draft-ietf-roll-useofrplinfo-04.txt   draft-ietf-roll-useofrplinfo-05.txt 
ROLL Working Group M. Robles ROLL Working Group M. Robles
Internet-Draft Ericsson Internet-Draft Ericsson
Intended status: Informational M. Richardson Intended status: Informational M. Richardson
Expires: October 7, 2016 SSW Expires: December 12, 2016 SSW
P. Thubert P. Thubert
Cisco Cisco
April 5, 2016 June 10, 2016
When to use RFC 6553, 6554 and IPv6-in-IPv6 When to use RFC 6553, 6554 and IPv6-in-IPv6
draft-ietf-roll-useofrplinfo-04 draft-ietf-roll-useofrplinfo-05
Abstract Abstract
This document looks at different data flows through LLN networks This document looks at different data flows through LLN (Low-Power
where RPL is used to establish routing. The document enumerates the and Lossy Networks) where RPL (IPv6 Routing Protocol for Low-Power
cases where RFC 6553, RFC 6554 and IPv6-in-IPv6 encapsulation is and Lossy Networks) is used to establish routing. The document
required. This analysis provides the basis on which to design enumerates the cases where RFC 6553, RFC 6554 and IPv6-in-IPv6
efficient compression of these headers. encapsulation is required. This analysis provides the basis on which
to design efficient compression of these headers.
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
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
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This Internet-Draft will expire on October 7, 2016. This Internet-Draft will expire on December 12, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology and Requirements Language . . . . . . . . . . . . 3 2. Terminology and Requirements Language . . . . . . . . . . . . 3
3. Sample/reference topology . . . . . . . . . . . . . . . . . . 3 3. Sample/reference topology . . . . . . . . . . . . . . . . . . 4
4. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5. Storing mode . . . . . . . . . . . . . . . . . . . . . . . . 8 5. Storing mode . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1. Example of Flow from RPL-aware-leaf to root . . . . . . . 9 5.1. Example of Flow from RPL-aware-leaf to root . . . . . . . 9
5.2. Example of Flow from root to RPL-aware-leaf . . . . . . . 9 5.2. Example of Flow from root to RPL-aware-leaf . . . . . . . 10
5.3. Example of Flow from root to not-RPL-aware-leaf . . . . . 10 5.3. Example of Flow from root to not-RPL-aware-leaf . . . . . 11
5.4. Example of Flow from not-RPL-aware-leaf to root . . . . . 11 5.4. Example of Flow from not-RPL-aware-leaf to root . . . . . 11
5.5. Example of Flow from RPL-aware-leaf to Internet . . . . . 11 5.5. Example of Flow from RPL-aware-leaf to Internet . . . . . 12
5.6. Example of Flow from Internet to RPL-aware-leaf . . . . . 12 5.6. Example of Flow from Internet to RPL-aware-leaf . . . . . 13
5.7. Example of Flow from not-RPL-aware-leaf to Internet . . . 12 5.7. Example of Flow from not-RPL-aware-leaf to Internet . . . 13
5.8. Example of Flow from Internet to non-RPL-aware-leaf . . . 13 5.8. Example of Flow from Internet to non-RPL-aware-leaf . . . 14
5.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf . . 14 5.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf . . 15
5.10. Example of Flow from RPL-aware-leaf to non-RPL-aware-leaf 15 5.10. Example of Flow from RPL-aware-leaf to non-RPL-aware-leaf 16
5.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf 17 5.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf 17
5.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware- 5.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware-
leaf . . . . . . . . . . . . . . . . . . . . . . . . . . 18 leaf . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6. Non Storing mode . . . . . . . . . . . . . . . . . . . . . . 19 6. Non Storing mode . . . . . . . . . . . . . . . . . . . . . . 19
6.1. Example of Flow from RPL-aware-leaf to root . . . . . . . 19 6.1. Example of Flow from RPL-aware-leaf to root . . . . . . . 19
6.2. Example of Flow from root to RPL-aware-leaf . . . . . . . 20 6.2. Example of Flow from root to RPL-aware-leaf . . . . . . . 20
6.3. Example of Flow from root to not-RPL-aware-leaf . . . . . 20 6.3. Example of Flow from root to not-RPL-aware-leaf . . . . . 20
6.4. Example of Flow from not-RPL-aware-leaf to root . . . . . 21 6.4. Example of Flow from not-RPL-aware-leaf to root . . . . . 21
6.5. Example of Flow from RPL-aware-leaf to Internet . . . . . 22 6.5. Example of Flow from RPL-aware-leaf to Internet . . . . . 22
6.6. Example of Flow from Internet to RPL-aware-leaf . . . . . 22 6.6. Example of Flow from Internet to RPL-aware-leaf . . . . . 22
6.7. Example of Flow from not-RPL-aware-leaf to Internet . . . 23 6.7. Example of Flow from not-RPL-aware-leaf to Internet . . . 23
6.8. Example of Flow from Internet to non-RPL-aware-leaf . . . 23 6.8. Example of Flow from Internet to non-RPL-aware-leaf . . . 24
6.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf . . 24 6.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf . . 24
6.10. Example of Flow from RPL-aware-leaf to not-RPL-aware-leaf 25 6.10. Example of Flow from RPL-aware-leaf to not-RPL-aware-leaf 25
6.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf 26 6.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf 26
6.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware- 6.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware-
leaf . . . . . . . . . . . . . . . . . . . . . . . . . . 26 leaf . . . . . . . . . . . . . . . . . . . . . . . . . . 27
7. Observations about the problem . . . . . . . . . . . . . . . 27 7. Observations about the problem . . . . . . . . . . . . . . . 27
7.1. Storing mode . . . . . . . . . . . . . . . . . . . . . . 27 7.1. Storing mode . . . . . . . . . . . . . . . . . . . . . . 27
7.2. Non-Storing mode . . . . . . . . . . . . . . . . . . . . 28 7.2. Non-Storing mode . . . . . . . . . . . . . . . . . . . . 28
8. 6LoRH Compression cases . . . . . . . . . . . . . . . . . . . 28 8. 6LoRH Compression cases . . . . . . . . . . . . . . . . . . . 29
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29
10. Security Considerations . . . . . . . . . . . . . . . . . . . 29 10. Security Considerations . . . . . . . . . . . . . . . . . . . 29
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 29 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 29
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 29 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 29
12.1. Normative References . . . . . . . . . . . . . . . . . . 29 12.1. Normative References . . . . . . . . . . . . . . . . . . 29
12.2. Informative References . . . . . . . . . . . . . . . . . 30 12.2. Informative References . . . . . . . . . . . . . . . . . 30
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 30
1. Introduction 1. Introduction
RPL [RFC6550] is a routing protocol for constrained networks. RFC RPL (IPv6 Routing Protocol for Low-Power and Lossy Networks)
6553 [RFC6553] defines the "RPL option" (RPI), carried within the [RFC6550] is a routing protocol for constrained networks. RFC 6553
IPv6 Hop-by-Hop header to quickly identify inconsistencies (loops) in [RFC6553] defines the "RPL option" (RPI), carried within the IPv6
the routing topology. RFC 6554 [RFC6554] defines the "RPL Source Hop-by-Hop header to quickly identify inconsistencies (loops) in the
Route Header" (RH3), an IPv6 Extension Header to deliver datagrams routing topology. RFC 6554 [RFC6554] defines the "RPL Source Route
within a RPL routing domain, particularly in non-storing mode. Header" (RH3), an IPv6 Extension Header to deliver datagrams within a
RPL routing domain, particularly in non-storing mode.
These various items are referred to as RPL artifacts, and they are These various items are referred to as RPL artifacts, and they are
seen on all of the data-plane traffic that occurs in RPL routed seen on all of the data-plane traffic that occurs in RPL routed
networks; they do not in general appear on the RPL control plane networks; they do not in general appear on the RPL control plane
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
skipping to change at page 3, line 44 skipping to change at page 3, line 45
Option information and Routing Header type 3 (RFC6554) and an Option information and Routing Header type 3 (RFC6554) and an
efficient IP-in-IP technique. Uses cases proposed for the efficient IP-in-IP technique. Uses cases proposed for the
[Second6TischPlugtest] involving 6loRH. [Second6TischPlugtest] involving 6loRH.
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", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
Terminology defined in [RFC7102] Terminology defined in [RFC7102] applies to this document: LBR, LLN,
RPL, RPL Domain and ROLL.
3. Sample/reference topology 3. Sample/reference topology
A RPL network is composed of a 6LBR (6LoWPAN Border Router), Backbone A RPL network is composed of a 6LBR (6LoWPAN Border Router), Backbone
Router (6BBR), 6LR (6LoWPAN Router) and 6LN (6LoWPAN Node) as leaf Router (6BBR), 6LR (6LoWPAN Router) and 6LN (6LoWPAN Node) as leaf
logically organized in a DODAG structure (Destination Oriented logically organized in a DODAG structure (Destination Oriented
Directed Acyclic Graph). Directed Acyclic Graph).
RPL defines the RPL Control messages (control plane ), a new ICMPv6 RPL defines the RPL Control messages (control plane), a new ICMPv6
message with Type 155. DIS, DIO and DAO messages are all RPL Control [RFC4443] message with Type 155. DIS (DODAG Information
messages but with different Code values. Solicitation), DIO (DODAG Information Object) and DAO (Destination
Advertisement Object) messages are all RPL Control messages but with
different Code values.
RPL supports two modes of Downward traffic: in storing mode, it is RPL supports two modes of Downward traffic: in storing mode (RPL-SM),
fully stateful or an in non-storing, it is fully source routed. A it is fully stateful or an in non-storing (RPL-NSM), it is fully
RPL Instance is either fully storing or fully non-storing, i.e. a RPL source routed. A RPL Instance is either fully storing or fully non-
Instance with a combination of storing and non-storing nodes is not storing, i.e. a RPL Instance with a combination of storing and non-
supported with the current specifications. storing nodes is not supported with the current specifications at the
time of writing this document.
+--------------+ +--------------+
| Upper Layers | | Upper Layers |
| | | |
+--------------+ +--------------+
| RPL | | RPL |
| | | |
+--------------+ +--------------+
| ICMPv6 | | ICMPv6 |
| | | |
skipping to change at page 5, line 10 skipping to change at page 5, line 10
| | | |
+--------------+ +--------------+
Figure 1: RPL Stack. Figure 1: RPL Stack.
