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6TSCH                                                       Q. Wang, Ed.
Internet-Draft                           Univ. of Sci. and Tech. Beijing
Intended status: Informational                             X. Vilajosana
Expires: January 14, 2014                Universitat Oberta de Catalunya
                                                             T. Watteyne
                                                       Linear Technology
                                                           July 13, 2013


                    6TSCH Operation Sublayer (6top)
                        draft-wang-6tsch-6top-00

Abstract

   The recently published [IEEE802154e] standard formalizes the concept
   of link-layer resources in LLNs.  Nodes are synchronized and follow a
   schedule.  A time slot in that schedule corresponds to an atomic
   link-layer resource, and can be allocated to any pair of neighbors in
   the network.  This allows the schedule to be built to tightly match
   each node's bandwidth, latency and energy constraints, while ensuring
   collision-free communication.  The [IEEE802154e] standard does not,
   however, present a mechanism to do so, as building and managing the
   schedule is out of the standard's scope.  Routing layers such as the
   IETF IPv6 Routing Protocol for LLNs (RPL) provide a mechanism to
   route multipoint-to-point traffic (from devices inside the LLN
   towards a central control point) and point-to-multipoint traffic
   (from the central control point to the devices inside the LLN).
   Network layer overlays cannot be optimized and adapted to take
   advantage of the cell-based topology created by the underlying TSCH
   MAC layer as a missing set of functionalities need to be defined.
   This document describes the 6TSCH Operation Sublayer (6top) and the
   main commands it provides to upper network layers such as RPL or
   GMPLS.  The set of functionalities includes feedback metrics from
   cell states so network layers can take routing decisions, TSCH
   configuration and control procedures, and the support for centralized
   and decentralized scheduling policies.  In addition, 6top can be
   configured to enable packet switching at layer 2.5, analogous to
   GMPLS.  Once a multi-hop track is defined, input cells can be mapped
   to output cells and packets can be relayed without the need of higher
   layer routing. 6top defines the operations so input cells and output
   cells can be mapped and the configuration maintained.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.





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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  6TSCH Operation Sublayer (6top) . . . . . . . . . . . . . . .   4
     2.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .   5
     2.2.  Cell Model  . . . . . . . . . . . . . . . . . . . . . . .   5
       2.2.1.  hard cells  . . . . . . . . . . . . . . . . . . . . .   7
       2.2.2.  soft cells  . . . . . . . . . . . . . . . . . . . . .   7
     2.3.  Data Convey Model . . . . . . . . . . . . . . . . . . . .   7
     2.4.  Commands  . . . . . . . . . . . . . . . . . . . . . . . .   9
       2.4.1.  Cell Commands . . . . . . . . . . . . . . . . . . . .   9
       2.4.2.  Slotframe Commands  . . . . . . . . . . . . . . . . .  14
       2.4.3.  Monitoring Commands . . . . . . . . . . . . . . . . .  15
       2.4.4.  Statistics Commands . . . . . . . . . . . . . . . . .  17
       2.4.5.  Network Formation Commands  . . . . . . . . . . . . .  19
       2.4.6.  Time Source Neighbor Commands . . . . . . . . . . . .  21
       2.4.7.  Neighbor Commands . . . . . . . . . . . . . . . . . .  22
       2.4.8.  Queueing Commands . . . . . . . . . . . . . . . . . .  24
       2.4.9.  Security Commands . . . . . . . . . . . . . . . . . .  27
       2.4.10. Data Commands . . . . . . . . . . . . . . . . . . . .  29
       2.4.11. Label Switching Commands  . . . . . . . . . . . . . .  30



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     2.5.  Message Formats . . . . . . . . . . . . . . . . . . . . .  31
       2.5.1.  Information Elements  . . . . . . . . . . . . . . . .  32
       2.5.2.  Packet Formats  . . . . . . . . . . . . . . . . . . .  40
     2.6.  Time Sequence . . . . . . . . . . . . . . . . . . . . . .  45
       2.6.1.  Network Formation . . . . . . . . . . . . . . . . . .  45
       2.6.2.  Creating soft cells . . . . . . . . . . . . . . . . .  46
       2.6.3.  Deleting soft cells . . . . . . . . . . . . . . . . .  47
       2.6.4.  Maintaining soft cells  . . . . . . . . . . . . . . .  48
       2.6.5.  Creating hard cells . . . . . . . . . . . . . . . . .  48
       2.6.6.  Deleting hard cells . . . . . . . . . . . . . . . . .  48
     2.7.  Statistics  . . . . . . . . . . . . . . . . . . . . . . .  49
       2.7.1.  Statistics Metrics  . . . . . . . . . . . . . . . . .  49
       2.7.2.  Statistics Configuration  . . . . . . . . . . . . . .  49
     2.8.  Monitoring  . . . . . . . . . . . . . . . . . . . . . . .  50
       2.8.1.  Monitor Configuration . . . . . . . . . . . . . . . .  50
       2.8.2.  Actuation . . . . . . . . . . . . . . . . . . . . . .  50
     2.9.  Label Switching . . . . . . . . . . . . . . . . . . . . .  51
   3.  Using 6top  . . . . . . . . . . . . . . . . . . . . . . . . .  51
     3.1.  RPL on 6top . . . . . . . . . . . . . . . . . . . . . . .  51
       3.1.1.  Support to Neighbor Discovery and Parent Selection  .  51
       3.1.2.  Support of Rank Computation . . . . . . . . . . . . .  52
       3.1.3.  Support of Control Messages Broadcast . . . . . . . .  53
       3.1.4.  Support to QoS  . . . . . . . . . . . . . . . . . . .  53
     3.2.  GMPLS on 6top . . . . . . . . . . . . . . . . . . . . . .  55
       3.2.1.  Cell Reservation Support for GMPLS on 6top  . . . . .  55
       3.2.2.  Supporting QoS  . . . . . . . . . . . . . . . . . . .  55
   4.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  56
     4.1.  Normative References  . . . . . . . . . . . . . . . . . .  56
     4.2.  Informative References  . . . . . . . . . . . . . . . . .  56
     4.3.  External Informative References . . . . . . . . . . . . .  59
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  60

