draft-ietf-roll-useofrplinfo-02.txt   draft-ietf-roll-useofrplinfo-03.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: September 22, 2016 SSW Expires: October 6, 2016 SSW
P. Thubert P. Thubert
Cisco Cisco
March 21, 2016 April 4, 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-02 draft-ietf-roll-useofrplinfo-03
Abstract Abstract
This document states different cases where RFC 6553, RFC 6554 and This document looks at different data flows through LLN networks
IPv6-in-IPv6 encapsulation is required to set the bases to help where RPL is used to establish routing. The document enumerates the
defining the compression of RPL routing information in LLN cases where RFC 6553, RFC 6554 and IPv6-in-IPv6 encapsulation is
environments. 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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Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
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time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 22, 2016. This Internet-Draft will expire on October 6, 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
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 14 skipping to change at page 2, line 15
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
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 . . . . . . . . . . . . . . . . . . 3
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 . . . . . . . 8 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 . . . . . 10
5.4. Example of Flow from not-RPL-aware-leaf to root . . . . . 10 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 . . . . . 11 5.6. Example of Flow from Internet to RPL-aware-leaf . . . . . 12
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 . . 14
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 15
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 . . . . . 21 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 . . . 24 6.8. Example of Flow from Internet to non-RPL-aware-leaf . . . 23
6.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf . . 25 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 26 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 27 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 . . . . . . . . . . . . . . . . . . . . . . . . . . 27 leaf . . . . . . . . . . . . . . . . . . . . . . . . . . 26
7. Problem statement . . . . . . . . . . . . . . . . . . . . . . 28 7. Observations about the problem . . . . . . . . . . . . . . . 27
8. 6LoRH Compression cases . . . . . . . . . . . . . . . . . . . 29 7.1. Storing mode . . . . . . . . . . . . . . . . . . . . . . 27
7.2. Non-Storing mode . . . . . . . . . . . . . . . . . . . . 28
8. 6LoRH Compression cases . . . . . . . . . . . . . . . . . . . 28
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 . . . . . . . . . . . . . . . . . . . . . . . 30 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 30
1. Introduction 1. Introduction
RPL [RFC6550] is a routing protocol for constrained networks. RFC RPL [RFC6550] is a routing protocol for constrained networks. RFC
6553 [RFC6553] defines the "RPL option", carried within the IPv6 Hop- 6553 [RFC6553] defines the "RPL option" (RPI), carried within the
by-Hop header to quickly identify inconsistencies in the routing IPv6 Hop-by-Hop header to quickly identify inconsistencies (loops) in
topology. RFC 6554 [RFC6554] defines the "RPL Source Route Header", the routing topology. RFC 6554 [RFC6554] defines the "RPL Source
an IPv6 Extension Header to deliver datagrams within a RPL routing Route Header" (RH3), an IPv6 Extension Header to deliver datagrams
domain. within a RPL routing domain, particularly in non-storing mode.
Several discussions in the ROLL/6lo/6TiSCH Mailing Lists took place These various items are referred to as RPL artifacts, and they are
focusing in the definition of how to compress RPL Information in seen on all of the data-plane traffic that occurs in RPL routed
constrained environment. ROLL Virtual Interim Meeting (02-2015) networks; they do not in general appear on the RPL control plane
concluded that there is a need to define how to use [RFC6553], traffic at all which is mostly hop-by-hop traffic (one exception
[RFC6554] and IPv6-in-IPv6 encapsulation to be able to set the being DAO messages in non-storing mode).
correct environment for compression A Routing Header Dispatch for
6LoWPAN (6LoRH) [I-D.ietf-6lo-routing-dispatch] defines a method to
compress RPL Option information and Routing Header type 3 (RFC6554)
and an efficient IP-in-IP technique. Uses cases proposed for the
[Second6TischPlugtest] involving 6loRH: When the packet travel inside
the RPL domain, the IP in IP 6LoRH is not be presented in the packet
and when the packet travel outside a RPL domain, Ip in IP 6LoRH is
present in the packet.
This document is going to be focused in data plane messages and how It has become clear from attempts to do multi-vendor
can be transmitted within the above mentioned RFCs. interoperability, and from a desire to compress as many of the above
artifacts as possible that not all implementors agree when artifacts
are necessary, or when they can be safely omitted, or removed.
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
discussion. This document should not be defining anything new, but
it may clarify what is correct and incorrect behaviour.
The related document A Routing Header Dispatch for 6LoWPAN (6LoRH)
[I-D.ietf-roll-routing-dispatch] defines a method to compress RPL
Option information and Routing Header type 3 (RFC6554) and an
efficient IP-in-IP technique. Uses cases proposed for the
[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]
3. Sample/reference topology 3. Sample/reference topology
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 | |DODAG | node:01
+---------+Root +----------+ +---------+Root +----------+
| |6LBR | | | |6LBR | |
| +----+--+ | | +----+--+ |
| | | | | |
| | | | | |
... ... ... ... ... ...
| | | | | |
+-----+-+ +--+---+ +--+---+ +-----+-+ +--+---+ +--+---+
|6LR | | | | | |6LR | | | | |
+-----+ | | | | | +-----+ | | | | |
| | | | | | +------+ | | 11 | | 12 | | 13 +------+
| +-----+-+ +-+----+ +-+----+ | | +-----+-+ +-+----+ +-+----+ |
| | | | | | | | | |
| | | | | | | | | |
| | | | | | 21 | 22 | 23 | 24 | 25
+-+---+ +-+---+ +--+--+ +- --+ +---+-+ +-+---+ +-+---+ +--+--+ +- --+ +---+-+
|Leaf | | | | | | | | | |Leaf | | | | | |Leaf| |Leaf |
|6LN | | | | | | | | | | 6LR | | | | | | 6LN| | 6LR |
+-----+ +-----+ +-----+ +----+ +-----+ +-----+ +-----+ +-----+ +----+ +-----+
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
referenced in subsequent sections. The leaf marked 6LN (24) is a
device which does not speak RPL at all, but uses Router-
Advertisements, 6LowPAN DAR/DAC and efficient-ND only to participate
in the network.
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 Architecture is a Backbone Link that
federates multiple LLNs (mesh) as a single IPv6 Multi-Link Subnet. federates multiple LLNs (mesh) as a single IPv6 Multi-Link Subnet.