+---------+ +---------+
+---+Internet | +---+Internet |
| +---------+ | +---------+
| |
+----+--+ +----+--+
|DODAG | node:01 | DODAG | node:01
+---------+Root +----------+ +---------+ Root +----------+
| |6LBR | | | | 6LBR | |
| +----+--+ | | +----+--+ |
| | | | | |
| | | | | |
... ... ... ... ... ...
| | | | | |
+-----+-+ +--+---+ +--+---+ +-----+-+ +--+---+ +--+---+
|6LR | | | | | |6LR | | | | |
+-----+ | | | | | +-----+ | | | | |
| | 11 | | 12 | | 13 +------+ | | 11 | | 12 | | 13 +------+
| +-----+-+ +-+----+ +-+----+ | | +-----+-+ +-+----+ +-+----+ |
| | | | | | | | | |
| | | | | | | | | |
| 21 | 22 | 23 | 24 | 25 | 21 | 22 | 23 | 24 | 25
+-+---+ +-+---+ +--+--+ +- --+ +---+-+ +-+---+ +-+---+ +--+--+ +- --+ +---+-+
|Leaf | | | | | |Leaf| |Leaf | |Leaf | | | | | |Leaf| |Leaf |
| 6LR | | | | | | 6LN| | 6LR | | 6LN | | | | | | 6LN| | 6LN |
+-----+ +-----+ +-----+ +----+ +-----+ +-----+ +-----+ +-----+ +----+ +-----+
Figure 2: A reference RPL Topology. Figure 2: A reference RPL Topology.
The numbers in or above the nodes are there so that they may be The numbers in or above the nodes are there so that they may be
referenced in subsequent sections. The leaf marked 6LN (24) is a referenced in subsequent sections. In the figure 2, 6LN can be a
device which does not speak RPL at all, but uses Router- router or a host. The 6LN leaf marked as (21) and (25) are routers.
Advertisements, 6LowPAN DAR/DAC and efficient-ND only to participate The leaf marked 6LN (24) is a device which does not speak RPL at all
in the network. (not-RPL-aware), but uses Router-Advertisements, 6LowPAN DAR/DAC and
efficient-ND only to participate in the network [RFC6775]. In the
document this leaf (24) is mentioned as well as IPv6 node. The 6LBR
in the figure is the root of the Global DODAG.
This document is in part motivated by the work that is ongoing at the This document is in part motivated by the work that is ongoing at the
6TiSCH working group. The 6TiSCH architecture 6TiSCH working group. The 6TiSCH architecture
[I-D.ietf-6tisch-architecture] draft explains the network [I-D.ietf-6tisch-architecture] draft explains the network
architecture of a 6TiSCH network. This architecture is used for the architecture of a 6TiSCH network. This architecture is used for the
remainder of this document. remainder of this document.
The scope of the 6TiSCH Architecture is a Backbone Link that The scope of the 6TiSCH (IPv6 over the TSCH mode of IEEE 802.15.4e)
federates multiple LLNs (mesh) as a single IPv6 Multi-Link Subnet. Architecture is a Backbone Link that federates multiple LLNs (mesh)
Each LLN in the subnet is anchored at a Backbone Router (6BBR). The as a single IPv6 Multi-Link Subnet. Each LLN in the subnet is
Backbone Routers interconnect the LLNs over the Backbone Link and anchored at a Backbone Router (6BBR). The Backbone Routers
emulate that the LLN nodes are present on the Backbone thus creating interconnect the LLNs over the Backbone Link and emulate that the LLN
a so-called: Multi-Link Subnet. An LLN node can move freely from an nodes are present on the Backbone thus creating a so-called: Multi-
LLN anchored at a Backbone Router to another LLN anchored at the same Link Subnet. An LLN node can move freely from an LLN anchored at a
or a different Backbone Router inside the Multi-Link Subnet and Backbone Router to another LLN anchored at the same or a different
conserve its addresses. Backbone Router inside the Multi-Link Subnet and conserve its
addresses. Internet is connected through the 6BBR. For the
following uses cases the 6BBR would be mapped to 6LBR and the
Backbone router to 6LR.
+---------+
+---+Internet |
| +---------+
|
| |
+-----+ +-----+
| | Border Router to the RPL domain | | Border Router to the RPL domain
| | (may be a RPL virtual root) | | (may be a RPL virtual root)
+-----+ +-----+
| |
| Backbone | Backbone
+-------------------+-------------------+ +-------------------+-------------------+
| | | | | |
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+
skipping to change at page 6, line 28 skipping to change at page 6, line 38
| | router | | router | | router | | router | | router | | router
+|---|+ +-|||-+ +-[_]-+ +|---|+ +-|||-+ +-[_]-+
| | PCI-exp / | \ USB | Ethernet | | PCI-exp / | \ USB | Ethernet
( ) ( ) ( )( )( ) (6LBR == RPL DODAG root) ( ) ( ) ( )( )( ) (6LBR == RPL DODAG root)
o o o o o o o o o o o o o o o o o o o o o o o o
o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o
o o o o o o o o o o 6LR == RPL router) o o o o o o o o o o o o 6LR == RPL router) o o
o o o o o o o z o o o o o o o z
o o o o o o (6LoWPAN Host) o o o o o o (6LoWPAN Host)
<----------------------- RPL Instance ------------------------> <----------------------- RPL Instances ------------------------>
Figure 3: RPL domain architecture Figure 3: RPL domain architecture
4. Use cases 4. Use cases
In data plane context a combination of RFC6553, RFC6554 and IPv6-in- In data plane context a combination of RFC6553, RFC6554 and IPv6-in-
IPv6 encapsulation is going to be analyzed for the following traffic IPv6 encapsulation is going to be analyzed for the following traffic
flows: flows:
RPL-aware-leaf to root RPL-aware-leaf to root
skipping to change at page 7, line 22 skipping to change at page 7, line 32
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
This document assumes a rule that a Header cannot be inserted or This document assumes a rule that a Header cannot be inserted or
removed on the fly inside an IPv6 packet that is being routed. This removed on the fly inside an IPv6 packet that is being routed. This
is a fundamental precept of the IPv6 architecture as outlined in is a fundamental precept of the IPv6 architecture as outlined in
[RFC2460] is that Extensions may not be added or removed except by [RFC2460] is that Extensions may not be added or removed except by
the sender or the receiver. the sender or the receiver.
Note: current discussions on [I-D.ietf-6man-rfc2460bis] related to
extensions headers may affect some cases in this document (Ticket
nro. 9) in 6man. [TO DO].
A second important thing is that packets with a Hop-by-Hop option A second important thing is that packets with a Hop-by-Hop option
which are marked with option type 01 ([RFC2460] section 4.2) must be which are marked with option type 01 ([RFC2460] section 4.2) must be
discarded if received by a host or router which does not understand discarded if received by a host or router which does not understand
that option. This means that in general, any packet that leaves the that option. This means that in general, any packet that leaves the
RPL domain of an LLN (or leaves the LLN entirely) is likely to be RPL domain of an LLN (or leaves the LLN entirely) is likely to be
discarded if it still contains an [RFC6553] RPL Option Header known discarded if it still contains an [RFC6553] RPL Option Header known
as the RPI. as the RPI.
The combination of these two rules means that the arrangement of The combination of these two rules means that the arrangement of
headers must be done so that traffic intended to exit the RPL domain headers must be done so that traffic intended to exit the RPL domain
skipping to change at page 8, line 7 skipping to change at page 8, line 21
Both RPI and RH3 headers may be modified by routers on the path of Both RPI and RH3 headers may be modified by routers on the path of
the packet without the need to add to remove an encapsulating header. the packet without the need to add to remove an encapsulating header.
Both headers were designed with this modification in mind, and both Both headers were designed with this modification in mind, and both
the RPL RH and the RPL option are marked mutable but recoverable, so the RPL RH and the RPL option are marked mutable but recoverable, so
an IPsec AH security header can be applied across these headers, but an IPsec AH security header can be applied across these headers, but
it may not secure all the values in those headers. it may not secure all the values in those headers.
RPI should be present in every single RPL data packet. There is one RPI should 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
route. In a downward non-storing mode, the entire route is written, root. In a downward non-storing mode, the entire route is written,
so there can be no loops by construction, nor any confusion about so there can be no loops by construction, nor any confusion about
which forwarding table to use. There may be cases (such as in which forwarding table to use. There may be cases (such as in
6tisch) where the instanceID may still be needed to pick an 6tisch) where the instanceID may still be needed to pick an
appropriate priority or channel at each hop. appropriate priority or channel at each hop.
The applicability for storing (RPL-SN) and non-Storing (RPL-NSN) The applicability for storing (RPL-SM) and non-Storing (RPL-NSM)
modes for the previous cases is showed as follows: modes for the previous cases is showed as follows:
In tables, the term "RPL aware leaf" is has been shortened to "Raf", In tables, the term "RPL aware leaf" is has been shortened to "Raf",
and "not-RPL aware leaf" has been shortened to "~Raf" to make the and "not-RPL aware leaf" has been shortened to "~Raf" to make the
table fit in available space. table fit in available space.
The earlier examples are more complete to make sure that the process The earlier examples are more complete to make sure that the process
is clear, while later examples are more consise. is clear, while later examples are more consise.
5. Storing mode 5. Storing mode
This table summarizes what headers are needed in the following In storing mode (fully stateful), determinate whether the destination
scenarios, and indicates the IPIP header must be inserted on a hop- is RPL capable is not currently discernible by the sender and thus
by-hop basis, and when it can target the destination node directly. would need an IP-in-IP header. The IP-in-IP header needs to be
There are three possible situations: hop-by-hop necessary (indicated addressed on a hop-by-hop basis so that the last 6LR can remove the
by "hop"), or destination address possible (indicated by "dst"). In RPI header. Additionally, The sender can determine if the
all cases hop by hop can be used. In cases where no IPIP header is destination is inside the LLN by looking if the destination address
needed, the column is left blank. is matched by the DIO's PIO option.
