ROLL Working Group M. Robles
Internet-Draft Ericsson
Intended status: Informational M. Richardson
Expires: October 7, 2016 SSW
P. Thubert
Cisco
April 5, 2016
When to use RFC 6553, 6554 and IPv6-in-IPv6
draft-ietf-roll-useofrplinfo-04
Abstract
This document looks at different data flows through LLN networks
where RPL is used to establish routing. The document enumerates the
cases where RFC 6553, RFC 6554 and IPv6-in-IPv6 encapsulation is
required. This analysis provides the basis on which to design
efficient compression of these headers.
Status of This Memo
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This Internet-Draft will expire on October 7, 2016.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
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include Simplified BSD License text as described in Section 4.e of
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology and Requirements Language . . . . . . . . . . . . 3
3. Sample/reference topology . . . . . . . . . . . . . . . . . . 3
4. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5. Storing mode . . . . . . . . . . . . . . . . . . . . . . . . 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
5.3. Example of Flow from root to not-RPL-aware-leaf . . . . . 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
5.6. Example of Flow from Internet to RPL-aware-leaf . . . . . 12
5.7. Example of Flow from not-RPL-aware-leaf to Internet . . . 12
5.8. Example of Flow from Internet to non-RPL-aware-leaf . . . 13
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
5.11. 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-
leaf . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6. Non Storing mode . . . . . . . . . . . . . . . . . . . . . . 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
6.3. Example of Flow from root to not-RPL-aware-leaf . . . . . 20
6.4. Example of Flow from not-RPL-aware-leaf to root . . . . . 21
6.5. Example of Flow from RPL-aware-leaf to Internet . . . . . 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
6.8. Example of Flow from Internet to non-RPL-aware-leaf . . . 23
6.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf . . 24
6.10. Example of Flow from RPL-aware-leaf to not-RPL-aware-leaf 25
6.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf 26
6.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware-
leaf . . . . . . . . . . . . . . . . . . . . . . . . . . 26
7. Observations about the problem . . . . . . . . . . . . . . . 27
7.1. Storing mode . . . . . . . . . . . . . . . . . . . . . . 27
7.2. Non-Storing mode . . . . . . . . . . . . . . . . . . . . 28
8. 6LoRH Compression cases . . . . . . . . . . . . . . . . . . . 28
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29
10. Security Considerations . . . . . . . . . . . . . . . . . . . 29
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 29
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 29
12.1. Normative References . . . . . . . . . . . . . . . . . . 29
12.2. Informative References . . . . . . . . . . . . . . . . . 30
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Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 30
1. Introduction
RPL [RFC6550] is a routing protocol for constrained networks. RFC
6553 [RFC6553] defines the "RPL option" (RPI), carried within the
IPv6 Hop-by-Hop header to quickly identify inconsistencies (loops) in
the routing topology. RFC 6554 [RFC6554] defines the "RPL Source
Route Header" (RH3), an IPv6 Extension Header to deliver datagrams
within a RPL routing domain, particularly in non-storing mode.
These various items are referred to as RPL artifacts, and they are
seen on all of the data-plane traffic that occurs in RPL routed
networks; they do not in general appear on the RPL control plane
traffic at all which is mostly hop-by-hop traffic (one exception
being DAO messages in non-storing mode).
It has become clear from attempts to do multi-vendor
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
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Terminology defined in [RFC7102]
3. Sample/reference topology
A RPL network is composed of a 6LBR (6LoWPAN Border Router), Backbone
Router (6BBR), 6LR (6LoWPAN Router) and 6LN (6LoWPAN Node) as leaf
logically organized in a DODAG structure (Destination Oriented
Directed Acyclic Graph).
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RPL defines the RPL Control messages (control plane ), a new ICMPv6
message with Type 155. DIS, DIO and DAO messages are all RPL Control
messages but with different Code values.
RPL supports two modes of Downward traffic: in storing mode, it is
fully stateful or an in non-storing, it is fully source routed. A
RPL Instance is either fully storing or fully non-storing, i.e. a RPL
Instance with a combination of storing and non-storing nodes is not
supported with the current specifications.
+--------------+
| Upper Layers |
| |
+--------------+
| RPL |
| |
+--------------+
| ICMPv6 |
| |
+--------------+
| IPv6 |
| |
+--------------+
| 6LoWPAN |
| |
+--------------+
| PHY-MAC |
| |
+--------------+
Figure 1: RPL Stack.
