accept both 0x63 and 0x23 when processing. accept both 0x63 and 0x23 when processing.
When forwarding packets, implementations SHOULD use the same value as In the cases where a forwarding node is forwarding traffic that is
it was received (This is required because, RPI type code can not be not addressed directly to it (such as when the outer IPv6-in-IPv6
changed by [RFC8200]). It allows to the network to be incrementally header is not a Link-Local address), then RFC8200 forbids changing
upgraded, and for the DODAG root to know which parts of the network the RPI type code when forwarding.
are upgraded.
When originating new packets, implementations SHOULD have an option When forwarding traffic that is wrapped in Link-Local IPv6-in-IPv6
to determine which value to originate with, this option is controlled headers, the forwarding node is in effect originating new packets,
by the DIO option described below. and it MAY make a choice as to whether to use the old (0x63) RPI Type
code, or the new (0x23) RPI Type code. In that situation,
implementations SHOULD use the same value as was received. This
allows to the network to be incrementally upgraded, and in some cases
may allow the DODAG root to know which parts of the network are
upgraded.
A network which is switching from straight 6lowpan compression A network which is switching from straight 6lowpan compression
mechanism to those described in [RFC8138] will experience a flag day mechanism to those described in [RFC8138] will experience a flag day
in the data compression anyway, and if possible this change can be in the data compression anyway, and if possible this change can be
deployed at the same time. deployed at the same time.
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
therefore no longer a necessity to remove the artifacts when sending
traffic to the Internet. This change clarifies when to use an IPv6-
in-IPv6 header, and how to address them: The Hop-by-Hop Options
Header containing the RPI option SHOULD always be added when 6LRs
originate packets (without IPv6-in-IPv6 headers), and IPv6-in-IPv6
headers SHOULD always be added when a 6LR find that it needs to
insert a Hop-by-Hop Options Header containing the RPI option. The
IPv6-in-IPv6 header is to be addressed to the RPL root when on the
way up, and to the end-host when on the way down.
Non-constrained uses of RPL are not in scope of this document, and
applicability statements for those uses MAY provide different advice,
E.g. [I-D.ietf-anima-autonomic-control-plane].
In the non-storing case, dealing with non-RPL aware leaf nodes is
much easier as the 6LBR (DODAG root) has complete knowledge about the
connectivity of all DODAG nodes, and all traffic flows through the
root node.
The 6LBR can recognize non-RPL aware leaf nodes because it will
receive a DAO about that node from the 6LR immediately above that
non-RPL aware node. This means that the non-storing mode case can
avoid ever using hop-by-hop IPv6-in-IPv6 headers for traffic
originating from the root to leafs.
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
change does not adversely affect the non-storing case.
3.2. Updates to RFC 8138 3.2. Updates to RFC 8138
RPI-6LoRH header provides a compressed form for the RPL RPI RPI-6LoRH header provides a compressed form for the RPL RPI [RFC8138]
[RFC8138]. It should be considered when the Option Type in RPL in section 6. A node that is decompressing this header MUST
Option is decompressed, should take the value of 0x23 instead of decompress using the RPL RPI option type that is currently active:
0x63. that is, a choice between 0x23 (new) and 0x63 (old). The node will
know which to use based upon the presence of the DODAG Configuration
Option described in the next section. E.g. If the network is in
0x23 mode (by DIO option), then it should be decompressed to 0x23.
[RFC8138] section 7 documents how to compress the IPv6-in-IPv6
header.
There are potential significant advantages to having a single code
path that always processes IPv6-in-IPv6 headers with no options.
In Storing Mode, for the examples of Flow from RPL-aware-leaf to non-
RPL-aware-leaf and non-RPL-aware-leaf to non-RPL-aware-leaf comprise
an IPv6-in-IPv6 and RPI compression headers. The use of the IPv6-in-
IPv6 header is MANDATORY in this case, and it SHOULD be compressed
with [RFC8138] section 7.
+--+-----+---+--------------+-----------+-----------+-----------+
|1 | 0|0 |TSE| 6LoRH Type 6 | Hop Limit | RPI-6LoRH |LOWPAN IPHC|
+--+-----+---+--------------+-----------+-----------+-----------+
Figure 3: Critical IPv6-in-IPv6 (RPI).
3.3. Updates to RFC 6550: Indicating the new RPI in the DODAG 3.3. Updates to RFC 6550: 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 (0x23) and old RPI (0x63) nodes, when there is a mix of new new RPI (0x23) and old RPI (0x63) nodes, this section defines a flag
nodes and old nodes, the new nodes may be put into a compatibility in the DIO Configuration Option, to indicate when then new RPI value
mode until all of the old nodes are replaced or upgraded. can be safely used. Without this, there could be a mix of new nodes
(which understand 0x23 and 0x63), and old nodes (which understand
0x63 only). A new node would not know if it was safe to use 0x23.
This can be done via a DODAG Configuration Option flag which will This is done via a DODAG Configuration Option flag which will
propogate through the network. Failure to receive this information propagate through the network. If the flag is received with a value
will cause new nodes to remain in compatibility mode, and originate zero (which is the default), then new nodes will remain in RFC6553
traffic with the old-RPI (0x63) value. Compatible Mode; originating traffic with the old-RPI (0x63) value.
As stated in [RFC6550] the DODAG Configuration option is present in As stated in [RFC6550] the DODAG Configuration option is present in
DIO messages. The DODAG Configuration option distributes DIO messages. The DODAG Configuration option distributes
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.
The DODAG Configuration Option has a Flags field which is modified by The DODAG Configuration Option has a Flag field which is modified by
this document. Currently, the DODAG Configuration Option in this document. Currently, the DODAG Configuration Option in
[RFC6550] is as follows. . [RFC6550] states: "the unused bits MUST be initialize to zero by the
sender and MUST be ignored by the receiver".
Flags: The 4-bits remaining unused in the Flags field are reserved
for flags. The field MUST be initialized to zero by the sender and
MUST be ignored by the receiver.
0 1 2 3
+-----------------+---------------------------------------------------+
| Type = 0x04 | Opt Length = 14| Flags | A | PCS| DIOIntDoubl. |
+---------------------------------------------------------------------+
| DIOIntMin. | DIORedund. | MaxRankIncrease |
+-----------------+---------------------------------------------------+
| MinHopRankIncrease | OCP |
+-----------------+---------------------------------------------------+
|Reserved | Def. Lifetime | Lifetime Unit |
+-----------------+-----------------+---------------------------------+
Figure 3: DODAG Configuration Option.
Bit number three of flag field in the DODAG Configuration option is Bit number three of the flag field in the DODAG Configuration option
to be used as follows: is to be used as follows:
+------------+-----------------+---------------+ +------------+-----------------+---------------+
| 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 case of rebooting, the node does not remember the flag. Thus, the In case of rebooting, the node (6LN or 6LR) does not remember if the
DIO is sent with flag indicating the new RPI value. flag is set, so DIO messages would be set with the flag unset until a
DIO is received with the flag set.
4. Sample/reference topology 4. Sample/reference topology
A RPL network in general is composed of a 6LBR (6LoWPAN Border A RPL network in general is composed of a 6LBR (6LoWPAN Border
Router), Backbone Router (6BBR), 6LR (6LoWPAN Router) and 6LN Router), Backbone Router (6BBR), 6LR (6LoWPAN Router) and 6LN
(6LoWPAN Node) as leaf logically organized in a DODAG structure. (6LoWPAN Node) as leaf logically organized in a DODAG structure.
(Destination Oriented Directed Acyclic Graph).
RPL defines the RPL Control messages (control plane), a new ICMPv6 Figure 4 shows the reference RPL Topology for this document. The
[RFC4443] message with Type 155. DIS (DODAG Information letters above the nodes are there so that they may be referenced in
Solicitation), DIO (DODAG Information Object) and DAO (Destination subsequent sections. In the figure, 6LR represents a full router
Advertisement Object) messages are all RPL Control messages but with node. The 6LN is a RPL aware router, or host (as a leaf).
different Code values. A RPL Stack is showed in Figure 5. Additionally, for simplification purposes, it is supposed that the
6LBR has direct access to Internet, thus the 6BBR is not present in
the figure.
RPL supports two modes of Downward traffic: in storing mode (RPL-SM), The 6LN leaves (Raf - "RPL aware leaf"-) marked as (F, H and I) are
it is fully stateful; in non-storing (RPL-NSM), it is fully source RPL nodes with no children hosts.
routed. A RPL Instance is either fully storing or fully non-storing,
i.e. a RPL Instance with a combination of storing and non-storing
nodes is not supported with the current specifications at the time of
writing this document.
+--------------+ The leafs marked as ~Raf "not-RPL aware leaf" (G and J) are devices
| Upper Layers | which do not speak RPL at all (not-RPL-aware), but uses Router-
| | Advertisements, 6LowPAN DAR/DAC and efficient-ND only to participate
+--------------+ in the network [RFC6775]. In the document these leafs (G and J) are
| RPL | also referred to as an IPv6 node.
| |
+--------------+
| ICMPv6 |
| |
+--------------+
| IPv6 |
| |
+--------------+
| 6LoWPAN |
| |
+--------------+
| PHY-MAC |
| |
+--------------+
Figure 5: RPL Stack. The 6LBR ("A") in the figure is the root of the Global DODAG.
+------------+ +------------+
| INTERNET ----------+ | INTERNET ----------+
| | | | | |
+------------+ | +------------+ |
| |
| |
| |
A | A |
+-------+ +-------+
skipping to change at page 10, line 46 skipping to change at page 11, line 46
| | +--+ | | | | +--+ | |
| | | | | | | | | |
| | | | | | | | | |
| | | I | J | | | | I | J |
F | | G | H | | F | | G | H | |
+-----+-+ +-|-----+ +---|--+ +---|---+ +---|---+ +-----+-+ +-|-----+ +---|--+ +---|---+ +---|---+
| Raf | | ~Raf | | Raf | | Raf | | ~Raf | | Raf | | ~Raf | | Raf | | Raf | | ~Raf |
| 6LN | | 6LN | | 6LN | | 6LN | | 6LN | | 6LN | | 6LN | | 6LN | | 6LN | | 6LN |
+-------+ +-------+ +------+ +-------+ +-------+ +-------+ +-------+ +------+ +-------+ +-------+
Figure 6: A reference RPL Topology. Figure 5: A reference RPL Topology.
Figure 2 shows the reference RPL Topology for this document. The RPL defines the RPL Control messages (control plane), a new ICMPv6
letters above the nodes are there so that they may be referenced in [RFC4443] message with Type 155. DIS (DODAG Information
subsequent sections. In the figure, 6LR represents a full router Solicitation), DIO (DODAG Information Object) and DAO (Destination
node. The 6LN is a RPL aware router, or host. Advertisement Object) messages are all RPL Control messages but with
different Code values. A RPL Stack is shown in Figure 5.
But, the 6LN leaves (Raf - "RPL aware leaf"-) marked as (F, H and I) +--------------+
are RPL nodes with no children hosts. | Upper Layers |
| |
+--------------+
| RPL |
| |
+--------------+
| ICMPv6 |
| |
+--------------+
| IPv6 |
| |
+--------------+
| 6LoWPAN |
| |
+--------------+
| PHY-MAC |
| |
+--------------+
The leafs marked as ~Raf "not-RPL aware leaf" (G and J) are devices Figure 6: RPL Stack.
which do not speak RPL at all (not-RPL-aware), but uses Router-
Advertisements, 6LowPAN DAR/DAC and efficient-ND only to participate
in the network [RFC6775]. In the document these leafs (G and J) are
also refered to as an IPv6 node.
The 6LBR ("A") in the figure is the root of the Global DODAG. RPL supports two modes of Downward traffic: in storing mode (RPL-SM),
it is fully stateful; in non-storing (RPL-NSM), it is fully source
routed. A RPL Instance is either fully storing or fully non-storing,
i.e. a RPL Instance with a combination of storing and non-storing
nodes is not supported with the current specifications at the time of
writing this document.
5. Use cases 5. 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
(0x23). (0x23).
The uses cases describe the communication between RPL-aware-nodes, The uses cases describe the communication between RPL-aware-nodes,
with the root (6LBR), and with Internet. This document also describe with the root (6LBR), and with Internet. This document also describe
the communication between nodes acting as leaves that do not the communication between nodes acting as leaves that do not
understand RPL, but are part of the LLN. We name these nodes as not- understand RPL, but are part of the LLN. these nodes are named as
RPL-aware-leaf. (e.g. Section 6.1.4 Flow from not-RPL-aware-leaf to not-RPL-aware-leaf, mentioned previously. (e.g. Section 6.1.4 Flow
root) We describe also how is the communication inside of the LLN from not-RPL-aware-leaf to root) This document describes also how is
when it has the final destination addressed outside of the LLN e.g. the communication inside of the LLN when it has the final destination
with destination to Internet. (e.g. Section 6.2.3 Flow from not- addressed outside of the LLN e.g. with destination to Internet.
RPL-aware-leaf to Internet) (e.g. Section 6.2.3 Flow from not-RPL-aware-leaf to Internet)
The uses cases comprise as follow: The uses cases comprise as follow:
Interaction between Leaf and Root: Interaction between Leaf and Root:
RPL-aware-leaf to root RPL-aware-leaf to root
root to RPL-aware-leaf root to RPL-aware-leaf
not-RPL-aware-leaf to root not-RPL-aware-leaf to root
skipping to change at page 12, line 34 skipping to change at page 14, line 5
by the sender or the receiver. by the sender or the receiver.
However, unlike [RFC6553], the Hop-by-Hop Option Header used for the However, unlike [RFC6553], the Hop-by-Hop Option Header used for the
RPI artifact has the first two bits set to '00'. This means that the RPI artifact has the first two bits set to '00'. This means that the
RPI artifact will be ignored when received by a host or router that RPI artifact will be ignored when received by a host or router that
does not understand that option ( Section 4.2 [RFC8200]). does not understand that option ( Section 4.2 [RFC8200]).
This means that when the no-drop RPI option code 0x23 is used, a This means that when the no-drop RPI option code 0x23 is used, a
packet that leaves the RPL domain of an LLN (or that leaves the LLN packet that leaves the RPL domain of an LLN (or that leaves the LLN
entirely) will not be discarded when it contains the [RFC6553] RPL entirely) will not be discarded when it contains the [RFC6553] RPL
Hop-by-Hop option known as RPI. Thus, the RPI Hop-by-Hop option MAY Hop-by-Hop option known as RPI. Thus, the RPI Hop-by-Hop option is
be left in place even if the end host does not understand it. left in place even if the end host does not understand it.
NOTE: There is some possible security risk when the RPI information NOTE: There is some possible security risk when the RPI information
is released to the Internet. At this point this is a theoretical is released to the Internet. At this point this is a theoretical
situation; no clear attack has been described. At worst, it is clear situation; no clear attack has been described. At worst, it is clear
that the RPI option would waste some network bandwidth when it that the RPI option would waste some network bandwidth when it
escapes. This is traded off against the savings in the LLN by not escapes. This is traded off against the savings in the LLN by not
having to encapsulate the packet in order to remove the artifact. having to encapsulate the packet in order to remove the artifact.
As the rank information in the RPI artifact is changed at each hop,
it will typically be zero when it arrives at the DODAG root. The
DODAG root SHOULD force it to zero when passing the packet out to the
Internet. The Internet will therefore not see any SenderRank
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 (SHR3 or intermediate router that needs to add an extension header (RH3 or RPI
RPI Option) MUST still encapsulate the packet in an (additional) Option) MUST still encapsulate the packet in an (additional) outer IP
outer IP header. The new header is placed after this new outer IP header. The new header is placed after this new outer IP header.
header.
A corollory is that an SHR3 or RPI Option can only be removed by an A corollary is that an RH3 or RPI 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 addresses. addressed to the next hop router using link-local address.
Both RPI and RH3 headers may be modified in very specific ways by Both RPI and RH3 headers may be modified in very specific ways by
routers on the path of the packet without the need to add to remove routers on the path of the packet without the need to add to remove
an encapsulating header. Both headers were designed with this an encapsulating header. Both headers were designed with this
modification in mind, and both the RPL RH and the RPL option are modification in mind, and both the RPL RH3 and the RPL option are
marked mutable but recoverable: so an IPsec AH security header can be marked mutable but recoverable: so an IPsec AH security header can be
applied across these headers, but it can not secure the values which applied across these headers, but it can not secure the values which
mutate. mutate.