+--------------+-------+-------+-----------+-----------+ The following table summarizes what headers are needed in the
| Use Case | RPI | RH3 | IP-in-IP | IPIP dst | following scenarios, and indicates the IP-in-IP header must be
+--------------+-------+-------+-----------+-----------+ inserted on a hop-by-hop basis, and when it can target the
| Raf to root | Yes | No | No | -- | destination node directly. There are three possible situations: hop-
| root to Raf | Yes | No | No | -- | by-hop necessary (indicated by "hop"), or destination address
| root to ~Raf | Yes | No | Yes | hop | possible (indicated by "dst"). In all cases hop by hop can be used.
| ~Raf to root | Yes | No | Yes | root |
| Raf to Int | Yes | No | Yes | root | In cases where no IP-in-IP header is needed, the column is left
| Int to Raf | Yes | No | Yes | raf | blank.
| ~Raf to Int | Yes | No | Yes | root |
| Int to ~Raf | Yes | No | Yes | hop | The leaf can be a router 6LR or a host, both indicated as 6LN.
| Raf to Raf | Yes | No | No | -- |
| Raf to ~Raf | Yes | No | Yes | hop | +--------------+-------+-------+-----------+---------------+
| ~Raf to Raf | Yes | No | Yes | dst | | Use Case | RPI | RH3 | IP-in-IP | IP-in-IP dst |
| ~Raf to ~Raf | Yes | No | Yes | hop | +--------------+-------+-------+-----------+---------------+
+--------------+-------+-------+-----------+-----------+ | Raf to root | Yes | No | No | -- |
| root to Raf | Yes | No | No | -- |
| root to ~Raf | Yes | No | Yes | hop |
| ~Raf to root | Yes | No | Yes | root |
| Raf to Int | Yes | No | Yes | root |
| Int to Raf | Yes | No | Yes | raf |
| ~Raf to Int | Yes | No | Yes | root |
| Int to ~Raf | Yes | No | Yes | hop |
| Raf to Raf | Yes | No | No | -- |
| Raf to ~Raf | Yes | No | Yes | hop |
| ~Raf to Raf | Yes | No | Yes | dst |
| ~Raf to ~Raf | Yes | No | Yes | hop |
+--------------+-------+-------+-----------+---------------+
Table 1: Headers needed in Storing mode: RPI, RH3, IP-in-IP Table 1: Headers needed in Storing mode: RPI, RH3, IP-in-IP
encapsulation encapsulation
5.1. Example of Flow from RPL-aware-leaf to root 5.1. Example of Flow from RPL-aware-leaf to root
As states in Section 16.2 of [RFC6550] a RPL-aware-leaf node does In storing mode, RFC 6553 (RPI) is used to send RPL Information
instanceID and rank information.
As stated in Section 16.2 of [RFC6550] a RPL-aware-leaf node does
not generally issue DIO messages; a leaf node accepts DIO messages not generally issue DIO messages; a leaf node accepts DIO messages
from upstream. (When the inconsistency in routing occurs, a leaf from upstream. (When the inconsistency in routing occurs, a leaf
node will generate a DIO with an infinite rank, to fix it). It may node will generate a DIO with an infinite rank, to fix it). It may
issue DAO and DIS messages though it generally ignores DAO and DIS issue DAO and DIS messages though it generally ignores DAO and DIS
messages. messages.
In storing mode, it is suitable to use RFC 6553 (RPI) to send RPL In storing mode, RFC 6553 (RPI) is used to send RPL Information
Information instanceID and rank information. instanceID and rank information.
In this case the flow comprises: In this case the flow comprises:
RPL-aware-leaf (6LN) --> 6LR --> 6LR,... --> root (6LBR) RPL-aware-leaf (6LN) --> 6LR --> 6LR,... --> root (6LBR)
Note: In this document 6LRs, 6LBR are always full-fledge RPL routers, As it was mentioned In this document 6LRs, 6LBR are always full-
and are the RPL root node. fledge RPL routers, and are the RPL root node.
The 6LN inserts the RPI header, and send the packet to 6LR which The 6LN inserts the RPI header, and sends the packet to 6LR which
decrement the rank in RPI and send the packet up. When the packet decrements the rank in RPI and sends the packet up. When the packet
arrives to 6LBR, the RPI is removed and the packet is processed. arrives at 6LBR, the RPI is removed and the packet is processed.
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 in order to be able to make use of this scenario. The with the 6LBR in order to be able to make use of this scenario. The
6LN can know the address of the 6LBR because it knows the address of 6LN can know the address of the 6LBR because it knows the address of
the root via the DODAGID in the DIO messages. the root via the DODAGID in the DIO messages.
+-------------------+-----+------+------+ +-------------------+-----+------+------+
| Header | 6LN | 6LR | 6LBR | | Header | 6LN | 6LR | 6LBR |
+-------------------+-----+------+------+ +-------------------+-----+------+------+
skipping to change at page 10, line 4 skipping to change at page 10, line 32
| Untouched headers | -- | -- | -- | | Untouched headers | -- | -- | -- |
+-------------------+-----+------+------+ +-------------------+-----+------+------+
Storing: Summary of the use of headers from RPL-aware-leaf to root Storing: Summary of the use of headers from RPL-aware-leaf to root
5.2. Example of Flow from root to RPL-aware-leaf 5.2. Example of Flow from root to RPL-aware-leaf
In this case the flow comprises: In this case the flow comprises:
root (6LBR)--> 6LR --> RPL-aware-leaf (6LN) root (6LBR)--> 6LR --> RPL-aware-leaf (6LN)
In this case the 6LBR insert RPI header and send the packet down, the In this case the 6LBR insert RPI header and send the packet down, the
6LR is going to increment the rank in RPI (examines instanceID for 6LR is going to increment the rank in RPI (examines instanceID for
multiple tables), the packet is processed in 6LN and RPI removed. multiple tables), the packet is processed in 6LN and RPI removed.
No IPIP header is required. No IP-in-IP header is required.
+-------------------+------+-------+------+ +-------------------+------+-------+------+
| Header | 6LBR | 6LR | 6LN | | Header | 6LBR | 6LR | 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 Storing: Summary of the use of headers from root to RPL-aware-leaf
5.3. Example of Flow from root to not-RPL-aware-leaf 5.3. 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 --> not-RPL-aware-leaf (6LN) root (6LBR)--> 6LR --> not-RPL-aware-leaf (6LN)
It includes IPv6-in-IPv6 encapsulation to transmit information not
related with the RPL domain. In the 6LBR the RPI header is inserted
into an IPv6-in-IPv6 header addressed to the last 6LR, which removes
the header before pass the packet to the IPv6 node.
The question in this scenario is how the root knows how to address The question in this scenario is how the root knows how to address
the IPv6-in-IPv6 header. It can not know that the destination isn't the IPv6-in-IPv6 header. It can not know that the destination isn't
RPL aware, so it must insert an IPv6 that can be removed on the last RPL aware, so it must insert an IPv6 header that can be removed on
RPL aware node. Since the root can not know in a storing network the last RPL aware node. Since the root can not know in a storing
where the last RPL aware node is, the IPv6-in-IPv6 header must added network where the last RPL aware node is, the IPv6-in-IPv6 header
hop-by-hop along the path from root to leaf. must be added hop-by-hop along the path from root to leaf.
The root (6LBR) uses IPv6-in-IPv6 encapsulation to transmit
information not related with the RPL domain. In the 6LBR the RPI
header is inserted into an IPv6-in-IPv6 header addressed to the last
6LR, which removes the header before it passes the packet to the IPv6
node (6LN).
An alternative option is to add an attribute in the RPL Target Option An alternative option is to add an attribute in the RPL Target Option
to indicate that the target is not RPL aware: future work may explore to indicate that the target is not RPL aware: future work may explore
this possibility. this possibility.
+-------------------+-----------+-----------+------+ +-------------------+---------------+---------------+------+
| Header | 6LBR | 6LR | IPv6 | | Header | 6LBR | 6LR | IPv6 |
+-------------------+-----------+-----------+------+ +-------------------+---------------+---------------+------+
| Inserted headers | IPIP(RPI) | -- | -- | | Inserted headers | IP-in-IP(RPI) | -- | -- |
| Removed headers | -- | IPIP(RPI) | -- | | Removed headers | -- | IP-in-IP(RPI) | -- |
| Re-added headers | -- | -- | -- | | Re-added headers | -- | -- | -- |
| Modified headers | -- | -- | -- | | Modified headers | -- | -- | -- |
| Untouched headers | -- | -- | -- | | Untouched headers | -- | -- | -- |
+-------------------+-----------+-----------+------+ +-------------------+---------------+---------------+------+
Storing: Summary of the use of headers from root to not-RPL-aware- Storing: Summary of the use of headers from root to not-RPL-aware-
leaf leaf
5.4. Example of Flow from not-RPL-aware-leaf to root 5.4. 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 (6LN) --> 6LR --> root (6LBR) not-RPL-aware-leaf (6LN) --> 6LR --> root (6LBR)
When the packet arrives from IPv6 node to 6LR, the 6LR will insert an When the packet arrives from IPv6 node to 6LR, the 6LR will insert an
RPI header, encapsuladed in a IPv6-in-IPv6 header. The IPv6-in-IPv6 RPI header, encapsuladed in a IPv6-in-IPv6 header. The IPv6-in-IPv6
header can be addressed to the next hop, or to the root. The root header can be addressed to the next hop, or to the root. The root
removes the header and process the packet. removes the header and processes the packet.
+-------------------+------+------------+-----------+ +-------------------+------+----------------+---------------+
| Header | IPv6 | 6LR | 6LBR | | Header | IPv6 | 6LR | 6LBR |
+-------------------+------+------------+-----------+ +-------------------+------+----------------+---------------+
| Inserted headers | -- | IPIP(RPI) | -- | | Inserted headers | -- | IP-in-IP(RPI) | -- |
| Removed headers | -- | -- | IPIP(RPI) | | Removed headers | -- | -- | IP-in-IP(RPI) |
| Re-added headers | -- | -- | -- | | Re-added headers | -- | -- | -- |
| Modified headers | -- | -- | -- | | Modified headers | -- | -- | -- |
| Untouched headers | -- | -- | -- | | Untouched headers | -- | -- | -- |
+-------------------+------+------------+-----------+ +-------------------+------+----------------+---------------+
Storing: Summary of the use of headers from not-RPL-aware-leaf to Storing: Summary of the use of headers from not-RPL-aware-leaf to
root root
5.5. Example of Flow from RPL-aware-leaf to Internet 5.5. Example of Flow from RPL-aware-leaf to Internet
RPL information from RFC 6553 should not go out to Internet as it RPL information from RFC 6553 should not go out to Internet as it
will cause the packet to be discarded at the first non-RPI aware will cause the packet to be discarded at the first non-RPI aware
router. The 6LBR must be able to take this information out before router. The 6LBR must be able to take this information out before
sending the packet upwards to the Internet. This requires the RPI sending the packet upwards to the Internet. This requires the RPI
header be placed in an IPIP header that the root can remove. header be placed in an IP-in-IP header that the root can remove.
