ROLL Working Group                                             M. Robles
Internet-Draft                                                  Ericsson
Intended status: Informational                             M. Richardson
Expires: March 17, April 21, 2016                                              SSW
                                                      September 14,
                                                              P. Thubert
                                                                   Cisco
                                                        October 19, 2015

              When to use RFC 6553, 6554 and IPv6-in-IPv6
                   draft-robles-roll-useofrplinfo-01
                   draft-robles-roll-useofrplinfo-02

Abstract

   This document states different cases where RFC 6553, RFC 6554 and
   IPv6-in-IPv6 encapsulation is required to set the bases to help
   defining the compression of RPL routing information in LLN
   environments.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology and Requirements Language . . . . . . . . . . . .   3
   3.  Sample/reference topology . . . . . . . . . . . . . . . . . .   4   3
   4.  Use cases . . . . . . . . . . . . . . . . . . . . . . . . . .   5   6
   5.  Storing mode  . . . . . . . . . . . . . . . . . . . . . . . .   7   8
     5.1.  Example of Flow from RPL-aware-leaf to root . . . . . . .   7
       5.1.1.  Summary of the use of headers . . . . . . . . . . . .   8
     5.2.  Example of Flow from root to RPL-aware-leaf . . . . . . .   8
       5.2.1.  Summary of the use of headers . . . . . . . . . . . .   8   9
     5.3.  Example of Flow from root to not-RPL-aware-leaf . . . . .   9
       5.3.1.  Summary of the use of headers . . . . . . . . . . . .   9  10
     5.4.  Example of Flow from not-RPL-aware-leaf to root . . . . .   9
       5.4.1.  Summary of the use of headers . . . . . . . . . . . .  10
     5.5.  Example of Flow from RPL-aware-leaf to Internet . . . . .  10
       5.5.1.  Summary of the use of headers . . . . . . . . . . . .  10  11
     5.6.  Example of Flow from Internet to RPL-aware-leaf . . . . .  11
       5.6.1.  Summary of the use of headers . . . . . . . . . . . .  11
     5.7.  Example of Flow from not-RPL-aware-leaf to Internet . . .  11
       5.7.1.  Summary of the use of headers . . . . . . . . . . . .  11  12
     5.8.  Example of Flow from Internet to not-RPL-aware-leaf . . .  12
       5.8.1.  Summary of the use of headers . . . . . . . . . . . .  12  13
     5.9.  Example of Flow from RPL-aware-leaf to RPL-aware-leaf . .  12
       5.9.1.  Summary of the use of headers . . . . . . . . . . . .  13  14
     5.10. Example of Flow from RPL-aware-leaf to not-RPL-aware-leaf  13
       5.10.1.  Summary of the use of headers  . . . . . . . . . . .  13 non-RPL-aware-leaf  15
     5.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf  13
       5.11.1.  Summary of the use of headers  . . . . . . . . . . .  14  16
     5.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware-
           leaf  . . . . . . . . . . . . . . . . . . . . . . . . . .  14
       5.12.1.  Summary of the use of headers  . . . . . . . . . . .  14  17
   6.  Non Storing mode  . . . . . . . . . . . . . . . . . . . . . .  15  18
     6.1.  Example of Flow from RPL-aware-leaf to root . . . . . . .  15
       6.1.1.  Summary of the use of headers . . . . . . . . . . . .  15  18
     6.2.  Example of Flow from root to RPL-aware-leaf . . . . . . .  16
       6.2.1.  Summary of the use of headers . . . . . . . . . . . .  16  19
     6.3.  Example of Flow from root to not-RPL-aware-leaf . . . . .  16
       6.3.1.  Summary of the use of headers . . . . . . . . . . . .  16  19
     6.4.  Example of Flow from not-RPL-aware-leaf to root . . . . .  17
       6.4.1.  Summary of the use of headers . . . . . . . . . . . .  17  20
     6.5.  Example of Flow from RPL-aware-leaf to Internet . . . . .  17
       6.5.1.  Summary of the use of headers . . . . . . . . . . . .  18  20
     6.6.  Example of Flow from Internet to RPL-aware-leaf . . . . .  18
       6.6.1.  Summary of the use of headers . . . . . . . . . . . .  18  21
     6.7.  Example of Flow from not-RPL-aware-leaf to Internet . . .  18
       6.7.1.  Summary of the use of headers . . . . . . . . . . . .  19  22
     6.8.  Example of Flow from Internet to not-RPL-aware-leaf . . .  19
       6.8.1.  Summary of the use of headers . . . . . . . . . . . .  19  23
     6.9.  Example of Flow from RPL-aware-leaf to RPL-aware-leaf . .  19
       6.9.1.  Summary of the use of headers . . . . . . . . . . . .  20  24
     6.10. Example of Flow from RPL-aware-leaf to not-RPL-aware-leaf  20
       6.10.1.  Summary of the use of headers  . . . . . . . . . . .  20  25
     6.11. Example of Flow from not-RPL-aware-leaf to RPL-aware-leaf  20
       6.11.1.  Summary of the use  26
     6.12. Example of headers Flow from not-RPL-aware-leaf to not-RPL-aware-
           leaf  . . . . . . . . . . .  21
     6.12. Example of Flow from not-RPL-aware-leaf to not-RPL-aware-
           leaf . . . . . . . . . . . . . . .  26
   7.  Future RPL work . . . . . . . . . . .  21
       6.12.1.  Summary of the use of headers . . . . . . . . . . .  21
   7. .  27
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  22
   8.  27
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  22
   9.  27
   10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  22
   10.  27
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  22
     10.1.  28
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  22
     10.2.  28
     11.2.  Informative References . . . . . . . . . . . . . . . . .  23  28
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  23  29

1.  Introduction

   RPL [RFC6550] is a routing protocol for constrained networks.  RFC
   6553 [RFC6553] defines the "RPL option", carried within the IPv6 Hop-
   by-Hop header to quickly identify inconsistencies in the routing
   topology.  RFC 6554 [RFC6554] defines the "RPL Source Route Header",
   an IPv6 Extension Header to deliver datagrams within a RPL routing
   domain.