Each LLN in the subnet is anchored at a Backbone Router (6BBR). The Each LLN in the subnet is anchored at a Backbone Router (6BBR). The
Backbone Routers interconnect the LLNs over the Backbone Link and Backbone Routers interconnect the LLNs over the Backbone Link and
skipping to change at page 6, line 36 skipping to change at page 6, line 38
<----------------------- RPL Instance ------------------------> <----------------------- RPL Instance ------------------------>
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:
-Flow from RPL-aware-leaf to root RPL-aware-leaf to root
-Flow from root to RPL-aware-leaf root to RPL-aware-leaf
-Flow from not-RPL-aware-leaf to root not-RPL-aware-leaf to root
-Flow from root to not-RPL-aware-leaf root to not-RPL-aware-leaf
-Flow from RPL-aware-leaf to Internet RPL-aware-leaf to Internet
-Flow from Internet to RPL-aware-leaf Internet to RPL-aware-leaf
not-RPL-aware-leaf to Internet
-Flow from not-RPL-aware-leaf to Internet Internet to not-RPL-aware-leaf
-Flow from Internet to not-RPL-aware-leaf RPL-aware-leaf to RPL-aware-leaf
-Flow from RPL-aware-leaf to RPL-aware-leaf
-Flow from RPL-aware-leaf to not-RPL-aware-leaf RPL-aware-leaf to not-RPL-aware-leaf
-Flow from not-RPL-aware-leaf to RPL-aware-leaf not-RPL-aware-leaf to RPL-aware-leaf
-Flow from 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. removed on the fly inside an IPv6 packet that is being routed. This
is a fundamental precept of the IPv6 architecture as outlined in
[RFC2460] is that Extensions may not be added or removed except by
the sender or the receiver.
- This means that an intermediate router that needs to add a header A second important thing is that packets with a Hop-by-Hop option
must encapsulate the packet in an outer IP header where the new which are marked with option type 01 ([RFC2460] section 4.2) must be
header can be placed. discarded if received by a host or router which does not understand
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
discarded if it still contains an [RFC6553] RPL Option Header known
as the RPI.
- This also means that a Header can only be removed by an The combination of these two rules means that the arrangement of
intermediate router if it is placed in an encapsulating IPv6 Header, headers must be done so that traffic intended to exit the RPL domain
and in that case, the whole encapsulating header must be removed - a can have the RPI option removed prior to leaving the RPL domain.
replacement may be added.
This document recognizes that some headers such as a Routing Header An intermediate router that needs to add a header must encapsulate
or a Hop-by-Hop header may be modified by routers on the path of the the packet in an (additional) outer IP header where the new header
packet without the need to add to remove an encapsulating header. can be placed.
The RPL RH and the RPL option are mutable but recoverable . 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
case, the whole encapsulating header must be removed - a replacement
may be added. Further, an intermediate router can only remove such
an outer header if that outer header has the router as the
destination!
RPI should be present in every single RPL data packet. There is an Both RPI and RH3 headers may be modified by routers on the path of
exception in non-storing mode, when a packet is going down from the the packet without the need to add to remove an encapsulating header.
route: the entire route is written, so there are no loops of Both headers were designed with this modification in mind, and both
confusion about which table to use (purpose of instanceID). 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
it may not secure all the values in those headers.
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
route. In a downward non-storing mode, the entire route is written,
so there can be no loops by construction, nor any confusion about
which forwarding table to use. There may be cases (such as in
6tisch) where the instanceID may still be needed to pick an
appropriate priority or channel at each hop.
The applicability for storing (RPL-SN) and non-Storing (RPL-NSN) The applicability for storing (RPL-SN) and non-Storing (RPL-NSN)
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",
| Use Case | RPL- | RPL- | RPL-SN | RPL- | RPL- | RPL-NSN | and "not-RPL aware leaf" has been shortened to "~Raf" to make the
| | SN | SN | IP-in- | NSN | NSN | IP-in- | table fit in available space.
| | RPI | RH3 | IP | RPI | RH3 | IP |
| | (RFC | (RFC | | | | |
| | 6553 | 6554 | | | | |
| | ) | ) | | | | |
+---------------+------+------+---------+--------+--------+---------+
| RPL-aware- | Yes | No | No | Yes | No | No |
| leaf to root | | | | | | |
| root to RPL- | Yes | No | No | Yes | Yes | No |
| aware-leaf | | | | | | |
| not-RPL- | Yes | No | Yes | Yes | No | Yes |
| aware-leaf to | | | | | | |
| root | | | | | | |
| root to not- | Yes | No | Yes | Yes | Yes | Yes |
| RPL-aware- | | | | | | |
| leaf | | | | | | |
| RPL-aware- | Yes | No | Yes | Yes | No | Yes |
| leaf to | | | | | | |
| Internet | | | | | | |
| Internet to | Yes | No | Yes | Yes | Yes | Yes |
| RPL-aware- | | | | | | |
| leaf | | | | | | |
| not-RPL- | Yes | No | Yes | Yes | No | Yes |
| aware-leaf to | | | | | | |
| Internet | | | | | | |
| Internet to | Yes | No | Yes | Yes | Yes | Yes |
| not-RPL- | | | | | | |
| aware-leaf | | | | | | |
| RPL-aware- | Yes | No | No | Yes | Yes | Yes |
| leaf to RPL- | | | | | | |
| aware-leaf | | | | | | |
| RPL-aware- | Yes | No | Yes | Yes | Yes | Yes |
| leaf to not- | | | | | | |
| RPL-aware- | | | | | | |
| leaf | | | | | | |
| not-RPL- | Yes | No | Yes | Yes | Yes | Yes |
| aware-leaf to | | | | | | |
| RPL-aware- | | | | | | |
| leaf | | | | | | |
| not-RPL- | Yes | No | Yes | Yes | Yes | Yes |
| aware-leaf to | | | | | | |
| not-RPL- | | | | | | |
| aware-leaf | | | | | | |
+---------------+------+------+---------+--------+--------+---------+
Table 1: Posibility to transmit in Storing or Non-Storing mode: RPI, The earlier examples are more complete to make sure that the process
RH3, IP-in-IP encapsulation is clear, while later examples are more consise.
5. Storing mode 5. Storing mode
This table summarizes what headers are needed in the following
scenarios, and indicates the IPIP header must be inserted on a hop-
by-hop basis, and when it can target the destination node directly.
There are three possible situations: hop-by-hop necessary (indicated
by "hop"), or destination address possible (indicated by "dst"). In
all cases hop by hop can be used. In cases where no IPIP header is
needed, the column is left blank.
+---------------+--------------+--------------+----------+----------+
| Use Case | RPI (RFC | RH3 (RFC | IP-in-IP | IPIP dst |
| | 6553) | 6554) | | |
+---------------+--------------+--------------+----------+----------+
| 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 | Yes | No | Yes | root |
| Internet | | | | |
| Internet to | Yes | No | Yes | raf |
| Raf | | | | |
| ~Raf to | Yes | No | Yes | root |
| Internet | | | | |
| Internet to | Yes | No | Yes | hop |
| ~Raf | | | | |
| 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
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 As states 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
(In inconsistency a leaf node generates DIO with infinite rank, to from upstream. (When the inconsistency in routing occurs, a leaf
fix it). It may issue DAO and DIS messages though it generally node will generate a DIO with an infinite rank, to fix it). It may
ignores DAO and DIS messages. issue DAO and DIS messages though it generally ignores DAO and DIS
messages.