In this case the flow comprises: In this case the flow comprises:
RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) --> Internet RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) --> Internet
The 6LN will insert the RPI in a IPv6-in-IPv6 in a outer header, The 6LN will insert the RPI in a IPv6-in-IPv6 in a outer header,
which may be addressed to the 6LBR (root), or alternatively, it could which may be addressed to the 6LBR (root), or alternatively, it could
be addressed hop-by-hop. be addressed hop-by-hop.
+-------------------+-----------+------+-----------+----------+ +-----------------+---------------+------+---------------+----------+
| Header | 6LN | 6LR | 6LBR | Internet | | Header | 6LN | 6LR | 6LBR | Internet |
+-------------------+-----------+------+-----------+----------+ +-----------------+---------------+------+---------------+----------+
| Inserted headers | IPIP(RPI) | -- | -- | -- | | Inserted | IP-in-IP(RPI) | -- | -- | -- |
| Removed headers | -- | -- | IPIP(RPI) | -- | | headers | | | | |
| Re-added headers | -- | -- | -- | -- | | Removed headers | -- | -- | IP-in-IP(RPI) | -- |
| Modified headers | -- | RPI | -- | -- | | Re-added | -- | -- | -- | -- |
| Untouched headers | -- | -- | -- | -- | | headers | | | | |
+-------------------+-----------+------+-----------+----------+ | Modified | -- | RPI | -- | -- |
| headers | | | | |
| Untouched | -- | -- | -- | -- |
| headers | | | | |
+-----------------+---------------+------+---------------+----------+
Storing: Summary of the use of headers from RPL-aware-leaf to Storing: Summary of the use of headers from RPL-aware-leaf to
Internet Internet
5.6. Example of Flow from Internet to RPL-aware-leaf 5.6. 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 --> RPL-aware-leaf (6LN) Internet --> root (6LBR) --> 6LR --> RPL-aware-leaf (6LN)
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 send 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 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 | Internet | 6LBR | 6LR | 6LN | | Header | Internet | 6LBR | 6LR | 6LN |
+-------------------+----------+------------+------+------------+ +-----------------+----------+---------------+------+---------------+
| Inserted headers | -- | IPIP(RPI) | -- | -- | | Inserted | -- | IP-in-IP(RPI) | -- | -- |
| Removed headers | -- | -- | -- | IPIP(RPI) | | headers | | | | |
| Re-added headers | -- | -- | -- | -- | | Removed headers | -- | -- | -- | IP-in-IP(RPI) |
| Modified headers | -- | -- | RPI | -- | | Re-added | -- | -- | -- | -- |
| Untouched headers | -- | -- | -- | -- | | headers | | | | |
+-------------------+----------+------------+------+------------+ | Modified | -- | -- | RPI | -- |
| headers | | | | |
| Untouched | -- | -- | -- | -- |
| headers | | | | |
+-----------------+----------+---------------+------+---------------+
Storing: Summary of the use of headers from Internet to RPL-aware- Storing: Summary of the use of headers from Internet to RPL-aware-
leaf leaf
5.7. Example of Flow from not-RPL-aware-leaf to Internet 5.7. 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 (6LN) --> 6LR --> root (6LBR) --> Internet not-RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) --> Internet
The 6LR node will add an IPIP(RPI) header addressed either to the
The 6LR node will add an IP-in-IP(RPI) header addressed either to the
root, or hop-by-hop such that the root can remove the RPI header root, or hop-by-hop such that the root can remove the RPI header
before passing upwards. before passing upwards.
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 it can be better compressed through the LLN, and the 6LBR so that it can be better compressed through the LLN, and the 6LBR
will set the flow label to a non-zero value when sending to the will set the flow label to a non-zero value when sending to the
Internet. Internet.
+-------------------+------+------------+------------+----------+ +-----------------+------+---------------+---------------+----------+
| Header | 6LN | 6LR | 6LBR | Internet | | Header | 6LN | 6LR | 6LBR | Internet |
+-------------------+------+------------+------------+----------+ +-----------------+------+---------------+---------------+----------+
| Inserted headers | -- | IPIP(RPI) | -- | -- | | Inserted | -- | IP-in-IP(RPI) | -- | -- |
| Removed headers | -- | -- | IPIP(RPI) | -- | | headers | | | | |
| Re-added headers | -- | -- | -- | -- | | Removed headers | -- | -- | IP-in-IP(RPI) | -- |
| Modified headers | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- |
| Untouched headers | -- | -- | -- | -- | | headers | | | | |
+-------------------+------+------------+------------+----------+ | Modified | -- | -- | -- | -- |
| headers | | | | |
| Untouched | -- | -- | -- | -- |
| headers | | | | |
+-----------------+------+---------------+---------------+----------+
Storing: Summary of the use of headers from not-RPL-aware-leaf to Storing: Summary of the use of headers from not-RPL-aware-leaf to
Internet Internet
5.8. Example of Flow from Internet to non-RPL-aware-leaf 5.8. 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 --> not-RPL-aware-leaf (6LN) Internet --> root (6LBR) --> 6LR --> not-RPL-aware-leaf (6LN)
The 6LBR will have to add an RPI header within an IPIP header. The The 6LBR will have to add an RPI header within an IP-in-IP header.
IPIP will need to be addressed hop-by-hop along the path as in The IP-in-IP will need to be addressed hop-by-hop along the path as
storing mode, the 6LBR has no idea if the 6LN is RPL aware or not, in storing mode, the 6LBR has no idea if the 6LN is RPL aware or not,
nor what the closest attached 6LR node is. nor what the closest attached 6LR node is.
The 6LBR MAY set the flow label on the inner IPIP header to zero in The 6LBR MAY set the flow label on the inner IP-in-IP header to zero
order to aid in compression, as the packet will not emerge again from in order to aid in compression, as the packet will not emerge again
the LLN. from the LLN.
+-------------------+----------+------------+------------+------+ +-----------------+----------+---------------+---------------+------+
| Header | Internet | 6LBR | 6LR | IPv6 | | Header | Internet | 6LBR | 6LR | IPv6 |
+-------------------+----------+------------+------------+------+ +-----------------+----------+---------------+---------------+------+
| Inserted headers | -- | IPIP(RPI) | -- | -- | | Inserted | -- | IP-in-IP(RPI) | -- | -- |
| Removed headers | -- | -- | IPIP(RPI) | -- | | headers | | | | |
| Re-added headers | -- | -- | -- | -- | | Removed headers | -- | -- | IP-in-IP(RPI) | -- |
| Modified headers | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- |
| Untouched headers | -- | -- | -- | -- | | headers | | | | |
+-------------------+----------+------------+------------+------+ | Modified | -- | -- | -- | -- |
| headers | | | | |
| Untouched | -- | -- | -- | -- |
| headers | | | | |
+-----------------+----------+---------------+---------------+------+
Storing: Summary of the use of headers from Internet to non-RPL- Storing: Summary of the use of headers from Internet to non-RPL-
aware-leaf aware-leaf
5.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf 5.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf
In [RFC6550] RPL allows a simple one-hop optimization for both In [RFC6550] RPL allows a simple one-hop optimization for both
storing and non-storing networks. A node may send a packet destined storing and non-storing networks. A node may send a packet destined
to a one-hop neighbor directly to that node. Section 9 in [RFC6550]. to a one-hop neighbor directly to that node. Section 9 in [RFC6550].
In this case the flow comprises: In this case the flow comprises:
6LN --> 6LR --> common parent (6LR) --> 6LR --> 6LN 6LN --> 6LR --> common parent (6LR) --> 6LR --> 6LN
This case is assumed in the same RPL Domain. In the common parent, This case is assumed in the same RPL Domain. In the common parent,
the direction of RPI is changed (from increasing to decreasing the the direction of RPI is changed (from increasing to decreasing the
rank). 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 IPIP headers are necessary. The ability to do remove the RPI, so no IP-in-IP headers are necessary. The ability to
this depends upon the sending know that the destination is: a) inside do this depends upon the sending know that the destination is: a)
the LLN, and b) RPL capable. inside the LLN, and b) RPL capable.
The sender can determine if the destination is inside the LLN by The sender can determine if the destination is inside the LLN by
looking if the destination address is matched by the DIO's PIO looking if the destination address is matched by the DIO's PIO
option. This check may be modified by the use of backbone routers, option. This check may be modified by the use of backbone routers,
but in this case it is assumed that the backbone routers are RPL but in this case it is assumed that the backbone routers are RPL
capable and so can process the RPI header correctly. capable and so can process the RPI header correctly.
The other check, that the destination is RPL capable is not currently The other check, that the destination is RPL capable is not currently
discernible by the sender. This information is necessary to discernible by the sender. This information is necessary to
distinguish this test case from Section 5.10. distinguish this test case from Section 5.10.
skipping to change at page 15, line 32 skipping to change at page 16, line 12
Storing: Summary of the use of headers for RPL-aware-leaf to RPL- Storing: Summary of the use of headers for RPL-aware-leaf to RPL-
aware-leaf aware-leaf
5.10. Example of Flow from RPL-aware-leaf to non-RPL-aware-leaf 5.10. 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 --> common parent (6LR) --> 6LR --> not-RPL-aware 6LN 6LN --> 6LR --> common parent (6LR) --> 6LR --> not-RPL-aware 6LN
The sender, being aware out of band, that the receiver is not RPL The sender, being aware out of band, that the receiver is not RPL
aware, sends adds an RPI header inside an IPIP header. The IPIP aware, sends adds an RPI header inside an IP-in-IP header. The IP-
header needs to be addressed on a hop-by-hop basis so that the last in-IP header needs to be addressed on a hop-by-hop basis so that the
6LR can remove the RPI header. last 6LR can remove the RPI header.
,---. ,---.
