draft-ietf-roll-useofrplinfo-05.txt   draft-ietf-roll-useofrplinfo-06.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: December 12, 2016 SSW Expires: January 19, 2017 SSW
P. Thubert P. Thubert
Cisco Cisco
June 10, 2016 July 18, 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-05 draft-ietf-roll-useofrplinfo-06
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, RFC 6554 and IPv6-in-IPv6
encapsulation is required. This analysis provides the basis on which encapsulation is required. This analysis provides the basis on which
to design efficient compression of these headers. to design efficient compression of these headers.
skipping to change at page 1, line 38 skipping to change at page 1, line 38
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This Internet-Draft will expire on December 12, 2016. This Internet-Draft will expire on January 19, 2017.
Copyright Notice Copyright Notice
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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
2.1. hop-by-hop IPv6-in-IPv6 headers . . . . . . . . . . . . . 4
3. Sample/reference topology . . . . . . . . . . . . . . . . . . 4 3. Sample/reference topology . . . . . . . . . . . . . . . . . . 4
4. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 7
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 . . . . . . . 10 5.2. Example of Flow from root to RPL-aware-leaf . . . . . . . 10
5.3. Example of Flow from root to not-RPL-aware-leaf . . . . . 11 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 . . . . . 12
5.5. Example of Flow from RPL-aware-leaf to Internet . . . . . 12 5.5. Example of Flow from RPL-aware-leaf to Internet . . . . . 12
5.6. Example of Flow from Internet to RPL-aware-leaf . . . . . 13 5.6. Example of Flow from Internet to RPL-aware-leaf . . . . . 13
5.7. Example of Flow from not-RPL-aware-leaf to Internet . . . 13 5.7. Example of Flow from not-RPL-aware-leaf to Internet . . . 14
5.8. Example of Flow from Internet to non-RPL-aware-leaf . . . 14 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 . . 15 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 16 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 18
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 . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6. Non Storing mode . . . . . . . . . . . . . . . . . . . . . . 19 6. Non Storing mode . . . . . . . . . . . . . . . . . . . . . . 20
6.1. Example of Flow from RPL-aware-leaf to root . . . . . . . 19 6.1. Example of Flow from RPL-aware-leaf to root . . . . . . . 20
6.2. Example of Flow from root to RPL-aware-leaf . . . . . . . 20 6.2. Example of Flow from root to RPL-aware-leaf . . . . . . . 21
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 . . . . . 21
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 . . . . . 22
6.5. Example of Flow from RPL-aware-leaf to Internet . . . . . 22 6.5. Example of Flow from RPL-aware-leaf to Internet . . . . . 23
6.6. Example of Flow from Internet to RPL-aware-leaf . . . . . 22 6.6. Example of Flow from Internet to RPL-aware-leaf . . . . . 23
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 . . . 24
6.8. Example of Flow from Internet to non-RPL-aware-leaf . . . 24 6.8. Example of Flow from Internet to non-RPL-aware-leaf . . . 25
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 . . 25
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 26
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 27
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 . . . . . . . . . . . . . . . . . . . . . . . . . . 27 leaf . . . . . . . . . . . . . . . . . . . . . . . . . . 28
7. Observations about the problem . . . . . . . . . . . . . . . 27 7. Observations about the problem . . . . . . . . . . . . . . . 28
7.1. Storing mode . . . . . . . . . . . . . . . . . . . . . . 27 7.1. Storing mode . . . . . . . . . . . . . . . . . . . . . . 28
7.2. Non-Storing mode . . . . . . . . . . . . . . . . . . . . 28 7.2. Non-Storing mode . . . . . . . . . . . . . . . . . . . . 29
8. 6LoRH Compression cases . . . . . . . . . . . . . . . . . . . 29 8. 6LoRH Compression cases . . . . . . . . . . . . . . . . . . . 30
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30
10. Security Considerations . . . . . . . . . . . . . . . . . . . 29 10. Security Considerations . . . . . . . . . . . . . . . . . . . 30
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 29 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 30
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 29 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 30
12.1. Normative References . . . . . . . . . . . . . . . . . . 29 12.1. Normative References . . . . . . . . . . . . . . . . . . 30
12.2. Informative References . . . . . . . . . . . . . . . . . 30 12.2. Informative References . . . . . . . . . . . . . . . . . 31
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32
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.