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+---------+
+---+Internet |
| +---------+
|
+----+--+
|DODAG | node:01
+---------+Root +----------+
| |6LBR | |
| +----+--+ |
| | |
| | |
... ... ...
| | |
+-----+-+ +--+---+ +--+---+
|6LR | | | | |
+-----+ | | | | |
| | 11 | | 12 | | 13 +------+
| +-----+-+ +-+----+ +-+----+ |
| | | | |
| | | | |
| 21 | 22 | 23 | 24 | 25
+-+---+ +-+---+ +--+--+ +- --+ +---+-+
|Leaf | | | | | |Leaf| |Leaf |
| 6LR | | | | | | 6LN| | 6LR |
+-----+ +-----+ +-----+ +----+ +-----+
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
6TiSCH working group. The 6TiSCH architecture
[I-D.ietf-6tisch-architecture] draft explains the network
architecture of a 6TiSCH network. This architecture is used for the
remainder of this document.
The scope of the 6TiSCH 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
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or a different Backbone Router inside the Multi-Link Subnet and
conserve its addresses.
|
+-----+
| | 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 Instance ------------------------>
Figure 3: RPL domain architecture
4. Use cases
In data plane context a combination of RFC6553, RFC6554 and IPv6-in-
IPv6 encapsulation is going to be analyzed for the following traffic
flows:
RPL-aware-leaf to root
root to RPL-aware-leaf
not-RPL-aware-leaf to root
root to not-RPL-aware-leaf
RPL-aware-leaf to Internet
Internet to RPL-aware-leaf
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not-RPL-aware-leaf to Internet
Internet to not-RPL-aware-leaf
RPL-aware-leaf to RPL-aware-leaf
RPL-aware-leaf to not-RPL-aware-leaf
not-RPL-aware-leaf to RPL-aware-leaf
not-RPL-aware-leaf to not-RPL-aware-leaf
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
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.
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
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.
The combination of these two rules means that the arrangement of
headers must be done so that traffic intended to exit the RPL domain
can have the RPI option removed prior to leaving the RPL domain.
An intermediate router that needs to add a header must encapsulate
the packet in an (additional) outer IP header where the new header
can be placed.
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!
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.
Both headers were designed with this modification in mind, and both
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.
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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)
modes for the previous cases is showed as follows:
In tables, the term "RPL aware leaf" is has been shortened to "Raf",
and "not-RPL aware leaf" has been shortened to "~Raf" to make the
table fit in available space.
The earlier examples are more complete to make sure that the process
is clear, while later examples are more consise.
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 | RH3 | IP-in-IP | IPIP dst |
+--------------+-------+-------+-----------+-----------+
| Raf to root | Yes | No | No | -- |
| root to Raf | Yes | No | No | -- |
| root to ~Raf | Yes | No | Yes | hop |
| ~Raf to root | Yes | No | Yes | root |
| Raf to Int | Yes | No | Yes | root |
| Int to Raf | Yes | No | Yes | raf |
| ~Raf to Int | Yes | No | Yes | root |
| Int to ~Raf | Yes | No | Yes | hop |
| Raf to Raf | Yes | No | No | -- |
| Raf to ~Raf | Yes | No | Yes | hop |
| ~Raf to Raf | Yes | No | Yes | dst |
| ~Raf to ~Raf | Yes | No | Yes | hop |
+--------------+-------+-------+-----------+-----------+
Table 1: Headers needed in Storing mode: RPI, RH3, IP-in-IP
encapsulation
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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
not generally issue DIO messages; a leaf node accepts DIO messages
from upstream. (When the inconsistency in routing occurs, a leaf
node will generate a DIO with an infinite rank, to fix it). It may
issue DAO and DIS messages though it generally ignores DAO and DIS
messages.
In storing mode, it is suitable to use RFC 6553 (RPI) to send RPL
Information instanceID and rank information.
In this case the flow comprises:
RPL-aware-leaf (6LN) --> 6LR --> 6LR,... --> root (6LBR)
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
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.
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 |
+-------------------+-----+------+------+
| Inserted headers | RPI | -- | -- |
| Removed headers | -- | -- | RPI |
| Re-added headers | -- | -- | -- |
| Modified headers | -- | RPI | -- |
| Untouched headers | -- | -- | -- |
+-------------------+-----+------+------+
Storing: Summary of the use of headers from RPL-aware-leaf to root
5.2. Example of Flow from root to RPL-aware-leaf
In this case the flow comprises:
root (6LBR)--> 6LR --> RPL-aware-leaf (6LN)
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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
multiple tables), the packet is processed in 6LN and RPI removed.
No IPIP header is required.