1.  Introduction

   As presented in [I-D.watteyne-6tsch-tsch-lln-context], the
   [IEEE802154e] standard defines the mechanisms for a TSCH node to
   communicate, given a schedule.  It does not, however, define the
   policies to build and maintain the TSCH schedule, match that schedule
   to the multi-hop paths maintained by a network layer such as RPL or a
   2.5 layer such as GMPLS, adapt the resources allocated between
   neighbor nodes to the data traffic flows, enforce a differentiated
   treatment for data generated at the application layer and signaling
   messages needed by 6LoWPAN and RPL to discover neighbors, react to
   topology changes, self-configure IP addresses, or manage keying
   material.

   In a TSCH network, the MAC layer is not in charge of setting up the
   schedule that controls the connectivity graph of the network and the



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   resources allocated to each cell in that topology.  This
   responsibility is left to an upper layer, defined in this document
   and called "6top".

   This document describes the 6TSCH Operation Sublayer (6top) and the
   main commands provided to upper network layers such as RPL or GMPLS.
   The set of functionalities include feedback metrics from cell state
   so the network layer can take routing decisions, TSCH configuration
   and control procedures, and support for centralized and decentralized
   scheduling policies. 6top addresses the set of functionalities
   described in [I-D.watteyne-6tsch-tsch-lln-context].

   For example, network formation in a TSCH network is handled by the
   use of Enhanced Beacons (EB).  EBs include information for joining
   nodes to be able to synchronize and set up an initial network
   topology.  However, [IEEE802154e] does not specify how the period of
   EBs is configured, nor the rules for a node to select a particular
   node to join. 6top offers a set of commands so control mechanisms can
   be introduced on top of TSCH to configure nodes to join a specific
   node and obtain a unique 16-bit identifier from the network.  Once a
   network is formed, 6top maintains the network's health, allowing for
   nodes to stay synchronized.  It supplies mechanisms to manage each
   node's time source neighbor and configure the EB interval.  Network
   layers running on top of 6top take advantage of the TSCH MAC layer
   information so routing metrics, topological information, energy
   consumption and latency requirements can be adjusted to TSCH, and
   adapted to application requirements.

   TSCH requires a mechanism to manage its schedule; 6top provides a set
   of commands for upper layers to set up specific schedules, either
   explicitly by detailing specific cell information, or by allowing
   6top to establish a schedule given a bandwidth or latency
   requirement. 6top is designed to enable centralized, decentralized or
   hybrid scheduling entities. 6top enables internal TSCH queuing
   configuration, size of buffers, packet priorities, transmission
   failure behavior, and defines mechanisms to encrypt and authenticate
   MAC slotframes.

   As described in [label-switching-154e], due to the slotted nature of
   TSCH networks, it is possible to use a label switched architecture on
   top of TSCH cells.  As a cell belongs to a specific track, a label
   header is not needed at each packet; the input cell (or bundle) and
   the output cell (or bundle) uniquely identify the data flow.  The
   6top sublayer provides operations to manage the cell mappings.

2.  6TSCH Operation Sublayer (6top)





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2.1.  Overview

   6top is a sublayer which is the next-higher layer for TSCH, as
   detailed in [I-D.thubert-6tsch-architecture]. 6top offers both
   management and data interfaces to an upper layer.  It includes
   monitoring and statistics collection, both of which are configurable
   through the management interface.

   6top distinguishes between hard cells and soft cells.  It therefore
   requires an extra flag to all cells in the TSCH schedule, as detailed
   in Section 2.2.

   When a higher layer gives 6top a 6LoWPAN packet for transmission,
   6top maps it to the appropriate outgoing priority-based queue, as
   detailed in Section 2.3.

   All commands of the management and data interfaces are detailed in
   Section 2.4.  This set of commands is designed to support
   centralized, decentralized and hybrid scheduling entities.

   6top defines TSCH Information Elements (IEs) for neighbors nodes to
   negociate scheduling cells in the TSCH schedule.  The format of those
   is given in Section 2.5.

   Example data exchanges between neighbor nodes are illustrated in
   Section 2.6.

   Section 2.7 defines how 6top gathers statistics (e.g. link quality,
   energy level, queue usage), and what commands an upper layer can use
   to configure and retrieve statistics.

   6top can be configured to monitor some cells it has scheduled in
   order to detect cells with poor performance.  It can then
   automatically move those cells inside the TSCH schedule.  This
   behavior is described in Section 2.8

2.2.  Cell Model

   IEEE802.15.4e defines a set of options attached to each cell.  A cell
   can be a Transmit cell, a Receive cell, a Shared cell or a
   Timekeeping cell.  These options are not exclusive, as a cell can be
   qualified with more than one of them.  The IEEE802.15.4e MLME-SET-
   LINK.request command uses a linkOptions bitmap to specify the options
   of a cell.  Acceptable values are:

      b0 = Transmit

      b1 = Receive



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      b2 = Shared

      b3 = Timekeeping

      b4-b7 = Reserved

   Only Transmit cells can also be marked as Shared cells.  When the
   shared bit is set, a back-off procedure is applied to handle
   collisions.  Shared behavior does not apply to Receive cells.

   6top allows an upper layer to schedule a cell at a specific timeslot
   and channel offset, in a specific slotframe. 6top follows the hard
   cell reservation process described in Section 2.6.5.