/ \ / \
( 6LR2 ) IP3,RPI,IP,ULP ( 6LR2 ) IP3,RPI,IP,ULP
,-" . ,-" .
,-" `---' `. ,-" `---' `.
,' `. ,' `.
,---. ,-" `,---. ,---. ,-" `,---.
/ +" / \ / +" / \
( 6LR1 ) Remove the IP3,RPI( 6LR3 ) ( 6LR1 ) Remove the IP3,RPI( 6LR3 )
skipping to change at page 16, line 30 skipping to change at page 16, line 41
/ \ +--+----+ / \ +--+----+
( 6LN ) | | ( 6LN ) | |
\ / | IPv6 | IP,ULP \ / | IPv6 | IP,ULP
`-----' | | `-----' | |
IP1,RPI,IP,ULP +-------+ IP1,RPI,IP,ULP +-------+
Figure 4: Solution IPv6-in-IPv6 in each hop Figure 4: Solution IPv6-in-IPv6 in each hop
Alternatively, if the definition of the Option Type field of RPL Alternatively, if the definition of the Option Type field of RPL
Option '01' were changed so that it isn't a "discard if not Option '01' were changed so that it isn't a "discard if not
recognized", then no IPIP header would be necessary. This change is recognized", then no IP-in-IP header would be necessary. This change
an incompatible on-the-wire change and would require some kind of is an incompatible on-the-wire change and would require some kind of
flag day, possibly a change that is done simultaenously with an flag day, possibly a change that is done simultaenously with an
updated 6LoRH compress. updated 6LoRH compress.
+-----------+-----------+-----------+------------+-----------+------+ +--------+------------+------------+------------+------------+------+
| Header | 6LN | 6LR | 6LR | 6LR | IPv6 | | Header | 6LN | 6LR | 6LR | 6LR | IPv6 |
| | | | (common | | | | | | | (common | | |
| | | | parent) | | | | | | | parent) | | |
+-----------+-----------+-----------+------------+-----------+------+ +--------+------------+------------+------------+------------+------+
| Inserted | IPIP(RPI) | -- | -- | -- | -- | | Insert | IP-in- | -- | -- | -- | -- |
| headers | | | | | | | ed hea | IP(RPI) | | | | |
| Removed | -- | -- | -- | IPIP(RPI) | -- | | ders | | | | | |
| headers | | | | | | | Remove | -- | -- | -- | IP-in- | -- |
| Re-added | -- | -- | -- | -- | -- | | d head | | | | IP(RPI) | |
| headers | | | | | | | ers | | | | | |
| Modified | -- | IPIP(RPI) | IPIP(RPI) | -- | -- | | Re- | -- | -- | -- | -- | -- |
| headers | | | | | | | added | | | | | |
| Untouched | -- | -- | -- | -- | -- | | header | | | | | |
| headers | | | | | | | s | | | | | |
+-----------+-----------+-----------+------------+-----------+------+ | Modifi | -- | IP-in- | IP-in- | -- | -- |
| ed hea | | IP(RPI) | IP(RPI) | | |
| ders | | | | | |
| Untouc | -- | -- | -- | -- | -- |
| hed he | | | | | |
| aders | | | | | |
+--------+------------+------------+------------+------------+------+
Storing: Summary of the use of headers from RPL-aware-leaf to not- Storing: Summary of the use of headers from RPL-aware-leaf to not-
RPL-aware-leaf RPL-aware-leaf
5.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf 5.11. 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 --> 6LR --> common parent (6LR) --> 6LR --> 6LN not-RPL-aware 6LN --> 6LR --> common parent (6LR) --> 6LR --> 6LN
The 6LR receives the packet from the the IPv6 node and inserts and The 6LR receives the packet from the the IPv6 node and inserts and
the RPI header encapsulated in IPv6-in-IPv6 header. The IPIP header the RPI header encapsulated in IPv6-in-IPv6 header. The IP-in-IP
could be addresses to the 6LN if the destination is known to the RPL header could be addresses to the 6LN if the destination is known to
aware, otherwise must send the packet using a hop-by-hop IPIP header. the RPL aware, otherwise must send the packet using a hop-by-hop IP-
Similar considerations apply from section Section 5.10. in-IP header. Similar considerations apply from section
Section 5.10.
+-----------+------+-----------+------------+-----------+-----------+ +--------+------+------------+------------+------------+------------+
| Header | IPv6 | 6LR | common | 6LR | 6LN | | Header | IPv6 | 6LR | common | 6LR | 6LN |
| | | | parent | | | | | | | parent | | |
| | | | (6LR) | | | | | | | (6LR) | | |
+-----------+------+-----------+------------+-----------+-----------+ +--------+------+------------+------------+------------+------------+
| Inserted | -- | IPIP(RPI) | -- | -- | -- | | Insert | -- | IP-in- | -- | -- | -- |
| headers | | | | | | | ed hea | | IP(RPI) | | | |
| Removed | -- | -- | -- | -- | IPIP(RPI) | | ders | | | | | |
| headers | | | | | | | Remove | -- | -- | -- | -- | IP-in- |
| Re-added | -- | -- | -- | -- | -- | | d head | | | | | IP(RPI) |
| headers | | | | | | | ers | | | | | |
| Modified | -- | -- | IPIP(RPI) | IPIP(RPI) | -- | | Re- | -- | -- | -- | -- | -- |
| headers | | | | | | | added | | | | | |
| Untouched | -- | -- | -- | -- | -- | | header | | | | | |
| headers | | | | | | | s | | | | | |
+-----------+------+-----------+------------+-----------+-----------+ | Modifi | -- | -- | IP-in- | IP-in- | -- |
| ed hea | | | IP(RPI) | IP(RPI) | |
| ders | | | | | |
| Untouc | -- | -- | -- | -- | -- |
| hed he | | | | | |
| aders | | | | | |
+--------+------+------------+------------+------------+------------+
Storing: Summary of the use of headers from not-RPL-aware-leaf to Storing: Summary of the use of headers from not-RPL-aware-leaf to
RPL-aware-leaf RPL-aware-leaf
5.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware-leaf 5.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware-leaf
In this case the flow comprises: In this case the flow comprises:
not-RPL-aware 6LN (IPv6 node)--> 6LR --> root (6LBR) --> 6LR --> not- not-RPL-aware 6LN (IPv6 node)--> 6LR --> root (6LBR) --> 6LR --> not-
RPL-aware 6LN (IPv6 node) RPL-aware 6LN (IPv6 node)
This flow combines the problems of the two previous sections. There This flow combines the problems of the two previous sections. There
is no choice at the first 6LR: it must insert an RPI, and to do that is no choice at the first 6LR: it must insert an RPI, and to do that
it must add an IPIP header. That IPIP header must be addressed on a it must add an IP-in-IP header. That IP-in-IP header must be
hop-by-hop basis. addressed on a hop-by-hop basis.
+-------------+--------+-----------+-----------+-----------+--------+ +-----------+------+---------------+---------+---------------+------+
| Header | IPv6 | 6LR | 6LR | 6LR | IPv6 | | Header | IPv6 | 6LR | 6LR | 6LR | IPv6 |
| | src | | (common | | dst | | | src | | (common | | dst |
| | | | parent) | | | | | | | parent) | | |
+-------------+--------+-----------+-----------+-----------+--------+ +-----------+------+---------------+---------+---------------+------+
| Inserted | -- | IPIP(RPI) | -- | -- | -- | | Inserted | -- | IP-in-IP(RPI) | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
| Removed | -- | -- | -- | IPIP(RPI) | -- | | Removed | -- | -- | -- | IP-in-IP(RPI) | -- |
| headers | | | | | | | headers | | | | | |
| Re-added | -- | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
| Modified | -- | -- | -- | -- | -- | | Modified | -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
| Untouched | -- | -- | -- | -- | -- | | Untouched | -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
+-------------+--------+-----------+-----------+-----------+--------+ +-----------+------+---------------+---------+---------------+------+
Storing: Summary of the use of headers from not-RPL-aware-leaf to Storing: Summary of the use of headers from not-RPL-aware-leaf to
not-RPL-aware-leaf not-RPL-aware-leaf
6. Non Storing mode 6. Non Storing mode
+--------------+------+------+-------+-----------+ +--------------+------+------+-----------+---------------+
| Use Case | RPI | RH3 | IPIP | IPIP dst | | Use Case | RPI | RH3 | IP-in-IP | IP-in-IP dst |
+--------------+------+------+-------+-----------+ +--------------+------+------+-----------+---------------+
| Raf to root | Yes | No | No | -- | | Raf to root | Yes | No | No | -- |
| root to Raf | Yes | Yes | No | -- | | root to Raf | Yes | Yes | No | -- |
| root to ~Raf | No | Yes | Yes | 6LR | | root to ~Raf | No | Yes | Yes | 6LR |
| ~Raf to root | Yes | No | Yes | root | | ~Raf to root | Yes | No | Yes | root |
| Raf to Int | Yes | No | Yes | root | | Raf to Int | Yes | No | Yes | root |
| Int to Raf | opt | Yes | Yes | dst | | Int to Raf | opt | Yes | Yes | dst |
| ~Raf to Int | Yes | No | Yes | root | | ~Raf to Int | Yes | No | Yes | root |
| Int to ~Raf | opt | Yes | Yes | 6LR | | Int to ~Raf | opt | Yes | Yes | 6LR |
| Raf to Raf | Yes | Yes | Yes | root/dst | | Raf to Raf | Yes | Yes | Yes | root/dst |
| Raf to ~Raf | Yes | Yes | Yes | root/6LR | | Raf to ~Raf | Yes | Yes | Yes | root/6LR |
| ~Raf to Raf | Yes | Yes | Yes | root/6LN | | ~Raf to Raf | Yes | Yes | Yes | root/6LN |
| ~Raf to ~Raf | Yes | Yes | Yes | root/6LR | | ~Raf to ~Raf | Yes | Yes | Yes | root/6LR |
+--------------+------+------+-------+-----------+ +--------------+------+------+-----------+---------------+
Table 2: Headers needed in Non-Storing mode: RPI, RH3, IP-in-IP Table 2: Headers needed in Non-Storing mode: RPI, RH3, IP-in-IP
encapsulation encapsulation
6.1. Example of Flow from RPL-aware-leaf to root 6.1. 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 to avoid/detect
loops. loops.
skipping to change at page 20, line 29 skipping to change at page 20, line 29
Non Storing: Summary of the use of headers from RPL-aware-leaf to Non Storing: Summary of the use of headers from RPL-aware-leaf to
root root
6.2. Example of Flow from root to RPL-aware-leaf 6.2. Example of Flow from root to RPL-aware-leaf
In this case the flow comprises: In this case the flow comprises:
root (6LBR)--> 6LR --> RPL-aware-leaf (6LN) root (6LBR)--> 6LR --> RPL-aware-leaf (6LN)
The 6LBR will insert an RH3, and may optionally insert an RPI header. The 6LBR will insert an RH3, and may optionally insert an RPI header.