RPI should be present in every single RPL data packet. There is one RPI MUST be present in every single RPL data packet. There is one
exception in non-storing mode: when a packet is going down from the exception in non-storing mode: when a packet is going down from the
root. In a downward non-storing mode, the entire route is written, root the RPI MAY be omitted. The rational is that in a downward non-
so there can be no loops by construction, nor any confusion about storing mode, the entire route is written, so there can be no loops
which forwarding table to use (as the root has already made all by construction, nor any confusion about which forwarding table to
routing decisions). However, there are still cases, such as in use (as the root has already made all routing decisions). However,
6tisch, where the instanceID portion of the RPI header may still be there are still cases, such as in 6tisch, where the instanceID
needed to pick an appropriate priority or channel at each hop. portion of the RPI header may still be needed [RFC8180] to pick an
appropriate priority or channel at each hop.
In the tables present in this document, the term "RPL aware leaf" is Prior to [RFC8138], there was significant interest in removing the
has been shortened to "Raf", and "not-RPL aware leaf" has been RPI for downward flows in non-storing mode. The exception covered a
shortened to "~Raf" to make the table fit in available space. very small number of cases, and causes significant interoperability
challenges, yet costed significant code and testing complexity. The
ability to compress the RPI down to three bytes or less removes much
of the pressure to 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.
6. Storing mode 6. Storing mode
In storing mode (fully stateful), the sender can determine if the In storing mode (fully stateful), the sender can determine if the
destination is inside the LLN by looking if the destination address destination is inside the LLN by looking if the destination address
is matched by the DIO's PIO option. is matched by the DIO's Prefix Information Option (PIO) option.
The following table itemizes which headers are needed in the The following table itemizes which headers are needed in each of the
following scenarios, and indicates if the IP-in-IP header must be following scenarios. It indicate if an IPv6-in-IPv6 header MUST be
inserted on a hop-by-hop basis, or when it can target the destination inserted, and whether the destination address of the IPv6-in-IPv6
node directly. There are these possible situations: hop-by-hop header is the next hop, or the final target address. There are these
necessary (indicated by "hop"), or destination address possible possible situations: hop-by-hop necessary (indicated by "hop"), or
(indicated by "dst"). In all cases hop by hop MAY be used. final target address possible (indicated by "tgt"). In all cases hop
by hop MAY be used rather than the final target address.
In cases where no IP-in-IP header is needed, the column is left In cases where no IPv6-in-IPv6 header is needed, the column states as
blank. "No".
In all cases the RPI headers are needed, since it identifies In all cases the RPI headers are needed, since it identifies
inconsistencies (loops) in the routing topology. In all cases the inconsistencies (loops) in the routing topology. In all cases the
RH3 is not needed because we do not indicate the route in storing RH3 is not needed because it is not used in storing mode.
mode.
In each case, 6LR_i are the intermediate routers from source to In each case, 6LR_i are the intermediate routers from source to
destination. "1 <= i >= n", n is the number of routers (6LR) that destination. "1 <= i <= n", n is the number of routers (6LR) that
the packet go through from source (6LN) to destination. the packet go through from source (6LN) to destination.
The leaf can be a router 6LR or a host, both indicated as 6LN (see The leaf can be a router 6LR or a host, both indicated as 6LN (see
Figure 6). Figure 5).
+---------------------+--------------+----------+--------------+ +---------------------+--------------+------------+--------------+
| Interaction between | Use Case | IP-in-IP | IP-in-IP dst | | Interaction between | Use Case |IPv6-in-IPv6| v6-in-v6 dst |
+---------------------+--------------+----------+--------------+ +---------------------+--------------+------------+--------------+
| | Raf to root | No | -- | | | Raf to root | No | No |
+ +--------------+----------+--------------+ + +--------------+------------+--------------+
| Leaf - Root | root to Raf | No | -- | | Leaf - Root | root to Raf | No | No |
+ +--------------+----------+--------------+ + +--------------+------------+--------------+
| | root to ~Raf | No | -- | | | root to ~Raf | No | No |
+ +--------------+----------+--------------+ + +--------------+------------+--------------+
| | ~Raf to root | Yes | root | | | ~Raf to root | MUST | root |
+---------------------+--------------+----------+--------------+ +---------------------+--------------+------------+--------------+
| | Raf to Int | No | -- | | | Raf to Int | No | No |
+ +--------------+----------+--------------+ + +--------------+------------+--------------+
| Leaf - Internet | Int to Raf | Yes | Raf | | Leaf - Internet | Int to Raf | MUST | tgt (Raf) |
+ +--------------+----------+--------------+ + +--------------+------------+--------------+
| | ~Raf to Int | Yes | root | | | ~Raf to Int | MUST | root |
+ +--------------+----------+--------------+ + +--------------+------------+--------------+
| | Int to ~Raf | Yes | hop | | | Int to ~Raf | MUST | hop |
+---------------------+--------------+----------+--------------+ +---------------------+--------------+------------+--------------+
| | Raf to Raf | No | -- | | | Raf to Raf | No | No |
+ +--------------+----------+--------------+ + +--------------+------------+--------------+
| | Raf to ~Raf | No | -- | | | Raf to ~Raf | No | No |
+ Leaf - Leaf +--------------+----------+--------------+ + Leaf - Leaf +--------------+------------+--------------+
| | ~Raf to Raf | Yes | dst | | | ~Raf to Raf | MUST | tgt (Raf) |
+ +--------------+----------+--------------+ + +--------------+------------+--------------+
| | ~Raf to ~Raf | Yes | hop | | | ~Raf to ~Raf | Yes | hop |
+---------------------+--------------+----------+--------------+ +---------------------+--------------+------------+--------------+
Figure 7: IP-in-IP encapsulation in Storing mode. Figure 7: IPv6-in-IPv6 encapsulation in Storing mode.
6.1. Storing Mode: Interaction between Leaf and Root 6.1. Storing Mode: Interaction between Leaf and Root
In this section we are going to describe the communication flow in In this section is described the communication flow in storing mode
storing mode (SM) between, (SM) between,
RPL-aware-leaf to root RPL-aware-leaf to root
root to RPL-aware-leaf root to RPL-aware-leaf
not-RPL-aware-leaf to root not-RPL-aware-leaf to root
root to not-RPL-aware-leaf root to not-RPL-aware-leaf
6.1.1. SM: Example of Flow from RPL-aware-leaf to root 6.1.1. SM: Example of Flow from RPL-aware-leaf to root
In storing mode, RFC 6553 (RPI) is used to send RPL Information In storing mode, RFC 6553 (RPI) is used to send RPL Information
instanceID and rank information. instanceID and rank information.
As stated in Section 16.2 of [RFC6550] an RPL-aware-leaf node does As stated in Section 16.2 of [RFC6550] a RPL-aware-leaf node does not
not generally issue DIO messages; a leaf node accepts DIO messages generally issue DIO messages; a leaf node accepts DIO messages from
from upstream. (When the inconsistency in routing occurs, a leaf upstream. (When the inconsistency in routing occurs, a leaf node
node will generate a DIO with an infinite rank, to fix it). It may will generate a DIO with an infinite rank, to fix it). It may issue
issue DAO and DIS messages though it generally ignores DAO and DIS DAO and DIS messages though it generally ignores DAO and DIS
messages. messages.
In this case the flow comprises: In this case the flow comprises:
RPL-aware-leaf (6LN) --> 6LR_i --> root(6LBR) RPL-aware-leaf (6LN) --> 6LR_i --> root(6LBR)
For example, a communication flow could be: Node F --> Node E --> For example, a communication flow could be: Node F --> Node E -->
Node B --> Node A root(6LBR) Node B --> Node A root(6LBR)
As it was mentioned in this document 6LRs, 6LBR are always full- As it was mentioned in this document 6LRs, 6LBR are always full-
fledged RPL routers. fledged RPL routers.
The 6LN (Node F) inserts the RPI header, and sends the packet to 6LR The 6LN (Node F) inserts the RPI header, and sends the packet to 6LR
(Node E) which decrements the rank in RPI and sends the packet up. (Node E) which decrements the rank in RPI and sends the packet up.
When the packet arrives at 6LBR (Node A), the RPI is removed and the When the packet arrives at 6LBR (Node A), the RPI is removed and the
packet is processed. packet is processed.
No IP-in-IP header is required. No IPv6-in-IPv6 header is required.
The RPI header can be removed by the 6LBR because the packet is The RPI header can be removed by the 6LBR because the packet is
addressed to the 6LBR. The 6LN must know that it is communicating addressed to the 6LBR. The 6LN must know that it is communicating
with the 6LBR to make use of this scenario. The 6LN can know the with the 6LBR to make use of this scenario. The 6LN can know the
address of the 6LBR because it knows the address of the root via the address of the 6LBR because it knows the address of the root via the
DODAGID in the DIO messages. DODAGID in the DIO messages.
+-------------------+-----+-------+------+ +-------------------+-----+-------+------+
| Header | 6LN | 6LR_i | 6LBR | | Header | 6LN | 6LR_i | 6LBR |
+-------------------+-----+-------+------+ +-------------------+-----+-------+------+
| Inserted headers | RPI | -- | -- | | Inserted headers | RPI | -- | -- |
| Removed headers | -- | -- | RPI | | Removed headers | -- | -- | RPI |
| Re-added headers | -- | -- | -- | | Re-added headers | -- | -- | -- |
| Modified headers | -- | RPI | -- | | Modified headers | -- | RPI | -- |
| Untouched headers | -- | -- | -- | | Untouched headers | -- | -- | -- |
+-------------------+-----+-------+------+ +-------------------+-----+-------+------+
Storing: Summary of the use of headers from RPL-aware-leaf to root Table 1: Storing: Summary of the use of headers from RPL-aware-leaf
to root
6.1.2. SM: Example of Flow from root to RPL-aware-leaf 6.1.2. SM: Example of Flow from root to RPL-aware-leaf
In this case the flow comprises: In this case the flow comprises:
root (6LBR) --> 6LR_i --> RPL-aware-leaf (6LN) root (6LBR) --> 6LR_i --> RPL-aware-leaf (6LN)
For example, a communication flow could be: Node A root(6LBR) --> For example, a communication flow could be: Node A root(6LBR) -->
Node B --> Node D --> Node F Node B --> Node D --> Node F
In this case the 6LBR inserts RPI header and sends the packet down, In this case the 6LBR inserts RPI header and sends the packet down,
the 6LR is going to increment the rank in RPI (it examines the the 6LR is going to increment the rank in RPI (it examines the
instanceID to identify the right forwarding table), the packet is instanceID to identify the right forwarding table), the packet is
processed in the 6LN and the RPI removed. processed in the 6LN and the RPI removed.
No IP-in-IP header is required. No IPv6-in-IPv6 header is required.
+-------------------+------+-------+------+ +-------------------+------+-------+------+
| Header | 6LBR | 6LR_i | 6LN | | Header | 6LBR | 6LR_i | 6LN |
+-------------------+------+-------+------+ +-------------------+------+-------+------+
| Inserted headers | RPI | -- | -- | | Inserted headers | RPI | -- | -- |
| Removed headers | -- | -- | RPI | | Removed headers | -- | -- | RPI |
| Re-added headers | -- | -- | -- | | Re-added headers | -- | -- | -- |
| Modified headers | -- | RPI | -- | | Modified headers | -- | RPI | -- |
| Untouched headers | -- | -- | -- | | Untouched headers | -- | -- | -- |
+-------------------+------+-------+------+ +-------------------+------+-------+------+
Storing: Summary of the use of headers from root to RPL-aware-leaf Table 2: Storing: Summary of the use of headers from root to RPL-
aware-leaf
6.1.3. SM: Example of Flow from root to not-RPL-aware-leaf 6.1.3. SM: Example of Flow from root to not-RPL-aware-leaf
In this case the flow comprises: In this case the flow comprises:
root (6LBR) --> 6LR_i --> not-RPL-aware-leaf (IPv6) root (6LBR) --> 6LR_i --> not-RPL-aware-leaf (IPv6)
For example, a communication flow could be: Node A root(6LBR) --> For example, a communication flow could be: Node A root(6LBR) -->
Node B --> Node E --> Node G Node B --> Node E --> Node G
As the RPI extension can be ignored by the not-RPL-aware leaf, this As the RPI extension can be ignored by the not-RPL-aware leaf, this
situation is identical to the previous scenario. situation is identical to the previous scenario.
+-------------------+------+-------+----------------+ +-------------------+------+-------+----------------+
| Header | 6LBR | 6LR_i | IPv6 | | Header | 6LBR | 6LR_i | IPv6 |
+-------------------+------+-------+----------------+ +-------------------+------+-------+----------------+
| Inserted headers | RPI | -- | -- | | Inserted headers | RPI | -- | -- |
| Removed headers | -- | -- | -- | | Removed headers | -- | -- | -- |
| Re-added headers | -- | -- | -- | | Re-added headers | -- | -- | -- |
| Modified headers | -- | RPI | -- | | Modified headers | -- | RPI | -- |
skipping to change at page 17, line 17 skipping to change at page 19, line 15
+-------------------+------+-------+----------------+ +-------------------+------+-------+----------------+
| Header | 6LBR | 6LR_i | IPv6 | | Header | 6LBR | 6LR_i | IPv6 |
+-------------------+------+-------+----------------+ +-------------------+------+-------+----------------+
| Inserted headers | RPI | -- | -- | | Inserted headers | RPI | -- | -- |
| Removed headers | -- | -- | -- | | Removed headers | -- | -- | -- |
| Re-added headers | -- | -- | -- | | Re-added headers | -- | -- | -- |
| Modified headers | -- | RPI | -- | | Modified headers | -- | RPI | -- |
| Untouched headers | -- | -- | RPI (Ignored) | | Untouched headers | -- | -- | RPI (Ignored) |
+-------------------+------+-------+----------------+ +-------------------+------+-------+----------------+
Storing: Summary of the use of headers from root to not-RPL-aware- Table 3: Storing: Summary of the use of headers from root to not-RPL-
leaf aware-leaf
6.1.4. SM: Example of Flow from not-RPL-aware-leaf to root 6.1.4. SM: Example of Flow from not-RPL-aware-leaf to root
In this case the flow comprises: In this case the flow comprises:
not-RPL-aware-leaf (IPv6) --> 6LR_1 --> 6LR_i --> root (6LBR) not-RPL-aware-leaf (IPv6) --> 6LR_1 --> 6LR_i --> root (6LBR)
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(6LBR) Node B --> Node A root(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 header, encapsuladed in a IPv6-in-IPv6 the 6LR_1 will insert a RPI header, encapsuladed in a IPv6-in-IPv6
header. The IPv6-in-IPv6 header can be addressed to the next hop header. The IPv6-in-IPv6 header can be addressed to the next hop
(Node B), or to the root (Node A). The root removes the header and (Node B), or to the root (Node A). The root removes the header and
processes the packet. processes the packet.
+------------+------+---------------+---------------+---------------+ +---------+-----+---------------+------------------+----------------+
| Header | IPv6 | 6LR_1 | 6LR_i | 6LBR | | Header | IPv | 6LR_1 | 6LR_i | 6LBR |
+------------+------+---------------+---------------+---------------+ | | 6 | | | |
| Inserted | -- | IP-in-IP(RPI) | -- | -- | +---------+-----+---------------+------------------+----------------+
| headers | | | | | | Inserte | -- | IPv6-in- | IPv6-in- | -- |
| Removed | -- | -- | -- | IP-in-IP(RPI) | | d | | IPv6(RPI) | IPv6(RPI)(1) | |
| headers | | | | | | headers | | | | |
| Re-added | -- | -- | -- | -- | | Removed | -- | -- | -- | IPv6-in- |
| headers | | | | | | headers | | | | IPv6(RPI) |
| Modified | -- | -- | IP-in-IP(RPI) | -- | | Re- | -- | -- | IPv6-in- | -- |
| headers | | | | | | added | | | IPv6(RPI)(1) | |
| Untouched | -- | -- | -- | -- | | headers | | | | |
| headers | | | | | | Modifie | -- | -- | IPv6-in- | -- |
+------------+------+---------------+---------------+---------------+ | d | | | IPv6(RPI)(2) | |
| headers | | | | |
| Untouch | -- | -- | -- | -- |
| ed | | | | |
| headers | | | | |
+---------+-----+---------------+------------------+----------------+
Storing: Summary of the use of headers from not-RPL-aware-leaf to Table 4: Storing: Summary of the use of headers from not-RPL-aware-
root leaf to root. (1) Case where the IPv6-in-IPv6 header is addressed to
the next hop (Node B). (2) Case where the IPv6-in-IPv6 header is
addressed to the root (Node A)
6.2. Storing Mode: Interaction between Leaf and Internet 6.2. Storing Mode: Interaction between Leaf and Internet.
In this section we are going to describe the communication flow in In this section is described the communication flow in storing mode
storing mode (SM) between, (SM) between,
RPL-aware-leaf to Internet RPL-aware-leaf to Internet
Internet to RPL-aware-leaf Internet to RPL-aware-leaf
not-RPL-aware-leaf to Internet not-RPL-aware-leaf to Internet
Internet to not-RPL-aware-leaf Internet to not-RPL-aware-leaf
6.2.1. SM: Example of Flow from RPL-aware-leaf to Internet 6.2.1. SM: Example of Flow from RPL-aware-leaf to Internet
RPL information from RFC 6553 MAY go out to Internet as it will be 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. ignored by nodes which have not been configured to be RPI aware.