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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 should not be defining anything new, but discussion. This document should not be defining anything new, but
it may clarify what is correct and incorrect behaviour. it may clarify what is correct and incorrect behaviour.
The related document A Routing Header Dispatch for 6LoWPAN (6LoRH) The related document A Routing Header Dispatch for 6LoWPAN (6LoRH)
[I-D.ietf-roll-routing-dispatch] defines a method to compress RPL [I-D.ietf-roll-routing-dispatch] defines a method to compress RPL
Option information and Routing Header type 3 (RFC6554) and an Option information and Routing Header type 3 [RFC6554], an efficient
efficient IP-in-IP technique. Uses cases proposed for the IP-in-IP technique, and use 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] 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.
2.1. hop-by-hop IPv6-in-IPv6 headers
The term "hop-by-hop IPv6-in-IPv6" header refers to: adding a header
that originates from a node to an adjacent node, using the addresses
(usually the GUA or ULA, but could use the link-local addresses) of
each node. If the packet must traverse multiple hops, then it must
be decapsulated at each hop, and then re-encapsulated again in a
similar fashion.
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
[RFC4443] message with Type 155. DIS (DODAG Information [RFC4443] message with Type 155. DIS (DODAG Information
Solicitation), DIO (DODAG Information Object) and DAO (Destination Solicitation), DIO (DODAG Information Object) and DAO (Destination
Advertisement Object) messages are all RPL Control messages but with Advertisement Object) messages are all RPL Control messages but with
different Code values. different Code values. A RPL Stack is showed in Figure 1.
RPL supports two modes of Downward traffic: in storing mode (RPL-SM), RPL supports two modes of Downward traffic: in storing mode (RPL-SM),
it is fully stateful or an in non-storing (RPL-NSM), it is fully it is fully stateful or an in non-storing (RPL-NSM), it is fully
source routed. A RPL Instance is either fully storing or fully non- 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, i.e. a RPL Instance with a combination of storing and non-
storing nodes is not supported with the current specifications at the storing nodes is not supported with the current specifications at the
time of writing this document. time of writing this document.
+--------------+ +--------------+
| Upper Layers | | Upper Layers |
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| | | | | | | | | |
| | | | | | | | | |
| 21 | 22 | 23 | 24 | 25 | 21 | 22 | 23 | 24 | 25
+-+---+ +-+---+ +--+--+ +- --+ +---+-+ +-+---+ +-+---+ +--+--+ +- --+ +---+-+
|Leaf | | | | | |Leaf| |Leaf | |Leaf | | | | | |Leaf| |Leaf |
| 6LN | | | | | | 6LN| | 6LN | | 6LN | | | | | | 6LN| | 6LN |
+-----+ +-----+ +-----+ +----+ +-----+ +-----+ +-----+ +-----+ +----+ +-----+
Figure 2: A reference RPL Topology. Figure 2: A reference RPL Topology.
In Figure 2 is showed the reference RPL Topology for this document.
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. In the figure 2, 6LN can be a referenced in subsequent sections. In the figure, a 6LN can be a
router or a host. The 6LN leaf marked as (21) and (25) are routers. router or a host. The 6LN leafs marked as (21) and (25) are routers.