   In addition, 6top allows an upper layer to schedule a certain amount
   of bandwidth to a neighbor, without having to specify the exact
   timeslot(s) and channel offset(s). 6top follows the soft cell
   reservation process described in Section 2.6.2.  Once bandwidth is
   reserved, 6top is in charge of ensuring that this requirement is
   continuously satisfied, as described in Section 2.8. 6top dynamically
   reallocates slots if needed, and overprovisions if required.

   6top allows an upper layer to associate a hard/soft cell with a
   specific track by using a TrackID.  A TrackID is a tuple
   (TrackOwnerAddr,InstanceID), where TrackOwnerAddr is the address of
   the node which initalizes the process of creating the track, i.e. the
   owner of the track; and InstanceID is an instance identifier given by
   the owner of the track.  InstanceID comes from upper layer;
   InstanceID could for example be the local instance ID defined in RPL.

   If the TrackID is set to (0,0), the cell can be used by the best-
   effort QoS configuration or as a Shared cell.  If the TrackID is not
   set to (0,0), i.e. the cell belongs to a specific track, the cell
   must not be set as Shared cell.

   Given this mechanism, 6top defines hard cells (which have been
   requested specifically) and soft cells (which that can be reallocated
   dynamically).  The hard/soft flag is introduced by the 6top sublayer
   as an extension of the IEEE802.15.4e LinkOption flags.  This option
   is mandatory; all cells are either hard or soft.

   With the addition of the Hard/Soft flag, the resulting flags are:

      b0 = Transmit

      b1 = Receive

      b2 = Shared



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      b3 = Timekeeping

      b4 = Hard (1)/Soft (0)

      b5-b7 = Reserved

2.2.1.  hard cells

   A hard cell is a cell that cannot be dynamically reallocated by 6top.
   A hard cell is uniquely identified by the following tuple:

      slotframe id: id of the slotframe this cell is part of.

      timeslot: the slot within the slotframe.

      channel offset.

      LinkOption bitmap: bitmap as defined in Section 2.2, including the
      hard/soft bit which must be set to 1.

2.2.2.  soft cells

   A soft cell is a cell that can be reallocated by 6top dynamically.
   The hard/soft bit must be set to 0.  This cell is installed by 6top
   given a specific bandwidth requirement. soft cells are installed
   through the soft cell negotiation procedure described in Section 2.6.

2.3.  Data Convey Model

   Once a TSCH schedule is established, 6top is responsible for feeding
   the data flow from the upper layer into TSCH.  This section describes
   how 6top shapes data from the upper layer (e.g. RPL, 6LoWPAN), and
   feeds it to TSCH.  Since 6top is a sublayer between TSCH and 6LoWPAN,
   the properties associated with a packet/fragment from the upper layer
   includes the next hop neighbor (DestAddr) and expected sending
   priority of the packet (Priority), and/or TrackID(s).  The output to
   TSCH is the fragment corresponding to the next active cell in the
   TSCH schedule.

   6top Data Convey Model











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                       |
                       | (DestAddr, Priority, Fragment)
                       |
   +---------------------------------------+
   |                 I-MUX                 |
   +---------------------------------------+
     |       |       |       |    ....   |
     |       |       |       |           |
   +---+   +---+   +---+   +---+       +---+
   |   |   |   |   |   |   |   |       |   |
   |Q1 |   |Q2 |   |Q3 |   |Q4 |       |Qn |
   |   |   |   |   |   |   |   |       |   |
   +---+   +---+   +---+   +---+       +---+
     |       |       |       |           |
     |       |       |       |           |
   +---------------------------------------+
   |                 MUX                   |
   +---------------------------------------+
                      |
                      |
                    +---+
                    |PDU|
                    +---+
                      |
                      | TSCH MAC-payload
                      |

                                 Figure 1

   In Figure 1, Qi represents a queue, which is either broadcast or
   unicast, and is assigned a priority.  The number of queues is
   configurable.  The relationship between queues and tracks is
   configurable.  For example, for a given queue, only one specific
   track can be used, or all of the tracks can be used, or a subset of
   tracks can be used.

   When 6top receives a packet to transmit through a Send.data command
   (Section 2.4.10), the I-MUX module selects a queue in which to insert
   it.  If the packet's destination address is a unicast (resp.
   broadcast) address, it will be inserted into a unicast (resp.
   broadcast) queue.

   The MUX module is invoked at each scheduled transmit cell by TSCH.
   When invoked, the MUX module goes through the queues, looking for the
   best frame to send.  If it finds a frame, it hands it over to TSCH
   for transmission.  If the next active cell is a broadcast cell, it
   selects a fragment only from broadcast queues.




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   How the MUX module selects the best frame is configurable.
   Typically, the following rules are used:

      The frame's layer 2 destination address must match the neighbor
      address associated with the transmit cell.

      If the transmit cell is associated with a specific track, the
      frames in the queue corresponding to the TrackID have the highest
      priority.

      If the transmit cell is not associated with a specific track, i.e.
      TrackID=(0,0), frames from a queue with a higher priority must be
      sent before frames from a queue with a lower priority.

   Further rules can be configured to satisfy specific QoS requirements.

2.4.  Commands

   6top provides a set of commands a higher layer can call, including
   management commands and data commands.  Most of these commands are
   related to the management of slotframes, time slots and scheduling
   information. 6top also provides an interface allowing an upper layer
   to retrieve status information and statistics.  This section lists
   the commands offered by 6top.

2.4.1.  Cell Commands

   The following methods allow an upper layer to manage the network
   schedule:

2.4.1.1.  CREATE.hardcell

   Creates one or more hard cells in the schedule.  Fails if the cell
   already exists.  A cell is uniquely identified by the tuple
   (slotframe id, timeslot, channel offset).