In this case the flow comprises: In this case the flow comprises:
RPL-aware-leaf (6LN) --> 6LR_i --> root (6LBR) --> Internet RPL-aware-leaf (6LN) --> 6LR_i --> root (6LBR) --> Internet
For example, the communication flow could be: Node F --> Node D --> For example, the communication flow could be: Node F --> Node D -->
Node B --> Node A root(6LBR) --> Internet Node B --> Node A root(6LBR) --> Internet
No IP-in-IP header is required. No IPv6-in-IPv6 header is required.
Note: In this use case we use a node as leaf, but this use case can Note: In this use case it is used a node as leaf, but this use case
be also applicable to any RPL-node type (e.g. 6LR) can be also applicable to any RPL-node type (e.g. 6LR)
+-------------------+------+-------+------+----------------+ +-------------------+------+-------+------+----------------+
| Header | 6LN | 6LR_i | 6LBR | Internet | | Header | 6LN | 6LR_i | 6LBR | Internet |
+-------------------+------+-------+------+----------------+ +-------------------+------+-------+------+----------------+
| Inserted headers | RPI | -- | -- | -- | | Inserted headers | RPI | -- | -- | -- |
| Removed headers | -- | -- | -- | -- | | Removed headers | -- | -- | -- | -- |
| Re-added headers | -- | -- | -- | -- | | Re-added headers | -- | -- | -- | -- |
| Modified headers | -- | RPI | -- | -- | | Modified headers | -- | RPI | -- | -- |
| Untouched headers | -- | -- | RPI | RPI (Ignored) | | Untouched headers | -- | -- | RPI | RPI (Ignored) |
+-------------------+------+-------+------+----------------+ +-------------------+------+-------+------+----------------+
Storing: Summary of the use of headers from RPL-aware-leaf to Table 5: Storing: Summary of the use of headers from RPL-aware-leaf
Internet to Internet
6.2.2. SM: Example of Flow from Internet to RPL-aware-leaf 6.2.2. SM: Example of Flow from Internet to RPL-aware-leaf
In this case the flow comprises: In this case the flow comprises:
Internet --> root (6LBR) --> 6LR_i --> RPL-aware-leaf (6LN) Internet --> root (6LBR) --> 6LR_i --> RPL-aware-leaf (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 --> Node D --> Node F root(6LBR) --> Node B --> Node D --> Node F
When the packet arrives from Internet to 6LBR the RPI header is added When the packet arrives from Internet to 6LBR the RPI header is added
in a outer IPv6-in-IPv6 header and sent to 6LR, which modifies the in a outer IPv6-in-IPv6 header and sent to 6LR, which modifies the
rank in the RPI. When the packet arrives at 6LN the RPI header is rank in the RPI. When the packet arrives at 6LN the RPI header is
removed and the packet processed. removed and the packet processed.
+----------+---------+--------------+---------------+---------------+ +---------+--------+---------------+---------------+----------------+
| Header | Interne | 6LBR | 6LR_i | 6LN | | Header | Intern | 6LBR | 6LR_i | 6LN |
| | t | | | | | | et | | | |
+----------+---------+--------------+---------------+---------------+ +---------+--------+---------------+---------------+----------------+
| Inserted | -- | IP-in- | -- | -- | | Inserte | -- | IPv6-in- | -- | -- |
| headers | | IP(RPI) | | | | d | | IPv6(RPI) | | |
| Removed | -- | -- | -- | IP-in-IP(RPI) | | headers | | | | |
| headers | | | | | | Removed | -- | -- | -- | IPv6-in- |
| Re-added | -- | -- | -- | -- | | headers | | | | IPv6(RPI) |
| headers | | | | | | Re- | -- | -- | -- | -- |
| Modified | -- | -- | IP-in-IP(RPI) | -- | | added | | | | |
| headers | | | | | | headers | | | | |
| Untouche | -- | -- | -- | -- | | Modifie | -- | -- | IPv6-in- | -- |
| d | | | | | | d | | | IPv6(RPI) | |
| headers | | | | | | headers | | | | |
+----------+---------+--------------+---------------+---------------+ | Untouch | -- | -- | -- | -- |
| ed | | | | |
| headers | | | | |
+---------+--------+---------------+---------------+----------------+
Storing: Summary of the use of headers from Internet to RPL-aware- Table 6: Storing: Summary of the use of headers from Internet to RPL-
leaf aware-leaf
6.2.3. SM: Example of Flow from not-RPL-aware-leaf to Internet 6.2.3. SM: Example of Flow from not-RPL-aware-leaf to Internet
In this case the flow comprises: In this case the flow comprises:
not-RPL-aware-leaf (IPv6) --> 6LR_1 --> 6LR_i -->root (6LBR) --> not-RPL-aware-leaf (IPv6) --> 6LR_1 --> 6LR_i -->root (6LBR) -->
Internet Internet
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(6LBR) --> Internet Node B --> Node A root(6LBR) --> Internet
The 6LR_1 (i=1) node will add an IP-in-IP(RPI) header addressed The 6LR_1 (i=1) node will add an IPv6-in-IPv6(RPI) header addressed
either to the root, or hop-by-hop such that the root can remove the either to the root, or hop-by-hop such that the root can remove the
RPI header before passing upwards. The IP-in-IP addressed to the RPI header before passing upwards. The IPv6-in-IPv6 addressed to the
root cause less processing overhead. On the other hand, with hop-by- root cause less processing overhead. On the other hand, with hop-by-
hop the intermediate routers can check the routing tables for a hop the intermediate routers can check the routing tables for a
better routing path, thus it could be more efficient and faster. better routing path, thus it could be more efficient and faster.
Implementation should decide wich approach to take. Implementation should decide which approach to take.
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. sending to the Internet.
+---------+-----+-------------+-------------+-------------+---------+ +-------+----+-------------+---------------+---------------+--------+
| Header | IPv | 6LR_1 | 6LR_i | 6LBR | Interne | | Heade | IP | 6LR_1 | 6LR_i | 6LBR | Intern |
| | 6 | | [i=2,..,n]_ | | t | | r | v6 | | [i=2,..,n]_ | | et |
+---------+-----+-------------+-------------+-------------+---------+ +-------+----+-------------+---------------+---------------+--------+
| Inserte | -- | IP-in- | -- | -- | -- | | Inser | -- | IPv6-in- | IPv6-in- | -- | -- |
| d | | IP(RPI) | | | | | ted h | | IPv6(RPI) | IPv6(RPI)(2) | | |
| headers | | | | | | | eader | | | | | |
| Removed | -- | -- | -- | IP-in- | -- | | s | | | | | |
| headers | | | | IP(RPI) | | | Remov | -- | -- | IPv6-in- | IPv6-in- | -- |
| Re- | -- | -- | -- | -- | -- | | ed he | | | IPv6(RPI)(2) | IPv6(RPI)(1) | |
| added | | | | | | | aders | | | | | |
| headers | | | | | | | Re- | -- | -- | -- | -- | -- |
| Modifie | -- | -- | IP-in- | -- | -- | | added | | | | | |
| d | | | IP(RPI) | | | | heade | | | | | |
| headers | | | | | | | rs | | | | | |
| Untouch | -- | -- | -- | -- | -- | | Modif | -- | -- | IPv6-in- | -- | -- |
| ed | | | | | | | ied h | | | IPv6(RPI)(1) | | |
| headers | | | | | | | eader | | | | | |
+---------+-----+-------------+-------------+-------------+---------+ | s | | | | | |
| Untou | -- | -- | -- | -- | -- |
| ched | | | | | |
| heade | | | | | |
| rs | | | | | |
+-------+----+-------------+---------------+---------------+--------+
Storing: Summary of the use of headers from not-RPL-aware-leaf to Table 7: Storing: Summary of the use of headers from not-RPL-aware-
Internet leaf to Internet. (1) Case when packet is addressed to the root.
(2) Case when the packet is addressed hop-by-hop.
6.2.4. SM: Example of Flow from Internet to non-RPL-aware-leaf 6.2.4. SM: Example of Flow from Internet to non-RPL-aware-leaf.
In this case the flow comprises: In this case the flow comprises:
Internet --> root (6LBR) --> 6LR_i --> not-RPL-aware-leaf (IPv6) Internet --> root (6LBR) --> 6LR_i --> not-RPL-aware-leaf (IPv6)
For example, a communication flow could be: Internet --> Node A For example, a communication flow could be: Internet --> Node A
root(6LBR) --> Node B --> Node E --> Node G root(6LBR) --> Node B --> Node E --> Node G
The 6LBR will have to add an RPI header within an IP-in-IP header. The 6LBR will have to add an RPI header within an IPv6-in-IPv6
The IP-in-IP is addressed to the not-RPL-aware-leaf, leaving the RPI header. The IPv6-in-IPv6 is addressed to the not-RPL-aware-leaf,
inside. leaving the RPI inside.
Note that there is a requirement that the final node be able to Note that there is a requirement that the final node be able to
remove one or more IP-in-IP headers which are all addressed to it, remove one or more IPv6-in-IPv6 headers which are all addressed to
mentioned in [I-D.thubert-roll-unaware-leaves] : it, mentioned in [I-D.thubert-roll-unaware-leaves] :
"RPL data packets are often encapsulated using IP in IP. The 6LN "RPL data packets are often encapsulated using IP in IP. The 6LN
MUST be able to decapsulate a packet when it is the destination of MUST be able to decapsulate a packet when it is the destination of
the outer header and process correctly the inner header." the outer header and process correctly the inner header."
The 6LBR MAY set the flow label on the inner IP-in-IP header to zero
in order to aid in compression.
+-----------+----------+---------------+---------------+------------+ The 6LBR MAY set the flow label on the inner IPv6-in-IPv6 header to
| Header | Internet | 6LBR | 6LR_i | IPv6 | zero in order to aid in compression.
+-----------+----------+---------------+---------------+------------+
| Inserted | -- | IP-in-IP(RPI) | -- | -- |
| headers | | | | |
| Removed | -- | -- | -- | -- |
| headers | | | | |
| Re-added | -- | -- | -- | -- |
| headers | | | | |
| Modified | -- | -- | IP-in-IP(RPI) | -- |
| headers | | | | |
| Untouched | -- | -- | -- | RPI |
| headers | | | | (Ignored) |
+-----------+----------+---------------+---------------+------------+
Storing: Summary of the use of headers from Internet to non-RPL- +--------+---------+---------------+---------------+----------------+
aware-leaf | Header | Interne | 6LBR | 6LR_i | IPv6 |
| | t | | | |
+--------+---------+---------------+---------------+----------------+
| Insert | -- | IPv6-in- | -- | -- |
| ed hea | | IPv6(RPI) | | |
| ders | | | | |
| Remove | -- | -- | -- | IPv6-in- |
| d head | | | | IPv6(RPI)- RPI |
| ers | | | | (Ignored) |
| Re- | -- | -- | -- | -- |
| added | | | | |
| header | | | | |
| s | | | | |
| Modifi | -- | -- | IPv6-in- | -- |
| ed hea | | | IPv6(RPI) | |
| ders | | | | |
| Untouc | -- | -- | -- | -- |
| hed he | | | | |
| aders | | | | |
+--------+---------+---------------+---------------+----------------+
Table 8: Storing: Summary of the use of headers from Internet to non-
RPL-aware-leaf
6.3. Storing Mode: Interaction between Leaf and Leaf 6.3. Storing Mode: Interaction between Leaf and Leaf
In this section we are going to describe the communication flow in In this section is described the communication flow in storing mode
storing mode (SM) between, (SM) between,
RPL-aware-leaf to RPL-aware-leaf RPL-aware-leaf to RPL-aware-leaf
RPL-aware-leaf to not-RPL-aware-leaf RPL-aware-leaf to not-RPL-aware-leaf
not-RPL-aware-leaf to RPL-aware-leaf not-RPL-aware-leaf to RPL-aware-leaf
not-RPL-aware-leaf to not-RPL-aware-leaf not-RPL-aware-leaf to not-RPL-aware-leaf
6.3.1. SM: Example of Flow from RPL-aware-leaf to RPL-aware-leaf 6.3.1. SM: Example of Flow from RPL-aware-leaf to RPL-aware-leaf
skipping to change at page 22, line 4 skipping to change at page 25, line 19
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:
6LN --> 6LR_ia --> common parent (6LR_x) --> 6LR_id --> 6LN 6LN --> 6LR_ia --> common parent (6LR_x) --> 6LR_id --> 6LN
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 E --> Node H Node B --> Node E --> Node H
6LR_ia (Node D) are the intermediate routers from source to the 6LR_ia (Node D) are 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) In this case, "1 <= ia <= n", n is the
number of routers (6LR) that the packet go through from 6LN (Node F) number of routers (6LR) that the packet go through from 6LN (Node F)
to the common parent (6LR_x). to the common parent (6LR_x).
6LR_id (Node E) are the intermediate routers from the common parent 6LR_id (Node E) are the intermediate routers from the common parent
(6LR_x) (Node B) to destination 6LN (Node H). In this case, "1 <= id (6LR_x) (Node B) to destination 6LN (Node H). In this case, "1 <= id
>= m", m is the number of routers (6LR) that the packet go through <= m", m is the number of routers (6LR) that the packet go through
from the common parent (6LR_x) to destination 6LN. from the common parent (6LR_x) to destination 6LN.
It is assume that the two nodes are in the same RPL Domain (that they It is assumed that the two nodes are in the same RPL Domain (that
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 increasing to decreasing the rank). direction of RPI is changed (from increasing to decreasing the rank).
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 IP-in-IP headers are necessary. This may be remove the RPI, so no IPv6-in-IPv6 headers are necessary. This may
done regardless of where the destination is, as the included RPI will be done regardless of where the destination is, as the included RPI
be ignored by the receiver. will be ignored by the receiver.
+---------------+--------+--------+---------------+--------+--------+ +---------------+--------+--------+---------------+--------+--------+
| Header | 6LN | 6LR_ia | 6LR_x (common | 6LR_id | 6LN | | Header | 6LN | 6LR_ia | 6LR_x (common | 6LR_id | 6LN |
| | src | | parent) | | dst | | | src | | parent) | | dst |
+---------------+--------+--------+---------------+--------+--------+ +---------------+--------+--------+---------------+--------+--------+
| Inserted | RPI | -- | -- | -- | -- | | Inserted | RPI | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
| Removed | -- | -- | -- | -- | RPI | | Removed | -- | -- | -- | -- | RPI |
| headers | | | | | | | headers | | | | | |
| Re-added | -- | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
| Modified | -- | RPI | RPI | RPI | -- | | Modified | -- | RPI | RPI | RPI | -- |
| headers | | | | | | | headers | | | | | |
| Untouched | -- | -- | -- | -- | -- | | Untouched | -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
+---------------+--------+--------+---------------+--------+--------+ +---------------+--------+--------+---------------+--------+--------+
Storing: Summary of the use of headers for RPL-aware-leaf to RPL- Table 9: Storing: Summary of the use of headers for RPL-aware-leaf to
aware-leaf RPL-aware-leaf
6.3.2. SM: Example of Flow from RPL-aware-leaf to non-RPL-aware-leaf 6.3.2. SM: Example of Flow from RPL-aware-leaf to non-RPL-aware-leaf
In this case the flow comprises: In this case the flow comprises:
6LN --> 6LR_ia --> common parent (6LR_x) --> 6LR_id --> not-RPL-aware 6LN --> 6LR_ia --> common parent (6LR_x) --> 6LR_id --> not-RPL-aware
6LN (IPv6) 6LN (IPv6)
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 E --> Node G Node B --> Node E --> Node G
skipping to change at page 23, line 4 skipping to change at page 26, line 33
6.3.2. SM: Example of Flow from RPL-aware-leaf to non-RPL-aware-leaf 6.3.2. SM: Example of Flow from RPL-aware-leaf to non-RPL-aware-leaf
In this case the flow comprises: In this case the flow comprises:
6LN --> 6LR_ia --> common parent (6LR_x) --> 6LR_id --> not-RPL-aware 6LN --> 6LR_ia --> common parent (6LR_x) --> 6LR_id --> not-RPL-aware
6LN (IPv6) 6LN (IPv6)
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 E --> Node G Node B --> Node E --> Node G
6LR_ia are the intermediate routers from source (6LN) to the common 6LR_ia are the intermediate routers from source (6LN) to the common
parent (6LR_x) In this case, "1 <= ia >= n", n is the number of parent (6LR_x) In this case, "1 <= ia <= n", n is the number of
routers (6LR) that the packet go through from 6LN to the common routers (6LR) that the packet go through from 6LN to the common
parent (6LR_x). parent (6LR_x).