The leaf marked 6LN (24) is a device which does not speak RPL at all The leaf marked 6LN (24) is a device which does not speak RPL at all
(not-RPL-aware), but uses Router-Advertisements, 6LowPAN DAR/DAC and (not-RPL-aware), but uses Router-Advertisements, 6LowPAN DAR/DAC and
efficient-ND only to participate in the network [RFC6775]. In the efficient-ND only to participate in the network [RFC6775]. In the
document this leaf (24) is mentioned as well as IPv6 node. The 6LBR document this leaf (24) is often named IPv6 node. The 6LBR in the
in the figure is the root of the Global DODAG. 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.
remainder of this document.
The scope of the 6TiSCH (IPv6 over the TSCH mode of IEEE 802.15.4e)
Architecture is a Backbone Link that federates multiple LLNs (mesh)
as a single IPv6 Multi-Link Subnet. Each LLN in the subnet is
anchored at a Backbone Router (6BBR). The Backbone Routers
interconnect the LLNs over the Backbone Link and emulate that the LLN
nodes are present on the Backbone thus creating a so-called: Multi-
Link Subnet. An LLN node can move freely from an LLN anchored at a
Backbone Router to another LLN anchored at the same or a different
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
| | (may be a RPL virtual root)
+-----+
|
| Backbone
+-------------------+-------------------+
| | |
+-----+ +-----+ +-----+
| | Backbone | | Backbone | | Backbone
| | router | | router | | router
+|---|+ +-|||-+ +-[_]-+
| | PCI-exp / | \ USB | Ethernet
( ) ( ) ( )( )( ) (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 6LR == RPL router) o o
o o o o o o o z
o o o o o o (6LoWPAN Host)
<----------------------- RPL Instances ------------------------>
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
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
RPL-aware-leaf to Internet RPL-aware-leaf to Internet
Internet to RPL-aware-leaf Internet to RPL-aware-leaf
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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
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. A
is a fundamental precept of the IPv6 architecture as outlined in fundamental precept of the IPv6 architecture as outlined in [RFC2460]
[RFC2460] is that Extensions may not be added or removed except by is that Extensions may not be added or removed except by the sender
the sender or the receiver. or the receiver.
Note: current discussions on [I-D.ietf-6man-rfc2460bis] related to Note: current discussions on [I-D.ietf-6man-rfc2460bis] related to
extensions headers may affect some cases in this document (Ticket extensions headers may affect some cases in this document (Ticket
nro. 9) in 6man. [TO DO]. 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
skipping to change at page 8, line 13 skipping to change at page 8, line 21
can be placed. can be placed.
This also means that a Header can only be removed by an intermediate This also means that a Header can only be removed by an intermediate
router if it is placed in an encapsulating IPv6 Header, and in that router if it is placed in an encapsulating IPv6 Header, and in that
case, the whole encapsulating header must be removed - a replacement case, the whole encapsulating header must be removed - a replacement
may be added. Further, an intermediate router can only remove such may be added. Further, an intermediate router can only remove such
an outer header if that outer header has the router as the an outer header if that outer header has the router as the
destination! destination!
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 or 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
root. 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-SM) and non-Storing (RPL-NSM) 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 the tables present in this document, the term "RPL aware leaf" is
and "not-RPL aware leaf" has been shortened to "~Raf" to make the has been shortened to "Raf", and "not-RPL aware leaf" has been
table fit in available space. shortened to "~Raf" to make the table fit in available space.
The earlier examples are more complete 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 consise. is clear, while later examples are more consise.
5. Storing mode 5. Storing mode
In storing mode (fully stateful), determinate whether the destination In storing mode (fully stateful), the sender cannot determine whether
is RPL capable is not currently discernible by the sender and thus the destination is RPL-capable and thus would need an IP-in-IP
would need an IP-in-IP header. The IP-in-IP header needs to be header. The IP-in-IP header needs to be addressed on a hop-by-hop
addressed on a hop-by-hop basis so that the last 6LR can remove the basis so that the last 6LR can remove the RPI header. Additionally,
RPI header. Additionally, The sender can determine if the The sender can determine if the destination is inside the LLN by
destination is inside the LLN by looking if the destination address looking if the destination address is matched by the DIO's PIO
is matched by the DIO's PIO option. option.