+-------------------+------+-------+------+
| Header | 6LBR | 6LR | 6LN |
+-------------------+------+-------+------+
| Inserted headers | RPI | -- | -- |
| Removed headers | -- | -- | RPI |
| Re-added headers | -- | -- | -- |
| Modified headers | -- | RPI | -- |
| Untouched headers | -- | -- | -- |
+-------------------+------+-------+------+
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
In this case the flow comprises:
root (6LBR)--> 6LR --> not-RPL-aware-leaf (6LN)
It includes IPv6-in-IPv6 encapsulation to transmit information not
related with the RPL domain. In the 6LBR the RPI header is inserted
into an IPv6-in-IPv6 header addressed to the last 6LR, which removes
the header before pass the packet to the IPv6 node.
The question in this scenario is how the root knows how to address
the IPv6-in-IPv6 header. It can not know that the destination isn't
RPL aware, so it must insert an IPv6 that can be removed on the last
RPL aware node. Since the root can not know in a storing network
where the last RPL aware node is, the IPv6-in-IPv6 header must added
hop-by-hop along the path from root to leaf.
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.
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+-------------------+-----------+-----------+------+
| 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-
leaf
5.4. Example of Flow from not-RPL-aware-leaf to root
In this case the flow comprises:
not-RPL-aware-leaf (6LN) --> 6LR --> root (6LBR)
When the packet arrives from IPv6 node to 6LR, the 6LR will insert an
RPI header, encapsuladed in a IPv6-in-IPv6 header. The IPv6-in-IPv6
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 |
+-------------------+------+------------+-----------+
| Inserted headers | -- | IPIP(RPI) | -- |
| Removed headers | -- | -- | IPIP(RPI) |
| Re-added headers | -- | -- | -- |
| Modified headers | -- | -- | -- |
| Untouched headers | -- | -- | -- |
+-------------------+------+------------+-----------+
Storing: Summary of the use of headers from not-RPL-aware-leaf to
root
5.5. Example of Flow from RPL-aware-leaf to Internet
RPL information from RFC 6553 should not go out to Internet as it
will cause the packet to be discarded at the first non-RPI aware
router. The 6LBR must be able to take this information out before
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:
RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) --> Internet
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The 6LN will insert the RPI in a IPv6-in-IPv6 in a outer header,
which may be addressed to the 6LBR (root), or alternatively, it could
be addressed hop-by-hop.
+-------------------+-----------+------+-----------+----------+
| Header | 6LN | 6LR | 6LBR | Internet |
+-------------------+-----------+------+-----------+----------+
| Inserted headers | IPIP(RPI) | -- | -- | -- |
| Removed headers | -- | -- | IPIP(RPI) | -- |
| Re-added headers | -- | -- | -- | -- |
| Modified headers | -- | RPI | -- | -- |
| Untouched headers | -- | -- | -- | -- |
+-------------------+-----------+------+-----------+----------+
Storing: Summary of the use of headers from RPL-aware-leaf to
Internet
5.6. Example of Flow from Internet to RPL-aware-leaf
In this case the flow comprises:
Internet --> root (6LBR) --> 6LR --> RPL-aware-leaf (6LN)
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
rank in the RPI. When the packet arrives 6LN the RPI header is
removed and the packet processed.
+-------------------+----------+------------+------+------------+
| Header | Internet | 6LBR | 6LR | 6LN |
+-------------------+----------+------------+------+------------+
| Inserted headers | -- | IPIP(RPI) | -- | -- |
| Removed headers | -- | -- | -- | IPIP(RPI) |
| Re-added headers | -- | -- | -- | -- |
| Modified headers | -- | -- | RPI | -- |
| Untouched headers | -- | -- | -- | -- |
+-------------------+----------+------------+------+------------+
Storing: Summary of the use of headers from Internet to RPL-aware-
leaf
5.7. Example of Flow from not-RPL-aware-leaf to Internet
In this case the flow comprises:
not-RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) --> Internet
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The 6LR node will add an IPIP(RPI) header addressed either to the
root, or hop-by-hop such that the root can remove the RPI header
before passing upwards.
The originating node will ideally leave the IPv6 flow label as zero
so that it can be better compressed through the LLN, and the 6LBR
will set the flow label to a non-zero value when sending to the
Internet.
+-------------------+------+------------+------------+----------+
| Header | 6LN | 6LR | 6LBR | Internet |
+-------------------+------+------------+------------+----------+
| Inserted headers | -- | IPIP(RPI) | -- | -- |
| Removed headers | -- | -- | IPIP(RPI) | -- |
| Re-added headers | -- | -- | -- | -- |
| Modified headers | -- | -- | -- | -- |
| Untouched headers | -- | -- | -- | -- |
+-------------------+------+------------+------------+----------+
Storing: Summary of the use of headers from not-RPL-aware-leaf to
Internet
5.8. Example of Flow from Internet to non-RPL-aware-leaf
In this case the flow comprises:
Internet --> root (6LBR) --> 6LR --> not-RPL-aware-leaf (6LN)
The 6LBR will have to add an RPI header within an IPIP header. The
IPIP will need to be addressed hop-by-hop along the path as in
storing mode, the 6LBR has no idea if the 6LN is RPL aware or not,
nor what the closest attached 6LR node is.