   Several discussions in the ROLL/6lo/6TiSCH Mailing Lists took place
   focusing in the definition of how to compress RPL Information in
   constrained environment.  ROLL Virtual Interim Meeting (02-2015)
   concluded that there is a need to define how to use [RFC6553],
   [RFC6554] and IP-in-IP IPv6-in-IPv6 encapsulation to be able to set the
   correct environment for compression.  A Routing Header Dispatch for
   6LoWPAN (6LoRH) [I-D.thubert-6lo-routing-dispatch] defines a method
   to compress RPL Option information and Routing Header type 3
   (RFC6554) and an efficient IP-in-IP technique.

   This document is going to be focused in data plane messages and how
   can be transmitted within the above mentioned RFCs.

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).

   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: Storing, in storing mode, it is
   fully stateful or Non-Storing 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.

                                    +---------+
                                +---+Internet |
                                |   +---------+
                                |
                           +----+--+
                           |DODAG  |
                 +---------+Root   +----------+
                 |         |6LBR   |          |
                 |         +----+--+          |
                 |              |             |
                 |              |             |
                ...            ...           ...
                 |              |             |
           +-----+-+         +--+---+      +--+---+
           |6LR    |         |      |      |      |
     +-----+       |         |      |      |      |
     |     |       |         |      |      |      +------+
     |     +-----+-+         +-+----+      +-+----+      |
     |           |             |             |           |
     |           |             |             |           |
     |           |             |             |           |
   +-+---+     +-+---+      +--+--+       +- --+     +---+-+
   |Leaf |     |     |      |     |       |    |     |     |
   |6LN  |     |     |      |     |       |    |     |     |
   +-----+     +-----+      +-----+       +----+     +-----+

                    Figure 2: A reference RPL Topology.

   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
   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 IP-in-IP IPv6-in-
   IPv6 encapsulation is going to be analyzed for the following traffic
   flows:

      -Flow from RPL-aware-leaf to root

      -Flow from root to RPL-aware-leaf

      -Flow from not-RPL-aware-leaf to root

      -Flow from root to not-RPL-aware-leaf

      -Flow from RPL-aware-leaf to Internet

      -Flow from Internet to RPL-aware-leaf

      -Flow from not-RPL-aware-leaf to Internet

      -Flow from Internet to not-RPL-aware-leaf
      -Flow from RPL-aware-leaf to RPL-aware-leaf

      -Flow from RPL-aware-leaf to not-RPL-aware-leaf

      -Flow from not-RPL-aware-leaf to RPL-aware-leaf

      -Flow from 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 means that an intermediate router that needs to add a header
   must encapsulate the packet in an 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.

   This document recognizes that some headers such as a Routing Header
   or a Hop-by-Hop header may be modified by routers on the path of the
   packet without the need to add to remove an encapsulating header.

   The RPL RH and the RPL option are mutable but recoverable .

   RPI should be present in every single RPL data packet.  There is an
   exception in non-storing mode, when a packet is going down from the
   route: the entire route is written, so there are no loops of
   confusion about which table to use (purpose of instanceID).

   The applicability for Storing storing (RPL-SN) and Non-Storing (Non-S) non-Storing (RPL-NSN)
   modes for the previous cases is showed as follows:

   +-----------------+------+------+---------+-------+-------+---------+

   +---------------+------+------+---------+--------+--------+---------+
   | Use Case      | RPI RPL- | RH3 RPL- | RPL-SN  | RPL-   | RPL-   | RPL-NSN |
   |               | SN   | SN   | IP-in-  | Non-S NSN    | Non-S NSN    | Non-S IP-in-  |
   |               | (RFC RPI  | (RFC RH3  | IP      | RPI    | RH3    | IP-in- IP      |
   |               | (RFC | (RFC |         |        |        |         |
   |               | 6553 | 6554 |         |        |        | IP         |
   |               | )    | )    |         |        |        |         |
   +-----------------+------+------+---------+-------+-------+---------+
   +---------------+------+------+---------+--------+--------+---------+
   | RPL-aware-leaf RPL-aware-    | Yes  | ? No   | Yes No      | Yes    | ? No     | Yes No      |
   | leaf to root  |      |      |         |        |        |         |
   | root to RPL-  | ?    | ?    | Yes  | ? No   | No      | ? Yes    | Yes    | No      |
   | aware-leaf    |      |      |         |        |        |         |
   | not-RPL-aware- not-RPL-      | Yes  | ? No   | Yes     | Yes    | ? No     | Yes     |
   | leaf aware-leaf to |      |      |         |        |        |         |
   | root          |      |      |         |        |        |         |
   | root to not-  | ? Yes  | ? No   | Yes     | ? Yes    | ? Yes    | Yes     |
   | RPL-aware-leaf RPL-aware-    |      |      |         |        |        |         |
   | RPL-aware-leaf leaf          |      |      |         |        |        |         |
   | RPL-aware-    | Yes  | ? No   | Yes     | Yes    | ? No     | Yes     |
   | leaf to       |      |      |         |        |        |         |
   | Internet      |      |      |         |        |        |         |
   | Internet to   | ? Yes  | No   | ? Yes     | ? Yes    | ? Yes    | ? Yes     | ?
   | RPL-aware-    | RPL-aware-leaf      |      |         |        |        |         |
   | leaf          | not-RPL-aware-      | ?      | ?         | yes        | ?        | ?         |
   | not-RPL-      | Yes  | No   | leaf Yes     | Yes    | No     | Yes     |
   | aware-leaf to |      |      |         |        |        |         |
   | Internet      |      |      |         |        |        |         |
   | Internet to   | ? Yes  | ? No   | Yes     | ? Yes    | ? Yes    | Yes     |
   | not-RPL-aware- not-RPL-      |      |      |         |        |        |         |
   | leaf aware-leaf    |      |      |         |        |        |         |
   | RPL-aware-leaf RPL-aware-    | Yes  | ? No   | Yes No      | Yes    | ? Yes    | Yes     |
   | leaf to RPL-aware- RPL-  |      |      |         |        |        |         |
   | leaf aware-leaf    |      |      |         |        |        |         |
   | RPL-aware-leaf RPL-aware-    | ? Yes  | ? No   | Yes     | ? Yes    | ? Yes    | Yes     |
   | leaf to not-RPL- not-  |      |      |         |        |        |         |
   | aware-leaf RPL-aware-    |      |      |         |        |        |         |
   | not-RPL-aware- leaf          |      |      |         |        |        | ?         | ?
   | not-RPL-      | Yes  | ? No   | ? Yes     | Yes    | Yes    | leaf Yes     |
   | aware-leaf to RPL- |      |      |         |        |        |         |
   | aware-leaf RPL-aware-    |      |      |         |        |        |         |
   | not-RPL-aware- leaf          |      |      |         | ?        | ?        |         |
   | not-RPL-      | Yes  | ? No   | ? Yes     | Yes    | Yes    | leaf Yes     |
   | aware-leaf to not- |      |      |         |        |        |         |
   | RPL-aware-leaf not-RPL-      |      |      |         |        |        |         |
   | aware-leaf    |      |      |         |        |        |         |
   +-----------------+------+------+---------+-------+-------+---------+
   +---------------+------+------+---------+--------+--------+---------+

   Table 1: Posibility to transmit in Storing or Non-Storing mode: RPI,
                        RH3, IP-in-IP encapsulation

5.  Storing mode

5.1.  Example of Flow from RPL-aware-leaf to root

   As states in Section 16.2 of [RFC6550]  a leaf RPL-aware-leaf node does
   not generally issue DIO messages, a leaf node accepts DIO messages
   (In inconsistency a leaf node generates DIO with infinite rank, to
   fix it).  It may issue DAO and DIS messages though it generally
   ignores DAO and DIS messages.

   Related to RFC 6554 the Source Header route is added and removed by
   DODAG root.  RFC 6554 was created to strictly send information
   between RPL routers in the same RPL routing domain.

   In storing mode is suitable the use of RFC 6553 to send RPL
   Information through HBH field checking the routing table to find out
   where to send the message.  It may include IP-in-IP encapsulation to
   transmit information not related with the RPL domain.

   In this case the flow comprises:

   RPL-aware-leaf (6LN) --> 6LR --> 6LR,... --> root (6LBR)

   TODO: ADD explanation Note: In
   this document 6LRs, 6LBR are always full-fledge RPL routers

   The 6LN inserts the RPI header, and picture based on send the following table.

5.1.1.  Summary of packet to 6LR which
   decrement the use of headers

   TODO: What about fragmentations headers?

                 +-------------------+-----+-----+------+ rank in RPI and send the packet up.  When the packet
   arrives to 6LBR, the RPI is removed and the packet is processed.

                 +-------------------+-----+------+------+
                 | 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)

   TODO: ADD explanation

   In this case the 6LBR insert RPI header and picture based on send the following table

5.2.1.  Summary of packet down, the use of headers

   TODO: What about fragmentations headers?
                 +-------------------+------+-----+-----+
   6LR is going to increment the rank in RPI (examines instanceID for
   multiple tables), the packet is processed in 6LN and RPI removed.

                +-------------------+------+-------+------+
                | 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)

   TODO: ADD explanation and picture based on

   It includes IPv6-in-IPv6 encapsulation to transmit information not
   related with the following table

5.3.1.  Summary of RPL domain.  In the use of headers

   TODO: What about fragmentations headers?

          +-------------------+------+-----+-------------------+ 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.

   +-------------------+-------------------+-------------------+------+
   | Header            | 6LBR              | 6LR               | not-RPL-aware 6LN IPv6 |
          +-------------------+------+-----+-------------------+
   +-------------------+-------------------+-------------------+------+
   | Inserted headers  | ? IPv6-in-IPv6(RPI) | ? --                | ? --   |
   | Removed headers   | ? --                | ? IPv6-in-IPv6(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)

   TODO: ADD explanation and picture based on

   When the following table

5.4.1.  Summary of packet arrives from IPv6 node to 6LR.  This router insert
   the use of headers

   TODO: What about fragmentations headers?

          +-------------------+-------------------+-----+------+ RPI encapsuladed in a IPv6-in-IPv6 header addressed to the root.
   The root removes the header and process the packet

   +-------------------+------+--------------------+-------------------+
   | Header            | not-RPL-aware 6LN IPv6 | 6LR                | 6LBR              |
          +-------------------+-------------------+-----+------+
   +-------------------+------+--------------------+-------------------+
   | Inserted headers  | ? --   | ? IPv6-in-IPv6(RPI)  | ? --                |
   | Removed headers   | ? --   | ? --                 | ? IPv6-in-IPv6(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.  The
   router should take this information out before send the packet to
   Internet.  The HBH Option is going to be analyzed in each node to the
   root.