No IPIP header is necessary as the traffic originates with an RPL No IP-in-IP header is necessary as the traffic originates with an RPL
aware node. aware node.
+-------------------+-----------------+------+----------+ +-------------------+-----------------+------+----------+
| Header | 6LBR | 6LR | 6LN | | Header | 6LBR | 6LR | 6LN |
+-------------------+-----------------+------+----------+ +-------------------+-----------------+------+----------+
| Inserted headers | (opt: RPI), RH3 | -- | -- | | Inserted headers | (opt: RPI), RH3 | -- | -- |
| Removed headers | -- | -- | RH3,RPI | | Removed headers | -- | -- | RH3,RPI |
| Re-added headers | -- | -- | -- | | Re-added headers | -- | -- | -- |
| Modified headers | -- | RH3 | -- | | Modified headers | -- | RH3 | -- |
| Untouched headers | -- | -- | -- | | Untouched headers | -- | -- | -- |
skipping to change at page 21, line 6 skipping to change at page 21, line 6
6.3. Example of Flow from root to not-RPL-aware-leaf 6.3. 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 --> not-RPL-aware-leaf (IPv6 node) root (6LBR)--> 6LR --> not-RPL-aware-leaf (IPv6 node)
In 6LBR the RH3 is added, and modified in 6LR where it is fully In 6LBR the RH3 is added, and modified in 6LR where it is fully
consumed, but left there. If the RPI is left present, the IPv6 node consumed, but left there. If the RPI is left present, the IPv6 node
which does not understand it will drop it, therefore the RPI should which does not understand it will drop it, therefore the RPI should
be removed before reaching the IPv6-only node. To permit removal, an be removed before reaching the IPv6-only node. To permit removal, an
IPIP header (hop-by-hop) or addressed to the last 6LR is necessary. IP-in-IP header (hop-by-hop) or addressed to the last 6LR is
Due the complete knowledge of the topology at the root, the 6LBR is necessary. Due the complete knowledge of the topology at the root,
able to address the IPIP header to the last 6LR. the 6LBR is able to address the IP-in-IP header to the last 6LR.
Omitting the RPI entirely is therefore a better solution, as no IPIP Omitting the RPI entirely is therefore a better solution, as no IP-
header is necessary. in-IP header is necessary.
+-------------------+------+-----+------+ +-------------------+------+-----+------+
| Header | 6LBR | 6LR | IPv6 | | Header | 6LBR | 6LR | IPv6 |
+-------------------+------+-----+------+ +-------------------+------+-----+------+
| Inserted headers | RH3 | -- | -- | | Inserted headers | RH3 | -- | -- |
| Removed headers | -- | -- | -- | | Removed headers | -- | -- | -- |
| Re-added headers | -- | -- | -- | | Re-added headers | -- | -- | -- |
| Modified headers | -- | RH3 | -- | | Modified headers | -- | RH3 | -- |
| Untouched headers | -- | -- | -- | | Untouched headers | -- | -- | -- |
+-------------------+------+-----+------+ +-------------------+------+-----+------+
skipping to change at page 21, line 33 skipping to change at page 21, line 33
Non Storing: Summary of the use of headers from root to not-RPL- Non Storing: Summary of the use of headers from root to not-RPL-
aware-leaf aware-leaf
6.4. Example of Flow from not-RPL-aware-leaf to root 6.4. Example of Flow from not-RPL-aware-leaf to root
In this case the flow comprises: In this case the flow comprises:
IPv6-node --> 6LR1 --> 6LR2 --> root (6LBR) IPv6-node --> 6LR1 --> 6LR2 --> root (6LBR)
In this case the RPI is added by the first 6LR, encapsulated in an In this case the RPI is added by the first 6LR, encapsulated in an
IPIP header, and is not modified in the followings 6LRs. The RPI and IP-in-IP header, and is not modified in the followings 6LRs. The RPI
entire packet is consumed by the root. and entire packet is consumed by the root.
+-------------------+------+------------+------+------------+ +-------------------+------+----------------+------+----------------+
| Header | IPv6 | 6LR1 | 6LR2 | 6LBR | | Header | IPv6 | 6LR1 | 6LR2 | 6LBR |
+-------------------+------+------------+------+------------+ +-------------------+------+----------------+------+----------------+
| Inserted headers | -- | IPIP(RPI) | -- | -- | | Inserted headers | -- | IP-in-IP(RPI) | -- | -- |
| Removed headers | -- | -- | -- | IPIP(RPI) | | Removed headers | -- | -- | -- | IP-in-IP(RPI) |
| Re-added headers | -- | -- | -- | -- | | Re-added headers | -- | -- | -- | -- |
| Modified headers | -- | -- | -- | -- | | Modified headers | -- | -- | -- | -- |
| Untouched headers | -- | IPIP(RPI) | -- | -- | | Untouched headers | -- | IP-in-IP(RPI) | -- | -- |
+-------------------+------+------------+------+------------+ +-------------------+------+----------------+------+----------------+
Non Storing: Summary of the use of headers from not-RPL-aware-leaf to Non Storing: Summary of the use of headers from not-RPL-aware-leaf to
root root
6.5. Example of Flow from RPL-aware-leaf to Internet 6.5. 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 --> root (6LBR) --> Internet RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) --> Internet
This case requires that the RPI be added, but remoted by the 6LBR. This case requires that the RPI be added, but remoted by the 6LBR.
The 6LN must therefore add the RPI inside an IPIP header, addressed The 6LN must therefore add the RPI inside an IP-in-IP header,
to the root. This case is identical to storing-mode case. addressed to the root. 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 | 6LBR | Internet | | Header | 6LN | 6LR | 6LBR | Internet |
+-------------------+-----------+------+------------+----------+ +-----------------+---------------+------+---------------+----------+
| Inserted headers | IPIP(RPI) | -- | -- | -- | | Inserted | IP-in-IP(RPI) | -- | -- | -- |
| Removed headers | -- | -- | IPIP(RPI) | -- | | headers | | | | |
| Re-added headers | -- | -- | -- | -- | | Removed headers | -- | -- | IP-in-IP(RPI) | -- |
| Modified headers | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- |
| Untouched headers | -- | RPI | -- | -- | | headers | | | | |
+-------------------+-----------+------+------------+----------+ | Modified | -- | -- | -- | -- |
| headers | | | | |
| Untouched | -- | RPI | -- | -- |
| headers | | | | |
+-----------------+---------------+------+---------------+----------+
Non Storing: Summary of the use of headers from RPL-aware-leaf to Non Storing: Summary of the use of headers from RPL-aware-leaf to
Internet Internet
6.6. Example of Flow from Internet to RPL-aware-leaf 6.6. 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 --> RPL-aware-leaf (6LN) Internet --> root (6LBR) --> 6LR --> RPL-aware-leaf (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 not, it can address the IPIP header to that address of the target not, it can address the IP-in-IP header to that
node. The 6LBR will zero the flow label upon entry in order to aid node. The 6LBR will zero the flow label upon entry in order to aid
compression. compression.
The RPI may be added or not. The RPI may be added or not.
+----------------+----------+--------------------+------------+-----+ +----------+----------+-----------------------+---------------+-----+
| Header | Internet | 6LBR | 6LR | 6LN | | Header | Internet | 6LBR | 6LR | 6LN |
+----------------+----------+--------------------+------------+-----+ +----------+----------+-----------------------+---------------+-----+
| Inserted | -- | IPIP(RH3,opt:RPI) | -- | -- | | Inserted | -- | IP-in-IP(RH3,opt:RPI) | -- | -- |
| headers | | | | | | headers | | | | |
| Removed | -- | -- | IPIP(RH3) | -- | | Removed | -- | -- | IP-in-IP(RH3) | -- |
| headers | | | | | | headers | | | | |
| Re-added | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- |
| headers | | | | | | headers | | | | |
| Modified | -- | -- | IPIP(RH3) | -- | | Modified | -- | -- | IP-in-IP(RH3) | -- |
| headers | | | | | | headers | | | | |
| Untouched | -- | -- | -- | -- | | Untouche | -- | -- | -- | -- |
| headers | | | | | | d | | | | |
+----------------+----------+--------------------+------------+-----+ | headers | | | | |
+----------+----------+-----------------------+---------------+-----+
Non Storing: Summary of the use of headers from Internet to RPL- Non Storing: Summary of the use of headers from Internet to RPL-
aware-leaf aware-leaf
6.7. Example of Flow from not-RPL-aware-leaf to Internet 6.7. 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 (6LN) --> 6LR --> root (6LBR) --> Internet not-RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) --> Internet
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 6LN will node. As RPL headers are added in the IPv6 node, the first 6LN will
add an RPI header inside a new IPIP header. The IPIP header will be add an RPI header inside a new IP-in-IP header. The IP-in-IP header
addressed to the root. This case is identical to the storing-mode will be addressed to the root. This case is identical to the
case. storing-mode case.