6LR_id (Node E) are the intermediate routers from the common parent 6LR_id (Node E) are the intermediate routers from the common parent
(6LR_x) (Node B) to destination not-RPL-aware 6LN (IPv6) (Node G). (6LR_x) (Node B) to destination not-RPL-aware 6LN (IPv6) (Node G).
In this case, "1 <= id >= m", m is the number of routers (6LR) that In this case, "1 <= id <= m", m is the number of routers (6LR) that
the packet go through from the common parent (6LR_x) to destination the packet go through from the common parent (6LR_x) to destination
6LN. 6LN.
This situation is identical to the previous situation Section 6.3.1 This situation is identical to the previous situation Section 6.3.1
+-----------+------+--------+---------------+--------+--------------+ +-----------+------+--------+---------------+--------+--------------+
| Header | 6LN | 6LR_ia | 6LR_x(common | 6LR_id | IPv6 | | Header | 6LN | 6LR_ia | 6LR_x(common | 6LR_id | IPv6 |
| | src | | parent) | | | | | src | | parent) | | |
+-----------+------+--------+---------------+--------+--------------+ +-----------+------+--------+---------------+--------+--------------+
| Inserted | RPI | -- | -- | -- | -- | | Inserted | RPI | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
| Removed | -- | -- | -- | -- | -- | | Removed | -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
| Re-added | -- | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
skipping to change at page 23, line 33 skipping to change at page 27, line 20
| Removed | -- | -- | -- | -- | -- | | Removed | -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
| Re-added | -- | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
| Modified | -- | RPI | RPI | RPI | -- | | Modified | -- | RPI | RPI | RPI | -- |
| headers | | | | | | | headers | | | | | |
| Untouched | -- | -- | -- | -- | RPI(Ignored) | | Untouched | -- | -- | -- | -- | RPI(Ignored) |
| headers | | | | | | | headers | | | | | |
+-----------+------+--------+---------------+--------+--------------+ +-----------+------+--------+---------------+--------+--------------+
Storing: Summary of the use of headers for RPL-aware-leaf to non-RPL- Table 10: Storing: Summary of the use of headers for RPL-aware-leaf
aware-leaf to non-RPL-aware-leaf
6.3.3. SM: Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf 6.3.3. SM: Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf
In this case the flow comprises: In this case the flow comprises:
not-RPL-aware 6LN (IPv6) --> 6LR_ia --> common parent (6LR_x) --> not-RPL-aware 6LN (IPv6) --> 6LR_ia --> common parent (6LR_x) -->
6LR_id --> 6LN 6LR_id --> 6LN
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 D --> Node F Node B --> Node D --> Node F
6LR_ia (Node E) are the intermediate routers from source (not-RPL- 6LR_ia (Node E) are the intermediate routers from source (not-RPL-
aware 6LN (IPv6)) (Node G) to the common parent (6LR_x) (Node B). In aware 6LN (IPv6)) (Node G) to the common parent (6LR_x) (Node B). In
this case, "1 <= ia >= n", n is the number of routers (6LR) that the this case, "1 <= ia <= n", n is the number of routers (6LR) that the
packet go through from source to the common parent. packet go through from source to the common parent.
6LR_id (Node D) are the intermediate routers from the common parent 6LR_id (Node D) are the intermediate routers from the common parent
(6LR_x) (Node B) to destination 6LN (Node F). In this case, "1 <= id (6LR_x) (Node B) to destination 6LN (Node F). In this case, "1 <= id
>= m", m is the number of routers (6LR) that the packet go through <= m", m is the number of routers (6LR) that the packet go through
from the common parent (6LR_x) to destination 6LN. from the common parent (6LR_x) to destination 6LN.
The 6LR_ia (ia=1) (Node E) receives the packet from the the IPv6 node The 6LR_ia (ia=1) (Node E) receives the packet from the the IPv6 node
(Node G) and inserts and the RPI header encapsulated in IPv6-in-IPv6 (Node G) and inserts and the RPI header encapsulated in IPv6-in-IPv6
header. The IP-in-IP header is addressed to the destination 6LN header. The IPv6-in-IPv6 header is addressed to the destination 6LN
(Node F). (Node F).
+--------+------+------------+------------+------------+------------+ +-------+----+------------+-------------+-------------+-------------+
| Header | IPv6 | 6LR_ia | common | 6LR_id | 6LN | | Heade | IP | 6LR_ia | common | 6LR_id | 6LN |
| | | | parent | | | | r | v6 | | parent | | |
| | | | (6LRx) | | | | | | | (6LRx) | | |
+--------+------+------------+------------+------------+------------+ +-------+----+------------+-------------+-------------+-------------+
| Insert | -- | IP-in- | -- | -- | -- | | Inser | -- | IPv6-in- | -- | -- | -- |
| ed hea | | IP(RPI) | | | | | ted h | | IPv6(RPI) | | | |
| ders | | | | | | | eader | | | | | |
| Remove | -- | -- | -- | -- | IP-in- | | s | | | | | |
| d head | | | | | IP(RPI) | | Remov | -- | -- | -- | -- | IPv6-in- |
| ers | | | | | | | ed he | | | | | IPv6(RPI) |
| Re- | -- | -- | -- | -- | -- | | aders | | | | | |
| added | | | | | | | Re- | -- | -- | -- | -- | -- |
| header | | | | | | | added | | | | | |
| s | | | | | | | heade | | | | | |
| Modifi | -- | -- | IP-in- | IP-in- | -- | | rs | | | | | |
| ed hea | | | IP(RPI) | IP(RPI) | | | Modif | -- | -- | IPv6-in- | IPv6-in- | -- |
| ders | | | | | | | ied h | | | IPv6(RPI) | IPv6(RPI) | |
| Untouc | -- | -- | -- | -- | -- | | eader | | | | | |
| hed he | | | | | | | s | | | | | |
| aders | | | | | | | Untou | -- | -- | -- | -- | -- |
+--------+------+------------+------------+------------+------------+ | ched | | | | | |
| heade | | | | | |
| rs | | | | | |
+-------+----+------------+-------------+-------------+-------------+
Storing: Summary of the use of headers from not-RPL-aware-leaf to Table 11: Storing: Summary of the use of headers from not-RPL-aware-
RPL-aware-leaf leaf to RPL-aware-leaf
6.3.4. SM: Example of Flow from not-RPL-aware-leaf to not-RPL-aware- 6.3.4. SM: Example of Flow from not-RPL-aware-leaf to not-RPL-aware-
leaf leaf
In this case the flow comprises: In this case the flow comprises:
not-RPL-aware 6LN (IPv6 src)--> 6LR_1--> 6LR_ia --> 6LR_id --> not- not-RPL-aware 6LN (IPv6 src)--> 6LR_1--> 6LR_ia --> 6LR_id --> not-
RPL-aware 6LN (IPv6 dst) RPL-aware 6LN (IPv6 dst)
For example, a communication flow could be: Node G --> Node E --> For example, a communication flow could be: Node G --> Node E -->
skipping to change at page 25, line 4 skipping to change at page 28, line 44
6.3.4. SM: Example of Flow from not-RPL-aware-leaf to not-RPL-aware- 6.3.4. SM: Example of Flow from not-RPL-aware-leaf to not-RPL-aware-
leaf leaf
In this case the flow comprises: In this case the flow comprises:
not-RPL-aware 6LN (IPv6 src)--> 6LR_1--> 6LR_ia --> 6LR_id --> not- not-RPL-aware 6LN (IPv6 src)--> 6LR_1--> 6LR_ia --> 6LR_id --> not-
RPL-aware 6LN (IPv6 dst) RPL-aware 6LN (IPv6 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 C --> Node J Node B --> Node A (root) --> Node C --> Node J
Internal nodes 6LR_ia (e.g: Node E or Node B) are the intermediate Internal nodes 6LR_ia (e.g: Node E or Node B) are the intermediate
routers from the not-RPL-aware source (Node G) to the root (6LBR) routers from the not-RPL-aware source (Node G) to the root (6LBR)
(Node A). In this case, "1 < ia >= n", n is the number of routers (Node A). In this case, "1 < ia <= n", n is the number of routers
(6LR) that the packet go through from IPv6 src to the root. (6LR) that the packet go through from IPv6 src to the root.
6LR_id (C) are the intermediate routers from the root (Node A) to the 6LR_id (C) are the intermediate routers from the root (Node A) to the
destination Node J. In this case, "1 <= id >= m", m is the number of destination Node J. In this case, "1 <= id <= m", m is the number of
routers (6LR) that the packet go through from the root to destination routers (6LR) that the packet go through from the root to destination
(IPv6 dst). (IPv6 dst).
Note that this flow is identical to Section 6.3.3, except for where Note that this flow is identical to Section 6.3.3, except for where
the IPIP header is inserted. the IPv6-in-IPv6 header is inserted.
The 6LR_1 (Node E) receives the packet from the the IPv6 node (Node The 6LR_1 (Node E) receives the packet from the the IPv6 node (Node
G) and inserts the RPI header (RPIa), encapsulated in an IPv6-in-IPv6 G) and inserts the RPI header (RPI), encapsulated in an IPv6-in-IPv6
header. The IPv6-in-IPv6 header is addressed to the final header. The IPv6-in-IPv6 header is addressed to the final
destination. destination (Node J).
+----------+-----+-------------+--------------+--------------+------+ +-------+----+------------+-------------+-------------+-------------+
| Header | IPv | 6LR_1 | 6LR_ia | 6LR_m | IPv6 | | Heade | IP | 6LR_1 | 6LR_ia | 6LR_m | IPv6 dst |
| | 6 | | | | dst | | r | v6 | | | | |
| | src | | | | | | | sr | | | | |
+----------+-----+-------------+--------------+--------------+------+ | | c | | | | |
| Inserted | -- | IP-in- | -- | -- | -- | +-------+----+------------+-------------+-------------+-------------+
| headers | | IP(RPI) | | | | | Inser | -- | IPv6-in- | -- | -- | -- |
| Removed | -- | -- | -- | -- | -- | | ted h | | IPv6(RPI) | | | |
| headers | | | | | | | eader | | | | | |
| Re-added | -- | -- | -- | -- | -- | | s | | | | | |
| headers | | | | | | | Remov | -- | -- | -- | -- | IPv6-in- |
| Modified | -- | -- | IP-in- | IP-in- | -- | | ed he | | | | | IPv6(RPI), |
| headers | | | IP(RPI) | IP(RPI) | | | aders | | | | | RPI Ignored |
| Untouche | -- | -- | -- | -- | -- | | Re- | -- | -- | -- | -- | -- |
| d | | | | | | | added | | | | | |
| headers | | | | | | | heade | | | | | |
+----------+-----+-------------+--------------+--------------+------+ | rs | | | | | |
| Modif | -- | -- | IPv6-in- | IPv6-in- | -- |
| ied h | | | IPv6(RPI) | IPv6(RPI) | |
| eader | | | | | |
| s | | | | | |
| Untou | -- | -- | -- | -- | -- |
| ched | | | | | |
| heade | | | | | |
| rs | | | | | |
+-------+----+------------+-------------+-------------+-------------+
Storing: Summary of the use of headers from not-RPL-aware-leaf to Table 12: Storing: Summary of the use of headers from not-RPL-aware-
non-RPL-aware-leaf leaf to non-RPL-aware-leaf
7. Non Storing mode 7. 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 non-RPL aware no need for all nodes to know about the existence of non-RPL aware
nodes. Only the 6LBR needs to act if compensation is necessary for nodes. Only the 6LBR needs to act if compensation is necessary for
non-RPL aware receivers. non-RPL aware receivers.
The following table summarizes what headers are needed in the The following table summarizes what headers are needed in the
following scenarios, and indicates when the RPI, RH3 and IP-in-IP following scenarios, and indicates when the RPI, RH3 and IPv6-in-IPv6
header must be inserted. There are these possible situations: header are to be inserted. There are these possible situations:
destination address possible (indicated by "dst"), to a 6LR, to a 6LN target destination address possible (indicated by "tgt"), to a 6LR,
or to the root. In cases where no IP-in-IP header is needed, the to a 6LN or to the root. In cases where no IPv6-in-IPv6 header is
column is left blank. needed, the column states as "No".
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 3). (Figure 3). In the Figure the (1) indicates a 6tisch case [RFC8180],
where the instanceID portion of the RPI header may still be needed to
pick an appropriate priority or channel at each hop.
+-----------------+--------------+-----+-----+----------+----------+ +-----------------+--------------+-----+-----+----------+----------+
| Interaction | Use Case | RPI | RH3 | IP-in-IP | IP-in-IP | | Interaction | Use Case | RPI | RH3 | v6-in-v6 | v6-in-v6 |
| between | | | | | dst | | between | | | | | dst |
+-----------------+--------------+-----+-----+----------+----------+ +-----------------+--------------+-----+-----+----------+----------+
| | Raf to root | Yes | No | No | -- | | | Raf to root | Yes | No | No | No |
+ +--------------+-----+-----+----------+----------+ + +--------------+-----+-----+----------+----------+
| Leaf - Root | root to Raf | Opt | Yes | No | -- | | Leaf - Root | root to Raf | Opt | Yes | No | No |
+ +--------------+-----+-----+----------+----------+ + +--------------+-----+-----+----------+----------+
| | root to ~Raf |no(1)| Yes | Yes | 6LR | | | root to ~Raf |No(1)| Yes | MUST | 6LR |
+ +--------------+-----+-----+----------+----------+ + +--------------+-----+-----+----------+----------+
| | ~Raf to root | Yes | No | Yes | root | | | ~Raf to root | Yes | No | MUST | root |
+-----------------+--------------+-----+-----+----------+----------+ +-----------------+--------------+-----+-----+----------+----------+
| | Raf to Int | Yes | No | Yes | root | | | Raf to Int | Yes | No | MUST | root |
+ +--------------+-----+-----+----------+----------+ + +--------------+-----+-----+----------+----------+
| Leaf - Internet | Int to Raf |no(1)| Yes | Yes | dst | | Leaf - Internet | Int to Raf |No(1)| Yes | MUST | tgt |
+ +--------------+-----+-----+----------+----------+ + +--------------+-----+-----+----------+----------+
| | ~Raf to Int | Yes | No | Yes | root | | | ~Raf to Int | Yes | No | MUST | root |
+ +--------------+-----+-----+----------+----------+ + +--------------+-----+-----+----------+----------+
| | Int to ~Raf |no(1)| Yes | Yes | 6LR | | | Int to ~Raf |No(1)| Yes | MUST | 6LR |
+-----------------+--------------+-----+-----+----------+----------+ +-----------------+--------------+-----+-----+----------+----------+
| | Raf to Raf | Yes | Yes | Yes | root/dst | | | Raf to Raf | Yes | Yes | MUST | root/tgt |
+ +--------------+-----+-----+----------+----------+ + +--------------+-----+-----+----------+----------+
| | Raf to ~Raf | Yes | Yes | Yes | root/6LR | | | Raf to ~Raf | Yes | Yes | MUST | root/6LR |
+ Leaf - Leaf +--------------+-----+-----+----------+----------+ + Leaf - Leaf +--------------+-----+-----+----------+----------+
| | ~Raf to Raf | Yes | Yes | Yes | root/6LN | | | ~Raf to Raf | Yes | Yes | MUST | root/6LN |
+ +--------------+-----+-----+----------+----------+ + +--------------+-----+-----+----------+----------+
| | ~Raf to ~Raf | Yes | Yes | Yes | root/6LR | | | ~Raf to ~Raf | Yes | Yes | MUST | root/6LR |
+-----------------+--------------+-----+-----+----------+----------+ +-----------------+--------------+-----+-----+----------+----------+
(1)-6tisch networks may need the RPI information. (1)-6tisch networks may need the RPI information.