   In this case the flow comprises:

   RPL-aware-leaf (6LN) --> 6LR --> root (6LBR) --> Internet

   TODO: ADD explanation

   6LN insert RPI in a IPv6-in-IPv6 in a outer header, and picture based on send the following table

5.5.1.  Summary of
   packet to 6LR, which modified the use of headers

   TODO: What about fragmentations headers?

            +-------------------+-----+-----+------+----------+ rank in the RPI.  When the packet
   arrives to 6LBR, the RPI is removed.

   +----------+-------------------+-----+-------------------+----------+
   | Header   | 6LN               | 6LR | 6LBR              | Internet |
            +-------------------+-----+-----+------+----------+
   +----------+-------------------+-----+-------------------+----------+
   | Inserted | IPv6-in-IPv6(RPI) | --  | --                | --       |
   | headers  | ?                   | ?     | ?                   | ?          |
   | Removed  | --                | --  | IPv6-in-IPv6(RPI) | --       |
   | headers  | ?                   | ?     | ?                   | ?          |
   | Re-added | --                | --  | --                | --       |
   | headers  | ?                   | ?     | ?                   | ?          |
   | Modified | --                | RPI | --                | --       |
   | headers  | ?                   | ?     | ?                   | ?          |
   | Untouched Untouche | --                | --  | --                | --       |
   | d        |                   |     |                   |          |
   | 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)

   TODO: ADD explanation

   When the packet arrives from Internet to 6LBR the RPI header is added
   in a outer IPv6-in-IPv6 header and picture based on send to 6LR, which modifies the following table

5.6.1.  Summary of
   rank in the use of headers

   TODO: What about fragmentations headers?

            +-------------------+----------+------+-----+-----+ RPI.  When the packet arrives 6LN the RPI header is
   removed and the packet processed.

   +----------+----------+-------------------+-----+-------------------+
   | Header   | Internet | 6LBR              | 6LR | 6LN               |
            +-------------------+----------+------+-----+-----+
   +----------+----------+-------------------+-----+-------------------+
   | Inserted | --       | IPv6-in-IPv6(RPI) | --  | --                |
   | headers  | ?          | ?                   | ?     | ?                   |
   | Removed  | --       | --                | --  | IPv6-in-IPv6(RPI) |
   | headers  | ?          | ?                   | ?     | ?                   |
   | Re-added | --       | --                | --  | --                |
   | headers  | ?          | ?                   | ?     | ?                   |
   | Modified | --       | --                | RPI | --                |
   | headers  | ?          | ?                   | ?     | ?                   |
   | Untouched Untouche | --       | --                | --  | --                |
   | d        |          |                   |     |                   |
   | 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) = IPv6 node --> 6LR --> root (6LBR) -->
   Internet

   TODO: ADD explanation

   In the IPv6 node the flow label is assumed to be zero, the packet is
   transmited to 6LR which encapsule the RPI header in an outer IPv6-in-
   IPv6 header and picture based on send to 6LBR, which removes this header and send the following table

5.7.1.  Summary of
   packet to Internet and might set the use of headers

   TODO: What about fragmentations headers?
     +-------------------+-------------------+-----+------+----------+ flow label field.

   +----------+-----+-------------------+-------------------+----------+
   | Header   | not-RPL-aware 6LN IPv | 6LR               | 6LBR              | Internet |
     +-------------------+-------------------+-----+------+----------+
   |          | 6   |                   |                   |          |
   +----------+-----+-------------------+-------------------+----------+
   | Inserted | --  | IPv6-in-IPv6(RPI) | --                | --       |
   | headers  | ?     | ?                   | ?                   | ?          |
   | Removed  | --  | --                | IPv6-in-IPv6(RPI) | --       |
   | headers  | ?     | ?                   | ?                   | ?          |
   | Re-added | --  | --                | --                | --       |
   | headers  | ?     | ?                   | ?                   | ?          |
   | Modified | --  | --                | --                | --       |
   | headers  | ?     | ?                   | ?                   | ?          |
   | Untouched Untouche | --  | --                | --                | --       |
   | d        |     |                   |                   |          |
   | headers  | ?     | ?                   | ?                   | ?          |
     +-------------------+-------------------+-----+------+----------+
   +----------+-----+-------------------+-------------------+----------+

     Storing: Summary of the use of headers from not-RPL-aware-leaf to
                                 Internet

5.8.  Example of Flow from Internet to not-RPL-aware-leaf

   In this case the flow comprises:

   Internet --> root (6LBR) --> 6LR --> not-RPL-aware-leaf (6LN)

   TODO: ADD explanation

   6LBR get the packet from Internet and picture based add a RPI header encapsulated
   in a IPv6-in-IPv6 header addressed to 6LR and send the packet down.
   The flow label is set to zero on inner IP.  The last 6LR removes the following table

5.8.1.  Summary of
   RPI header.  The IPv6 node might set the use of headers

     +-------------------+----------+------+-----+-------------------+ flow label since may arrive
   with zero value.