The 6LBR MAY set the flow label on the inner IPIP header to zero in
order to aid in compression, as the packet will not emerge again from
the LLN.
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+-------------------+----------+------------+------------+------+
| Header | Internet | 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 Internet to non-RPL-
aware-leaf
5.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf
In [RFC6550] RPL allows a simple one-hop optimization for both
storing and non-storing networks. A node may send a packet destined
to a one-hop neighbor directly to that node. Section 9 in [RFC6550].
In this case the flow comprises:
6LN --> 6LR --> common parent (6LR) --> 6LR --> 6LN
This case is assumed in the same RPL Domain. In the common parent,
the direction of RPI is changed (from increasing to decreasing the
rank).
While the 6LR nodes will update the RPI, no node needs to add or
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.
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+-------------+-------+---------------+---------------+-----+-------+
| Header | 6LN | 6LR | 6LR (common | 6LR | 6LN |
| | src | | parent) | | dst |
+-------------+-------+---------------+---------------+-----+-------+
| Inserted | RPI | -- | -- | -- | -- |
| headers | | | | | |
| Removed | -- | -- | -- | -- | RPI |
| headers | | | | | |
| Re-added | -- | -- | -- | -- | -- |
| headers | | | | | |
| Modified | -- | RPI | RPI | -- | -- |
| headers | | (decreasing | (increasing | | |
| | | rank) | rank) | | |
| Untouched | -- | -- | -- | -- | -- |
| headers | | | | | |
+-------------+-------+---------------+---------------+-----+-------+
Storing: Summary of the use of headers for RPL-aware-leaf to RPL-
aware-leaf
5.10. Example of Flow from RPL-aware-leaf to non-RPL-aware-leaf
In this case the flow comprises:
6LN --> 6LR --> common parent (6LR) --> 6LR --> not-RPL-aware 6LN
The sender, being aware out of band, that the receiver is not RPL
aware, sends adds an RPI header inside an IPIP header. The IPIP
header needs to be addressed on a hop-by-hop basis so that the last
6LR can remove the RPI header.
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,---.
/ \
( 6LR2 ) IP3,RPI,IP,ULP
,-" .
,-" `---' `.
,' `.
,---. ,-" `,---.
/ +" / \
( 6LR1 ) Remove the IP3,RPI( 6LR3 )
\ / \ /
/---' `---'|
/ IP2,RPI,IP,ULP \
/ |
/ \
,---+-. |
/ \ +--+----+
( 6LN ) | |
\ / | IPv6 | IP,ULP
`-----' | |
IP1,RPI,IP,ULP +-------+
Figure 4: Solution IPv6-in-IPv6 in each hop
Alternatively, 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 IPIP 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.
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+-----------+-----------+-----------+------------+-----------+------+
| Header | 6LN | 6LR | 6LR | 6LR | IPv6 |
| | | | (common | | |
| | | | parent) | | |
+-----------+-----------+-----------+------------+-----------+------+
| Inserted | IPIP(RPI) | -- | -- | -- | -- |
| headers | | | | | |
| Removed | -- | -- | -- | IPIP(RPI) | -- |
| headers | | | | | |
| Re-added | -- | -- | -- | -- | -- |
| headers | | | | | |
| Modified | -- | IPIP(RPI) | IPIP(RPI) | -- | -- |
| headers | | | | | |
| Untouched | -- | -- | -- | -- | -- |
| headers | | | | | |
+-----------+-----------+-----------+------------+-----------+------+
Storing: Summary of the use of headers from RPL-aware-leaf to not-
RPL-aware-leaf
5.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf
In this case the flow comprises:
not-RPL-aware 6LN --> 6LR --> common parent (6LR) --> 6LR --> 6LN
The 6LR receives the packet from the the IPv6 node and inserts and
the RPI header encapsulated in IPv6-in-IPv6 header. The IPIP header
could be addresses to the 6LN if the destination is known to the RPL
aware, otherwise must send the packet using a hop-by-hop IPIP header.
Similar considerations apply from section Section 5.10.