Figure 8: Headers needed in Non-Storing mode: RPI, RH3, IP-in-IP Figure 8: Headers needed in Non-Storing mode: RPI, RH3, IPv6-in-IPv6
encapsulation. encapsulation.
7.1. Non-Storing Mode: Interaction between Leaf and Root 7.1. Non-Storing Mode: Interaction between Leaf and Root
In this section we are going to describe the communication flow in In this section is described the communication flow in Non Storing
Non Storing Mode (Non-SM) between, Mode (Non-SM) between,
RPL-aware-leaf to root RPL-aware-leaf to root
root to RPL-aware-leaf root to RPL-aware-leaf
not-RPL-aware-leaf to root not-RPL-aware-leaf to root
root to not-RPL-aware-leaf root to not-RPL-aware-leaf
7.1.1. Non-SM: Example of Flow from RPL-aware-leaf to root 7.1.1. Non-SM: Example of Flow from RPL-aware-leaf to root
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 header must be included to avoid/detect traffic to the root. The RPI header MUST be included since contains
loops. the rank information, which is used to avoid/detect loops.
RPL-aware-leaf (6LN) --> 6LR_i --> root(6LBR) RPL-aware-leaf (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 are the intermediate routers from source to destination. In 6LR_i are the intermediate routers from source to destination. In
this case, "1 <= i >= n", n is the number of routers (6LR) that the this case, "1 <= i <= n", n is the number of routers (6LR) that the
packet go through from source (6LN) to destination (6LBR). packet go through from source (6LN) to destination (6LBR).
This situation is the same case as storing mode. This situation is the same case as storing mode.
+-------------------+-----+-------+------+ +-------------------+-----+-------+------+
| Header | 6LN | 6LR_i | 6LBR | | Header | 6LN | 6LR_i | 6LBR |
+-------------------+-----+-------+------+ +-------------------+-----+-------+------+
| Inserted headers | RPI | -- | -- | | Inserted headers | RPI | -- | -- |
| Removed headers | -- | -- | RPI | | Removed headers | -- | -- | RPI |
| Re-added headers | -- | -- | -- | | Re-added headers | -- | -- | -- |
| Modified headers | -- | RPI | -- | | Modified headers | -- | RPI | -- |
| Untouched headers | -- | -- | -- | | Untouched headers | -- | -- | -- |
+-------------------+-----+-------+------+ +-------------------+-----+-------+------+
Non Storing: Summary of the use of headers from RPL-aware-leaf to Table 13: Non Storing: Summary of the use of headers from RPL-aware-
root leaf to root
7.1.2. Non-SM: Example of Flow from root to RPL-aware-leaf 7.1.2. Non-SM: Example of Flow from root to RPL-aware-leaf
In this case the flow comprises: In this case the flow comprises:
root (6LBR) --> 6LR_i --> RPL-aware-leaf (6LN) root (6LBR) --> 6LR_i --> RPL-aware-leaf (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 are the intermediate routers from source to destination. In 6LR_i are the intermediate routers from source to destination. In
this case, "1 <= i >= n", n is the number of routers (6LR) that the this case, "1 <= i <= n", n is the number of routers (6LR) that the
packet go through from source (6LBR) to destination (6LN). packet go through from source (6LBR) to destination (6LN).
The 6LBR will insert an RH3, and may optionally insert an RPI header. The 6LBR inserts an RH3, and a RPI header. No IPv6-in-IPv6 header is
No IP-in-IP header is necessary as the traffic originates with an RPL necessary as the traffic originates with an RPL aware node, the 6LBR.
aware node, the 6LBR. The destination is known to RPL-aware because, The destination is known to RPL-aware because, the root knows the
the root knows the whole topology in non-storing mode. whole topology in non-storing mode.
+-------------------+-----------------+-------+----------+ +-------------------+-----------------+-------+------------------+
| Header | 6LBR | 6LR_i | 6LN | | Header | 6LBR | 6LR_i | 6LN |
+-------------------+-----------------+-------+----------+ +-------------------+-----------------+-------+------------------+
| Inserted headers | (opt: RPI), RH3 | -- | -- | | Inserted headers | (opt: RPI), RH3 | -- | -- |
| Removed headers | -- | -- | RH3,RPI | | Removed headers | -- | -- | RH3, (opt: RPI) |
| Re-added headers | -- | -- | -- | | Re-added headers | -- | -- | -- |
| Modified headers | -- | RH3 | -- | | Modified headers | -- | RH3 | -- |
| Untouched headers | -- | -- | -- | | Untouched headers | -- | -- | -- |
+-------------------+-----------------+-------+----------+ +-------------------+-----------------+-------+------------------+
Non Storing: Summary of the use of headers from root to RPL-aware- Table 14: Non Storing: Summary of the use of headers from root to
leaf RPL-aware-leaf
7.1.3. Non-SM: Example of Flow from root to not-RPL-aware-leaf 7.1.3. Non-SM: Example of Flow from root to not-RPL-aware-leaf
In this case the flow comprises: In this case the flow comprises:
root (6LBR) --> 6LR_i --> not-RPL-aware-leaf (IPv6) root (6LBR) --> 6LR_i --> not-RPL-aware-leaf (IPv6)
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 --> Node E --> Node G
6LR_i are the intermediate routers from source to destination. In 6LR_i are the intermediate routers from source to destination. In
this case, "1 <= i >= n", n is the number of routers (6LR) that the this case, "1 <= i <= n", n is the number of routers (6LR) that the
packet go through from source (6LBR) to destination (IPv6). packet go through from source (6LBR) to destination (IPv6).
In 6LBR the RH3 is added, it is modified at each intermediate 6LR In 6LBR the RH3 is added, it is modified at each intermediate 6LR
(6LR_1 and so on) and it is fully consumed in the last 6LR (6LR_n), (6LR_1 and so on) and it is fully consumed in the last 6LR (6LR_n),
but left there. If RPI is left present, the IPv6 node which does not but left there. If RPI is left by the previous 6LR, then the IPv6
understand it will ignore it (following RFC8200), thus encapsulation node which does not understand the RPI, will ignore it (following
is not necesary. Due the complete knowledge of the topology at the RFC8200), thus encapsulation is not necessary. Due the complete
root, the 6LBR may optionally address the IP-in-IP header to the last knowledge of the topology at the root, the 6LBR may optionally
6LR, such that it is removed prior to the IPv6 node. address the IPv6-in-IPv6 header to the last 6LR, such that it is
removed prior to the IPv6 node. Please see Section 8 for
clarification of use of IPv6-in-IPv6 encapsulation.
+---------------+-------------+---------------+--------------+------+ +---------------+-------------+--------------+------------+---------+
| Header | 6LBR | 6LR_i(i=1) | 6LR_n(i=n) | IPv6 | | Header | 6LBR | 6LR_i(i=1) | 6LR_n(i=n) | IPv6 |
+---------------+-------------+---------------+--------------+------+ +---------------+-------------+--------------+------------+---------+
| Inserted | (opt: RPI), | -- | -- | -- | | Inserted | (opt: RPI), | -- | -- | -- |
| headers | RH3 | | | | | headers | RH3 | | | |
| Removed | -- | RH3 | -- | -- | | Removed | -- | -- | RH3 | -- |
| headers | | | | | | headers | | | | |
| Re-added | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- |
| headers | | | | | | headers | | | | |
| Modified | -- | (opt: RPI), | (opt: RPI), | -- | | Modified | -- | (opt: RPI), | (opt: RPI) | -- |
| headers | | RH3 | RH3 | | | headers | | RH3 | | |
| Untouched | -- | -- | -- | RPI | | Untouched | -- | -- | -- | opt: |
| headers | | | | | | headers | | | | RPI |
+---------------+-------------+---------------+--------------+------+ +---------------+-------------+--------------+------------+---------+
Non Storing: Summary of the use of headers from root to not-RPL- Table 15: Non Storing: Summary of the use of headers from root to
aware-leaf not-RPL-aware-leaf
7.1.4. Non-SM: Example of Flow from not-RPL-aware-leaf to root 7.1.4. Non-SM: Example of Flow from not-RPL-aware-leaf to root
In this case the flow comprises: In this case the flow comprises:
not-RPL-aware-leaf (IPv6) --> 6LR_1 --> 6LR_i --> root (6LBR) not-RPL-aware-leaf (IPv6) --> 6LR_1 --> 6LR_i --> root (6LBR)
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 are the intermediate routers from source to destination. In 6LR_i are the intermediate routers from source to destination. In
this case, "1 < i >= n", n is the number of routers (6LR) that the this case, "1 < i <= n", n is the number of routers (6LR) that the
packet go through from source (IPv6) to destination (6LBR). For packet go through from source (IPv6) to destination (6LBR). For
example, 6LR_1 (i=1) is the router that receives the packets from the example, 6LR_1 (i=1) is the router that receives the packets from the
IPv6 node. IPv6 node.
In this case the RPI is added by the first 6LR (6LR1) (Node E), In this case the RPI is added by the first 6LR (6LR1) (Node E),
encapsulated in an IP-in-IP header, and is modified in the following encapsulated in an IPv6-in-IPv6 header, and is modified in the
6LRs. The RPI and entire packet is consumed by the root. following 6LRs. The RPI and entire packet is consumed by the root.
+------------+------+---------------+---------------+---------------+ +---------+-----+----------------+----------------+-----------------+
| Header | IPv6 | 6LR_1 | 6LR_i | 6LBR | | Header | IPv | 6LR_1 | 6LR_i | 6LBR |
+------------+------+---------------+---------------+---------------+ | | 6 | | | |
| Inserted | -- | IP-in-IP(RPI) | -- | -- | +---------+-----+----------------+----------------+-----------------+
| headers | | | | | | Inserte | -- | IPv6-in- | -- | -- |
| Removed | -- | -- | -- | IP-in-IP(RPI) | | d | | IPv6(RPI) | | |
| headers | | | | | | headers | | | | |
| Re-added | -- | -- | -- | -- | | Removed | -- | -- | -- | IPv6-in- |
| headers | | | | | | headers | | | | IPv6(RPI) |
| Modified | -- | -- | IP-in-IP(RPI) | -- | | Re- | -- | -- | -- | -- |
| headers | | | | | | added | | | | |
| Untouched | -- | -- | -- | -- | | headers | | | | |
| headers | | | | | | Modifie | -- | -- | IPv6-in- | -- |
+------------+------+---------------+---------------+---------------+ | d | | | IPv6(RPI) | |
| headers | | | | |
| Untouch | -- | -- | -- | -- |
| ed | | | | |
| headers | | | | |
+---------+-----+----------------+----------------+-----------------+
Non Storing: Summary of the use of headers from not-RPL-aware-leaf to Table 16: Non Storing: Summary of the use of headers from not-RPL-
root aware-leaf to root
7.2. Non-Storing Mode: Interaction between Leaf and Internet 7.2. 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:
RPL-aware-leaf to Internet RPL-aware-leaf to Internet
Internet to RPL-aware-leaf Internet to RPL-aware-leaf
skipping to change at page 30, line 46 skipping to change at page 35, line 51
7.2.1. Non-SM: Example of Flow from RPL-aware-leaf to Internet 7.2.1. Non-SM: Example of Flow from RPL-aware-leaf to Internet
In this case the flow comprises: In this case the flow comprises:
RPL-aware-leaf (6LN) --> 6LR_i --> root (6LBR) --> Internet RPL-aware-leaf (6LN) --> 6LR_i --> root (6LBR) --> Internet
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 --> 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. In
this case, "1 <= i >= n", n is the number of routers (6LR) that the this case, "1 <= i <= n", n is the number of routers (6LR) that the
packet go through from source (6LN) to 6LBR. packet go through from source (6LN) to 6LBR.
This case is identical to storing-mode case. This case is identical to storing-mode case.
The IPv6 flow label should be set to zero to aid in compression, and The IPv6 flow label should be set to zero to aid in compression, and
the 6LBR will set it to a non-zero value when sending towards the the 6LBR will set it to a non-zero value when sending towards the
Internet. Internet.
+-------------------+------+-------+------+----------------+ +-------------------+------+-------+------+----------------+
| Header | 6LN | 6LR_i | 6LBR | Internet | | Header | 6LN | 6LR_i | 6LBR | Internet |
+-------------------+------+-------+------+----------------+ +-------------------+------+-------+------+----------------+
| Inserted headers | RPI | -- | -- | -- | | Inserted headers | RPI | -- | -- | -- |
| Removed headers | -- | -- | -- | -- | | Removed headers | -- | -- | -- | -- |
| Re-added headers | -- | -- | -- | -- | | Re-added headers | -- | -- | -- | -- |
| Modified headers | -- | RPI | -- | -- | | Modified headers | -- | RPI | -- | -- |
| Untouched headers | -- | -- | RPI | RPI (Ignored) | | Untouched headers | -- | -- | RPI | RPI (Ignored) |
+-------------------+------+-------+------+----------------+ +-------------------+------+-------+------+----------------+
Non Storing: Summary of the use of headers from RPL-aware-leaf to Table 17: Non Storing: Summary of the use of headers from RPL-aware-
Internet leaf to Internet
7.2.2. Non-SM: Example of Flow from Internet to RPL-aware-leaf 7.2.2. Non-SM: Example of Flow from Internet to RPL-aware-leaf
In this case the flow comprises: In this case the flow comprises:
Internet --> root (6LBR) --> 6LR_i --> RPL-aware-leaf (6LN) Internet --> root (6LBR) --> 6LR_i --> RPL-aware-leaf (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 (root) --> Node B --> Node D --> Node F
6LR_i are the intermediate routers from source to destination. In 6LR_i are the intermediate routers from source to destination. In
this case, "1 <= i >= n", n is the number of routers (6LR) that the this case, "1 <= i <= n", n is the number of routers (6LR) that the
packet go through from 6LBR to destination(6LN). packet go through from 6LBR to destination(6LN).
The 6LBR must add an 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 IP-in-IP 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. aid compression.
The RPI may be added or not as required by networks such as 6tisch. +-----------+----------+--------------+--------------+--------------+
The RPI is unnecessary for loop detection. | Header | Internet | 6LBR | 6LR_i | 6LN |
+-----------+----------+--------------+--------------+--------------+
+----------+---------+--------------+---------------+---------------+ | Inserted | -- | IPv6-in-IPv6 | -- | -- |
| Header | Interne | 6LBR | 6LR_i | 6LN | | headers | | (RH3,RPI) | | |
| | t | | | | | Removed | -- | -- | -- | IPv6-in-IPv6 |
+----------+---------+--------------+---------------+---------------+ | headers | | | | (RH3,RPI) |
| Inserted | -- | IP-in-IP (RH | -- | -- | | Re-added | -- | -- | -- | -- |
| headers | | 3,opt:RPI) | | | | headers | | | | |
| Removed | -- | -- | -- | IP-in-IP | | Modified | -- | -- | IPv6-in-IPv6 | -- |
| headers | | | | (RH3,opt:RPI) | | headers | | | (RH3,RPI) | |
| Re-added | -- | -- | -- | -- | | Untouched | -- | -- | -- | -- |
| headers | | | | | | headers | | | | |
| Modified | -- | -- | IP-in-IP | -- | +-----------+----------+--------------+--------------+--------------+
| headers | | | (RH3,opt:RPI) | |
| Untouche | -- | -- | -- | -- |
| d | | | | |
| headers | | | | |
+----------+---------+--------------+---------------+---------------+
Non Storing: Summary of the use of headers from Internet to RPL- Table 18: Non Storing: Summary of the use of headers from Internet to
aware-leaf RPL-aware-leaf
7.2.3. Non-SM: Example of Flow from not-RPL-aware-leaf to Internet 7.2.3. Non-SM: Example of Flow from not-RPL-aware-leaf to Internet
In this case the flow comprises: In this case the flow comprises:
not-RPL-aware-leaf (IPv6) --> 6LR_1 --> 6LR_i -->root (6LBR) --> not-RPL-aware-leaf (IPv6) --> 6LR_1 --> 6LR_i -->root (6LBR) -->
Internet Internet
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. In
this case, "1 < i >= n", n is the number of routers (6LR) that the this case, "1 < i <= n", n is the number of routers (6LR) that the
packet go through from source(IPv6) to 6LBR. e.g 6LR_1 (i=1). packet go through from source(IPv6) to 6LBR. e.g 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, the first 6LR node. As RPL headers are added in the IPv6 node packet, the first
(6LR_1) will add an RPI header inside a new IP-in-IP header. The IP- 6LR (6LR_1) will add a RPI header inside a new IPv6-in-IPv6 header.
in-IP header will be addressed to the root. This case is identical The IPv6-in-IPv6 header will be addressed to the root. This case is
to the storing-mode case (see Section 6.2.3). identical to the storing-mode case (see Section 6.2.3).