   +----------+---------+-------------------+-------------------+------+
   | Header   | Internet Interne | 6LBR              | 6LR               | not-RPL-aware 6LN IPv6 |
   |          | t       |                   |                   |
     +-------------------+----------+------+-----+-------------------+      |
   +----------+---------+-------------------+-------------------+------+
   | Inserted | --      | IPv6-in-IPv6(RPI) | --                | --   |
   | headers  | ?         | ?                   | ?                   | ?      |
   | Removed  | --      | --                | IPv6-in-IPv6(RPI) | --   |
   | headers  | ?         | ?                   | ?                   | ?      |
   | Re-added | --      | --                | --                | --   |
   | headers  | ?         | ?                   | ?                   | ?      |
   | Modified | --      | --                | --                | --   |
   | headers  | ?         | ?                   | ?                   | ?      |
   | Untouched Untouche | --      | --                | --                | --   |
   | d        |         |                   |                   |      |
   | headers  | ?         | ?                   | ?                   | ?      |
     +-------------------+----------+------+-----+-------------------+
   +----------+---------+-------------------+-------------------+------+

     Storing: Summary of the use of headers from Internet to not-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
   storing and non-storing networks.  A node may send a P2P packet
   destined to a one-hop neighbor directly to that node.  Section 9 in
   [RFC6550].

   In this case the flow comprises:

   6LN --> 6LR --> root (6LBR) common parent (6LR) --> 6LR --> 6LN

   TODO: ADD explanation and picture based on

   This case is assumed in the following table

5.9.1.  Summary of same RPL Domain.  In the use common parent,
   the direction of headers

          +-------------------+---------+-----+------+---------+ RPI is changed (from increasing to decreasing the
   rank).

   +-------------+-------+---------------+---------------+-----+-------+
   | Header      | 6LN src   | 6LR           | 6LBR 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 not-RPL-aware-leaf non-RPL-aware-leaf

   In this case the flow comprises:

   6LN --> 6LR --> root (6LBR) common parent (6LR) --> 6LR --> not-RPL-aware 6LN

   TODO: ADD explanation

   Somehow, the sender has to know that the receiver is not RPL aware,
   and picture based on needs to know 6LR, and not even the following table

5.10.1.  Summary of root knows where the use of headers

       +-------------------+-----+-----+------+--------------------+ 6LR is
   (in storing mode).  This case FAILS.

   +-------+------------+------------+-------------+-------------+-----+
   | Header Heade | 6LN        | 6LR        | 6LBR 6LR (common | not-RPL-aware 6LBR 6LR         |
       +-------------------+-----+-----+------+--------------------+ IPv | Inserted headers
   | ? r     | ?            | ?            | ? parent)     |             | Removed headers 6   | ?
   +-------+------------+------------+-------------+-------------+-----+
   | ? Inser | ? IPv6-in-   | ? --         | --          | Re-added headers --          | ? --  | ?
   | ? ted h | ? IPv6(RPI)  |            | Modified headers             | ?             | ?     | ?
   | ? eader |            | Untouched headers            | ?             | ?             | ?     | ?
   |
       +-------------------+-----+-----+------+--------------------+ s     |            |            |             |             |     |
   | Remov | --         | --         | --          | IPv6-in-    | --  |
   | ed he |            |            |             | IPv6(RPI)   |     |
   | aders |            |            |             |             |     |
   | Re-   | --         | --         | --          | --          | --  |
   | added |            |            |             |             |     |
   | heade |            |            |             |             |     |
   | rs    |            |            |             |             |     |
   | Modif | --         | IPv6-in-   | IPv6-in-    | --          | --  |
   | ied h |            | IPv6(RPI)  | IPv6(RPI)   |             |     |
   | eader |            |            |             |             |     |
   | s     |            |            |             |             |     |
   | Untou | --         | --         | --          | --          | --  |
   | ched  |            |            |             |             |     |
   | heade |            |            |             |             |     |
   | rs    |            |            |             |             |     |
   +-------+------------+------------+-------------+-------------+-----+

    Storing: Summary of the use of headers from 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 --> root (6LBR) common parent (6LR) --> 6LR --> 6LN

   TODO: ADD explanation and picture based on

   The 6LR that get the following table

5.11.1.  Summary of packet from IPv6 node, insert the use RPI header
   encapsulated in IPv6-in-IPv6 header with destination to 6LN, the
   common parent change the direction of headers

       +-------------------+--------------------+-----+------+-----+ RPI and finally it is removed
   by 6LN.

   +-------+----+------------+-------------+-------------+-------------+
   | Header Heade | not-RPL-aware 6LBR IP | 6LR        | 6LBR common      | 6LR         | 6LN         |
       +-------------------+--------------------+-----+------+-----+
   | Inserted headers r     | ? v6 | ?            | ? parent      | ?             |             | Removed headers
   | ?       | ?    | ?            | ? (6LR)       |             | Re-added headers             | ?
   +-------+----+------------+-------------+-------------+-------------+
   | ? Inser | ? -- | ? IPv6-in-   | --          | Modified headers --          | ? --          | ?
   | ? ted h |    | IPv6(RPI)  |             |             |             |
   | eader |    |            |             |             |             |
   | s     |    |            |             |             |             |
   | Remov | -- | --         | --          | --          | IPv6-in-    |
   | ed he |    |            |             |             | IPv6(RPI)   |
   | aders |    |            |             |             |             |
   | Re-   | -- | --         | --          | --          | --          |
   | added | ?    |            | Untouched headers             | ?             | ?             | ?
   | ? heade |
       +-------------------+--------------------+-----+------+-----+    |            |             |             |             |
   | rs    |    |            |             |             |             |
   | Modif | -- | --         | IPv6-in-    | IPv6-in-    | --          |
   | ied h |    |            | IPv6(RPI)   | IPv6(RPI)   |             |
   | eader |    |            |             |             |             |
   | s     |    |            |             |             |             |
   | Untou | -- | --         | --          | --          | --          |
   | ched  |    |            |             |             |             |
   | heade |    |            |             |             |             |
   | rs    |    |            |             |             |             |
   +-------+----+------------+-------------+-------------+-------------+

     Storing: Summary of the use of headers from not-RPL-aware-leaf to
                              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 --> 6LR --> root (6LBR) --> 6LR --> not-RPL-aware
   6LN

   TODO: ADD explanation and picture based on the following table

5.12.1.  Summary of

   The problem to solve is how to indicate where to send the use of headers

   +--------------+-------------------+-----+------+-------------------+ packet when
   get into LLN.