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+-----------+------+-----------+------------+-----------+-----------+
| Header | IPv6 | 6LR | common | 6LR | 6LN |
| | | | parent | | |
| | | | (6LR) | | |
+-----------+------+-----------+------------+-----------+-----------+
| Inserted | -- | IPIP(RPI) | -- | -- | -- |
| headers | | | | | |
| Removed | -- | -- | -- | -- | IPIP(RPI) |
| headers | | | | | |
| Re-added | -- | -- | -- | -- | -- |
| headers | | | | | |
| Modified | -- | -- | IPIP(RPI) | IPIP(RPI) | -- |
| headers | | | | | |
| Untouched | -- | -- | -- | -- | -- |
| headers | | | | | |
+-----------+------+-----------+------------+-----------+-----------+
Storing: Summary of the use of headers from not-RPL-aware-leaf to
RPL-aware-leaf
5.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware-leaf
In this case the flow comprises:
not-RPL-aware 6LN (IPv6 node)--> 6LR --> root (6LBR) --> 6LR --> not-
RPL-aware 6LN (IPv6 node)
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
it must add an IPIP header. That IPIP header must be addressed on a
hop-by-hop basis.
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+-------------+--------+-----------+-----------+-----------+--------+
| Header | IPv6 | 6LR | 6LR | 6LR | IPv6 |
| | src | | (common | | dst |
| | | | parent) | | |
+-------------+--------+-----------+-----------+-----------+--------+
| Inserted | -- | IPIP(RPI) | -- | -- | -- |
| headers | | | | | |
| Removed | -- | -- | -- | IPIP(RPI) | -- |
| headers | | | | | |
| Re-added | -- | -- | -- | -- | -- |
| headers | | | | | |
| Modified | -- | -- | -- | -- | -- |
| headers | | | | | |
| Untouched | -- | -- | -- | -- | -- |
| headers | | | | | |
+-------------+--------+-----------+-----------+-----------+--------+
Storing: Summary of the use of headers from not-RPL-aware-leaf to
not-RPL-aware-leaf
6. Non Storing mode
+--------------+------+------+-------+-----------+
| 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 | 6LR |
| ~Raf to root | Yes | No | Yes | root |
| Raf to Int | Yes | No | Yes | root |
| Int to Raf | opt | Yes | Yes | dst |
| ~Raf to Int | Yes | No | Yes | root |
| Int to ~Raf | opt | Yes | Yes | 6LR |
| Raf to Raf | Yes | Yes | Yes | root/dst |
| Raf to ~Raf | Yes | Yes | Yes | root/6LR |
| ~Raf to Raf | Yes | Yes | Yes | root/6LN |
| ~Raf to ~Raf | Yes | Yes | Yes | root/6LR |
+--------------+------+------+-------+-----------+
Table 2: Headers needed in Non-Storing mode: RPI, RH3, IP-in-IP
encapsulation
6.1. Example of Flow from RPL-aware-leaf to root
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.
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RPL-aware-leaf (6LN) --> 6LR --> root (6LBR)
This situation is the same case as storing mode.
+-------------------+-----+-----+------+
| Header | 6LN | 6LR | 6LBR |
+-------------------+-----+-----+------+
| Inserted headers | RPI | -- | -- |
| Removed headers | -- | -- | RPI |
| Re-added headers | -- | -- | RPI |
| Modified headers | -- | -- | -- |
| Untouched headers | -- | -- | -- |
+-------------------+-----+-----+------+
Non Storing: Summary of the use of headers from RPL-aware-leaf to
root
6.2. Example of Flow from root to RPL-aware-leaf
In this case the flow comprises:
root (6LBR)--> 6LR --> RPL-aware-leaf (6LN)
The 6LBR will insert an RH3, and may optionally insert an RPI header.
No IPIP header is necessary as the traffic originates with an RPL
aware node.
+-------------------+-----------------+------+----------+
| Header | 6LBR | 6LR | 6LN |
+-------------------+-----------------+------+----------+
| Inserted headers | (opt: RPI), RH3 | -- | -- |
| Removed headers | -- | -- | RH3,RPI |
| Re-added headers | -- | -- | -- |
| Modified headers | -- | RH3 | -- |
| Untouched headers | -- | -- | -- |
+-------------------+-----------------+------+----------+
Non Storing: Summary of the use of headers from root to RPL-aware-
leaf
6.3. Example of Flow from root to not-RPL-aware-leaf
In this case the flow comprises:
root (6LBR)--> 6LR --> not-RPL-aware-leaf (IPv6 node)
In 6LBR the RH3 is added, and modified in 6LR where it is fully
consumed, but left there. If the RPI is left present, the IPv6 node
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which does not understand it will drop it, therefore the RPI should
be removed before reaching the IPv6-only node. To permit removal, an
IPIP header (hop-by-hop) or addressed to the last 6LR is necessary.