   To create a hard cell, the upper layer specifies:

      slotframe id: id of the slotframe this slot will be scheduled in.

      time slot: the specific time slot number.

      channel offset: the frequency offset.

      LinkOption bitmap: bitmap as defined in Section 2.2






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      target node address: the address of that node to communicate with
      over this cell.  In case of broadcast cells this is the broadcast
      address.

      TrackID: id of the track the cell will belong to.

   6top schedules the cell and marks it as a hard cell, indicating that
   it cannot reschedule this cell.

2.4.1.2.  CREATE.softcell

   To create a soft cell, the upper layer specifies:

      slotframe id: id of the slotframe this slot will be scheduled in

      number of cells: the required number of soft cells.

      LinkOption bitmap: bitmap as defined in Section 2.2

      target node address: the address of that node to communicate with
      over this cell.  In case of broadcast cells this is the broadcast
      address.

      TrackID: id of the track the cell will belong to.

      QoS level: the cell redundancy policy.  The policy can be for
      example STRICT, BEST_EFFORT, etc.

   6top is responsible for picking the exact timeslot and channel offset
   in the schedule, and ensure that the target node choose the same cell
   and TrackID. 6top marks these cells as soft cell, indicating that it
   will continuously monitor their performance and reschedule if needed.

   6top deals with the allocation process by negotiation with the target
   node.  The negotiation process is described in Section 2.6.2.  The
   command returns the list of created cells defined by (slotframe id,
   time slot number, channel offset).  It fails if the required number
   of cells is higher than the available number of cells in the
   schedule.  It fails if the negotiation with the target node fails.
   It fails if the cell Option bitmap indicates that the cell MUST be
   Hard.

2.4.1.3.  READ.cell

   Given a (slotframe id, time slot number, channel offset), retrieves
   the cell information.  Fails if the cell does not exist.  The
   returned information contains:




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      slotframe id: the id of the slotframe where this cell is
      installed.

      time slot: the time slot where the cell is set.

      channel offset: the selected channel offset for the cell.

      LinkOption bitmap: bitmap as defined in Section 2.2

      target node address: the target address of that cell.  In case of
      broadcast cells this is the broadcast address.

      TrackID: id of the track the cell will belong to.

   A read command can be issued for any cell, hard or soft.

2.4.1.4.  UPDATE.cell

   Update a hard cell, i.e. move it to a different timeslot and/or
   channel offset.  Fails if the cell does not exist.  Requires a
   (slotframe id, time slot, channel offset), type of cell, target node
   and TrackID are the fields that can be updated. soft cells cannot be
   updated by the UPDATE.cell command.  REALLOCATE.softcell
   (Section 2.4.1.7) MUST be used instead.

2.4.1.5.  DELETE.hardcell

   To removes a hard cell, the upper layer specifies:

      slotframe id: the id of the slotframe where this cell is
      installed.

      time slot: the time slot where the cell is set.

      channel offset: the selected channel offset for the cell.

   This removes the hard cell from the node's schedule.

2.4.1.6.  DELETE.softcell

   To remove a (number of) soft cell(s), the upper layer specifies:

      slotframe id: the id of the slotframe where this cell is
      installed.

      number of cells: the number of cells to be removed

      LinkOption bitmap: bitmap as defined in Section 2.2



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      target node address: the target address of that cell.  In case of
      broadcast cells this is the broadcast address.

      TrackID: id of the track the cell will belong to.

   In the case a soft cell wants to be moved from the allocated slot so
   a hard cell can be installed instead, the REALLOCATE.softcell
   (Section 2.4.1.7) MUST be used.

2.4.1.7.  REALLOCATE.softcell

   To force a move of a soft cell, the upper layer specifies:

      slotframe id: the id of the slotframe where the cell is allocated.

      time slot: the slot number where that cell is installed.

      channel offset: the channel offset for that cell.

   The reallocated cell will be installed in a different slot, channel
   offset but slotframe and TrackID remain the same.  Hard cells cannot
   be reallocated.

2.4.1.8.  Hardcell Command Behavior

   The following table describe the behavior of 6top upon reception of
   the hard cell management commands.

   hard cell Operations behavior






















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   +---------------------------------+---------------------------------+
   |        6top commands            |          6top behavior          |
   +---------------------------------+---------------------------------+
   | Create.hardcell                 | 6top_ReserveHardCellReq() -ACK  |
   | (NeigAddr, TrackID, SlotframeID,|                                 |
   | SlotOffset,                     | If  NeigAddr ==Broadcast Address|
   | ChannelOffset, LinkOption)      | Then LinkType=ADVERTISING       |
   |                                 | Add cell to EB's FrameAndCellIE |
   +---------------------------------+---------------------------------+
   | Read.cell                       | MLME-GET.request                |
   |(NeigAddr, TrackID               |                                 |
   | SlotframeID,SlotOffset,         |                                 |
   | ChannelOffset, LinkOption)      |                                 |
   +---------------------------------+---------------------------------+
   | Delete.hardcell                 | 6top_RemoveHardCellReq() --ACK  |
   | (NeigAddr, TrackID,             |                                 |
   | SlotOffset,                     |                                 |
   | ChannelOffset, LinkOption)      | If LinkType=ADVERTISING, it is a|
   |                                 | broadcast cell, Then Remove cell|
   |                                 | from EB's FrameAndCellIE        |
   +---------------------------------+---------------------------------+
   | Update.cell                     | 6top_RemoveHardCellReq() --ACK  |
   | (OldFrameID, OldSlotOffset,     | 6top_ReserveHardCellReq() --ACK |
   |  OldChannelOffset, NewFrameID,  | (with same NeigAddr, TrackID,   |
   |  NewSlotOffset,NewChannelOffset)| LinkOption)                     |
   |                                 | If old cell is in EB            |
   |                                 | Then modify EB                  |
   +---------------------------------+---------------------------------+