   +---------+-----+----------------+---------+-----------------+------+
   | Header  | not-RPL-aware 6LN IPv | 6LR            | 6LBR 6LR     | not-RPL-aware 6LN 6LR             | IPv6 |
   | src         | 6   |                | (common |                 | dst  |
   +--------------+-------------------+-----+------+-------------------+
   | Inserted         | ? src |                | parent) |                 |      |
   +---------+-----+----------------+---------+-----------------+------+
   | Inserte | --  | IPv6-in-       | --      | --              | --   |
   | d       |     | IPv6(RPI)      | ?         | ?                 | ?      |
   | headers |     |                |         |                 |      |
   | Removed | ? --  | --             | ? --      | ? IPv6-in-        | ? --   |
   | headers |     |                |         | IPv6(RPI)       |      | Re-added
   | ? Re-     | --  | --             | --      | --              | --   |
   | added   |     |                | ?         | ?                 | ?      |
   | headers |     |                |         |                 |      | Modified
   | ? Modifie | --  | --             | --      | --              | --   |
   | d       |     |                | ?         | ?                 | ?      |
   | headers |     |                |         |                 |      | Untouched
   | ? Untouch | --  | --             | --      | --              | --   |
   | ed      |     |                | ?         | ?                 | ?      |
   | headers |     |                |         |                 |
   +--------------+-------------------+-----+------+-------------------+      |
   +---------+-----+----------------+---------+-----------------+------+

     Storing: Summary of the use of headers from not-RPL-aware-leaf to
                            not-RPL-aware-leaf

6.  Non Storing mode

6.1.  Example of Flow from RPL-aware-leaf to root

   In non-storing mode the leaf node uses Hop-By-Hop option (RFC 6553)
   to indicate the routing information to send messages to the DODAG
   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
   going to be removed, neither RH3, the flow comprises:

   RPL-aware-leaf (6LN) --> 6LR --> root (6LBR)

   +------------------+
   |  Dispatch        |
   |                  |
   +------------------+
   |  LowPAN_HC       |
   |                  |
   +------------------+
   |  rpl_option      |
   |                  |
   +------------------+
   |   SHR            |
   |                  |
   +------------------+
   | IPv6 payload     |
   |                  |
   +------------------+

              Figure 3: From leaf to Root - Non-Storing Mode

   TODO: ADD explanation/fix picture based on the following table

6.1.1.  Summary of

   This case is the use of headers
                 +-------------------+-----+-----+------+ same case as storing mode.

                 +-------------------+-----+------+------+
                 | Header            | 6LN | 6LR  | 6LBR |
                 +-------------------+-----+-----+------+
                 +-------------------+-----+------+------+
                 | Inserted headers  | ? RPI | ? --   | ? --   |
                 | Removed headers   | ? --  | ? --   | ? RPI  |
                 | Re-added headers  | ? --  | ? --   | ? --   |
                 | Modified headers  | ? --  | ? RPI  | ? --   |
                 | 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)

   TODO: ADD explanation

   6LBR might instert RPI header, and picture based on the following table

6.2.1.  Summary of the use of headers

                 +-------------------+------+-----+-----+ rute is indicated in RH3. 6LR
   updated RH3 and 6LN remove these headers.

      +-------------------+----------------------+------+----------+
      | Header            | 6LBR                 | 6LR  | 6LN      |
                 +-------------------+------+-----+-----+
      +-------------------+----------------------+------+----------+
      | Inserted headers  | ? (optional: 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 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 (6LN)

   TODO: ADD explanation (IPv6 node)

   In 6LBR the RH3 is added, and picture based on modified in 6LR where is fully
   consumed, but left there.  If the following table

6.3.1.  Summary of RPI is present, the use of headers
          +-------------------+------+-----+-------------------+ IPv6 node which
   does not understand it will drop it.  To avoid it the RPI should be
   removed before reach IPv6 node or it is recommended that RPI be
   omitted.  An IPv6-in-IPv6 header should be necessary in this case.
   The DAO from 6LR about IPv6 could say if that the final IPv6 is not
   RPL (RPI) capable.

                 +-------------------+------+-----+------+
                 | Header            | 6LBR | 6LR | not-RPL-aware 6LN 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 not-RPL-
                                aware-leaf

6.4.  Example of Flow from not-RPL-aware-leaf to root

   In this case the flow comprises:

   not-RPL-aware-leaf (6LN)

   IPv6-node --> 6LR 6LR1 --> 6LR2 --> root (6LBR)

   TODO: ADD explanation and picture based on

   In this case the following table

6.4.1.  Summary of RPI is encapsulated in the use of headers

          +-------------------+-------------------+-----+------+ first 6LR, and is not
   modified in the followings 6LRs.