In storing mode is suitable the use of RFC 6553 to send RPL In storing mode, it is suitable to use RFC 6553 (RPI) to send RPL
Information through HBH field checking the routing table to find out Information instanceID and rank information.
where to send the message.
In this case the flow comprises: In this case the flow comprises:
RPL-aware-leaf (6LN) --> 6LR --> 6LR,... --> root (6LBR) Note: In RPL-aware-leaf (6LN) --> 6LR --> 6LR,... --> root (6LBR)
this document 6LRs, 6LBR are always full-fledge RPL routers
Note: In this document 6LRs, 6LBR are always full-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 send the packet to 6LR which
decrement the rank in RPI and send the packet up. When the packet decrement the rank in RPI and send the packet up. When the packet
arrives to 6LBR, the RPI is removed and the packet is processed. arrives to 6LBR, the RPI is removed and the packet is processed.
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
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
the root via the 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 | -- | -- | -- |
+-------------------+-----+------+------+ +-------------------+-----+------+------+
skipping to change at page 9, line 40 skipping to change at page 10, line 33
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.
+-------------------+------+-------+------+ +-------------------+------+-------+------+
| 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 | -- | -- | -- |
+-------------------+------+-------+------+ +-------------------+------+-------+------+
skipping to change at page 10, line 10 skipping to change at page 11, line 4
| 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 It includes IPv6-in-IPv6 encapsulation to transmit information not
related with the RPL domain. In the 6LBR the RPI header is inserted 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 into an IPv6-in-IPv6 header addressed to the last 6LR, which removes
the header before pass the packet to the IPv6 node. the header before pass the packet to the IPv6 node.
+-------------------+-------------------+-------------------+------+ The question in this scenario is how the root knows how to address
| Header | 6LBR | 6LR | IPv6 | 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
| Inserted headers | IPv6-in-IPv6(RPI) | -- | -- | RPL aware node. Since the root can not know in a storing network
| Removed headers | -- | IPv6-in-IPv6(RPI) | -- | where the last RPL aware node is, the IPv6-in-IPv6 header must added
| Re-added headers | -- | -- | -- | hop-by-hop along the path from root to leaf.
| Modified headers | -- | -- | -- |
| Untouched headers | -- | -- | -- | 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
this possibility.
+-------------------+-----------+-----------+------+
| Header | 6LBR | 6LR | IPv6 |
+-------------------+-----------+-----------+------+
| Inserted headers | IPIP(RPI) | -- | -- |
| Removed headers | -- | IPIP(RPI) | -- |
| Re-added headers | -- | -- | -- |
| Modified 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. This router insert When the packet arrives from IPv6 node to 6LR, the 6LR will insert an
the RPI encapsuladed in a IPv6-in-IPv6 header addressed to the root. RPI header, encapsuladed in a IPv6-in-IPv6 header. The IPv6-in-IPv6
The root removes the header and process the packet header can be addressed to the next hop, or to the root. The root
removes the header and process the packet.
+-------------------+------+--------------------+-------------------+ +-------------------+------+------------+-----------+
| Header | IPv6 | 6LR | 6LBR | | Header | IPv6 | 6LR | 6LBR |
+-------------------+------+--------------------+-------------------+ +-------------------+------+------------+-----------+
| Inserted headers | -- | IPv6-in-IPv6(RPI) | -- | | Inserted headers | -- | IPIP(RPI) | -- |
| Removed headers | -- | -- | IPv6-in-IPv6(RPI) | | Removed headers | -- | -- | IPIP(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. The RPL information from RFC 6553 should not go out to Internet as it
router should take this information out before send the packet to will cause the packet to be discarded at the first non-RPI aware
Internet. The HBH Option is going to be analyzed in each node to the router. The 6LBR must be able to take this information out before
root. sending the packet upwards to the Internet. This requires the RPI
header be placed in an IPIP 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
6LN insert RPI in a IPv6-in-IPv6 in a outer header, and send the The 6LN will insert the RPI in a IPv6-in-IPv6 in a outer header,
packet to 6LR, which modified the rank in the RPI. When the packet which may be addressed to the 6LBR (root), or alternatively, it could
arrives to 6LBR, the RPI is removed. be addressed hop-by-hop.
+----------+-------------------+-----+-------------------+----------+ +-------------------+-----------+------+-----------+----------+
| Header | 6LN | 6LR | 6LBR | Internet | | Header | 6LN | 6LR | 6LBR | Internet |
+----------+-------------------+-----+-------------------+----------+ +-------------------+-----------+------+-----------+----------+
| Inserted | IPv6-in-IPv6(RPI) | -- | -- | -- | | Inserted headers | IPIP(RPI) | -- | -- | -- |
| headers | | | | | | Removed headers | -- | -- | IPIP(RPI) | -- |
| Removed | -- | -- | IPv6-in-IPv6(RPI) | -- | | Re-added headers | -- | -- | -- | -- |
| headers | | | | | | Modified headers | -- | RPI | -- | -- |
| Re-added | -- | -- | -- | -- | | Untouched headers | -- | -- | -- | -- |
| headers | | | | | +-------------------+-----------+------+-----------+----------+
| Modified | -- | RPI | -- | -- |
| headers | | | | |
| Untouche | -- | -- | -- | -- |
| d | | | | |
| 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 send 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 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 | -- | IPv6-in-IPv6(RPI) | -- | -- | | Inserted headers | -- | IPIP(RPI) | -- | -- |
| headers | | | | | | Removed headers | -- | -- | -- | IPIP(RPI) |
| Removed | -- | -- | -- | IPv6-in-IPv6(RPI) | | Re-added headers | -- | -- | -- | -- |
| headers | | | | | | Modified headers | -- | -- | RPI | -- |
| Re-added | -- | -- | -- | -- | | Untouched headers | -- | -- | -- | -- |
| headers | | | | | +-------------------+----------+------------+------+------------+
| Modified | -- | -- | RPI | -- |
| headers | | | | |
| Untouche | -- | -- | -- | -- |
| d | | | | |
| 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) = IPv6 node --> 6LR --> root (6LBR) --> not-RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) --> Internet
Internet
In the IPv6 node the flow label is assumed to be zero, the packet is The 6LR node will add an IPIP(RPI) header addressed either to the
transmited to 6LR which encapsule the RPI header in an outer IPv6-in- root, or hop-by-hop such that the root can remove the RPI header
IPv6 header and send to 6LBR, which removes this header and send the before passing upwards.
packet to Internet and might set the flow label field.