2.4.1.9.  Softcell Command Behavior

   The following table describe the behavior of 6top upon reception of
   the Softcell management commands.

   soft cell Operations behavior















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   +--------------------------------+----------------------------------+
   |         6top commands          |                 6top behavior    |
   +--------------------------------+----------------------------------+
   | Create.softcell                | 6top_ReserveSoftCellReq() -ACK   |
   |(NeigAddr, TrackID,             |                                  |
   | NumCell,LinkOption,            | ACK ---6top_ReserveSoftCellResp()|
   | SlotframeID, QoSLevel)         |                                  |
   +--------------------------------+----------------------------------+
   | Read.cell                      | MLME-GET.request                 |
   |(NeigAddr, TrackID,             |                                  |
   | SlotframeID,                   |                                  |
   | SlotOffset,ChannelOffset)      |                                  |
   +--------------------------------+----------------------------------+
   | Delete.softcell                | 6top_RemoveSoftCellReq() -- ACK  |
   | (NeigAddr, TrackID ,NumCell,   | If LinkType =ADVERTISING         |
   | LinkOption, SlotframeID)       | i.e. a broadcast cell Then Remove|
   |                                | cell from EB's FrameAndCellIE    |
   +--------------------------------+----------------------------------+
   | Reallocate.softcell            | 6top_RemoveSoftCellReq() -- ACK  |
   |(NeigAddr, TrackID              | 6top_ReserveSoftCellReq() -- ACK |
   | SlotframeID,                   | ACK ---6top_ReserveSoftCellResp()|
   | SlotOffset,ChannelOffset)      |                                  |
   +--------------------------------+----------------------------------+


2.4.2.  Slotframe Commands

   6top provides the following commands to manage TSCH slotframes.

2.4.2.1.  CREATE.slotframe

   Creates a new slotframe.  Returns the slotframe id that corresponds
   to its priority (SlotFrameHandle).  The command requires:

      number of slots: the required number of slots.

   Fails if the number of required slots is less than zero.

2.4.2.2.  READ.slotframe

   Returns the information of a slotframe given its slotframe id.  The
   command returns:

      slotframe id: the id of the slotframe.  (SlotFrameHandle)

      number of slots: the number of slots.

   Fails if the slotframe id does not exist.



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2.4.2.3.  UPDATE.slotframe

   Change the number of slots in a slotframe.  The command requires:

      slotframe id: the id of the slotframe.

      number of slots: the number of slots to be updated.

   Fails if the number of required slots is less than zero.  Fails if
   the slotframe id does not exist.

2.4.2.4.  DELETE.slotframe

   Deletes a slotframe.  The command requires:

      slotframe id: the id of the slotframe.

   Fails if the slotframe id does not exist.

2.4.2.5.  Slotframe Command Behavior

   The following table describes the behavior of 6top upon reception of
   the Slotframe management commands.

   Slotframe Management Operations behavior

   +--------------------------------+----------------------------------+
   |            6top commands       |             6top behavior        |
   +--------------------------------+----------------------------------+
   | Create.slotframe(NumSlot)      | MLME-SET-SLOTFRAME.request       |
   |                                |(operation=ADD)                   |
   +--------------------------------+----------------------------------+
   | Read.slotframe(SlotframeID)    | MLME-GET.request                 |
   +--------------------------------+----------------------------------+
   | Delete.slotframe(SlotframeID)  | MLME-SET-SLOTFRAME.request       |
   |                                |(operation=DELETE)                |
   +--------------------------------|----------------------------------+
   | Update.slotframe(SlotframeID   | MLME-SET-SLOTFRAME.request       |
   |  ,NumSlot)                     |(operation=MODIFY)                |
   +--------------------------------+----------------------------------+


2.4.3.  Monitoring Commands








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   Monitoring commands provide the means for upper layers to configure
   whether 6top must ensure the required bandwidth.  This procedure is
   achieved through over-provisioning according to cell status feedback.
   Monitoring is also in charge of reallocating soft cells that are
   under the required QoS.  The mechanism is described in Section 2.8.

2.4.3.1.  CONFIGURE.monitoring

   Configures the level of QoS the Monitoring process must enforce.  The
   command requires:

      slotframe id: the id of the slotframe.

      target node: the destination node.

      enforce policy: The policy used to enforce the QoS requirements.
      Can be for example DISABLE, BEST_EFFORT, STRICT, OVER-PROVISION,
      etc.

   Fails if the slotframe id does not exist.

2.4.3.2.  READ.monitoring.status

   Reads the current Monitoring status.  Requires the following
   parameters.

      slotframe id: the id of the slotframe.

      target node: the destination node.

   Returns the QoS levels for that Target node on that slotframe.

      allocated_hard: Number of hard cells allocated.

      allocated_soft: Number of soft cells allocated.

      provisioned: the extra provisioned cells. 0 if CONFIGURE.qos
      enforce is DISABLE.

      QoS: the current QoS.  Including overprovisioned cells, i.e what
      bandwidth is being obtained including the overprovisioned cells.

      RQoS: the real QoS without provisioned cells.  What is the actual
      bandwidth without taking into account the overprovisioned cells.

   Fails if the slotframe id does not exist.





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2.4.3.3.  Monitoring Command Behavior

   The following table describes the behavior of 6top upon reception of
   the Monitoring management commands.

   Monitoring Management Operations behavior

   +------------------------------------+------------------------------+
   |            6top commands           |             6top behavior    |
   +------------------------------------+------------------------------+
   | Configure.monitoring(NeigAdd,      | Create/Update Monitoring MIB |
   | SlotframeID,Enforce)               | Starts monitoring service    |
   +------------------------------------+------------------------------+
   | Read.monitoring.status(SlotframeID)| Reads 6top Monitoring MIB    |
   +------------------------------------+------------------------------+

                                 Figure 2

2.4.4.  Statistics Commands

   6top keeps track of TSCH statistics for upper layers to adapt
   correctly to medium changes.  The exact metrics for statistics are
   out of the scope of this document but the present commands should be
   used to configure and read monitored information regardless of the
   specific metric.