   +-------------+------+-------------------+------+-------------------+
   | Header      | not-RPL-aware 6LN IPv6 | 6LR 6LR1              | 6LR2 | 6LBR              |
          +-------------------+-------------------+-----+------+
   +-------------+------+-------------------+------+-------------------+
   | Inserted    | --   | IPv6-in-IPv6(RPI) | --   | --                |
   | headers     | ?      | ?                   | ?      |                   |
   | Removed     | --   | --                | --   | IPv6-in-IPv6(RPI) |
   | headers     | ?      | ?                   | ?      |                   |
   | Re-added    | --   | --                | --   | --                |
   | headers     | ?      | ?                   | ?      |                   |
   | Modified    | --   | --                | --   | --                |
   | headers     | ?      | ?                   | ?      |                   |
   | Untouched   | --   | IPv6-in-IPv6(RPI) | --   | --                |
   | headers     | ?      | ?                   | ?      |
          +-------------------+-------------------+-----+------+                   |
   +-------------+------+-------------------+------+-------------------+

   Non Storing: Summary of the use of headers from not-RPL-aware-leaf to
                                   root

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

   TODO: ADD explanation and picture based on

   This case requires that the following table

6.5.1.  Summary network is awareness of what is external
   to the use of headers

            +-------------------+-----+-----+------+----------+ LLN.  Internet node never sees RPI or IPv6-in-IPv6 header.  In
   the 6LBR the flow label is computed if it is zero.  RPI remains
   unmodified.

   +----------+-------------------+-----+-------------------+----------+
   | Header   | 6LN               | 6LR | 6LBR              | Internet |
            +-------------------+-----+-----+------+----------+
   +----------+-------------------+-----+-------------------+----------+
   | Inserted | IPV6-in-IPv6(RPI) | --  | --                | --       |
   | headers  | ?                   | ?     | ?                   | ?          |
   | Removed  | --                | --  | IPV6-in-IPv6(RPI) | --       |
   | headers  | ?                   | ?     | ?                   | ?          |
   | Re-added | --                | --  | --                | --       |
   | headers  | ?                   | ?     | ?                   | ?          |
   | Modified | --                | --  | --                | --       |
   | headers  | ?                   | ?     | ?                   | ?          |
   | Untouched Untouche | --                | RPI | --                | --       |
   | d        |                   |     |                   |          |
   | headers  | ?                   | ?     | ?                   | ?          |
            +-------------------+-----+-----+------+----------+
   +----------+-------------------+-----+-------------------+----------+

     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)

   TODO: ADD explanation and picture based on

   If the following table

6.6.1.  Summary of last RH3 entry is the use of headers

            +-------------------+----------+------+-----+-----+ 6LR, then the IPv6-in-IPv6 will be
   removed there, if the last entry is the 6LN, then the RH3 will go all
   the way to the leaf.  In 6LBR the flow label should be set to zero.

   +---------+--------+-------------------------+----------------+-----+
   | Header  | Internet Intern | 6LBR                    | 6LR            | 6LN |
            +-------------------+----------+------+-----+-----+
   | Inserted         | et     |                         |                |     |
   +---------+--------+-------------------------+----------------+-----+
   | Inserte | --     | IPv6-in-                | --             | --  |
   | d       |        | IPv6(RH3,optional:RPI)  |                |     |
   | headers | ?        | ?                         | ?                | ?     |
   | Removed | --     | --                      | IPv6-in-IPv6   | --  |
   | headers | ?        | ?                         | ? can be removed |     |
   |         |        |                         | if RH3         |     |
   |         |        |                         | consumed       |     |
   | Re-     | --     | --                      | --             | --  |
   | added   |        |                         |                | ?     |
   | Re-added headers | ?        | ?                         | ?                | ?     |
   | Modified Modifie | --     | --                      | IPv6-in-       | --  |
   | d       |        |                         | IPv6(RH3)      |     |
   | headers | ?        | ?                         | ?                | ?     |
   | Untouched Untouch | --     | --                      | --             | --  |
   | ed      |        |                         |                |     |
   | headers | ?        | ?                         | ?                | ?     |
            +-------------------+----------+------+-----+-----+
   +---------+--------+-------------------------+----------------+-----+

     Non Storing: Summary of the use of headers from Internet to RPL-aware-
                                   leaf 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

   TODO: ADD explanation and picture based on

   In this case the following table

6.7.1.  Summary of flow label is recommended to be zero in the use of IPv6
   node. no RPL headers

     +-------------------+-------------------+-----+------+----------+ are added in the IPv6 node, since it is ignorant
   of RPL.  Internet node does not see special headers.  In 6LBR the
   flow label is computed if it is zero.

   +----------+-----+-------------------+-------------------+----------+
   | Header   | not-RPL-aware 6LN IPv | 6LR               | 6LBR              | Internet |
     +-------------------+-------------------+-----+------+----------+
   |          | 6   |                   |                   |          |
   +----------+-----+-------------------+-------------------+----------+
   | Inserted | --  | IPv6-in-IPv6(RPI) | --                | --       |
   | headers  | ?     | ?                   | ?                   | ?          |
   | Removed  | --  | --                | IPv6-in-IPv6(RPI) | --       |
   | headers  | ?     | ?                   | ?                   | ?          |
   | Re-added | --  | --                | --                | --       |
   | headers  | ?     | ?                   | ?                   | ?          |
   | Modified | --  | --                | --                | --       |
   | headers  | ?     | ?                   | ?                   | ?          |
   | Untouched Untouche | --  | --                | --                | --       |
   | d        |     |                   |                   |          |
   | headers  | ?     | ?                   | ?                   | ?          |
     +-------------------+-------------------+-----+------+----------+
   +----------+-----+-------------------+-------------------+----------+

   Non Storing: Summary of the use of headers from not-RPL-aware-leaf to
                                 Internet

6.8.  Example of Flow from Internet to not-RPL-aware-leaf

   In this case the flow comprises:

   Internet --> root (6LBR) --> 6LR --> not-RPL-aware-leaf (6LN)

   TODO: ADD explanation and picture based on the following table

6.8.1.  Summary of

   In this case the use of headers

     +-------------------+----------+------+-----+-------------------+ flow label in 6LBR should be set zero in 6LBR, where
   RH3 is inserted and optionally RHI.  RH3 must end at 6LR.