+----------+-----+-------------------+-------------------+----------+ The originating node will ideally leave the IPv6 flow label as zero
| Header | IPv | 6LR | 6LBR | Internet | so that it can be better compressed through the LLN, and the 6LBR
| | 6 | | | | will set the flow label to a non-zero value when sending to the
+----------+-----+-------------------+-------------------+----------+ Internet.
| Inserted | -- | IPv6-in-IPv6(RPI) | -- | -- |
| headers | | | | | +-------------------+------+------------+------------+----------+
| Removed | -- | -- | IPv6-in-IPv6(RPI) | -- | | Header | 6LN | 6LR | 6LBR | Internet |
| headers | | | | | +-------------------+------+------------+------------+----------+
| Re-added | -- | -- | -- | -- | | Inserted headers | -- | IPIP(RPI) | -- | -- |
| headers | | | | | | Removed headers | -- | -- | IPIP(RPI) | -- |
| Modified | -- | -- | -- | -- | | Re-added headers | -- | -- | -- | -- |
| headers | | | | | | Modified headers | -- | -- | -- | -- |
| Untouche | -- | -- | -- | -- | | Untouched 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
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)
6LBR get the packet from Internet and add a RPI header encapsulated The 6LBR will have to add an RPI header within an IPIP header. The
in a IPv6-in-IPv6 header addressed to 6LR and send the packet down. IPIP will need to be addressed hop-by-hop along the path as in
The flow label is set to zero on inner IP. The last 6LR removes the storing mode, the 6LBR has no idea if the 6LN is RPL aware or not,
RPI header. The IPv6 node might set the flow label since may arrive nor what the closest attached 6LR node is.
with zero value. The RPI should be in IP-in-IP header.
+----------+---------+-------------------+-------------------+------+ The 6LBR MAY set the flow label on the inner IPIP header to zero in
| Header | Interne | 6LBR | 6LR | IPv6 | order to aid in compression, as the packet will not emerge again from
| | t | | | | the LLN.
+----------+---------+-------------------+-------------------+------+
| Inserted | -- | IPv6-in-IPv6(RPI) | -- | -- | +-------------------+----------+------------+------------+------+
| headers | | | | | | Header | Internet | 6LBR | 6LR | IPv6 |
| Removed | -- | -- | IPv6-in-IPv6(RPI) | -- | +-------------------+----------+------------+------------+------+
| headers | | | | | | Inserted headers | -- | IPIP(RPI) | -- | -- |
| Re-added | -- | -- | -- | -- | | Removed headers | -- | -- | IPIP(RPI) | -- |
| headers | | | | | | Re-added headers | -- | -- | -- | -- |
| Modified | -- | -- | -- | -- | | Modified headers | -- | -- | -- | -- |
| headers | | | | | | Untouched headers | -- | -- | -- | -- |
| Untouche | -- | -- | -- | -- | +-------------------+----------+------------+------------+------+
| d | | | | |
| 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 P2P optimization for both In [RFC6550] RPL allows a simple one-hop optimization for both
storing and non-storing networks. A node may send a P2P packet storing and non-storing networks. A node may send a packet destined
destined to a one-hop neighbor directly to that node. Section 9 in to a one-hop neighbor directly to that node. Section 9 in [RFC6550].
[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
remove the RPI, so no IPIP headers are necessary. The ability to do
this depends upon the sending know that the destination is: a) inside
the LLN, and b) RPL capable.
The sender can determine if the destination is inside the LLN by
looking if the destination address is matched by the DIO's PIO
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
capable and so can process the RPI header correctly.
The other check, that the destination is RPL capable is not currently
discernible by the sender. This information is necessary to
distinguish this test case from Section 5.10.
+-------------+-------+---------------+---------------+-----+-------+ +-------------+-------+---------------+---------------+-----+-------+
| Header | 6LN | 6LR | 6LR (common | 6LR | 6LN | | Header | 6LN | 6LR | 6LR (common | 6LR | 6LN |
| | src | | parent) | | dst | | | src | | parent) | | dst |
+-------------+-------+---------------+---------------+-----+-------+ +-------------+-------+---------------+---------------+-----+-------+
| Inserted | RPI | -- | -- | -- | -- | | Inserted | RPI | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
| Removed | -- | -- | -- | -- | RPI | | Removed | -- | -- | -- | -- | RPI |
| headers | | | | | | | headers | | | | | |
| Re-added | -- | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
skipping to change at page 15, line 31 skipping to change at page 15, line 41
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
Somehow, the sender has to know that the receiver is not RPL aware, The sender, being aware out of band, that the receiver is not RPL
and needs to know 6LR, and not even the root knows where the 6LR is aware, sends adds an RPI header inside an IPIP header. The IPIP
(in storing mode). header needs to be addressed on a hop-by-hop basis so that the last
6LR can remove the RPI header.
This case FAILS.
Possible solutions, which are not mutually exclusive:
1 - An IPv6-in-IPv6 header can be used on a hop-by-hop basis, using
either link-local addresses, or even IPv6 Global Unicast Addresses,
but each IPv6-in-IPv6 header needs to be added/removed at each hop.
,---. ,---.
/ \ / \
( 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 28 skipping to change at page 16, line 28
/ \ / \
,---+-. | ,---+-. |
/ \ +--+----+ / \ +--+----+
( 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
2- If the definition of the Option Type field of RPL Option '01' were Alternatively, if the definition of the Option Type field of RPL
changed so that it isn't a "discard if not recognized". This change Option '01' were changed so that it isn't a "discard if not
is an incompatible on-the-wire change. However, this change could recognized", then no IPIP header would be necessary. This change is
perhaps be done with the updated 6LoRH compression work, as that is an incompatible on-the-wire change and would require some kind of
also an incompatible on-the-wire change for which we presently have flag day, possibly a change that is done simultaenously with an
no way to signal. updated 6LoRH compress.