The following table summarizes what headers are needed in the The following table summarizes what headers are needed in the
following scenarios, and indicates the IP-in-IP header must be following scenarios, and indicates when the IP-in-IP header must be
inserted on a hop-by-hop basis, and when it can target the inserted on a hop-by-hop basis, and when it can target the
destination node directly. There are three possible situations: hop- destination node directly. There are three possible situations: hop-
by-hop necessary (indicated by "hop"), or destination address by-hop necessary (indicated by "hop"), or destination address
possible (indicated by "dst"). In all cases hop by hop can be used. possible (indicated by "dst"). In all cases hop by hop can be used.
In cases where no IP-in-IP header is needed, the column is left In cases where no IP-in-IP header is needed, the column is left
blank. blank.
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.
+--------------+-------+-------+-----------+---------------+ +--------------+-------+-------+-----------+---------------+
| Use Case | RPI | RH3 | IP-in-IP | IP-in-IP 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 | No | No | -- | | root to Raf | Yes | No | No | -- |
skipping to change at page 9, line 50 skipping to change at page 10, line 10
messages. messages.
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.
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)
As it was mentioned In this document 6LRs, 6LBR are always full- As it was mentioned In this document 6LRs, 6LBR are always full-
fledge RPL routers, and are the RPL root node. fledge RPL routers.
The 6LN inserts the RPI header, and sends the packet to 6LR which The 6LN inserts the RPI header, and sends the packet to 6LR which
decrements the rank in RPI and sends the packet up. When the packet decrements the rank in RPI and sends the packet up. When the packet
arrives at 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 to make use of this scenario. The 6LN can know the
6LN can know the address of the 6LBR because it knows the address of address of the 6LBR because it knows the address of the root via the
the root via the DODAGID in the DIO messages. DODAGID in the DIO messages.
+-------------------+-----+------+------+ +-------------------+-----+------+------+
| Header | 6LN | 6LR | 6LBR | | Header | 6LN | 6LR | 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 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 inserts RPI header and sends the packet down,
6LR is going to increment the rank in RPI (examines instanceID for the 6LR is going to increment the rank in RPI (examines instanceID
multiple tables), the packet is processed in 6LN and RPI removed. for multiple tables), the packet is processed in 6LN and RPI removed.
No IP-in-IP 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 | -- |
skipping to change at page 15, line 21 skipping to change at page 15, line 38
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 IP-in-IP headers are necessary. The ability to remove the RPI, so no IP-in-IP headers are necessary. The ability to
do this depends upon the sending know that the destination is: a) do this depends upon the sending the 6LN to know that the destination
inside the LLN, and b) RPL capable. is: a) 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 16, line 12 skipping to change at page 16, line 32
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 IP-in-IP header. The IP- aware, adds an RPI header inside an IP-in-IP header. The IP-in-IP
in-IP header needs to be addressed on a hop-by-hop basis so that the header needs to be addressed on a hop-by-hop basis so that the last
last 6LR can remove the RPI header. 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 37 skipping to change at page 17, line 26
/ IP2,RPI,IP,ULP \ / IP2,RPI,IP,ULP \
/ | / |
/ \ / \
,---+-. | ,---+-. |
/ \ +--+----+ / \ +--+----+
( 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 3: Solution IPv6-in-IPv6 in each hop
Alternatively, if the definition of the Option Type field of RPL As we mentioned previously, packets with a Hop-by-Hop option which
Option '01' were changed so that it isn't a "discard if not are marked with option type 01 ([RFC2460] section 4.2) must be
recognized", then no IP-in-IP header would be necessary. This change discarded if received by a host or router which does not understand
is an incompatible on-the-wire change and would require some kind of that option. This means that in general, any packet that leaves the
flag day, possibly a change that is done simultaenously with an RPL domain of an LLN (or leaves the LLN entirely) is likely to be
updated 6LoRH compress. discarded if it still contains an [RFC6553] RPL Option Header known
as the RPI. For this case, if the definition of the Option Type
field of RPL Option '01' were changed so that it isn't a "discard if
not recognized", then no IP-in-IP header would be necessary. This
change is an incompatible on-the-wire change and would require some
kind of flag day, possibly a change that is done simultaenously with
an updated 6LoRH compress.