+-----------+------+-----------+-------------+-----------+----------+ +---------+-----+------------+-------------+-------------+----------+
| Header | IPv6 | 6LR_1 | 6LR_i | 6LBR | Internet | | Header | IPv | 6LR_1 | 6LR_i | 6LBR | Internet |
| | | | [i=2,..,n]_ | | | | | 6 | | [i=2,..,n]_ | | |
+-----------+------+-----------+-------------+-----------+----------+ +---------+-----+------------+-------------+-------------+----------+
| Inserted | -- | IP-in-IP | -- | -- | -- | | Inserte | -- | IPv6-in- | -- | -- | -- |
| headers | | (RPI) | | | | | d | | IPv6 (RPI) | | | |
| Removed | -- | -- | -- | IP-in-IP | -- | | headers | | | | | |
| headers | | | | (RPI) | | | Removed | -- | -- | -- | IPv6-in- | -- |
| Re-added | -- | -- | -- | -- | -- | | headers | | | | IPv6 (RPI) | |
| headers | | | | | | | Re- | -- | -- | -- | -- | -- |
| Modified | -- | -- | IP-in-IP | -- | -- | | added | | | | | |
| headers | | | (RPI) | | | | headers | | | | | |
| Untouched | -- | -- | -- | -- | -- | | Modifie | -- | -- | IPv6-in- | -- | -- |
| headers | | | | | | | d | | | IPv6 (RPI) | | |
+-----------+------+-----------+-------------+-----------+----------+ | headers | | | | | |
| Untouch | -- | -- | -- | -- | -- |
| ed | | | | | |
| headers | | | | | |
+---------+-----+------------+-------------+-------------+----------+
Non Storing: Summary of the use of headers from not-RPL-aware-leaf to Table 19: Non Storing: Summary of the use of headers from not-RPL-
Internet aware-leaf to Internet
7.2.4. Non-SM: Example of Flow from Internet to not-RPL-aware-leaf 7.2.4. Non-SM: Example of Flow from Internet to not-RPL-aware-leaf
In this case the flow comprises: In this case the flow comprises:
Internet --> root (6LBR) --> 6LR_i --> not-RPL-aware-leaf (IPv6) Internet --> root (6LBR) --> 6LR_i --> not-RPL-aware-leaf (IPv6)
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 are the intermediate routers from source to destination. In 6LR_i are the intermediate routers from source to destination. In
this case, "1 < i >= n", n is the number of routers (6LR) that the this case, "1 < i <= n", n is the number of routers (6LR) that the
packet go through from 6LBR to not-RPL-aware-leaf (IPv6). packet go through from 6LBR to not-RPL-aware-leaf (IPv6).
The 6LBR must add an RH3 header inside an IP-in-IP header. The 6LBR The 6LBR must add an RH3 header inside an IPv6-in-IPv6 header. The
will know the path, and will recognize that the final node is not an 6LBR will know the path, and will recognize that the final node is
RPL capable node as it will have received the connectivity DAO from not an RPL capable node as it will have received the connectivity DAO
the nearest 6LR. The 6LBR can therefore make the IP-in-IP header from the nearest 6LR. The 6LBR can therefore make the IPv6-in-IPv6
destination be the last 6LR. The 6LBR will set to zero the flow header destination be the last 6LR. The 6LBR will set to zero the
label upon entry in order to aid compression. flow label upon entry in order to aid compression.
+----------+---------+---------+-----------+-----------------+------+ +---------+--------+------------+------------+---------------+------+
| Header | Interne | 6LBR | 6LR_1 | 6LR_i(i=2,..,n) | IPv6 | | Header | Intern | 6LBR | 6LR_1 | 6LR_i(i=2,.., | IPv6 |
| | t | | | | | | | et | | | n) | |
+----------+---------+---------+-----------+-----------------+------+ +---------+--------+------------+------------+---------------+------+
| Inserted | -- | IP-in- | -- | -- | -- | | Inserte | -- | IPv6-in- | -- | -- | -- |
| headers | | IP | | | | | d | | IPv6 (RH3, | | | |
| | | (RH3, o | | | | | headers | | RPI) | | | |
| | | pt:RPI) | | | | | Removed | -- | -- | -- | IPv6-in-IPv6 | -- |
| Removed | -- | -- | -- | IP-in-IP | -- | | headers | | | | (RH3,RPI)(1) | |
| headers | | | | (RH3,RPI) | | | Re- | -- | -- | -- | -- | -- |
| Re-added | -- | -- | -- | -- | -- | | added | | | | | |
| headers | | | | | | | headers | | | | | |
| Modified | -- | -- | IP-in-IP | IP-in-IP | -- | | Modifie | -- | -- | IPv6-in- | IPv6-in-IPv6 | -- |
| headers | | | (RH3,RPI) | (RH3,RPI) | | | d | | | IPv6 | (RH3, RPI) | |
| Untouche | -- | -- | -- | -- | RPI | | headers | | | (RH3,RPI) | | |
| d | | | | | | | Untouch | -- | -- | -- | -- | -- |
| headers | | | | | | | ed | | | | | |
+----------+---------+---------+-----------+-----------------+------+ | headers | | | | | |
+---------+--------+------------+------------+---------------+------+
NonStoring: Summary of the use of headers from Internet to non-RPL- Table 20: NonStoring: Summary of the use of headers from Internet to
aware-leaf non-RPL-aware-leaf (1) The last 6LR before the IPv6 node.
7.3. Non-Storing Mode: Interaction between Leafs 7.3. Non-Storing Mode: Interaction between Leafs
In this section we are going to describe the communication flow in In this section is described the communication flow in Non Storing
Non Storing Mode (Non-SM) between, Mode (Non-SM) between,
RPL-aware-leaf to RPL-aware-leaf RPL-aware-leaf to RPL-aware-leaf
RPL-aware-leaf to not-RPL-aware-leaf RPL-aware-leaf to not-RPL-aware-leaf
not-RPL-aware-leaf to RPL-aware-leaf not-RPL-aware-leaf to RPL-aware-leaf
not-RPL-aware-leaf to not-RPL-aware-leaf not-RPL-aware-leaf to not-RPL-aware-leaf
7.3.1. Non-SM: Example of Flow from RPL-aware-leaf to RPL-aware-leaf 7.3.1. Non-SM: Example of Flow from RPL-aware-leaf to RPL-aware-leaf
In this case the flow comprises: In this case the flow comprises:
6LN src --> 6LR_ia --> root (6LBR) --> 6LR_id --> 6LN dst 6LN src --> 6LR_ia --> root (6LBR) --> 6LR_id --> 6LN dst
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 E --> Node H Node B --> Node A (root) --> Node B --> Node E --> Node H
6LR_ia are the intermediate routers from source to the root In this 6LR_ia are the intermediate routers from source to the root In this
case, "1 <= ia >= n", n is the number of routers (6LR) that the case, "1 <= ia <= n", n is the number of routers (6LR) that the
packet go through from 6LN to the root. packet go through from 6LN to the root.
6LR_id are the intermediate routers from the root to the destination. 6LR_id are the intermediate routers from the root to the destination.
In this case, "1 <= ia >= m", m is the number of the intermediate In this case, "1 <= ia <= m", m is the number of the intermediate
routers (6LR). 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 an RPI header to the original packet, and send the node will add a RPI header to the original packet, and send the
packet upwards. packet upwards.
The originating node SHOULD put the RPI into an IP-in-IP header The originating node SHOULD put the RPI into an IPv6-in-IPv6 header
addressed to the root, so that the 6LBR can remove that header. If addressed to the root, so that the 6LBR can remove that header. If
it does not, then additional resources are wasted on the way down to it does not, then additional resources are wasted on the way down to
carry the useless RPI option. carry the useless RPI option.
The 6LBR will need to insert an RH3 header, which requires that it The 6LBR will need to insert an RH3 header, which requires that it
add an IP-in-IP header. It SHOULD be able to remove the RPI, as it add an IPv6-in-IPv6 header. It SHOULD be able to remove the RPI, as
was contained in an IP-in-IP header addressed to it. Otherwise, it was contained in an IPv6-in-IPv6 header addressed to it.
there MAY be an RPI header buried inside the inner IP header, which Otherwise, there MAY be a RPI header buried inside the inner IP
should get ignored. header, which should get ignored.
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 7.1.2, with the originating node acting as 6LBR. Section 7.1.2, with the originating node acting as 6LBR.
+-----------+----------+--------+-------------+--------+------------+ +---------+------------+-------+-------------+--------+-------------+
| Header | 6LN src | 6LR_ia | 6LBR | 6LR_id | 6LN dst | | Header | 6LN src | 6LR_i | 6LBR | 6LR_id | 6LN dst |
+-----------+----------+--------+-------------+--------+------------+ | | | a | | | |
| Inserted | IP-in-IP | -- | IP-in-IP | -- | -- | +---------+------------+-------+-------------+--------+-------------+
| headers | (RPI1) | | (RH3->6LN, | | | | Inserte | IPv6-in- | -- | IPv6-in- | -- | -- |
| | | | opt RPI2) | | | | d | IPv6 | | IPv6 | | |
| Removed | -- | -- | IP-in-IP | -- | IP-in-IP | | headers | (RPI1) | | (RH3->6LN, | | |
| headers | | | (RPI1) | | (RH3, opt | | | | | opt RPI2) | | |
| | | | | | RPI2) | | Removed | -- | -- | IPv6-in- | -- | IPv6-in- |
| Re-added | -- | -- | -- | -- | -- | | headers | | | IPv6 (RPI1) | | IPv6 (RH3, |
| headers | | | | | | | | | | | | opt RPI2) |
| Modified | -- | RPI1 | -- | RPI2 | -- | | Re- | -- | -- | -- | -- | -- |
| headers | | | | | | | added | | | | | |
| Untouched | -- | -- | -- | -- | -- | | headers | | | | | |
| headers | | | | | | | Modifie | -- | RPI1 | -- | RPI2 | -- |
+-----------+----------+--------+-------------+--------+------------+ | d | | | | | |
| headers | | | | | |
| Untouch | -- | -- | -- | -- | -- |
| ed | | | | | |
| headers | | | | | |
+---------+------------+-------+-------------+--------+-------------+
Non Storing: Summary of the use of headers for RPL-aware-leaf to RPL- Table 21: Non Storing: Summary of the use of headers for RPL-aware-
aware-leaf leaf to RPL-aware-leaf
7.3.2. Non-SM: Example of Flow from RPL-aware-leaf to not-RPL-aware- 7.3.2. Non-SM: Example of Flow from RPL-aware-leaf to not-RPL-aware-
leaf leaf
In this case the flow comprises: In this case the flow comprises:
6LN --> 6LR_ia --> root (6LBR) --> 6LR_id --> not-RPL-aware (IPv6) 6LN --> 6LR_ia --> root (6LBR) --> 6LR_id --> not-RPL-aware (IPv6)
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 E --> Node G Node B --> Node A (root) --> Node B --> Node E --> Node G
6LR_ia are the intermediate routers from source to the root In this 6LR_ia are the intermediate routers from source to the root In this
case, "1 <= ia >= n", n is the number of intermediate routers (6LR) case, "1 <= ia <= n", n is the number of intermediate routers (6LR)
6LR_id are the intermediate routers from the root to the destination. 6LR_id are the intermediate routers from the root to the destination.
In this case, "1 <= ia >= m", m is the number of the intermediate In this case, "1 <= ia <= m", m is the number of the intermediate
routers (6LR). routers (6LR).
As in the previous case, the 6LN will insert an RPI (RPI_1) header As in the previous case, the 6LN will insert a RPI (RPI_1) header
which MUST be in an IP-in-IP header addressed to the root so that the which MUST be in an IPv6-in-IPv6 header addressed to the root so that
6LBR can remove this RPI. The 6LBR will then insert an RH3 inside a the 6LBR can remove this RPI. The 6LBR will then insert an RH3
new IP-in-IP header addressed to the 6LN destination node. The RPI inside a new IPv6-in-IPv6 header addressed to the 6LR_id. The RPI is
is optional from 6LBR to 6LR_id (RPI_2). optional from 6LBR to 6LR_id (RPI_2).
+-----------+----------+----------+------------+------------+-------+ +---------+-----------+-----------+------------+------------+-------+
| Header | 6LN | 6LR_1 | 6LBR | 6LR_id | IPv6 | | Header | 6LN | 6LR_1 | 6LBR | 6LR_id | IPv6 |
+-----------+----------+----------+------------+------------+-------+ +---------+-----------+-----------+------------+------------+-------+
| Inserted | IP-in-IP | -- | IP-in-IP | -- | -- | | Inserte | IPv6-in- | -- | IPv6-in- | -- | -- |
| headers | (RPI1) | | (RH3, opt | | | | d | IPv6 | | IPv6 (RH3, | | |
| | | | RPI_2) | | | | headers | (RPI1) | | opt RPI_2) | | |
| Removed | -- | -- | IP-in-IP | IP-in-IP | -- | | Removed | -- | -- | IPv6-in- | IPv6-in- | -- |
| headers | | | (RPI_1) | (RH3, opt | | | headers | | | IPv6 | IPv6 (RH3, | |
| | | | | RPI_2) | | | | | | (RPI_1) | opt RPI_2) | |
| Re-added | -- | -- | -- | -- | -- | | Re- | -- | -- | -- | -- | -- |
| headers | | | | | | | added | | | | | |
| Modified | -- | IP-in-IP | -- | IP-in-IP | -- | | headers | | | | | |
| headers | | (RPI_1) | | (RH3, opt | | | Modifie | -- | IPv6-in- | -- | IPv6-in- | -- |
| | | | | RPI_2) | | | d | | IPv6 | | IPv6 (RH3, | |
| Untouched | -- | -- | -- | -- | opt | | headers | | (RPI_1) | | opt RPI_2) | |
| headers | | | | | RPI_2 | | Untouch | -- | -- | -- | -- | opt |
+-----------+----------+----------+------------+------------+-------+ | ed | | | | | RPI_2 |
| headers | | | | | |
+---------+-----------+-----------+------------+------------+-------+
Non Storing: Summary of the use of headers from RPL-aware-leaf to Table 22: Non Storing: Summary of the use of headers from RPL-aware-
not-RPL-aware-leaf leaf to not-RPL-aware-leaf
7.3.3. Non-SM: Example of Flow from not-RPL-aware-leaf to RPL-aware- 7.3.3. Non-SM: Example of Flow from not-RPL-aware-leaf to RPL-aware-
leaf leaf
In this case the flow comprises: In this case the flow comprises:
not-RPL-aware 6LN (IPv6) --> 6LR_ia --> root (6LBR) --> 6LR_id --> not-RPL-aware 6LN (IPv6) --> 6LR_ia --> root (6LBR) --> 6LR_id -->
6LN 6LN
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 E --> Node H Node B --> Node A (root) --> Node B --> Node E --> Node H
6LR_ia are the intermediate routers from source to the root. In this 6LR_ia are the intermediate routers from source to the root. In this
case, "1 <= ia >= n", n is the number of intermediate routers (6LR) case, "1 <= ia <= n", n is the number of intermediate routers (6LR)
6LR_id are the intermediate routers from the root to the destination. 6LR_id are the intermediate routers from the root to the destination.
In this case, "1 <= ia >= m", m is the number of the intermediate In this case, "1 <= ia <= m", m is the number of the intermediate
routers (6LR). routers (6LR).
This scenario is mostly identical to the previous one. The RPI is This scenario is mostly identical to the previous one. The RPI is
added by the first 6LR (6LR_1) inside an IP-in-IP header addressed to added by the first 6LR (6LR_1) inside an IPv6-in-IPv6 header
the root. The 6LBR will remove this RPI, and add it's own IP-in-IP addressed to the root. The 6LBR will remove this RPI, and add it's
header containing an RH3 header and optional RPI (RPI_2). own IPv6-in-IPv6 header containing an RH3 header and optional RPI
(RPI_2).