+-------+------------+------------+-------------+-------------+-----+ +-----------+-----------+-----------+------------+-----------+------+
| Heade | 6LN | 6LR | 6LR (common | 6LR | IPv | | Header | 6LN | 6LR | 6LR | 6LR | IPv6 |
| r | | | parent) | | 6 | | | | | (common | | |
+-------+------------+------------+-------------+-------------+-----+ | | | | parent) | | |
| Inser | IPv6-in- | -- | -- | -- | -- | +-----------+-----------+-----------+------------+-----------+------+
| ted h | IPv6(RPI) | | | | | | Inserted | IPIP(RPI) | -- | -- | -- | -- |
| eader | | | | | | | headers | | | | | |
| s | | | | | | | Removed | -- | -- | -- | IPIP(RPI) | -- |
| Remov | -- | -- | -- | IPv6-in- | -- | | headers | | | | | |
| ed he | | | | IPv6(RPI) | | | Re-added | -- | -- | -- | -- | -- |
| aders | | | | | | | headers | | | | | |
| Re- | -- | -- | -- | -- | -- | | Modified | -- | IPIP(RPI) | IPIP(RPI) | -- | -- |
| added | | | | | | | headers | | | | | |
| heade | | | | | | | Untouched | -- | -- | -- | -- | -- |
| rs | | | | | | | headers | | | | | |
| Modif | -- | IPv6-in- | IPv6-in- | -- | -- | +-----------+-----------+-----------+------------+-----------+------+
| ied h | | IPv6(RPI) | IPv6(RPI) | | |
| eader | | | | | |
| s | | | | | |
| Untou | -- | -- | -- | -- | -- |
| ched | | | | | |
| heade | | | | | |
| rs | | | | | |
+-------+------------+------------+-------------+-------------+-----+
Storing: Summary of the use of headers from 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 that get the packet from IPv6 node, insert the RPI header The 6LR receives the packet from the the IPv6 node and inserts and
encapsulated in IPv6-in-IPv6 header with destination to 6LN, the the RPI header encapsulated in IPv6-in-IPv6 header. The IPIP header
common parent change the direction of RPI and finally it is removed could be addresses to the 6LN if the destination is known to the RPL
by 6LN. aware, otherwise must send the packet using a hop-by-hop IPIP header.
Similar considerations apply from section Section 5.10.
+-------+----+------------+-------------+-------------+-------------+ +-----------+------+-----------+------------+-----------+-----------+
| Heade | IP | 6LR | common | 6LR | 6LN | | Header | IPv6 | 6LR | common | 6LR | 6LN |
| r | v6 | | parent | | | | | | | parent | | |
| | | | (6LR) | | | | | | | (6LR) | | |
+-------+----+------------+-------------+-------------+-------------+ +-----------+------+-----------+------------+-----------+-----------+
| Inser | -- | IPv6-in- | -- | -- | -- | | Inserted | -- | IPIP(RPI) | -- | -- | -- |
| ted h | | IPv6(RPI) | | | | | headers | | | | | |
| eader | | | | | | | Removed | -- | -- | -- | -- | IPIP(RPI) |
| s | | | | | | | headers | | | | | |
| Remov | -- | -- | -- | -- | IPv6-in- | | Re-added | -- | -- | -- | -- | -- |
| ed he | | | | | IPv6(RPI) | | headers | | | | | |
| aders | | | | | | | Modified | -- | -- | IPIP(RPI) | IPIP(RPI) | -- |
| Re- | -- | -- | -- | -- | -- | | headers | | | | | |
| added | | | | | | | Untouched | -- | -- | -- | -- | -- |
| heade | | | | | | | headers | | | | | |
| rs | | | | | | +-----------+------+-----------+------------+-----------+-----------+
| Modif | -- | -- | IPv6-in- | IPv6-in- | -- |
| ied h | | | IPv6(RPI) | IPv6(RPI) | |
| eader | | | | | |
| s | | | | | |
| Untou | -- | -- | -- | -- | -- |
| ched | | | | | |
| heade | | | | | |
| rs | | | | | |
+-------+----+------------+-------------+-------------+-------------+
Storing: Summary of the use of headers from not-RPL-aware-leaf to 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)
The problem to solve is how to indicate where to send the packet when This flow combines the problems of the two previous sections. There
get into LLN. One approach is that the 6LBR should know in which 6LR is no choice at the first 6LR: it must insert an RPI, and to do that
the IPv6 node is attached. The RPI information is encapsulated in a it must add an IPIP header. That IPIP header must be addressed on a
IPv6-in-IPv6 header, each IPv6-in-IPv6 header needs to be added/ hop-by-hop basis.
removed at each hop..
+---------+-----+----------------+---------+-----------------+------+ +-------------+--------+-----------+-----------+-----------+--------+
| Header | IPv | 6LR | 6LR | 6LR | IPv6 | | Header | IPv6 | 6LR | 6LR | 6LR | IPv6 |
| | 6 | | (common | | dst | | | src | | (common | | dst |
| | src | | parent) | | | | | | | parent) | | |
+---------+-----+----------------+---------+-----------------+------+ +-------------+--------+-----------+-----------+-----------+--------+
| Inserte | -- | IPv6-in- | -- | -- | -- | | Inserted | -- | IPIP(RPI) | -- | -- | -- |
| d | | IPv6(RPI) | | | | | headers | | | | | |
| headers | | | | | | | Removed | -- | -- | -- | IPIP(RPI) | -- |
| Removed | -- | -- | -- | IPv6-in- | -- | | headers | | | | | |
| headers | | | | IPv6(RPI) | | | Re-added | -- | -- | -- | -- | -- |
| Re- | -- | -- | -- | -- | -- | | headers | | | | | |
| added | | | | | | | Modified | -- | -- | -- | -- | -- |
| headers | | | | | | | headers | | | | | |
| Modifie | -- | -- | -- | -- | -- | | Untouched | -- | -- | -- | -- | -- |
| d | | | | | | | headers | | | | | |
| headers | | | | | | +-------------+--------+-----------+-----------+-----------+--------+
| Untouch | -- | -- | -- | -- | -- |
| ed | | | | | |
| 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
6.1. Example of Flow from RPL-aware-leaf to root +------------------+------+------+-------+-----------+
| Use Case | RPI | RH3 | IPIP | IPIP dst |
+------------------+------+------+-------+-----------+
| Raf to root | Yes | No | No | -- |
| root to Raf | Yes | Yes | No | -- |
| root to ~Raf | No | Yes | Yes | -- |
| ~Raf to root | Yes | No | Yes | root |
| Raf to Internet | Yes | No | Yes | root |
| Internet to Raf | opt | Yes | Yes | dst |
| ~Raf to Internet | Yes | No | Yes | root |
| Internet to ~Raf | opt | Yes | Yes | 6LR |
| Raf to Raf | Yes | Yes | Yes | root/dst |
| Raf to ~Raf | Yes | Yes | Yes | root/6LN |
| ~Raf to Raf | Yes | Yes | Yes | root/6LN |
| ~Raf to ~Raf | Yes | Yes | Yes | root/6LN |
+------------------+------+------+-------+-----------+
In non-storing mode the leaf node uses Hop-By-Hop option (RFC 6553) Table 2: Headers needed in Non-Storing mode: RPI, RH3, IP-in-IP
to indicate the routing information to send messages to the DODAG encapsulation
root, this message is going to be analyzed in each node until arrive
the DODAG root.
In this case not need to use IPv6-in-IPv6 because no header is not 6.1. Example of Flow from RPL-aware-leaf to root
going to be removed, neither RH3, the flow comprises:
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
loops.
RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) RPL-aware-leaf (6LN) --> 6LR --> root (6LBR)
This case 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 | -- | -- | -- | | Re-added headers | -- | -- | RPI |
| Modified headers | -- | RPI | -- | | 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)
6LBR might instert RPI header, and the rute is indicated in RH3. 6LR The 6LBR will insert an RH3, and may optionally insert an RPI header.
updated RH3 and 6LN remove these headers. No IPIP header is necessary as the traffic originates with an RPL
aware node.
+-------------------+----------------------+------+----------+ +-------------------+-----------------+------+----------+
| Header | 6LBR | 6LR | 6LN | | Header | 6LBR | 6LR | 6LN |
+-------------------+----------------------+------+----------+ +-------------------+-----------------+------+----------+
| Inserted headers | (optional: 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, and modified in 6LR where is fully In 6LBR the RH3 is added, and modified in 6LR where it is fully
consumed, but left there. If the RPI is present, the IPv6 node which consumed, but left there. If the RPI is left present, the IPv6 node
does not understand it will drop it. To avoid it the RPI should be which does not understand it will drop it, therefore the RPI should
removed before reach IPv6 node or it is recommended that RPI be be removed before reaching the IPv6-only node. To permit removal, an
omitted. An IPv6-in-IPv6 header should be necessary in this case. IPIP header (hop-by-hop) or addressed to the last 6LR is necessary.
The DAO from 6LR about IPv6 could say if that the final IPv6 is not Due the complete knowledge of the topology at the root, the 6LBR is
RPL (RPI) capable. able to address the IPIP header to the last 6LR.
Omitting the RPI entirely is therefore a better solution, as no IPIP
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 | -- | -- | -- |
+-------------------+------+-----+------+ +-------------------+------+-----+------+
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 encapsulated in the first 6LR, and is not In this case the RPI is added by the first 6LR, encapsulated in an
modified in the followings 6LRs. IPIP header, and is not modified in the followings 6LRs. The RPI and
entire packet is consumed by the root.
+-------------+------+-------------------+------+-------------------+ +-------------------+------+------------+------+------------+
| Header | IPv6 | 6LR1 | 6LR2 | 6LBR | | Header | IPv6 | 6LR1 | 6LR2 | 6LBR |
+-------------+------+-------------------+------+-------------------+ +-------------------+------+------------+------+------------+
| Inserted | -- | IPv6-in-IPv6(RPI) | -- | -- | | Inserted headers | -- | IPIP(RPI) | -- | -- |
| headers | | | | | | Removed headers | -- | -- | -- | IPIP(RPI) |
| Removed | -- | -- | -- | IPv6-in-IPv6(RPI) | | Re-added headers | -- | -- | -- | -- |
| headers | | | | | | Modified headers | -- | -- | -- | -- |
| Re-added | -- | -- | -- | -- | | Untouched headers | -- | IPIP(RPI) | -- | -- |
| headers | | | | | +-------------------+------+------------+------+------------+
| Modified | -- | -- | -- | -- |
| headers | | | | |
| Untouched | -- | IPv6-in-IPv6(RPI) | -- | -- |
| 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
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 network is awareness of what is external This case requires that the RPI be added, but remoted by the 6LBR.
to the LLN. Internet node never sees RPI or IPv6-in-IPv6 header. In The 6LN must therefore add the RPI inside an IPIP header, addressed
the 6LBR the flow label is computed if it is zero. RPI remains to the root. This case is identical to storing-mode case.
unmodified.
+----------+-------------------+-----+-------------------+----------+ The IPv6 flow label should be set to zero to aid in compression, and
| Header | 6LN | 6LR | 6LBR | Internet | the 6LBR will set it to a non-zero value when sending towards the
+----------+-------------------+-----+-------------------+----------+ Internet.
| Inserted | IPV6-in-IPv6(RPI) | -- | -- | -- |
| headers | | | | | +-------------------+-----------+------+------------+----------+
| Removed | -- | -- | IPV6-in-IPv6(RPI) | -- | | Header | 6LN | 6LR | 6LBR | Internet |
| headers | | | | | +-------------------+-----------+------+------------+----------+
| Re-added | -- | -- | -- | -- | | Inserted headers | IPIP(RPI) | -- | -- | -- |
| headers | | | | | | Removed headers | -- | -- | IPIP(RPI) | -- |
| Modified | -- | -- | -- | -- | | Re-added headers | -- | -- | -- | -- |
| headers | | | | | | Modified headers | -- | -- | -- | -- |
| Untouche | -- | RPI | -- | -- | | Untouched headers | -- | RPI | -- | -- |
| d | | | | | +-------------------+-----------+------+------------+----------+
| 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)
If the last RH3 entry is the 6LR, then the IPv6-in-IPv6 will be The 6LBR must add an RH3 header. As the 6LBR will know the path and
removed there, if the last entry is the 6LN, then the RH3 will go all address of the target not, it can address the IPIP header to that
the way to the leaf. In 6LBR the flow label should be set to zero. node. The 6LBR will zero the flow label upon entry in order to aid
compression.
+---------+--------+-------------------------+----------------+-----+ The RPI may be added or not.
| Header | Intern | 6LBR | 6LR | 6LN |
| | et | | | | +----------------+----------+--------------------+------------+-----+
+---------+--------+-------------------------+----------------+-----+ | Header | Internet | 6LBR | 6LR | 6LN |
| Inserte | -- | IPv6-in- | -- | -- | +----------------+----------+--------------------+------------+-----+
| d | | IPv6(RH3,optional:RPI) | | | | Inserted | -- | IPIP(RH3,opt:RPI) | -- | -- |
| headers | | | | | | headers | | | | |
| Removed | -- | -- | IPv6-in-IPv6 | -- | | Removed | -- | -- | IPIP(RH3) | -- |
| headers | | | can be removed | | | headers | | | | |
| | | | if RH3 | | | Re-added | -- | -- | -- | -- |
| | | | consumed | | | headers | | | | |
| Re- | -- | -- | -- | -- | | Modified | -- | -- | IPIP(RH3) | -- |
| added | | | | | | headers | | | | |
| headers | | | | | | Untouched | -- | -- | -- | -- |
| Modifie | -- | -- | IPv6-in- | -- | | headers | | | | |
| d | | | IPv6(RH3) | | +----------------+----------+--------------------+------------+-----+
| headers | | | | |
| Untouch | -- | -- | -- | -- |
| ed | | | | |
| 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. no RPL headers are added in the IPv6 node, since it is ignorant node. As RPL headers are added in the IPv6 node, the first 6LN will
of RPL. Internet node does not see special headers. In 6LBR the add an RPI header inside a new IPIP header. The IPIP header will be
flow label is computed if it is zero. addressed to the root. This case is identical to the storing-mode
case.