2.4.4.1.  CONFIGURE.statistics

   Configures Statistics process.  The command requires:

      slotframe id: the id of the slotframe.  If empty monitors all
      slotframe ids

      time slot: slot number to be monitored.  If empty all slots are
      monitored

      channel offset: specific channel offset to be monitored.  If empty
      all channels are monitored.

      target node: the destination node.  If empty, all target nodes are
      monitored.

      metric: metric to be monitored.  This may be PDR, ETX, queuing
      statistics, energy-related metrics, etc.)

      window: time window to be considered for the calculations.  If 0
      all historical data is considered.




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      enable: Enables statistics or disables them.

   Fails if the slotframe id does not exist.  The statistics service can
   be configured to retrieve statistics at different levels.  For
   example to aggregate information by slotframe id, or to retrieve
   statistics for a particular slot, etc.  the CONFIGURE.statistics
   enables flexible configuration by supporting empty parameters that
   will force the monitoring of the statistics by all members of that
   dimension.

2.4.4.2.  READ.statistics

   Reads a metric for the specified dimension.  Information is
   aggregated according to the parameters.  The command requires:

      slotframe id: the id of the slotframe.  If empty aggregates
      information of all slotframe ids

      time slot: the slot number for which the information is required.
      If empty all slots are aggregated

      channel offset: the specific channel offset for which the
      information is required.  If empty all channels are aggregated.

      target node: the destination node.  If empty all target nodes are
      aggregated.

      metric: metric to be read.

   Returns the value for the requested metric.

   Fails if empty metric or metric does not exits.

2.4.4.3.  RESET.statistics

   Resets the gathered statistics.  The command requires:

      slotframe id: the id of the slotframe.  If empty resets the
      information of all slotframe ids

      time slot: the slot number for which the information wants to be
      reset.  If empty statistics from all slots are reset

      channel offset: the specific channel offset for which the
      information wants to be reset.  If empty all statistics for all
      channels are reset.





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      target node: the destination node.  If empty all statistics for
      the target node are reset.

      metric: metric to be reset.

   Fails if empty metric or metric does not exits.

2.4.4.4.  Statistics Command Behavior

   The following table describes the behavior of 6top upon reception of
   the Statistics management commands.

   Statistics Management Operations behavior

   +--------------------------------+----------------------------------+
   |            6top commands       |             6top behavior        |
   +--------------------------------+----------------------------------+
   | Configure.statistics           |                                  |
   | (SlotFrameID,TSlot, ChannelOff,| Configures Statistics MIB.       |
   | NeigAdd,Metric,Window,En)      | Enables statistics service       |
   +--------------------------------+----------------------------------+
   | Read.statistics(SlotFrameID)   | Returns the statistic MIB for the|
   | Ch.Off,NeigAdd,Metric)         | requested parameters             |
   +--------------------------------+----------------------------------+
   | Reset.statistics(SlotFrameID)  | Resets the required statistic MIB|
   | Ch.Off,NeigAdd,Metric)         |                                  |
   +--------------------------------+----------------------------------+


2.4.5.  Network Formation Commands

   EBs need to be configured, including their transmission period, the
   slot number and channel offset that they should be sent on, and the
   priority announced.  The parameters for that command are optional and
   enable a very flexible configuration of EBs.  If slotframe id is
   specified, the EBs will be configured to use that specific slotframe;
   if not they will use the first slotframe where the configured time
   slot is allocated.  Time slot enforces the EB to a specific time
   slot.  In case time slot parameter is not present, the EB is sent in
   the first available transmit time slot.  In case channel offset
   parameter is not set, the EB is configured to use the first available
   channel.









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2.4.5.1.  CONFIGURE.eb

   Configures EBs.  The command requires:

      slotframe id: the id of the slotframe where the EBs MUST be sent.
      Zero if any slotframe can be used.

      time slot: the slot number where the EBs MUST be sent.  Zero if
      any timeslot can be used.

      channel offset: the channel offset where the EBs MUST be sent.
      Zero if any channel offset can be used.

      period: the EBs period, in seconds.

      expires: when the EBs periodicity will stop.  If Zero the period
      never stops.

      priority: the joining priority model that will be used for
      advertisement.  Joining priority MAY be for example
      SAME_AS_PARENT, RANDOM, BEST_PARENT+1.

   Fails if the tuple (slotframe id, timeslot, channel offset) is
   already scheduled.

2.4.5.2.  READ.eb

   Reads the EBs configuration.  No parameters are required.

   Returns the current EBs configuraton for that slotframe, which
   contains:

      slotframe id: the slotframe where the EB is being sent.

      time slot: the slot number where the EBs is being sent.

      channel offset: the channel offset the EBs is being sent on.

      period: the EBs period.

      expires: when the EBs periodicity stops.  If 0 the period never
      stops.

      priority: the joining priority that this node advertises.

   Fails if the slotframe id does not exist.





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2.4.5.3.  Network Formation Command Behavior

   The following table describes the behavior of 6top upon reception of
   the Network Configuration management commands.

   Network Configuration Management Operations behavior

   +----------------------------------+--------------------------------+
   |            6top commands         |             6top behavior      |
   +----------------------------------+--------------------------------+
   | Configure.EB(SlotFrameID,TSlot,  | Configures the 6top MIB        |
   | Ch.Off,Period,Expires,Prio,Con_p)| regarding EB configuration     |
   +----------------------------------+--------------------------------+
   | Read.EB()                        | Reads 6top EB MIB              |
   |                                  |                                |
   +----------------------------------+--------------------------------+


2.4.6.  Time Source Neighbor Commands

   Commands to select time source neighbors.