Due the complete knowledge of the topology at the root, the 6LBR is
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 |
+-------------------+------+-----+------+
| Inserted headers | RH3 | -- | -- |
| Removed headers | -- | -- | -- |
| Re-added headers | -- | -- | -- |
| Modified headers | -- | RH3 | -- |
| Untouched headers | -- | -- | -- |
+-------------------+------+-----+------+
Non Storing: Summary of the use of headers from root to not-RPL-
aware-leaf
6.4. Example of Flow from not-RPL-aware-leaf to root
In this case the flow comprises:
IPv6-node --> 6LR1 --> 6LR2 --> root (6LBR)
In this case the RPI is added by the first 6LR, encapsulated in an
IPIP header, and is not modified in the followings 6LRs. The RPI and
entire packet is consumed by the root.
+-------------------+------+------------+------+------------+
| Header | IPv6 | 6LR1 | 6LR2 | 6LBR |
+-------------------+------+------------+------+------------+
| Inserted headers | -- | IPIP(RPI) | -- | -- |
| Removed headers | -- | -- | -- | IPIP(RPI) |
| Re-added headers | -- | -- | -- | -- |
| Modified headers | -- | -- | -- | -- |
| Untouched headers | -- | IPIP(RPI) | -- | -- |
+-------------------+------+------------+------+------------+
Non Storing: Summary of the use of headers from not-RPL-aware-leaf to
root
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6.5. Example of Flow from RPL-aware-leaf to Internet
In this case the flow comprises:
RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) --> Internet
This case requires that the RPI be added, but remoted by the 6LBR.
The 6LN must therefore add the RPI inside an IPIP header, addressed
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 6LBR will set it to a non-zero value when sending towards the
Internet.
+-------------------+-----------+------+------------+----------+
| Header | 6LN | 6LR | 6LBR | Internet |
+-------------------+-----------+------+------------+----------+
| Inserted headers | IPIP(RPI) | -- | -- | -- |
| Removed headers | -- | -- | IPIP(RPI) | -- |
| Re-added headers | -- | -- | -- | -- |
| Modified headers | -- | -- | -- | -- |
| Untouched headers | -- | RPI | -- | -- |
+-------------------+-----------+------+------------+----------+
Non Storing: Summary of the use of headers from RPL-aware-leaf to
Internet
6.6. Example of Flow from Internet to RPL-aware-leaf
In this case the flow comprises:
Internet --> root (6LBR) --> 6LR --> RPL-aware-leaf (6LN)
The 6LBR must add an RH3 header. As the 6LBR will know the path and
address of the target not, it can address the IPIP header to that
node. The 6LBR will zero the flow label upon entry in order to aid
compression.
The RPI may be added or not.
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+----------------+----------+--------------------+------------+-----+
| Header | Internet | 6LBR | 6LR | 6LN |
+----------------+----------+--------------------+------------+-----+
| Inserted | -- | IPIP(RH3,opt:RPI) | -- | -- |
| headers | | | | |
| Removed | -- | -- | IPIP(RH3) | -- |
| headers | | | | |
| Re-added | -- | -- | -- | -- |
| headers | | | | |
| Modified | -- | -- | IPIP(RH3) | -- |
| headers | | | | |
| Untouched | -- | -- | -- | -- |
| headers | | | | |
+----------------+----------+--------------------+------------+-----+
Non Storing: Summary of the use of headers from Internet to RPL-
aware-leaf
6.7. Example of Flow from not-RPL-aware-leaf to Internet
In this case the flow comprises:
not-RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) --> Internet
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
add an RPI header inside a new IPIP header. The IPIP header will be
addressed to the root. This case is identical to the storing-mode
case.
+-------------------+------+-----------+------------+----------+
| Header | IPv6 | 6LR | 6LBR | Internet |
+-------------------+------+-----------+------------+----------+
| Inserted headers | -- | IPIP(RPI) | -- | -- |
| Removed headers | -- | -- | IPIP(RPI) | -- |
| Re-added headers | -- | -- | -- | -- |
| Modified headers | -- | -- | -- | -- |
| Untouched headers | -- | -- | -- | -- |
+-------------------+------+-----------+------------+----------+
Non Storing: Summary of the use of headers from not-RPL-aware-leaf to
Internet
6.8. Example of Flow from Internet to non-RPL-aware-leaf
In this case the flow comprises:
Internet --> root (6LBR) --> 6LR --> not-RPL-aware-leaf (6LN)
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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.