+----------+-----+-------------------+-------------------+----------+ +-------------------+------+-----------+------------+----------+
| Header | IPv | 6LR | 6LBR | Internet | | Header | IPv6 | 6LR | 6LBR | Internet |
| | 6 | | | | +-------------------+------+-----------+------------+----------+
+----------+-----+-------------------+-------------------+----------+ | Inserted headers | -- | IPIP(RPI) | -- | -- |
| Inserted | -- | IPv6-in-IPv6(RPI) | -- | -- | | Removed headers | -- | -- | IPIP(RPI) | -- |
| headers | | | | | | Re-added headers | -- | -- | -- | -- |
| Removed | -- | -- | IPv6-in-IPv6(RPI) | -- | | Modified headers | -- | -- | -- | -- |
| headers | | | | | | Untouched headers | -- | -- | -- | -- |
| Re-added | -- | -- | -- | -- | +-------------------+------+-----------+------------+----------+
| headers | | | | |
| Modified | -- | -- | -- | -- |
| 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
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.
In this case the flow label in 6LBR should be set zero in 6LBR, where +--------------+----------+-------------------+--------------+------+
RH3 is inserted and optionally RHI. RH3 must end at 6LR. | Header | Internet | 6LBR | 6LR | IPv6 |
+--------------+----------+-------------------+--------------+------+
In Non-Storing mode, root knows that the non-RPL-aware-leaf is | Inserted | -- | IPIP(RH3,opt:RPI) | -- | -- |
attached to the parent 6LR, and builds RH3 with IPv6-in-IPv6 with | headers | | | | |
this 6LR as destination. | Removed | -- | -- | IPIP(RH3, | -- |
| headers | | | RPI) | |
+---------+--------+-------------------------+---------------+------+ | Re-added | -- | -- | -- | -- |
| Header | Intern | 6LBR | 6LR | IPv6 | | headers | | | | |
| | et | | | | | Modified | -- | -- | -- | -- |
+---------+--------+-------------------------+---------------+------+ | headers | | | | |
| Inserte | -- | IPv6-in- | -- | -- | | Untouched | -- | -- | -- | -- |
| d | | IPv6(RH3,optional:RPI) | | | | headers | | | | |
| headers | | | | | +--------------+----------+-------------------+--------------+------+
| Removed | -- | -- | IPv6-in- | -- |
| headers | | | IPv6(RH3, | |
| | | | RPI) | |
| Re- | -- | -- | -- | -- |
| added | | | | |
| headers | | | | |
| Modifie | -- | -- | -- | -- |
| d | | | | |
| headers | | | | |
| Untouch | -- | -- | -- | -- |
| ed | | | | |
| 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 comprises in the same RPL Domain. In the 6LN the RPI This case involves only nodes in same RPL Domain. The originating
header is inserted. In the 6LBR the RH3 header is inserted in a node will add an RPI header to the original packet, and send the
IPv6-in-IPv6 header and removed at the 6LN destination. packet upwards.
In case of the flow goes from RPL-aware-Leaf to RPL-aware-Leaf, the The originating node could put the RPI into an IPIP header addressed
RPI should be set in a IP-in-IP header, to avoid repetition of RPI to the root, so that the 6LBR can remove that header.
header.
+---------+---------------+---------------+-----+-------------------+ The 6LBR will need to insert an RH3 header, which requires that it
| Header | 6LN src | 6LBR | 6LR | 6LN dst | add an IPIP header. It may be able to remove the RPI if it was
+---------+---------------+---------------+-----+-------------------+ contained in an IPIP header addressed to it. Otherwise, there may be
| Inserte | IPv6-in- | IPv6-in- | -- | -- | an RPI header buried inside the inner IP header, which should get
| d | IPv6(RPI) | IPv6(RH3 to | | | ignored.
| headers | | 6LN,RPI) | | |
| | | {IP,payload} | | | Networks that use the RPL P2P extension [RFC6997] are essentially
| Removed | -- | -- | -- | IPv6-in- | non-storing DODAGs and fall into this scenario.
| headers | | | | IPv6(RH3,RPI) |
| | | | | {IP,RPI,payload} | +----------------+-----------+----------------+-----+---------------+
| Re- | -- | -- | -- | -- | | Header | 6LN src | 6LBR | 6LR | 6LN dst |
| added | | | | | +----------------+-----------+----------------+-----+---------------+
| headers | | | | | | Inserted | IPIP(RPI) | IPIP(RH3 to | -- | -- |
| Modifie | -- | -- | -- | -- | | headers | | 6LN,RPI) | | |
| d | | | | | | Removed | -- | -- | -- | IPIP(RH3,RPI) |
| headers | | | | | | headers | | | | |
| Untouch | -- | -- | -- | -- | | Re-added | -- | -- | -- | -- |
| ed | | | | | | headers | | | | |
| headers | | | | | | Modified | -- | -- | -- | -- |
+---------+---------------+---------------+-----+-------------------+ | headers | | | | |
| Untouched | -- | -- | -- | -- |
| 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
The 6LN insert the RPI in a IPv6-in-IPv6 header, which is addressed As in the previous case, the 6LN will insert an RPI header which MUST
to 6LBR. The 6LBR remove this RPI header and insert a RH3 header be in an IPIP header addressed to the root so that the 6LBR can
with an optional RPI. These headers are removed by 6LR before send remove this RPI. The 6LBR will then insert an RH3 inside a new IPIP
the packet to the IPv6 node. header addressed to the 6LN above the destination node.
+------------+-------------------+-------------+-------------+------+ +---------------+-----------+---------------+----------------+------+
| Header | 6LN | 6LBR | 6LR | IPv6 | | Header | 6LN | 6LBR | 6LR | IPv6 |
+------------+-------------------+-------------+-------------+------+ +---------------+-----------+---------------+----------------+------+
| Inserted | IPv6-in-IPv6(RPI) | IPIP(RH3, | -- | -- | | Inserted | IPIP(RPI) | IPIP(RH3, opt | -- | -- |
| headers | | opt RPI) | | | | headers | | RPI) | | |
| Removed | -- | IPIP(RPI) | IPIP(RH3, | -- | | Removed | -- | IPIP(RPI) | IPIP(RH3, opt | -- |
| headers | | | opt RPI) | | | headers | | | 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
RPI is added in 6LR until the root and then removed, then RH3 is This scenario is mostly identical to the previous one. The RPI is
added and removed at destination. added by the first 6LR inside an IPIP header addressed to the root.
The 6LBR will remove this RPI, and add it's own IPIP header
containing an RH3 header.