+--------+------------+------------+------------+------------+------+ +--------+------------+------------+------------+------------+------+
| Header | 6LN | 6LR | 6LR | 6LR | IPv6 | | Header | 6LN | 6LR | 6LR | 6LR | IPv6 |
| | | | (common | | | | | | | (common | | |
| | | | parent) | | | | | | | parent) | | |
+--------+------------+------------+------------+------------+------+ +--------+------------+------------+------------+------------+------+
| Insert | IP-in- | -- | -- | -- | -- | | Insert | IP-in- | -- | -- | -- | -- |
| ed hea | IP(RPI) | | | | | | ed hea | IP(RPI) | | | | |
| ders | | | | | | | ders | | | | | |
| Remove | -- | -- | -- | IP-in- | -- | | Remove | -- | -- | -- | IP-in- | -- |
skipping to change at page 17, line 39 skipping to change at page 18, line 39
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 IP-in-IP the RPI header encapsulated in IPv6-in-IPv6 header. The IP-in-IP
header could be addresses to the 6LN if the destination is known to header could be addressed to the 6LN if the destination is known to
the RPL aware, otherwise must send the packet using a hop-by-hop IP- the RPL aware, otherwise it must send the packet using a hop-by-hop
in-IP header. Similar considerations apply from section IP-in-IP header. Similar considerations apply from section
Section 5.10. Section 5.10.
+--------+------+------------+------------+------------+------------+ +--------+------+------------+------------+------------+------------+
| Header | IPv6 | 6LR | common | 6LR | 6LN | | Header | IPv6 | 6LR | common | 6LR | 6LN |
| | | | parent | | | | | | | parent | | |
| | | | (6LR) | | | | | | | (6LR) | | |
+--------+------+------------+------------+------------+------------+ +--------+------+------------+------------+------------+------------+
| Insert | -- | IP-in- | -- | -- | -- | | Insert | -- | IP-in- | -- | -- | -- |
| ed hea | | IP(RPI) | | | | | ed hea | | IP(RPI) | | | |
| ders | | | | | | | ders | | | | | |
skipping to change at page 19, line 5 skipping to change at page 20, line 5
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 IP-in-IP header. That IP-in-IP header must be it must add an IP-in-IP header. That IP-in-IP header must be
addressed on a hop-by-hop basis. addressed on a hop-by-hop basis.
+-----------+------+---------------+---------+---------------+------+ +----------+-----+-------------+--------------+--------------+------+
| Header | IPv6 | 6LR | 6LR | 6LR | IPv6 | | Header | IPv | 6LR | 6LR (common | 6LR | IPv6 |
| | src | | (common | | dst | | | 6 | | parent) | | dst |
| | | | parent) | | | | | src | | | | |
+-----------+------+---------------+---------+---------------+------+ +----------+-----+-------------+--------------+--------------+------+
| Inserted | -- | IP-in-IP(RPI) | -- | -- | -- | | Inserted | -- | IP-in- | -- | -- | -- |
| headers | | | | | | | headers | | IP(RPI) | | | |
| Removed | -- | -- | -- | IP-in-IP(RPI) | -- | | Removed | -- | -- | -- | IP-in- | -- |
| headers | | | | | | | headers | | | | IP(RPI) | |
| Re-added | -- | -- | -- | -- | -- | | Re-added | -- | IP-in- | IP-in- | IP-in- | -- |
| headers | | | | | | | headers | | IP(RPI) | IP(RPI) | IP(RPI) | |
| Modified | -- | -- | -- | -- | -- | | Modified | -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
| Untouched | -- | -- | -- | -- | -- | | Untouche | -- | -- | -- | -- | -- |
| headers | | | | | | | d | | | | | |
+-----------+------+---------------+---------+---------------+------+ | 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 | IP-in-IP | IP-in-IP dst | | Use Case | RPI | RH3 | IP-in-IP | IP-in-IP dst |
+--------------+------+------+-----------+---------------+ +--------------+------+------+-----------+---------------+
| Raf to root | Yes | No | No | -- | | Raf to root | Yes | No | No | -- |
skipping to change at page 20, line 9 skipping to change at page 21, line 9
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.
RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) RPL-aware-leaf (6LN) --> 6LR --> root (6LBR)
This situation is the same case as storing mode. This situation is the same case as storing mode.
+-------------------+-----+-----+------+ +-------------------+-----+------+------+
| Header | 6LN | 6LR | 6LBR | | Header | 6LN | 6LR | 6LBR |
+-------------------+-----+-----+------+ +-------------------+-----+------+------+
| Inserted headers | RPI | -- | -- | | Inserted headers | RPI | -- | -- |
| Removed headers | -- | -- | RPI | | Removed headers | -- | -- | RPI |
| Re-added headers | -- | -- | RPI | | Re-added headers | -- | RPI | -- |
| Modified headers | -- | -- | -- | | Modified headers | -- | -- | -- |
| Untouched headers | -- | -- | -- | | Untouched 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
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 IP-in-IP 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, the 6LBR. The destination is known to 6LBR because, the
root knows the whole topology in non-storing mode.
+-------------------+-----------------+------+----------+ +-------------------+-----------------+------+----------+
| 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 | -- | -- | -- |
+-------------------+-----------------+------+----------+ +-------------------+-----------------+------+----------+
Non Storing: Summary of the use of headers from root to RPL-aware- Non Storing: Summary of the use of headers from root to RPL-aware-
leaf leaf
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, modified in each intermediate 6LR and it is
In 6LBR the RH3 is added, and modified in 6LR where it is fully fully consumed in the last 6LR, but left there. If the RPI is left
consumed, but left there. If the RPI is left present, the IPv6 node present, the IPv6 node which does not understand it will drop it,
which does not understand it will drop it, therefore the RPI should therefore the RPI should be removed before reaching the IPv6-only
be removed before reaching the IPv6-only node. To permit removal, an node. To permit removal, an IP-in-IP header (hop-by-hop) or
IP-in-IP header (hop-by-hop) or addressed to the last 6LR is addressed to the last 6LR is necessary. Due the complete knowledge
necessary. Due the complete knowledge of the topology at the root, of the topology at the root, the 6LBR is able to address the IP-in-IP
the 6LBR is able to address the IP-in-IP header to the last 6LR. header to the last 6LR.
Omitting the RPI entirely is therefore a better solution, as no IP- Omitting the RPI entirely is therefore a better solution, as no IP-
in-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 | -- | -- | -- |
skipping to change at page 22, line 11 skipping to change at page 23, line 11
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 removed by the 6LBR.
The 6LN must therefore add the RPI inside an IP-in-IP header, The 6LN must therefore add the RPI inside an IP-in-IP header,
addressed 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 |
+-----------------+---------------+------+---------------+----------+ +-----------------+---------------+------+---------------+----------+
skipping to change at page 23, line 34 skipping to change at page 24, line 34
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 IP-in-IP header. The IP-in-IP header add an RPI header inside a new IP-in-IP header. The IP-in-IP header
will be addressed to the root. This case is identical to the will be addressed to the root. This case is identical to the
storing-mode case. storing-mode case (Section 5.7).