2.4.6.1.  CONFIGURE.timesource

   Configures the Time Source Neighbor selection process.  More than one
   time source neighbor can be selected.  The command requires:

      selection policy: The policy used to select the time parent.  The
      policy MAY be for example ALL_PARENTS, BEST_CONNECTED,
      LOWEST_JOIN_PRIORITY, etc.

   Fails if any of the time source neighbors do not exist or it is not
   reachable.

2.4.6.2.  READ.timesource

   Retrieves information about the time parents of that node.  The
   command does not require any parameter.

   Returns the following information for each of the time sources:

      target node: address of the time parent.

      statistics: includes for example minimum, maximum, average time
      correction for that time parent

      policy: the used policy




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   Fails if the slotframe id or no time source neighbors exist.

2.4.6.3.  Time Source Neighbor Command Behavior

   The following table describes the behavior of 6top upon reception of
   the Time Source Neighbor Configuration management commands.

   Time Source Neighbors Configuration Management Operations behavior

   +---------------------------------+---------------------------------+
   |            6top commands        |             6top behavior       |
   +---------------------------------+---------------------------------+
   | Configure.timesource(Policy)    | Configures the 6top MIB         |
   |                                 | regarding timesource parents    |
   +---------------------------------+---------------------------------+
   | Read.timesource()               | Read 6top timesource MIB        |
   |                                 |                                 |
   +---------------------------------+---------------------------------+

                                 Figure 3

2.4.7.  Neighbor Commands

   Commands to manage neighbor table.  The commands SHOULD be used by
   the upper layer to query the neighbor related information and by the
   lower layer to keep track of neighbors information.

2.4.7.1.  CREATE.neighbor

   Creates an entry for a neighbor in the neighbor table.

      neighbor address: The address of the neighbor.

      neighbor stats: for example, RSSI of the last received packet from
      that neighbor, ASN when that neighbor has been added, etc.

   Returns whether the neighbor is created or not.

2.4.7.2.  READ.all.neighbor

   Returns the list of neighbors of that node.  Fails if empty.  For
   each neighbor in the list it returns:

      neighbor address: The address of the neighbor.

      neighbor stats: for example, RSSI of the last received packet from
      that neighbor, ASN when that neighbor has been added, packets
      received from that neighbor, packets sent to it, etc. .



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2.4.7.3.  READ.neighbor

   Returns the information of a specific neighbors of that node
   specified by its neighbor address.  Fails if it does not exists.  For
   that neighbor it returns:

      neighbor address: The address of the neighbor.

      neighbor stats: for example, RSSI of the last received packet from
      that neighbor, ASN when that neighbor has been added, packets
      received from that neighbor, packets sent to it, etc.

2.4.7.4.  UPDATE.neighbor

   Updates an entry for a neighbor in the neighbor table.  Fails if the
   neighbor does not exist.  Updates stats parameters.  Requires:

      neighbor address: The address of the neighbor.

      neighbor stats: for example, RSSI of the last received packet from
      that neighbor, ASN when that neighbor has been added, etc. .

   Returns whether the neighbor is updated or not.

2.4.7.5.  DELETE.neighbor

   Deletes a neighbor given its address.  Fails if the neighbor does not
   exists.

2.4.7.6.  Neighbors Command Behavior

   The following table describes the behavior of 6top upon reception of
   the Neighbors Configuration management commands.

   Neighbors Management Operations behavior
















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   +---------------------------------+---------------------------------+
   |            6top commands        |             6top behavior       |
   +---------------------------------+---------------------------------+
   | Create.neighbor(address,stats)  | Adds a neighbor to the neighbor |
   |                                 | table in the 6top MIB.          |
   +---------------------------------+---------------------------------+
   | Read.all.neighbor()             | lists all neighbors from the    |
   |                                 | neighbor table.                 |
   +---------------------------------+---------------------------------+
   | Read.neighbor(address)          | Reads neighbor information from |
   |                                 | neighbor table in the 6top MIB  |
   +---------------------------------+---------------------------------+
   | Update.neighbor(address,stats)  | Updates an entry for a neighbor |
   |                                 | in the 6top MIB                 |
   +---------------------------------+---------------------------------+
   | Delete.neighbor(address)        | Removes the neighbor from the   |
   |                                 | 6top MIB                        |
   +---------------------------------+---------------------------------+


2.4.8.  Queueing Commands

   TSCH MAC layer queues need to be configured.  This includes queue
   length, retransmission policy, discarding of packets, etc.

2.4.8.1.  CREATE.queue

   Creates and Configures TSCH Queues.  The command SHOULD be applied
   for each required queue.  The command requires:

      txqlength: the desired transmission queue length.

      rxqlength: the desired reception queue length.

      numrtx: number of allowed retransmissions.

      age: discard packet according to its age on the queue. 0 if no
      discards are allowed.

      rtxbackoff: retransmission back off in number of slotframes. 0 if
      next available slot wants to be used.

      statswindow: window of time used to compute stats.

      queue priority: the priority of this queue.

      TrackIDs: a set of TrackIDs.  While it is empty, no specific track
      is associated with the queue



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   Returns the queue id.

2.4.8.2.  READ.queue

   Reads the queue configuration.  Requires the queue id.

   The command returns:

      txqlength: the transmission queue length.

      rxqlength: the reception queue length.

      numrtx: number of allowed retransmissions.

      age: maximum age of a packet befoer being discarded. 0 if no
      discards are allowed.

      rtxbackoff: retransmission backoff in number of slotframes. 0 if
      next available slot is used.

2.4.8.3.  READ.queue.stats

   Reads the queue stats.  Requires queue id.