+-------------------+------+------------+-----------+------------+ +-------------------+------+------------+-----------+------------+
| Header | IPv6 | 6LR | 6LBR | 6LN | | Header | IPv6 | 6LR | 6LBR | 6LN |
+-------------------+------+------------+-----------+------------+ +-------------------+------+------------+-----------+------------+
| Inserted headers | -- | IPIP(RPI) | IPIP(RH3) | -- | | Inserted headers | -- | IPIP(RPI) | IPIP(RH3) | -- |
| Removed headers | -- | IPIP(RPI) | -- | IPIP(RH3) | | Removed headers | -- | IPIP(RPI) | -- | IPIP(RH3) |
| Re-added headers | -- | -- | -- | -- | | Re-added headers | -- | -- | -- | -- |
| Modified headers | -- | -- | -- | -- | | Modified headers | -- | -- | -- | -- |
| Untouched 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
RPI is added in 6LR until the root and then might be removed, then
RH3 is added. These headers are removed at 6LR before go to This scenario is the combination of the previous two cases.
destination.
+--------------+------+-----------+-----------+--------------+------+ +--------------+------+-----------+-----------+--------------+------+
| Header | IPv6 | 6LR | 6LBR | 6LR | IPv6 | | Header | IPv6 | 6LR | 6LBR | 6LR | IPv6 |
+--------------+------+-----------+-----------+--------------+------+ +--------------+------+-----------+-----------+--------------+------+
| Inserted | -- | IPIP(RPI) | IPIP(RH3) | -- | -- | | Inserted | -- | IPIP(RPI) | IPIP(RH3) | -- | -- |
| headers | | | | | | | headers | | | | | |
| Removed | -- | -- | IPIP(RPI) | IPIP(RH3, | -- | | Removed | -- | -- | IPIP(RPI) | IPIP(RH3, | -- |
| headers | | | | opt 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 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. Problem statement 7. Observations about the problem
There are cases from above that are not clear how to send the 7.1. Storing mode
information. It requires furhter analysis on how to proceed to send
the information from source to destination.
From the above cases, we have in storing mode: 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
destination is RPL aware, and therefore it must always use hop-by-hop
IPIP encapsulation, and it can never omit the IPIP encapsulation.
See table Table 1
- Flow from RPL-aware-leaf to non-RPL-aware-leaf: Somehow, the sender The simplest fully general stiaution for storing mode is to always
has to know that the receiver is not RPL aware, and needs to know put in hop-by-hop IPIP headers. [I-D.ietf-roll-routing-dispatch]
6LR, and not even the root knows where the 6LR is located. shows that this hop-by-hop IPIP header can be compressed down to
{TBD} bytes.
- Flow from not-RPL-aware-leaf to not-RPL-aware-leaf: The problem to There are potential significant advantages to having a single code
solve is how to indicate where to send the packet when get into LLN. path that always processes IPIP headers with no options.
One approach is the 6LBR should be aware in which 6LR is the IPv6
node attached.
As was mentioned above in the document, a possible solution could be If all RPL aware nodes can be told/configured that there are no non-
adapted to all cases: An IPv6-in-IPv6 header can be used on a hop-by- RPL aware leaf nodes, then the only case where an IPIP header is
hop basis, using either link-local addresses, or even IPv6 Global needed is when communicating outside the LLN. The 6LBR knows well
Unicast Addresses, but each IPv6-in-IPv6 header needs to be added/ when the communication is from the outside, and the 6LN can tell by
removed at each hop. comparing the destination address to the prefix provided in the PIO.
If it is known that there are no communications outside the RPL
domain (noting that the RPL domain may well extend to outside the
LLN), then RPI headers can be included in all packets, and IPIP
headers are *never* needed. This may be significantly advantageous
in relatively closed systems such as in building or industrial
automation. Again, there are advantages to having a single code
path.
In order to support the above two cases with full generality, the
different situations (always do IPIP vs never use IPIP) should be
signaled in the RPL protocol itself.
7.2. Non-Storing mode
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
connectivity of all nodes, and all traffic flows through the root
node.
The 6LBR can recognize non-RPL aware leaf nodes because it will
receive a DAO about that node from the 6LN immediately above that
node. This means that the non-storing mode case can avoid ever using
hop-by-hop IPIP headers.
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
header, and therefore consume the RH3 as well, and then 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 retained. This is
a new kind of IPv6 packet processing. Therefore it may be that on
the outbound leg of non-storing RPL networks, that hop-by-hop IPIP
header can NOT be used.
[I-D.ietf-roll-routing-dispatch] shows how the destination=root, and
destination=6LN IPIP header can be compressed down to {TBD} bytes.
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
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
aware nodes.
8. 6LoRH Compression cases 8. 6LoRH Compression cases
The [I-D.ietf-6lo-routing-dispatch] proposes a compression method for The [I-D.ietf-roll-routing-dispatch] proposes a compression method
RPI, RH3 and IPv6-in-IPv6. for RPI, RH3 and IPv6-in-IPv6.
The uses cases mentioned in this draft MUST use 6LoRH. Examples of In Storing Mode, for the examples of Flow from RPL-aware-leaf to non-
the use of 6LoRH are found in Apendix A of RPL-aware-leaf and non-RPL-aware-leaf to non-RPL-aware-leaf comprise
[I-D.ietf-6lo-routing-dispatch]. an IP-in-IP and RPI compression headers. The type of this case is
critical since IP-in-IP is encapsulating a RPI header.
+--+-----+---+--------------+-----------+-------------+-------------+
|1 | 0|0 |TSE| 6LoRH Type 6 | Hop Limit | RPI - 6LoRH | LOWPAN IPHC |
+--+-----+---+--------------+-----------+-------------+-------------+
Figure 5: 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.
skipping to change at page 29, line 41 skipping to change at page 29, line 38
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
(IPv6) Specification", RFC 2460, December 1998.
[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
Information in Data-Plane Datagrams", RFC 6553, Information in Data-Plane Datagrams", RFC 6553,
skipping to change at page 30, line 13 skipping to change at page 30, line 19
<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-6lo-routing-dispatch]
Thubert, P., Bormann, C., Toutain, L., and R. Cragie,
"6LoWPAN Routing Header", draft-ietf-6lo-routing-
dispatch-05 (work in progress), February 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-09 (work
in progress), November 2015. in progress), November 2015.
[I-D.ietf-roll-routing-dispatch]
Thubert, P., Bormann, C., Toutain, L., and R. Cragie,
"6LoWPAN Routing Header", draft-ietf-roll-routing-
dispatch-00 (work in progress), March 2016.
[RFC6997] Goyal, M., Ed., Baccelli, E., Philipp, M., Brandt, A., and
J. Martocci, "Reactive Discovery of Point-to-Point Routes
in Low-Power and Lossy Networks", RFC 6997,
DOI 10.17487/RFC6997, August 2013,
<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>.
[Second6TischPlugtest] [Second6TischPlugtest]
"2nd 6Tisch Plugtest", <http://www.ietf.org/mail- "2nd 6Tisch Plugtest", <http://www.ietf.org/mail-
archive/web/6tisch/current/pdfgDMQcdCkRz.pdf>. archive/web/6tisch/current/pdfgDMQcdCkRz.pdf>.
Authors' Addresses Authors' Addresses
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