+-------------------+------+-----------+------------+----------+ +-----------------+------+---------------+---------------+----------+
| Header | IPv6 | 6LR | 6LBR | Internet | | Header | IPv6 | 6LR | 6LBR | Internet |
+-------------------+------+-----------+------------+----------+ +-----------------+------+---------------+---------------+----------+
| Inserted headers | -- | IPIP(RPI) | -- | -- | | Inserted | -- | IP-in-IP(RPI) | -- | -- |
| Removed headers | -- | -- | IPIP(RPI) | -- | | headers | | | | |
| Re-added headers | -- | -- | -- | -- | | Removed headers | -- | -- | IP-in-IP(RPI) | -- |
| Modified headers | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- |
| Untouched headers | -- | -- | -- | -- | | headers | | | | |
+-------------------+------+-----------+------------+----------+ | Modified | -- | -- | -- | -- |
| headers | | | | |
| Untouched | -- | -- | -- | -- |
| headers | | | | |
+-----------------+------+---------------+---------------+----------+
Non Storing: Summary of the use of headers from not-RPL-aware-leaf to Non Storing: Summary of the use of headers from not-RPL-aware-leaf to
Internet Internet
6.8. Example of Flow from Internet to non-RPL-aware-leaf 6.8. 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 --> not-RPL-aware-leaf (6LN) Internet --> root (6LBR) --> 6LR --> not-RPL-aware-leaf (6LN)
The 6LBR must add an RH3 header inside an IPIP header. The 6LBR will
know the path, and will recognize that the final node is not an RPL
capable node as it will have received the connectivity DAO from the
nearest 6LR. The 6LBR can therefore make the IPIP header destination
be the last 6LR. The 6LBR will zero the flow label upon entry in
order to aid compression.
+--------------+----------+-------------------+--------------+------+ The 6LBR must add an RH3 header inside an IP-in-IP header. The 6LBR
| Header | Internet | 6LBR | 6LR | IPv6 | will know the path, and will recognize that the final node is not an
+--------------+----------+-------------------+--------------+------+ RPL capable node as it will have received the connectivity DAO from
| Inserted | -- | IPIP(RH3,opt:RPI) | -- | -- | the nearest 6LR. The 6LBR can therefore make the IP-in-IP header
| headers | | | | | destination be the last 6LR. The 6LBR will zero the flow label upon
| Removed | -- | -- | IPIP(RH3, | -- | entry in order to aid compression.
| headers | | | RPI) | |
| Re-added | -- | -- | -- | -- | +----------+---------+-----------------------+---------------+------+
| headers | | | | | | Header | Interne | 6LBR | 6LR | IPv6 |
| Modified | -- | -- | -- | -- | | | t | | | |
| headers | | | | | +----------+---------+-----------------------+---------------+------+
| Untouched | -- | -- | -- | -- | | Inserted | -- | IP-in-IP(RH3,opt:RPI) | -- | -- |
| headers | | | | | | headers | | | | |
+--------------+----------+-------------------+--------------+------+ | Removed | -- | -- | IP-in-IP(RH3, | -- |
| headers | | | RPI) | |
| Re-added | -- | -- | -- | -- |
| headers | | | | |
| Modified | -- | -- | -- | -- |
| headers | | | | |
| Untouche | -- | -- | -- | -- |
| d | | | | |
| headers | | | | |
+----------+---------+-----------------------+---------------+------+
NonStoring: Summary of the use of headers from Internet to non-RPL- NonStoring: Summary of the use of headers from Internet to non-RPL-
aware-leaf aware-leaf
6.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf 6.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf
In this case the flow comprises: In this case the flow comprises:
6LN --> 6LR --> root (6LBR) --> 6LR --> 6LN 6LN --> 6LR --> root (6LBR) --> 6LR --> 6LN
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 an RPI header to the original packet, and send the
packet upwards. packet upwards.
The originating node could put the RPI into an IPIP header addressed The originating node could put the RPI into an IP-in-IP header
to the root, so that the 6LBR can remove that header. addressed to the root, so that the 6LBR can remove that header.
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 IPIP header. It may be able to remove the RPI if it was add an IP-in-IP header. It may be able to remove the RPI if it was
contained in an IPIP header addressed to it. Otherwise, there may be contained in an IP-in-IP header addressed to it. Otherwise, there
an RPI header buried inside the inner IP header, which should get may be an RPI header buried inside the inner IP header, which should
ignored. 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. non-storing DODAGs and fall into this scenario.
+----------------+-----------+----------------+-----+---------------+ +----------+---------------+--------------+-----+-------------------+
| Header | 6LN src | 6LBR | 6LR | 6LN dst | | Header | 6LN src | 6LBR | 6LR | 6LN dst |
+----------------+-----------+----------------+-----+---------------+ +----------+---------------+--------------+-----+-------------------+
| Inserted | IPIP(RPI) | IPIP(RH3 to | -- | -- | | Inserted | IP-in-IP(RPI) | IP-in-IP(RH3 | -- | -- |
| headers | | 6LN,RPI) | | | | headers | | to 6LN,RPI) | | |
| Removed | -- | -- | -- | IPIP(RH3,RPI) | | Removed | -- | -- | -- | IP-in-IP(RH3,RPI) |
| headers | | | | | | headers | | | | |
| Re-added | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- |
| headers | | | | | | headers | | | | |
| Modified | -- | -- | -- | -- | | Modified | -- | -- | -- | -- |
| headers | | | | | | headers | | | | |
| Untouched | -- | -- | -- | -- | | Untouche | -- | -- | -- | -- |
| headers | | | | | | d | | | | |
+----------------+-----------+----------------+-----+---------------+ | headers | | | | |
+----------+---------------+--------------+-----+-------------------+
Non Storing: Summary of the use of headers for RPL-aware-leaf to RPL- Non Storing: Summary of the use of headers for RPL-aware-leaf to RPL-
aware-leaf aware-leaf
6.10. Example of Flow from RPL-aware-leaf to not-RPL-aware-leaf 6.10. Example of Flow from RPL-aware-leaf to not-RPL-aware-leaf
In this case the flow comprises: In this case the flow comprises:
6LN --> 6LR --> root (6LBR) --> 6LR --> not-RPL-aware 6LN 6LN --> 6LR --> root (6LBR) --> 6LR --> not-RPL-aware 6LN
As in the previous case, the 6LN will insert an RPI header which MUST As in the previous case, the 6LN will insert an RPI header which MUST
be in an IPIP header addressed to the root so that the 6LBR can be in an IP-in-IP header addressed to the root so that the 6LBR can
remove this RPI. The 6LBR will then insert an RH3 inside a new IPIP remove this RPI. The 6LBR will then insert an RH3 inside a new IP-
header addressed to the 6LN above the destination node. in-IP header addressed to the 6LN above the destination node.
+---------------+-----------+---------------+----------------+------+ +-----------+---------------+---------------+----------------+------+
| Header | 6LN | 6LBR | 6LR | IPv6 | | Header | 6LN | 6LBR | 6LR | IPv6 |
+---------------+-----------+---------------+----------------+------+ +-----------+---------------+---------------+----------------+------+
| Inserted | IPIP(RPI) | IPIP(RH3, opt | -- | -- | | Inserted | IP-in-IP(RPI) | IP-in-IP(RH3, | -- | -- |
| headers | | RPI) | | | | headers | | opt RPI) | | |
| Removed | -- | IPIP(RPI) | IPIP(RH3, opt | -- | | Removed | -- | IP-in-IP(RPI) | IP-in-IP(RH3, | -- |
| headers | | | RPI) | | | headers | | | opt RPI) | |
| Re-added | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- |
| headers | | | | | | headers | | | | |
| Modified | -- | -- | -- | -- | | Modified | -- | -- | -- | -- |
| headers | | | | | | headers | | | | |
| Untouched | -- | -- | -- | -- | | Untouched | -- | -- | -- | -- |
| headers | | | | | | headers | | | | |
+---------------+-----------+---------------+----------------+------+ +-----------+---------------+---------------+----------------+------+
Non Storing: Summary of the use of headers from RPL-aware-leaf to Non Storing: Summary of the use of headers from RPL-aware-leaf to
not-RPL-aware-leaf not-RPL-aware-leaf
6.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf 6.11. 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 --> 6LR --> root (6LBR) --> 6LR --> 6LN not-RPL-aware 6LN --> 6LR --> root (6LBR) --> 6LR --> 6LN
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 inside an IPIP header addressed to the root. added by the first 6LR inside an IP-in-IP header addressed to the
The 6LBR will remove this RPI, and add it's own IPIP header root. The 6LBR will remove this RPI, and add it's own IP-in-IP
containing an RH3 header. header containing an RH3 header.
+-------------------+------+------------+-----------+------------+ +------------+------+---------------+---------------+---------------+
| Header | IPv6 | 6LR | 6LBR | 6LN | | Header | IPv6 | 6LR | 6LBR | 6LN |
+-------------------+------+------------+-----------+------------+ +------------+------+---------------+---------------+---------------+
| Inserted headers | -- | IPIP(RPI) | IPIP(RH3) | -- | | Inserted | -- | IP-in-IP(RPI) | IP-in-IP(RH3) | -- |
| Removed headers | -- | IPIP(RPI) | -- | IPIP(RH3) | | headers | | | | |
| Re-added headers | -- | -- | -- | -- | | Removed | -- | IP-in-IP(RPI) | -- | IP-in-IP(RH3) |
| Modified headers | -- | -- | -- | -- | | headers | | | | |
| Untouched headers | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- |
+-------------------+------+------------+-----------+------------+ | headers | | | | |
| Modified | -- | -- | -- | -- |
| headers | | | | |
| Untouched | -- | -- | -- | -- |
| headers | | | | |
+------------+------+---------------+---------------+---------------+
Non Storing: Summary of the use of headers from not-RPL-aware-leaf to Non Storing: Summary of the use of headers from not-RPL-aware-leaf to
RPL-aware-leaf RPL-aware-leaf
6.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware-leaf 6.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware-leaf
In this case the flow comprises: In this case the flow comprises:
not-RPL-aware 6LN --> 6LR --> root (6LBR) --> 6LR --> not-RPL-aware not-RPL-aware 6LN --> 6LR --> root (6LBR) --> 6LR --> not-RPL-aware
6LN 6LN
This scenario is the combination of the previous two cases. This scenario is the combination of the previous two cases.