+-----------+------+----------+-----------+------------+------------+ +---------+-----+------------+------------+------------+------------+
| Header | IPv6 | 6LR_1 | 6LBR | 6LR_id | 6LN | | Header | IPv | 6LR_1 | 6LBR | 6LR_id | 6LN |
+-----------+------+----------+-----------+------------+------------+ | | 6 | | | | |
| Inserted | -- | IP-in-IP | IP-in-IP | -- | -- | +---------+-----+------------+------------+------------+------------+
| headers | | (RPI_1) | (RH3, opt | | | | Inserte | -- | IPv6-in- | IPv6-in- | -- | -- |
| | | | RPI_2) | | | | d | | IPv6 | IPv6 (RH3, | | |
| Removed | -- | -- | IP-in-IP | -- | IP-in-IP | | headers | | (RPI_1) | opt RPI_2) | | |
| headers | | | (RPI_1) | | (RH3, opt | | Removed | -- | -- | IPv6-in- | -- | IPv6-in- |
| | | | | | RPI_2) | | headers | | | IPv6 | | IPv6 (RH3, |
| Re-added | -- | -- | -- | -- | -- | | | | | (RPI_1) | | opt RPI_2) |
| headers | | | | | | | Re- | -- | -- | -- | -- | -- |
| Modified | -- | -- | -- | IP-in-IP | -- | | added | | | | | |
| headers | | | | (RH3, opt | | | headers | | | | | |
| | | | | RPI_2) | | | Modifie | -- | -- | -- | IPv6-in- | -- |
| Untouched | -- | -- | -- | -- | -- | | d | | | | IPv6 (RH3, | |
| headers | | | | | | | headers | | | | opt RPI_2) | |
+-----------+------+----------+-----------+------------+------------+ | Untouch | -- | -- | -- | -- | -- |
| ed | | | | | |
| headers | | | | | |
+---------+-----+------------+------------+------------+------------+
Non Storing: Summary of the use of headers from not-RPL-aware-leaf to Table 23: Non Storing: Summary of the use of headers from not-RPL-
RPL-aware-leaf aware-leaf to RPL-aware-leaf
7.3.4. Non-SM: Example of Flow from not-RPL-aware-leaf to not-RPL- 7.3.4. Non-SM: Example of Flow from not-RPL-aware-leaf to not-RPL-
aware-leaf aware-leaf
In this case the flow comprises: In this case the flow comprises:
not-RPL-aware 6LN (IPv6 src)--> 6LR_ia --> root (6LBR) --> 6LR_id --> not-RPL-aware 6LN (IPv6 src)--> 6LR_ia --> root (6LBR) --> 6LR_id -->
not-RPL-aware (IPv6 dst) not-RPL-aware (IPv6 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 C --> Node J Node B --> Node A (root) --> Node C --> Node J
6LR_ia are the intermediate routers from source to the root. In this 6LR_ia are the intermediate routers from source to the root. In this
case, "1 <= ia >= n", n is the number of intermediate routers (6LR) case, "1 <= ia <= n", n is the number of intermediate routers (6LR)
6LR_id are the intermediate routers from the root to the destination. 6LR_id are the intermediate routers from the root to the destination.
In this case, "1 <= ia >= m", m is the number of the intermediate In this case, "1 <= ia <= m", m is the number of the intermediate
routers (6LR). routers (6LR).
This scenario is the combination of the previous two cases. This scenario is the combination of the previous two cases.
+------------+-------+-----------+------------+-------------+-------+ +----------+-----+-------------+--------------+--------------+------+
| Header | IPv6 | 6LR_1 | 6LBR | 6LR_id | IPv6 | | Header | IPv | 6LR_1 | 6LBR | 6LR_id | IPv6 |
| | src | | | | dst | | | 6 | | | | dst |
+------------+-------+-----------+------------+-------------+-------+ | | src | | | | |
| Inserted | -- | IP-in-IP | IP-in-IP | -- | -- | +----------+-----+-------------+--------------+--------------+------+
| headers | | (RPI_1) | (RH3) | | | | Inserted | -- | IPv6-in- | IPv6-in-IPv6 | -- | -- |
| Removed | -- | -- | IP-in-IP | IP-in-IP | -- | | headers | | IPv6 | (RH3, opt | | |
| headers | | | (RPI_1) | (RH3, opt | | | | | (RPI_1) | RPI_2) | | |
| | | | | RPI_2) | | | Removed | -- | -- | IPv6-in-IPv6 | IPv6-in-IPv6 | -- |
| Re-added | -- | -- | -- | -- | -- | | headers | | | (RPI_1) | (RH3, opt | |
| headers | | | | | | | | | | | RPI_2) | |
| Modified | -- | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
| Untouched | -- | -- | -- | -- | -- | | Modified | -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
+------------+-------+-----------+------------+-------------+-------+ | Untouche | -- | -- | -- | -- | -- |
| d | | | | | |
| headers | | | | | |
+----------+-----+-------------+--------------+--------------+------+
Non Storing: Summary of the use of headers from not-RPL-aware-leaf to Table 24: Non Storing: Summary of the use of headers from not-RPL-
not-RPL-aware-leaf aware-leaf to not-RPL-aware-leaf
8. Observations about the cases 8. Operational Considerations of supporting not-RPL-aware-leaves
8.1. Storing mode Roughly half of the situations described in this document involve
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
headers, and ones that continue to process a packet that has RPI and/
or RH3 headers.
[RFC8138] shows that the hop-by-hop IP-in-IP header can be compressed [RFC8200] provides for new rules that suggest that nodes that have
using IP-in-IP 6LoRH (IP-in-IP-6LoRH) header as described in not been configured (explicitly) to examine Hop-by-Hop headers,
Section 7 of the document. should ignore those headers, and continue processing the packet.
Despite this, and despite the switch from 0x63 to 0x23, there may be
hosts that are pre-RFC8200, or simply intolerant. Those hosts will
drop packets that continue to have RPL artifacts in them. In
general, such hosts can not be easily supported in RPL LLNs.
There are potential significant advantages to having a single code There are some specific cases where it is possible to remove the RPL
path that always processes IP-in-IP headers with no options. artifacts prior to forwarding the packet to the leaf host. The
critical thing is that the artifacts have been inserted by the RPL
root inside an IPv6-in-IPv6 header, and that the header has been
addressed to the 6LR immediately prior to the leaf node. In that
case, in the process of removing the IPv6-in-IPv6 header, the
artifacts can also be removed.
Thanks to the change of the RPI option type from 0x63 to 0x23, there The above case occurs whenever traffic originates from the outside
is no longer any uncertainty about when to use an IP-in-IP header in the LLN (the "Internet" cases above), and non-storing mode is used.
the storing mode. A Hop-by-Hop Options Header containing the RPI In non-storing mode, the RPL root knows the exact topology (as it
option SHOULD always be added when 6LRs originate packets (without must be create the RH3 header), and therefore knows what the 6LR
IP-in-IP headers), and IP-in-IP headers should always be added prior to the leaf --- the 6LR_n.
(addressed to the root when on the way up, to the end-host when on
the way down) when a 6LR find that it needs to insert a Hop-by-Hop
Options Header containing the RPI option.
8.2. Non-Storing mode Traffic originating from the RPL root (such as when the data
collection system is co-located on the RPL root), does not require an
IPv6-in-IPv6 header (in either mode), as the packet is originating at
the root, and the root can insert the RPI and RH3 headers directly
into the packet, as it is formed. Such a packet is slightly smaller,
but only can be sent to nodes (whether RPL aware or not), that will
tolerate the RPL artifacts.
In the non-storing case, dealing with non-RPL aware leaf nodes is An operator that finds itself with a lot of traffic from the RPL root
much easier as the 6LBR (DODAG root) has complete knowledge about the to RPL-not-aware-leaves, will have to do IPv6-in-IPv6 encapsulation
connectivity of all DODAG nodes, and all traffic flows through the if the leaf is not tolerant of the RPL artifacts. Such an operator
root node. could otherwise omit this unnecessary header if it was certain of the
properties of the leaf.
The 6LBR can recognize non-RPL aware leaf nodes because it will As storing mode can not know the final path of the traffic,
receive a DAO about that node from the 6LN immediately above that intolerant (that drop packets with RPL artifacts) leaf nodes can not
node. This means that the non-storing mode case can avoid ever using be supported.
hop-by-hop IP-in-IP headers for traffic originating from the root to
leafs.
The non-storing mode case does not require the type change from 0x63 9. Operational considerations of introducing 0x23
to 0x23, as the root can always create the right packet. The type
change does not adversely affect the non-storing case.
9. 6LoRH Compression cases This section describes the operational considerations
The [RFC8138] proposes a compression method for RPI, RH3 and IPv6-in- 9.1. Has deployment been discussed?
IPv6.
In Storing Mode, for the examples of Flow from RPL-aware-leaf to non- There are no known multivendor deployments outside of the research
RPL-aware-leaf and non-RPL-aware-leaf to non-RPL-aware-leaf comprise groups! All known deployments of RPL are in market verticals, with a
an IP-in-IP and RPI compression headers. The type of this case is single vendor providing all components. Research groups typically
critical since IP-in-IP is encapsulating a RPI header. are using Contiki, RiotOS, or OpenWSN., and these are easily adapted
to 0x23 functionality. Compatibility issue of RPL Option type not
seems to be quite relevant for research groups.
+--+-----+---+--------------+-----------+-------------+-------------+ 9.2. Has installation and initial setup been discussed??
|1 | 0|0 |TSE| 6LoRH Type 6 | Hop Limit | RPI - 6LoRH | LOWPAN IPHC |
+--+-----+---+--------------+-----------+-------------+-------------+
Figure 9: Critical IP-in-IP (RPI). During bootstrapping the node get the DIO with the information of RPL
Option Type and Indicating the new RPI in the DODAG Configuration
Option Flag. The DODAG root is in charge to configure the current
network to the new value gradually, through DIO messages and when all
the nodes are set with the new value. The DODAG should change to a
new DODAG version. Not able to send data plane messages. Should
drop the packet. In case of rebooting, the node does not remember
the RPL Option Type. Thus, the DIO is sent with flag indicating the
new RPI value.
9.3. Has the migration path been discussed?
TBD
9.4. Have the Requirements on other protocols and functional components
been discussed?
It allows to send packets to non-RPL nodes, the 0x23?..
TBD
9.5. Has the impact on network operation been discussed?
Missconfiguration in case that a node join.
TBD
9.6. Have suggestions for verifying correct operation been discussed?
TBD
9.7. Has management interoperability been discussed?
TBD
9.8. Are there fault or threshold conditions that should be reported?
TBD
9.9. Is configuration discussed?
TBD
10. IANA Considerations 10. 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. Options and Hop-by-Hop Options registry from 0x63 to 0x23.
[RFCXXXX] represents this document. [RFCXXXX] represents this document.
Hex Value Binary Value Hex Value Binary Value
act chg rest Description Reference act chg rest Description Reference
--------- --- --- ------- ----------------- ---------- --------- --- --- ------- ----------------- ----------
0x23 00 1 00011 RPL Option [RFCXXXX] 0x23 00 1 00011 RPL Option [RFCXXXX]
0x63 01 1 00011 RPL Option(DEPRECATED) [RFC6553][RFCXXXX] 0x63 01 1 00011 RPL Option(DEPRECATED) [RFC6553][RFCXXXX]
Figure 10: Option Type in RPL Option. Figure 9: Option Type in RPL Option.
The DODAG Configuration Option Flags in the DODAG Configuration The DODAG Configuration Option Flags in the DODAG Configuration
option is updated as follows: option is updated as follows:
+------------+-----------------+---------------+ +------------+-----------------+---------------+
| Bit number | Description | Reference | | Bit number | Description | Reference |
+------------+-----------------+---------------+ +------------+-----------------+---------------+
| 3 | RPI 0x23 enable | This document | | 3 | RPI 0x23 enable | This document |
+------------+-----------------+---------------+ +------------+-----------------+---------------+
Figure 11: DODAG Configuration Option Flag to indicate the RPI-flag- Figure 10: DODAG Configuration Option Flag to indicate the RPI-flag-
day. day.
11. Security Considerations 11. Security Considerations
The security considerations covering of [RFC6553] and [RFC6554] apply The security considerations covered in [RFC6553] and [RFC6554] apply
when the packets get into RPL Domain. when the packets are in the RPL Domain.
The IPIP mechanism described in this document is much more limited
than the general mechanism described in [RFC2473]. The willingness
of each node in the LLN to decapsulate packets and forward them could
be exploited by nodes to disguise the origin of an attack.
Nodes outside of the LLN will need to pass IPIP traffic through the
RPL root to perform this attack. To counter, the RPL root SHOULD
either restrict ingress of IPIP packets (the simpler solution), or it
SHOULD do a deep packet inspection wherein it walks the IP header
extension chain until it can inspect the upper-layer-payload as
described in [RFC7045]. In particular, the RPL root SHOULD do BCP38
([RFC2827]) processing on the source addresses of all IP headers that
it examines in both directions.
Note: there are some situations where a prefix will spread across
multiple LLNs via mechanisms such as described in
[I-D.ietf-6lo-backbone-router]. In this case the BCP38 filtering
needs to take this into account.
Nodes with the LLN can use the IPIP mechanism to mount an attack on The IPv6-in-IPv6 mechanism described in this document is much more
another part of the LLN, while disguising the origin of the attack. limited than the general mechanism described in [RFC2473]. The
The mechanism can even be abused to make it appear that the attack is willingness of each node in the LLN to decapsulate packets and
coming from outside the LLN, and unless countered, this could be used forward them could be exploited by nodes to disguise the origin of an
to mount a Distributed Denial Of Service attack upon nodes elsewhere attack.
in the Internet. See [DDOS-KREBS] for an example of such attacks
already seen in the real world.
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, they could still have a significant
impact, particularly if the attack was on another LLN! Additionally, impact, particularly if the attack was on another LLN! Additionally,
some uses of RPL involve large backbone ISP scale equipment some uses of RPL involve large backbone ISP scale equipment
[I-D.ietf-anima-autonomic-control-plane], which may be equipped with [I-D.ietf-anima-autonomic-control-plane], which may be equipped with
multiple 100Gb/s interfaces. multiple 100Gb/s interfaces.
Blocking or careful filtering of IPIP traffic entering the LLN as Blocking or careful filtering of IPv6-in-IPv6 traffic entering the
described above will make sure that any attack that is mounted must LLN as described above will make sure that any attack that is mounted
originate compromised nodes within the LLN. The use of BCP38 must originate from compromised nodes within the LLN. The use of
filtering at the RPL root on egress traffic will both alert the BCP38 filtering at the RPL root on egress traffic will both alert the
operator to the existence of the attack, as well as drop the attack operator to the existence of the attack, as well as drop the attack
traffic. As the RPL network is typically numbered from a single traffic. As the RPL network is typically numbered from a single
prefix, which is itself assigned by RPL, BCP38 filtering involves a prefix, which is itself assigned by RPL, BCP38 filtering involves a
single prefix comparison and should be trivial to automatically single prefix comparison and should be trivial to automatically
configure. configure.
There are some scenarios where IPIP traffic SHOULD be allowed to pass There are some scenarios where IPv6-in-IPv6 traffic should be allowed
through the RPL root, such as the IPIP mediated communications to pass through the RPL root, such as the IPv6-in-IPv6 mediated
between a new Pledge and the Join Registrar/Coordinator (JRC) when communications between a new Pledge and the Join Registrar/
using [I-D.ietf-anima-bootstrapping-keyinfra] and Coordinator (JRC) when using [I-D.ietf-anima-bootstrapping-keyinfra]
[I-D.ietf-6tisch-dtsecurity-secure-join]. This is the case for the and [I-D.ietf-6tisch-dtsecurity-secure-join]. This is the case for
RPL root to do careful filtering: it occurs only when the Join the RPL root to do careful filtering: it occurs only when the Join
Coordinator is not co-located inside the RPL root. Coordinator is not co-located inside the RPL root.
With the above precautions, an attack using IPIP tunnels will be by a With the above precautions, an attack using IPv6-in-IPv6 tunnels will
node within the LLN on another node within the LLN. Such an attack be by a node within the LLN on another node within the LLN. Such an
could, of course, be done directly. An attack of this kind is attack could, of course, be done directly. An attack of this kind is
meaningful only if the source addresses are either fake or if the meaningful only if the source addresses are either fake or if the
point is to amplify return traffic. Such an attack, could also be point is to amplify return traffic. Such an attack, could also be
done without the use of IPIP headers using forged source addresses. done without the use of IPv6-in-IPv6 headers using forged source
addresses. If the attack requires bi-directional communication, then
If the attack requires bi-directional communication, then IPIP IPv6-in-IPv6 provides no advantages.
provides no advantages.