+--------------+----------+-------------------+--------------+------+
| Header | Internet | 6LBR | 6LR | IPv6 |
+--------------+----------+-------------------+--------------+------+
| Inserted | -- | IPIP(RH3,opt:RPI) | -- | -- |
| headers | | | | |
| Removed | -- | -- | IPIP(RH3, | -- |
| headers | | | RPI) | |
| Re-added | -- | -- | -- | -- |
| headers | | | | |
| Modified | -- | -- | -- | -- |
| headers | | | | |
| Untouched | -- | -- | -- | -- |
| headers | | | | |
+--------------+----------+-------------------+--------------+------+
NonStoring: Summary of the use of headers from Internet to non-RPL-
aware-leaf
6.9. Example of Flow from RPL-aware-leaf to RPL-aware-leaf
In this case the flow comprises:
6LN --> 6LR --> root (6LBR) --> 6LR --> 6LN
This case involves only nodes in same RPL Domain. The originating
node will add an RPI header to the original packet, and send the
packet upwards.
The originating node could put the RPI into an IPIP header addressed
to the root, so that the 6LBR can remove that header.
The 6LBR will need to insert an RH3 header, which requires that it
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
an RPI header buried inside the inner IP header, which should get
ignored.
Networks that use the RPL P2P extension [RFC6997] are essentially
non-storing DODAGs and fall into this scenario.
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+----------------+-----------+----------------+-----+---------------+
| Header | 6LN src | 6LBR | 6LR | 6LN dst |
+----------------+-----------+----------------+-----+---------------+
| Inserted | IPIP(RPI) | IPIP(RH3 to | -- | -- |
| headers | | 6LN,RPI) | | |
| Removed | -- | -- | -- | IPIP(RH3,RPI) |
| headers | | | | |
| Re-added | -- | -- | -- | -- |
| headers | | | | |
| Modified | -- | -- | -- | -- |
| headers | | | | |
| Untouched | -- | -- | -- | -- |
| headers | | | | |
+----------------+-----------+----------------+-----+---------------+
Non Storing: Summary of the use of headers for RPL-aware-leaf to RPL-
aware-leaf
6.10. Example of Flow from RPL-aware-leaf to not-RPL-aware-leaf
In this case the flow comprises:
6LN --> 6LR --> root (6LBR) --> 6LR --> not-RPL-aware 6LN
As in the previous case, the 6LN will insert an RPI header which MUST
be in an IPIP header addressed to the root so that the 6LBR can
remove this RPI. The 6LBR will then insert an RH3 inside a new IPIP
header addressed to the 6LN above the destination node.
+---------------+-----------+---------------+----------------+------+
| Header | 6LN | 6LBR | 6LR | IPv6 |
+---------------+-----------+---------------+----------------+------+
| Inserted | IPIP(RPI) | IPIP(RH3, opt | -- | -- |
| headers | | RPI) | | |
| Removed | -- | IPIP(RPI) | IPIP(RH3, opt | -- |
| headers | | | RPI) | |
| Re-added | -- | -- | -- | -- |
| headers | | | | |
| Modified | -- | -- | -- | -- |
| headers | | | | |
| Untouched | -- | -- | -- | -- |
| headers | | | | |
+---------------+-----------+---------------+----------------+------+
Non Storing: Summary of the use of headers from RPL-aware-leaf to
not-RPL-aware-leaf
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6.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf
In this case the flow comprises:
not-RPL-aware 6LN --> 6LR --> root (6LBR) --> 6LR --> 6LN
This scenario is mostly identical to the previous one. The RPI is
added by the first 6LR inside an IPIP header addressed to the root.
The 6LBR will remove this RPI, and add it's own IPIP header
containing an RH3 header.
+-------------------+------+------------+-----------+------------+
| Header | IPv6 | 6LR | 6LBR | 6LN |
+-------------------+------+------------+-----------+------------+
| Inserted headers | -- | IPIP(RPI) | IPIP(RH3) | -- |
| Removed headers | -- | IPIP(RPI) | -- | IPIP(RH3) |
| Re-added headers | -- | -- | -- | -- |
| Modified headers | -- | -- | -- | -- |
| Untouched headers | -- | -- | -- | -- |
+-------------------+------+------------+-----------+------------+
Non Storing: Summary of the use of headers from not-RPL-aware-leaf to
RPL-aware-leaf
6.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware-leaf
In this case the flow comprises:
not-RPL-aware 6LN --> 6LR --> root (6LBR) --> 6LR --> not-RPL-aware
6LN
This scenario is the combination of the previous two cases.