+-----------------+------+---------------+---------------+----------+ +-----------------+------+---------------+---------------+----------+
| Header | IPv6 | 6LR | 6LBR | Internet | | Header | IPv6 | 6LR | 6LBR | Internet |
+-----------------+------+---------------+---------------+----------+ +-----------------+------+---------------+---------------+----------+
| Inserted | -- | IP-in-IP(RPI) | -- | -- | | Inserted | -- | IP-in-IP(RPI) | -- | -- |
| headers | | | | | | headers | | | | |
| Removed headers | -- | -- | IP-in-IP(RPI) | -- | | Removed headers | -- | -- | IP-in-IP(RPI) | -- |
| Re-added | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- |
| headers | | | | | | headers | | | | |
| Modified | -- | -- | -- | -- | | Modified | -- | -- | -- | -- |
skipping to change at page 24, line 9 skipping to change at page 25, line 9
| headers | | | | | | 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 (IPv6 node)
The 6LBR must add an RH3 header inside an IP-in-IP header. The 6LBR The 6LBR must add an RH3 header inside an IP-in-IP header. The 6LBR
will know the path, and will recognize that the final node is not an 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 RPL capable node as it will have received the connectivity DAO from
the nearest 6LR. The 6LBR can therefore make the IP-in-IP header the nearest 6LR. The 6LBR can therefore make the IP-in-IP header
destination be the last 6LR. The 6LBR will zero the flow label upon destination be the last 6LR. The 6LBR will set to zero the flow
entry in order to aid compression. label upon entry in order to aid compression.
+----------+---------+-----------------------+---------------+------+ +----------+---------+-----------------------+---------------+------+
| Header | Interne | 6LBR | 6LR | IPv6 | | Header | Interne | 6LBR | 6LR | IPv6 |
| | t | | | | | | t | | | |
+----------+---------+-----------------------+---------------+------+ +----------+---------+-----------------------+---------------+------+
| Inserted | -- | IP-in-IP(RH3,opt:RPI) | -- | -- | | Inserted | -- | IP-in-IP(RH3,opt:RPI) | -- | -- |
| headers | | | | | | headers | | | | |
| Removed | -- | -- | IP-in-IP(RH3, | -- | | Removed | -- | -- | IP-in-IP(RH3, | -- |
| headers | | | RPI) | | | headers | | | RPI) | |
| Re-added | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- |
skipping to change at page 25, line 34 skipping to change at page 26, line 34
| headers | | | | | | 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 (IPv6 node)
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 IP-in-IP 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 IP- remove this RPI. The 6LBR will then insert an RH3 inside a new IP-
in-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 | IP-in-IP(RPI) | IP-in-IP(RH3, | -- | -- | | Inserted | IP-in-IP(RPI) | IP-in-IP(RH3, | -- | -- |
skipping to change at page 27, line 10 skipping to change at page 28, line 10
+------------+------+---------------+---------------+---------------+ +------------+------+---------------+---------------+---------------+
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 (IPv6 node)
This scenario is the combination of the previous two cases. This scenario is the combination of the previous two cases.