   +---------+--------+-------------------------+---------------+------+
   | Header  | Internet Intern | 6LBR                    | 6LR           | not-RPL-aware 6LN IPv6 |
   |         | et     |                         |               |      |
   +---------+--------+-------------------------+---------------+------+
   | Inserte | --     | IPv6-in-                | --            | --   |
   | d       |        | IPv6(RH3,optional:RPI)  |               |      |
     +-------------------+----------+------+-----+-------------------+
   | Inserted headers | ?        | ?                         | ?               | ?      |
   | Removed | --     | --                      | IPv6-in-      | --   |
   | headers | ?        | ?                         | ? IPv6(RH3,     |      |
   |         |        |                         | RPI)          |      |
   | Re-     | --     | --                      | --            | --   |
   | added   |        |                         |               | ?      |
   | Re-added headers | ?        | ?                         | ?               | ?      |
   | Modified Modifie | --     | --                      | --            | --   |
   | d       |        |                         |               |      |
   | headers | ?        | ?                         | ?               | ?      |
   | Untouched Untouch | --     | --                      | --            | --   |
   | ed      |        |                         |               |      |
   | headers | ?        | ?                         | ?               | ?      |
     +-------------------+----------+------+-----+-------------------+

     Storing:
   +---------+--------+-------------------------+---------------+------+

    NonStoring: Summary of the use of headers from Internet to not-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

   TODO: ADD explanation and picture based on

   This case comprises in the following table

6.9.1.  Summary of same RPL Domain.  In the use of headers

          +-------------------+---------+-----+------+---------+ 6LN the RPI
   header is inserted.  In the 6LBR the RH3 header is inserted in a
   IPv6-in-IPv6 header and removed at the 6LN destination.

   +-----------+------+---------------------+-----+--------------------+
   | Header    | 6LN src | 6LR  | 6LBR                | 6LR | 6LN dst            |
          +-------------------+---------+-----+------+---------+
   |           | src  |                     |     |                    |
   +-----------+------+---------------------+-----+--------------------+
   | Inserted  | RPI  | IPv6-in-IPv6(RH3 to | --  | --                 |
   | headers   | ?      | ? 6LN)                |     |                    |
   |           |      | {IP,RPI,payload}    | ?     | ?                    |
   | Removed   | --   | --                  | --  | IPv6-in-IPv6(RH3)  |
   | headers   | ?      | ?                     | ?     | ? {IP,RPI,payload}   |
   | 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

   TODO: ADD explanation

   The 6LN insert the RPI in a IPv6-in-IPv6 header, which is addressed
   to 6LBR.  The 6LBR remove this RPI header and picture based on insert a RH3 header
   with an optional RPI.  These headers are removed by 6LR before send
   the following table

6.10.1.  Summary of packet to the use of headers

       +-------------------+-----+-----+------+--------------------+ IPv6 node.

   +------------+-------------------+-------------+-------------+------+
   | Header     | 6LN               | 6LR | 6LBR        | not-RPL-aware 6LBR 6LR         | IPv6 |
       +-------------------+-----+-----+------+--------------------+
   +------------+-------------------+-------------+-------------+------+
   | Inserted   | IPv6-in-IPv6(RPI) | IPIP(RH3,   | --          | --   |
   | headers    | ?                   | ? opt RPI)    | ?             | ?      |
   | Removed    | --                | IPIP(RPI)   | IPIP(RH3,   | --   |
   | headers    | ?                   | ?             | ? opt 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
                            not-RPL-aware-leaf

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

   TODO: ADD explanation and picture based on the following table

6.11.1.  Summary of

   RPI is added in 6LR until the use of headers

       +-------------------+--------------------+-----+------+-----+ root and then removed, then RH3 is
   added and removed at destination.

    +-------------------+------+------------+-----------+------------+
    | Header            | not-RPL-aware 6LBR 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

   TODO: ADD explanation and picture based on the following table

6.12.1.  Summary of

   RPI is added in 6LR until the use of root and then might be removed, then
   RH3 is added.  These headers

   +--------------+-------------------+-----+------+-------------------+ are removed at 6LR before go to
   destination.

   +--------------+------+-----------+-----------+--------------+------+
   | Header       | not-RPL-aware 6LN IPv6 | 6LR       | 6LBR      | not-RPL-aware 6LN |
   |              | src               |     | 6LR          | dst 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.  Future RPL work

   There are cases from above that are not clear how to send the
   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:

   - Flow from RPL-aware-leaf to non-RPL-aware-leaf: Somehow, the sender
   has to know that the receiver is not RPL aware, and needs to know
   6LR, and not even the root knows where the 6LR is located.

   - Flow from not-RPL-aware-leaf to not-RPL-aware-leaf: The problem to
   solve is how to indicate where to send the packet when get into LLN.

8.  IANA Considerations

   There are no IANA considerations related to this document.

8.

9.  Security Considerations

   TODO.

9.

10.  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 Vilajosana and
   Pascal Thubert Robert Cragie.

   To be completed with additional Acknowledgments.

10.

11.  References

10.1.

11.1.  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>.

   [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>.

   [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>.

10.2.

11.2.  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-08 (work
              in progress), May 2015.

   [I-D.thubert-6lo-routing-dispatch]
              Thubert, P., Bormann, C., Toutain, L., and R. Cragie, "A
              Routing Header Dispatch for 6LoWPAN", draft-thubert-6lo-
              routing-dispatch-06 (work in progress), August 2015.

   [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>.

Authors' Addresses

   Maria Ines Robles
   Ericsson
   Hirsalantie 11
   Jorvas  02420
   Finland

   Email: maria.ines.robles@ericsson.com

   Michaelbl

   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