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+--------------+------+-----------+-----------+--------------+------+
| Header | IPv6 | 6LR | 6LBR | 6LR | IPv6 |
+--------------+------+-----------+-----------+--------------+------+
| Inserted | -- | IPIP(RPI) | IPIP(RH3) | -- | -- |
| headers | | | | | |
| Removed | -- | -- | IPIP(RPI) | IPIP(RH3, | -- |
| headers | | | | opt RPI) | |
| Re-added | -- | -- | -- | -- | -- |
| headers | | | | | |
| Modified | -- | -- | -- | -- | -- |
| headers | | | | | |
| Untouched | -- | -- | -- | -- | -- |
| headers | | | | | |
+--------------+------+-----------+-----------+--------------+------+
Non Storing: Summary of the use of headers from not-RPL-aware-leaf to
not-RPL-aware-leaf
7. Observations about the problem
7.1. 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
The simplest fully general stiaution for storing mode is to always
put in hop-by-hop IPIP headers. [I-D.ietf-roll-routing-dispatch]
shows that this hop-by-hop IPIP header can be compressed down to
{TBD} bytes.
There are potential significant advantages to having a single code
path that always processes IPIP headers with no options.
If all RPL aware nodes can be told/configured that there are no non-
RPL aware leaf nodes, then the only case where an IPIP header is
needed is when communicating outside the LLN. The 6LBR knows well
when the communication is from the outside, and the 6LN can tell by
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.
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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
The [I-D.ietf-roll-routing-dispatch] proposes a compression method
for RPI, RH3 and IPv6-in-IPv6.
In Storing Mode, for the examples of Flow from RPL-aware-leaf to non-
RPL-aware-leaf and non-RPL-aware-leaf to non-RPL-aware-leaf comprise
an IP-in-IP and RPI compression headers. The type of this case is
critical since IP-in-IP is encapsulating a RPI header.
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+--+-----+---+--------------+-----------+-------------+-------------+
|1 | 0|0 |TSE| 6LoRH Type 6 | Hop Limit | RPI - 6LoRH | LOWPAN IPHC |
+--+-----+---+--------------+-----------+-------------+-------------+
Figure 5: Critical IP-in-IP (RPI).
9. IANA Considerations
There are no IANA considerations related to this document.
10. Security Considerations
The security considerations covering of [RFC6553] and [RFC6554] apply
when the packets get into RPL Domain.
11. Acknowledgments
This work is partially funded by the FP7 Marie Curie Initial Training
Network (ITN) METRICS project (grant agreement No. 607728).
The authors would like to acknowledge the review, feedback, and
comments of Thomas Watteyne, Xavier Vilajosana, Robert Cragie and
Simon Duquennoy.
12. References
12.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<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.,
Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur,
JP., and R. Alexander, "RPL: IPv6 Routing Protocol for
Low-Power and Lossy Networks", RFC 6550,
DOI 10.17487/RFC6550, March 2012,
<http://www.rfc-editor.org/info/rfc6550>.
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[RFC6553] Hui, J. and JP. Vasseur, "The Routing Protocol for Low-
Power and Lossy Networks (RPL) Option for Carrying RPL
Information in Data-Plane Datagrams", RFC 6553,
DOI 10.17487/RFC6553, March 2012,
<http://www.rfc-editor.org/info/rfc6553>.
[RFC6554] Hui, J., Vasseur, JP., Culler, D., and V. Manral, "An IPv6
Routing Header for Source Routes with the Routing Protocol
for Low-Power and Lossy Networks (RPL)", RFC 6554,
DOI 10.17487/RFC6554, March 2012,
<http://www.rfc-editor.org/info/rfc6554>.
12.2. Informative References
[I-D.ietf-6tisch-architecture]
Thubert, P., "An Architecture for IPv6 over the TSCH mode
of IEEE 802.15.4", draft-ietf-6tisch-architecture-09 (work
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
Lossy Networks", RFC 7102, DOI 10.17487/RFC7102, January
2014, <http://www.rfc-editor.org/info/rfc7102>.
[Second6TischPlugtest]
"2nd 6Tisch Plugtest", <http://www.ietf.org/mail-
archive/web/6tisch/current/pdfgDMQcdCkRz.pdf>.
Authors' Addresses
Maria Ines Robles
Ericsson
Hirsalantie 11
Jorvas 02420
Finland
Email: maria.ines.robles@ericsson.com
Robles, et al. Expires October 7, 2016 [Page 30]
Internet-Draft Useof6553 April 2016
Michael C. Richardson
Sandelman Software Works
470 Dawson Avenue
Ottawa, ON K1Z 5V7
CA
Email: mcr+ietf@sandelman.ca
URI: http://www.sandelman.ca/
Pascal Thubert
Cisco Systems, Inc
Village d'Entreprises Green Side 400, Avenue de Roumanille
Batiment T3, Biot - Sophia Antipolis 06410
France
Email: pthubert@cisco.com
Robles, et al. Expires October 7, 2016 [Page 31]