+--------------+------+-----------+-----------+--------------+------+ +----------+-----+-------------+--------------+--------------+------+
| Header | IPv6 | 6LR | 6LBR | 6LR | IPv6 | | Header | IPv | 6LR | 6LBR | 6LR | IPv6 |
+--------------+------+-----------+-----------+--------------+------+ | | 6 | | | | |
| Inserted | -- | IPIP(RPI) | IPIP(RH3) | -- | -- | +----------+-----+-------------+--------------+--------------+------+
| headers | | | | | | | Inserted | -- | IP-in- | IP-in- | -- | -- |
| Removed | -- | -- | IPIP(RPI) | IPIP(RH3, | -- | | headers | | IP(RPI) | IP(RH3) | | |
| headers | | | | opt RPI) | | | Removed | -- | -- | IP-in- | IP-in- | -- |
| Re-added | -- | -- | -- | -- | -- | | headers | | | IP(RPI) | IP(RH3, opt | |
| headers | | | | | | | | | | | RPI) | |
| 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 Non Storing: Summary of the use of headers from not-RPL-aware-leaf to
not-RPL-aware-leaf not-RPL-aware-leaf
7. Observations about the problem 7. Observations about the problem
7.1. Storing mode 7.1. Storing mode
In the completely general storing case, which includes not-RPL aware In the completely general storing case, which includes not-RPL aware
leaf nodes, it is not possible for a sending node to know if the leaf nodes, it is not possible for a sending node to know if the
destination is RPL aware, and therefore it must always use hop-by-hop destination is RPL aware, and therefore it must always use hop-by-hop
IPIP encapsulation, and it can never omit the IPIP encapsulation. IP-in-IP encapsulation, and it can never omit the IP-in-IP
See table Table 1 encapsulation. See table Table 1
The simplest fully general stiaution for storing mode is to always The simplest fully general stiaution for storing mode is to always
put in hop-by-hop IPIP headers. [I-D.ietf-roll-routing-dispatch] put in hop-by-hop IP-in-IP headers. [I-D.ietf-roll-routing-dispatch]
shows that this hop-by-hop IPIP header can be compressed down to shows that this hop-by-hop IP-in-IP header can be compressed down to
{TBD} bytes. {TBD} bytes.
There are potential significant advantages to having a single code There are potential significant advantages to having a single code
path that always processes IPIP headers with no options. path that always processes IP-in-IP headers with no options.
If all RPL aware nodes can be told/configured that there are no non- If all RPL aware nodes can be told/configured that there are no non-
RPL aware leaf nodes, then the only case where an IPIP header is RPL aware leaf nodes, then the only case where an IP-in-IP header is
needed is when communicating outside the LLN. The 6LBR knows well needed is when communicating outside the LLN. The 6LBR knows well
when the communication is from the outside, and the 6LN can tell by when the communication is from the outside, and the 6LN can tell by
comparing the destination address to the prefix provided in the PIO. comparing the destination address to the prefix provided in the PIO.
If it is known that there are no communications outside the RPL If it is known that there are no communications outside the RPL
domain (noting that the RPL domain may well extend to outside the domain (noting that the RPL domain may well extend to outside the
LLN), then RPI headers can be included in all packets, and IPIP LLN), then RPI headers can be included in all packets, and IP-in-IP
headers are *never* needed. This may be significantly advantageous headers are *never* needed. This may be significantly advantageous
in relatively closed systems such as in building or industrial in relatively closed systems such as in building or industrial
automation. Again, there are advantages to having a single code automation. Again, there are advantages to having a single code
path. path.
In order to support the above two cases with full generality, the In order to support the above two cases with full generality, the
different situations (always do IPIP vs never use IPIP) should be different situations (always do IP-in-IP vs never use IP-in-IP)
signaled in the RPL protocol itself. should be signaled in the RPL protocol itself.
7.2. Non-Storing mode 7.2. Non-Storing mode
This the non-storing case, dealing with non-RPL aware leaf nodes is This the non-storing case, dealing with non-RPL aware leaf nodes is
much easier as the 6LBR (DODAG root) has complete knowledge about the much easier as the 6LBR (DODAG root) has complete knowledge about the
connectivity of all nodes, and all traffic flows through the root connectivity of all nodes, and all traffic flows through the root
node. node.
The 6LBR can recognize non-RPL aware leaf nodes because it will The 6LBR can recognize non-RPL aware leaf nodes because it will
receive a DAO about that node from the 6LN immediately above that receive a DAO about that node from the 6LN immediately above that
node. This means that the non-storing mode case can avoid ever using node. This means that the non-storing mode case can avoid ever using
hop-by-hop IPIP headers. hop-by-hop IP-in-IP headers.
It is unclear what it would mean for an RH3 header to be present in a It is unclear what it would mean for an RH3 header to be present in a
hop-by-hop IPIP header. The receiving node ought to consume the IPIP hop-by-hop IP-in-IP header. The receiving node ought to consume the
header, and therefore consume the RH3 as well, and then attempt to IP-in-IP header, and therefore consume the RH3 as well, and then
send the packet again. But intermediate 6LN nodes would not know how attempt to send the packet again. But intermediate 6LN nodes would
to forward the packet, so the RH3 would need to be retained. This is not know how to forward the packet, so the RH3 would need to be
a new kind of IPv6 packet processing. Therefore it may be that on retained. This is a new kind of IPv6 packet processing. Therefore
the outbound leg of non-storing RPL networks, that hop-by-hop IPIP it may be that on the outbound leg of non-storing RPL networks, that
header can NOT be used. hop-by-hop IP-in-IP header can NOT be used.
[I-D.ietf-roll-routing-dispatch] shows how the destination=root, and [I-D.ietf-roll-routing-dispatch] shows how the destination=root, and
destination=6LN IPIP header can be compressed down to {TBD} bytes. destination=6LN IP-in-IP header can be compressed down to {TBD}
bytes.
Unlike in the storing mode case, there are no need for all nodes to Unlike in the storing mode case, there are no need for all nodes to
know about the existence of non-RPL aware nodes. Only the 6LBR needs know about the existence of non-RPL aware nodes. Only the 6LBR needs
to change when there are non-RPL aware nodes. Further, in the non- to change when there are non-RPL aware nodes. Further, in the non-
storing case, the 6LBR is informed by the DAOs when there are non-RPL storing case, the 6LBR is informed by the DAOs when there are non-RPL
aware nodes. aware nodes.
8. 6LoRH Compression cases 8. 6LoRH Compression cases
The [I-D.ietf-roll-routing-dispatch] proposes a compression method The [I-D.ietf-roll-routing-dispatch] proposes a compression method
skipping to change at page 29, line 26 skipping to change at page 29, line 36
The security considerations covering of [RFC6553] and [RFC6554] apply The security considerations covering of [RFC6553] and [RFC6554] apply
when the packets get into RPL Domain. when the packets get into RPL Domain.
11. Acknowledgments 11. Acknowledgments
This work is partially funded by the FP7 Marie Curie Initial Training This work is partially funded by the FP7 Marie Curie Initial Training
Network (ITN) METRICS project (grant agreement No. 607728). Network (ITN) METRICS project (grant agreement No. 607728).
The authors would like to acknowledge the review, feedback, and The authors would like to acknowledge the review, feedback, and
comments of Thomas Watteyne, Xavier Vilajosana, Robert Cragie and comments of Thomas Watteyne, Xavier Vilajosana, Robert Cragie, Simon
Simon Duquennoy. Duquennoy and Peter van der Stok.
12. References 12. References
12.1. Normative References 12.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 1998. (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
December 1998, <http://www.rfc-editor.org/info/rfc2460>.
[RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J., [RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J.,
Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur, Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur,
JP., and R. Alexander, "RPL: IPv6 Routing Protocol for JP., and R. Alexander, "RPL: IPv6 Routing Protocol for
Low-Power and Lossy Networks", RFC 6550, Low-Power and Lossy Networks", RFC 6550,
DOI 10.17487/RFC6550, March 2012, DOI 10.17487/RFC6550, March 2012,
<http://www.rfc-editor.org/info/rfc6550>. <http://www.rfc-editor.org/info/rfc6550>.
[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
skipping to change at page 30, line 19 skipping to change at page 30, line 26
<http://www.rfc-editor.org/info/rfc6553>. <http://www.rfc-editor.org/info/rfc6553>.
[RFC6554] Hui, J., Vasseur, JP., Culler, D., and V. Manral, "An IPv6 [RFC6554] Hui, J., Vasseur, JP., Culler, D., and V. Manral, "An IPv6
Routing Header for Source Routes with the Routing Protocol Routing Header for Source Routes with the Routing Protocol
for Low-Power and Lossy Networks (RPL)", RFC 6554, for Low-Power and Lossy Networks (RPL)", RFC 6554,
DOI 10.17487/RFC6554, March 2012, DOI 10.17487/RFC6554, March 2012,
<http://www.rfc-editor.org/info/rfc6554>. <http://www.rfc-editor.org/info/rfc6554>.
12.2. Informative References 12.2. Informative References
[I-D.ietf-6man-rfc2460bis]
Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", draft-ietf-6man-rfc2460bis-04 (work
in progress), March 2016.
[I-D.ietf-6tisch-architecture] [I-D.ietf-6tisch-architecture]
Thubert, P., "An Architecture for IPv6 over the TSCH mode Thubert, P., "An Architecture for IPv6 over the TSCH mode
of IEEE 802.15.4", draft-ietf-6tisch-architecture-09 (work of IEEE 802.15.4", draft-ietf-6tisch-architecture-10 (work
in progress), November 2015. in progress), June 2016.
[I-D.ietf-roll-routing-dispatch] [I-D.ietf-roll-routing-dispatch]
Thubert, P., Bormann, C., Toutain, L., and R. Cragie, Thubert, P., Bormann, C., Toutain, L., and R. Cragie,
"6LoWPAN Routing Header", draft-ietf-roll-routing- "6LoWPAN Routing Header", draft-ietf-roll-routing-
dispatch-00 (work in progress), March 2016. dispatch-00 (work in progress), March 2016.
[RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet
Control Message Protocol (ICMPv6) for the Internet
Protocol Version 6 (IPv6) Specification", RFC 4443,
DOI 10.17487/RFC4443, March 2006,
<http://www.rfc-editor.org/info/rfc4443>.
[RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
Bormann, "Neighbor Discovery Optimization for IPv6 over
Low-Power Wireless Personal Area Networks (6LoWPANs)",
RFC 6775, DOI 10.17487/RFC6775, November 2012,
<http://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,
<http://www.rfc-editor.org/info/rfc6997>. <http://www.rfc-editor.org/info/rfc6997>.
[RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and [RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and
Lossy Networks", RFC 7102, DOI 10.17487/RFC7102, January Lossy Networks", RFC 7102, DOI 10.17487/RFC7102, January
2014, <http://www.rfc-editor.org/info/rfc7102>. 2014, <http://www.rfc-editor.org/info/rfc7102>.
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