[RFC2473] suggests that tunnel entry and exit points can be secured, [RFC2473] suggests that tunnel entry and exit points can be secured,
via the "Use IPsec". This solution has all the problems that via the "Use IPsec". The suggested solution has all the problems
[RFC5406] goes into. In an LLN such a solution would degenerate into that [RFC5406] goes into. In an LLN such a solution would degenerate
every node having a tunnel with every other node. It would provide a into every node having a tunnel with every other node. It would
small amount of origin address authentication at a very high cost; provide a small amount of origin address authentication at a very
doing BCP38 at every node (linking layer-3 addresses to layer-2 high cost; doing BCP38 at every node (linking layer-3 addresses to
addresses, and to already present layer-2 cryptographic mechanisms) layer-2 addresses, and to already present layer-2 cryptographic
would be cheaper should RPL be run in an environment where hostile mechanisms) would be cheaper should RPL be run in an environment
nodes are likely to be a part of the LLN. where hostile nodes are likely to be a part of the LLN.
The RH3 header usage described here can be abused in equivalent ways The RH3 header usage described here can be abused in equivalent ways
with an IPIP header to add the needed RH3 header. As such, the with an IPv6-in-IPv6 header to add the needed RH3 header. As such,
attacker's RH3 header will not be seen by the network until it the 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 a RH3 header which has additional hops which have
not yet been processed, and SHOULD ignore such a second RH3 header. not yet been processed, and SHOULD ignore such a second RH3 header.
In addition, the LLN will likely use [RFC8138] to compress the IPIP In addition, the LLN will likely use [RFC8138] to compress the IPv6-
and RH3 headers. As such, the compressor at the RPL-root will see in-IPv6 and RH3 headers. As such, the compressor at the RPL-root
the second RH3 header and MAY choose to discard the packet if the RH3 will see the second RH3 header and MAY choose to discard the packet
header has not been completely consumed. A consumed (inert) RH3 if the RH3 header has not been completely consumed. A consumed
header could be present in a packet that flows from one LLN, crosses (inert) RH3 header could be present in a packet that flows from one
the Internet, and enters another LLN. As per the discussion in this LLN, crosses the Internet, and enters another LLN. As per the
document, such headers do not need to be removed. However, there is discussion in this document, such headers do not need to be removed.
no case described in this document where an RH3 is inserted in a non- However, there is no case described in this document where an RH3 is
storing network on traffic that is leaving the LLN, but this document inserted in a non-storing network on traffic that is leaving the LLN,
SHOULD NOT preclude such a future innovation. It should just be but this document should not preclude such a future innovation. It
noted that an incoming RH3 must be fully consumed, or very carefully should just be noted that an incoming RH3 must be fully consumed, or
inspected. very carefully inspected.
The RPI header, if permitted to enter the LLN, could be used by an The RPI header, if permitted to enter the LLN, could be used by an
attacker to change the priority of a packet by selecting a different attacker to change the priority of a packet by selecting a different
RPL instanceID, 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 instanceID, but a change of instanceID would permit an default instanceID, but a change of instanceID would permit an
attacker to bypass such filtering. Like the RH3, an RPI header is to attacker to bypass such filtering. Like the RH3, a RPI header is to
be inserted by the RPL root on traffic entering the LLN by first be inserted by the RPL root on traffic entering the LLN by first
inserting an IPIP header. The attacker's RPI header therefore will inserting an IPv6-in-IPv6 header. The attacker's RPI header
not be seen by the network. Upon reaching the destination node the therefore will not be seen by the network. Upon reaching the
RPI header has no further meaning and is just skipped; the presence destination node the RPI header has no further meaning and is just
of a second RPI header will have no meaning to the end node as the skipped; the presence of a second RPI header will have no meaning to
packet has already been identified as being at it's final the end node as the packet has already been identified as being at
destination. it's final destination.
The RH3 and RPI headers could be abused by an attacker inside of the The RH3 and RPI headers could be abused by an attacker inside of the
network to route packets on non-obvious ways, perhaps eluding network to route packets on non-obvious ways, perhaps eluding
observation. This usage is in fact part of [RFC6997] and can not be observation. This usage is in fact part of [RFC6997] and can not be
restricted at all. This is a feature, not a bug. 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 IPIP headers, and this document does not change that to the use of IPv6-in-IPv6 headers, and this document does not change
analysis. that analysis.
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. The mechanism can even be abused to make it appear that the
attack is coming from outside the LLN, and unless countered, this
could be used to mount a Distributed Denial Of Service attack upon
nodes elsewhere in the Internet. See [DDOS-KREBS] for an example of
such attacks already seen in the real world.
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
root SHOULD either restrict ingress of IPv6-in-IPv6 packets (the
simpler solution), or it SHOULD do a deep packet inspection wherein
it walks the IP header extension chain until it can inspect the
upper-layer-payload as described in [RFC7045]. In particular, the
RPL root SHOULD do BCP38 ([RFC2827]) processing on the source
addresses of all IP headers that it examines in both directions.
Note: there are some situations where a prefix will spread across
multiple LLNs via mechanisms such as the one described in
[I-D.ietf-6lo-backbone-router]. In this case the BCP38 filtering
needs to take this into account, either by exchanging detailed
routing information on each LLN, or by moving the BCP38 filtering
further towards the Internet, so that the details of the multiple
LLNs do not matter.
12. Acknowledgments 12. Acknowledgments
This work is partially funded by the FP7 Marie Curie Initial Training We are very thankful to the grant by the Finnish Foundation for
Network (ITN) METRICS project (grant agreement No. 607728). Technology Promotion (Tekniikan Edistaemissaeaetioen - TES), and the
grant by the FP7 Marie Curie Initial Training Network (ITN) METRICS
project (grant agreement No. 607728)
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 3. Much of the redaction in that section is based on his Section 3. 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): Robert Cragie, Simon
Duquennoy, Ralph Droms, Cenk Guendogan, Rahul Jadhav, Matthias Duquennoy, Ralph Droms, Cenk Guendogan, Rahul Jadhav, Matthias
Kovatsch, Peter van der Stok, Xavier Vilajosana and Thomas Watteyne. Kovatsch, Peter van der Stok, Xavier Vilajosana and Thomas Watteyne.
13. References 13. References
13.1. Normative References 13.1. Normative References
[I-D.thubert-roll-unaware-leaves]
Thubert, P., "Routing for RPL Leaves", draft-thubert-roll-
unaware-leaves-06 (work in progress), November 2018.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in
IPv6 Specification", RFC 2473, DOI 10.17487/RFC2473,
December 1998, <https://www.rfc-editor.org/info/rfc2473>.
[RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering: [RFC2827] 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/rfc2827>. May 2000, <https://www.rfc-editor.org/info/rfc2827>.
[RFC5406] Bellovin, S., "Guidelines for Specifying the Use of IPsec
Version 2", BCP 146, RFC 5406, DOI 10.17487/RFC5406,
February 2009, <https://www.rfc-editor.org/info/rfc5406>.
[RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J., [RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J.,
Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur, Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur,
JP., and R. Alexander, "RPL: IPv6 Routing Protocol for JP., and R. Alexander, "RPL: IPv6 Routing Protocol for
Low-Power and Lossy Networks", RFC 6550, Low-Power and Lossy Networks", RFC 6550,
DOI 10.17487/RFC6550, March 2012, DOI 10.17487/RFC6550, March 2012,
<https://www.rfc-editor.org/info/rfc6550>. <https://www.rfc-editor.org/info/rfc6550>.
[RFC6553] Hui, J. and JP. Vasseur, "The Routing Protocol for Low- [RFC6553] Hui, J. and JP. Vasseur, "The Routing Protocol for Low-
Power and Lossy Networks (RPL) Option for Carrying RPL Power and Lossy Networks (RPL) Option for Carrying RPL
Information in Data-Plane Datagrams", RFC 6553, Information in Data-Plane Datagrams", RFC 6553,
skipping to change at page 44, line 34 skipping to change at page 50, line 39
[RFC7045] Carpenter, B. and S. Jiang, "Transmission and Processing [RFC7045] Carpenter, B. and S. Jiang, "Transmission and Processing
of IPv6 Extension Headers", RFC 7045, of IPv6 Extension Headers", RFC 7045,
DOI 10.17487/RFC7045, December 2013, DOI 10.17487/RFC7045, December 2013,
<https://www.rfc-editor.org/info/rfc7045>. <https://www.rfc-editor.org/info/rfc7045>.
[RFC8138] Thubert, P., Ed., Bormann, C., Toutain, L., and R. Cragie, [RFC8138] Thubert, P., Ed., Bormann, C., Toutain, L., and R. Cragie,
"IPv6 over Low-Power Wireless Personal Area Network "IPv6 over Low-Power Wireless Personal Area Network
(6LoWPAN) Routing Header", RFC 8138, DOI 10.17487/RFC8138, (6LoWPAN) Routing Header", RFC 8138, DOI 10.17487/RFC8138,
April 2017, <https://www.rfc-editor.org/info/rfc8138>. April 2017, <https://www.rfc-editor.org/info/rfc8138>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200, (IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017, DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>. <https://www.rfc-editor.org/info/rfc8200>.
13.2. Informative References 13.2. Informative References
[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-backbone-router] [I-D.ietf-6lo-backbone-router]
Thubert, P., "IPv6 Backbone Router", draft-ietf-6lo- Thubert, P., Perkins, C., and E. Levy-Abegnoli, "IPv6
backbone-router-06 (work in progress), February 2018. Backbone Router", draft-ietf-6lo-backbone-router-10 (work
in progress), January 2019.
[I-D.ietf-6man-rfc6434-bis]
Chown, T., Loughney, J., and T. Winters, "IPv6 Node
Requirements", draft-ietf-6man-rfc6434-bis-08 (work in
progress), March 2018.
[I-D.ietf-6tisch-dtsecurity-secure-join] [I-D.ietf-6tisch-dtsecurity-secure-join]
Richardson, M., "6tisch Secure Join protocol", draft-ietf- Richardson, M., "6tisch Secure Join protocol", draft-ietf-
6tisch-dtsecurity-secure-join-01 (work in progress), 6tisch-dtsecurity-secure-join-01 (work in progress),
February 2017. February 2017.
[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-13 (work in progress), December 2017. plane-18 (work in progress), August 2018.
[I-D.ietf-anima-bootstrapping-keyinfra] [I-D.ietf-anima-bootstrapping-keyinfra]
Pritikin, M., Richardson, M., Behringer, M., Bjarnason, Pritikin, M., Richardson, M., Behringer, M., Bjarnason,
S., and K. Watsen, "Bootstrapping Remote Secure Key S., and K. Watsen, "Bootstrapping Remote Secure Key
Infrastructures (BRSKI)", draft-ietf-anima-bootstrapping- Infrastructures (BRSKI)", draft-ietf-anima-bootstrapping-
keyinfra-15 (work in progress), April 2018. keyinfra-18 (work in progress), January 2019.
[I-D.thubert-roll-unaware-leaves] [RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in
Thubert, P., "Routing for RPL Leaves", draft-thubert-roll- IPv6 Specification", RFC 2473, DOI 10.17487/RFC2473,
unaware-leaves-04 (work in progress), March 2018. December 1998, <https://www.rfc-editor.org/info/rfc2473>.
[RFC4192] Baker, F., Lear, E., and R. Droms, "Procedures for [RFC4192] Baker, F., Lear, E., and R. Droms, "Procedures for
Renumbering an IPv6 Network without a Flag Day", RFC 4192, Renumbering an IPv6 Network without a Flag Day", RFC 4192,
DOI 10.17487/RFC4192, September 2005, DOI 10.17487/RFC4192, September 2005,
<https://www.rfc-editor.org/info/rfc4192>. <https://www.rfc-editor.org/info/rfc4192>.
[RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet [RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet
Control Message Protocol (ICMPv6) for the Internet Control Message Protocol (ICMPv6) for the Internet
Protocol Version 6 (IPv6) Specification", STD 89, Protocol Version 6 (IPv6) Specification", STD 89,
RFC 4443, DOI 10.17487/RFC4443, March 2006, RFC 4443, DOI 10.17487/RFC4443, March 2006,
<https://www.rfc-editor.org/info/rfc4443>. <https://www.rfc-editor.org/info/rfc4443>.
[RFC5406] Bellovin, S., "Guidelines for Specifying the Use of IPsec
Version 2", BCP 146, RFC 5406, DOI 10.17487/RFC5406,
February 2009, <https://www.rfc-editor.org/info/rfc5406>.
[RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
Bormann, "Neighbor Discovery Optimization for IPv6 over Bormann, "Neighbor Discovery Optimization for IPv6 over
Low-Power Wireless Personal Area Networks (6LoWPANs)", Low-Power Wireless Personal Area Networks (6LoWPANs)",
RFC 6775, DOI 10.17487/RFC6775, November 2012, RFC 6775, DOI 10.17487/RFC6775, November 2012,
<https://www.rfc-editor.org/info/rfc6775>. <https://www.rfc-editor.org/info/rfc6775>.
[RFC6997] Goyal, M., Ed., Baccelli, E., Philipp, M., Brandt, A., and [RFC6997] Goyal, M., Ed., Baccelli, E., Philipp, M., Brandt, A., and
J. Martocci, "Reactive Discovery of Point-to-Point Routes J. Martocci, "Reactive Discovery of Point-to-Point Routes
in Low-Power and Lossy Networks", RFC 6997, in Low-Power and Lossy Networks", RFC 6997,
DOI 10.17487/RFC6997, August 2013, DOI 10.17487/RFC6997, August 2013,
skipping to change at page 46, line 15 skipping to change at page 52, line 27
[RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and [RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and
Lossy Networks", RFC 7102, DOI 10.17487/RFC7102, January Lossy Networks", RFC 7102, DOI 10.17487/RFC7102, January
2014, <https://www.rfc-editor.org/info/rfc7102>. 2014, <https://www.rfc-editor.org/info/rfc7102>.
[RFC7416] Tsao, T., Alexander, R., Dohler, M., Daza, V., Lozano, A., [RFC7416] Tsao, T., Alexander, R., Dohler, M., Daza, V., Lozano, A.,
and M. Richardson, Ed., "A Security Threat Analysis for and M. Richardson, Ed., "A Security Threat Analysis for
the Routing Protocol for Low-Power and Lossy Networks the Routing Protocol for Low-Power and Lossy Networks
(RPLs)", RFC 7416, DOI 10.17487/RFC7416, January 2015, (RPLs)", RFC 7416, DOI 10.17487/RFC7416, January 2015,
<https://www.rfc-editor.org/info/rfc7416>. <https://www.rfc-editor.org/info/rfc7416>.
[Second6TischPlugtest] [RFC8180] Vilajosana, X., Ed., Pister, K., and T. Watteyne, "Minimal
"2nd 6Tisch Plugtest", <http://www.ietf.org/mail- IPv6 over the TSCH Mode of IEEE 802.15.4e (6TiSCH)
archive/web/6tisch/current/pdfgDMQcdCkRz.pdf>. Configuration", BCP 210, RFC 8180, DOI 10.17487/RFC8180,
May 2017, <https://www.rfc-editor.org/info/rfc8180>.
Authors' Addresses Authors' Addresses
Maria Ines Robles Maria Ines Robles
Ericsson Aalto University
Hirsalantie 11 Innopoli
Jorvas 02420 Espoo 02150
Finland Finland
Email: maria.ines.robles@ericsson.com Email: mariainesrobles@gmail.com
Michael C. Richardson Michael C. Richardson
Sandelman Software Works Sandelman Software Works
470 Dawson Avenue 470 Dawson Avenue
Ottawa, ON K1Z 5V7 Ottawa, ON K1Z 5V7
CA CA
Email: mcr+ietf@sandelman.ca Email: mcr+ietf@sandelman.ca
URI: http://www.sandelman.ca/mcr/ URI: http://www.sandelman.ca/mcr/
Pascal Thubert Pascal Thubert
Cisco Systems, Inc Cisco Systems, Inc
Village d'Entreprises Green Side 400, Avenue de Roumanille Village d'Entreprises Green Side 400, Avenue de Roumanille
Batiment T3, Biot - Sophia Antipolis 06410 Batiment T3, Biot - Sophia Antipolis 06410
France France
Email: pthubert@cisco.com Email: pthubert@cisco.com
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