+----------+-----+-------------+--------------+--------------+------+ +----------+-----+-------------+--------------+--------------+------+
| Header | IPv | 6LR | 6LBR | 6LR | IPv6 | | Header | IPv | 6LR | 6LBR | 6LR | IPv6 |
| | 6 | | | | | | | 6 | | | | |
+----------+-----+-------------+--------------+--------------+------+ +----------+-----+-------------+--------------+--------------+------+
| Inserted | -- | IP-in- | IP-in- | -- | -- | | Inserted | -- | IP-in- | IP-in- | -- | -- |
| headers | | IP(RPI) | IP(RH3) | | | | headers | | IP(RPI) | IP(RH3) | | |
| Removed | -- | -- | IP-in- | IP-in- | -- | | Removed | -- | -- | IP-in- | IP-in- | -- |
skipping to change at page 27, line 45 skipping to change at page 28, line 45
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
IP-in-IP encapsulation, and it can never omit the IP-in-IP IP-in-IP encapsulation, and it can never omit the IP-in-IP
encapsulation. See table Table 1 encapsulation. See table Table 1
The simplest fully general stiaution for storing mode is to always The simplest fully general approach for storing mode is to always put
put in hop-by-hop IP-in-IP headers. [I-D.ietf-roll-routing-dispatch] in hop-by-hop IP-in-IP headers. [I-D.ietf-roll-routing-dispatch]
shows that this hop-by-hop IP-in-IP 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 IP-in-IP 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 IP-in-IP 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
skipping to change at page 28, line 24 skipping to change at page 29, line 24
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 IP-in-IP vs never use IP-in-IP) different situations (always do IP-in-IP vs never use IP-in-IP)
should be 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 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 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 DODAG nodes, and all traffic flows through the
node. root 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 IP-in-IP 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 IP-in-IP header. The receiving node ought to consume the hop-by-hop IP-in-IP header. The receiving node ought to consume the
IP-in-IP header, and therefore consume the RH3 as well, and then IP-in-IP header, and therefore consume the RH3 as well, and then
attempt to send the packet again. But intermediate 6LN nodes would attempt to send the packet again. But intermediate 6LN nodes would
not know how to forward the packet, so the RH3 would need to be not know how to forward the packet (because they do not save the
retained. This is a new kind of IPv6 packet processing. Therefore sate), so the RH3 would need to be retained. This is a new kind of
it may be that on the outbound leg of non-storing RPL networks, that IPv6 packet processing. Therefore it may be that on the outbound leg
hop-by-hop IP-in-IP header can NOT be used. of non-storing RPL networks, that 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 IP-in-IP header can be compressed down to {TBD} destination=6LN IP-in-IP header can be compressed down to {TBD}
bytes. bytes.
Unlike in the storing mode case, there are no need for all nodes to Unlike in the storing mode case, there is 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
for RPI, RH3 and IPv6-in-IPv6. for RPI, RH3 and IPv6-in-IPv6.
In Storing Mode, for the examples of Flow from RPL-aware-leaf to non- 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 RPL-aware-leaf and non-RPL-aware-leaf to non-RPL-aware-leaf comprise
an IP-in-IP and RPI compression headers. The type of this case is an IP-in-IP and RPI compression headers. The type of this case is
critical since IP-in-IP is encapsulating a RPI header. critical since IP-in-IP is encapsulating a RPI header.
+--+-----+---+--------------+-----------+-------------+-------------+ +--+-----+---+--------------+-----------+-------------+-------------+
|1 | 0|0 |TSE| 6LoRH Type 6 | Hop Limit | RPI - 6LoRH | LOWPAN IPHC | |1 | 0|0 |TSE| 6LoRH Type 6 | Hop Limit | RPI - 6LoRH | LOWPAN IPHC |
+--+-----+---+--------------+-----------+-------------+-------------+ +--+-----+---+--------------+-----------+-------------+-------------+
Figure 5: Critical IP-in-IP (RPI). Figure 4: Critical IP-in-IP (RPI).
9. IANA Considerations 9. IANA Considerations
There are no IANA considerations related to this document. There are no IANA considerations related to this document.
10. Security Considerations 10. Security Considerations
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, Simon comments of Robert Cragie, Simon Duquennoy, Cenk Guendogan, Peter van
Duquennoy and Peter van der Stok. der Stok, Xavier Vilajosana and Thomas Watteyne.
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, DOI 10.17487/RFC2460, (IPv6) Specification", RFC 2460, December 1998.
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 27 skipping to change at page 31, line 27
[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] [I-D.ietf-6man-rfc2460bis]
Deering, S. and R. Hinden, "Internet Protocol, Version 6 Deering, D. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", draft-ietf-6man-rfc2460bis-04 (work (IPv6) Specification", draft-ietf-6man-rfc2460bis-05 (work
in progress), March 2016. in progress), June 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-10 (work of IEEE 802.15.4", draft-ietf-6tisch-architecture-10 (work
in progress), June 2016. 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.
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