   The command returns:

      txqlengthstats: average, maximum, minimum length of the
      transmission queue.

      rxqlengthstats: average, maximum, minimum length of the reception
      queue.

      numrtxstats: average, maximum, minimum number of retransmissions.

      agestats: average, maximum, minimum age of a packet in the queue.

      rtxbackoffstats: average, maximum, minimum retransmission backoff.

      queue priority: the priority of this queue.

      TrackIDs: a set of TrackIDs.

2.4.8.4.  UPDATE.queue

   Update a TSCH Queue.  The command requires:

      queueid: the queue id.




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      txqlength: the desired transmission queue length.

      rxqlength: the desired reception queue length.

      numrtx: number of allowed retransmissions.

      age: discard packet according to its age on the queue. 0 if no
      discards are allowed.

      rtxbackoff: retransmission backoff in number of slotframes. 0 if
      next available slot wants to be used.

      statswindow: window of time used to compute stats.

      queue priority: the desired priority of this queue.

      TrackIDs: the desired set of TrackIDs.

2.4.8.5.  DELETE.queue

   Deletes a TSCH Queue.  The command requires the queue id.  All
   packets in the queue are discarded and the queue is deleted.

2.4.8.6.  Queueing Command Behavior

   The following table describes the behavior of 6top upon reception of
   the Queue management commands.

   Queue Management Operations behavior






















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   +---------------------------------+---------------------------------+
   |            6top commands        |             6top behavior       |
   +---------------------------------+---------------------------------+
   | Create.queue(tqlen,trlen,numrtx,| Creates a queue with specified  |
   | age,rtxbackoff,prio,TrackIDs)   | parameters. Updates 6top MIB.   |
   +---------------------------------+---------------------------------+
   | Read.queue(id)                  | Reads the queue configuration   |
   |                                 | from 6top MIB.                  |
   +---------------------------------+---------------------------------+
   | Update.queue(id,tqlen,trlen,    | Updates the queue configuration |
   | numrtx,age,rtxbackoff,          | from 6top MIB. Readjustes actual|
   | prio, TrackIDs)                 | queue size if required.         |
   +---------------------------------+---------------------------------+
   | Delete.queue(id)                | Deletes the queue from MIB.     |
   |                                 |                                 |
   +---------------------------------+---------------------------------+
   | Read.queue.stats()              | Reads the queue                 |
   |                                 | stats from 6top MIB.            |
   +---------------------------------+---------------------------------+


2.4.9.  Security Commands

   The following commands are used to manage underlying layer security.
   In that case 6top acts as delegating interface to IEEE802.15.4
   security configuration commands.

2.4.9.1.  CONFIGURE.security

   Enables/Disables Security and configures the MAC PIB.  The command
   requires:

      enable: enables underlying layer security.

      macAutoRequestSecurityLevel: the security level used for automatic
      data requests as described by IEEE 802.15.4 table 61.

      macAutoRequestKeyIdMode: the key identifier mode used for
      automatic data requests as described by IEEE 802.15.4 table 61.

      macAutoRequestKeySource: the originator of the key for automatic
      data requests as described by IEEE 802.15.4 table 61.

      macAutoRequestKeyIndex: the index of the key used for automatic
      data requests as described by IEEE 802.15.4 table 61.

      macDefaultKeySource: the originator of the default key used for
      key identifier mode 0x01 as described by IEEE 802.15.4 table 61.



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      macPANCordinatorExtendedAddress: Address of the PAN coordinator as
      described by IEEE 802.15.4 table 61.

      macPANCordinatorShortAddress: Short address of the PAN coordinator
      as described by IEEE 802.15.4 table 61.

2.4.9.2.  CONFIGURE.security.macKeyTable

   Configures Security Keys.  The command requires:

      KeyIdLookupList: list of keyIdLookupDescriptor Entries as defined
      by IEEE 802.15.4 table 61.

      DeviceDescriptorHandleList: Implementation specific list of
      devices that are using this key.  As defined by IEEE 802.15.4
      table 61.

      KeyUsageList: List of slotframe types on which this key is being
      used as specified by IEEE 802.15.4 section 7.4.1.2

      Key: 16 octets key.  As specified by IEEE 802.15.4 table 61.

2.4.9.3.  CONFIGURE.security.macSecurityLevelTable

   Configures the set of security levels.  The command requires:

      FrameType: Slotframe type as defined by IEEE802.15.4e std.

      Command Identifier: The command identifier as defined by
      IEEE802.15.4e std.

      Security Minimum: The minimum required security level as specified
      by IEEE 802.15.4e

      Device Override Security Minimum: whether the minimum security
      level can be overridden as specified by IEEE 802.15.4 Table 64

      Allowed Security Levels: the key identifier field that identifies
      the key that is being used as specified by IEEE 802.15.4 section
      7.4.3

2.4.9.4.  Security Command Behavior

   6top offers the interface to upper layers so underlying MAC layer can
   be configured.  In that sense, 6top acts as a "none-layer" by only
   delegating the functionalities to the MAC security services.  For
   more details Section 7 on IEEE802.15.4-2011 and its amendments on
   IEEE802.15.4e-2012 should be referred.



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2.4.10.  Data Commands

2.4.10.1.  Send.data

   The command used by upper layers to queue a packet so underlying TSCH
   sends it.  According to the specific priority, the packet is pushed
   into a Queue with the equivalent priority or following a criteria out
   of the scope of this document.  Once a packet is inserted into a
   queue it waits to be transmitted by TSCH according to the model
   defined in Section 2.3.

   The required parameters are:

      src address: L2 source address

      dest address: L2 unicast or broadcast destination address

      priority: packet priority, usually is consistent with queue
      priority

      message length: the length of the message.

      message: control message or data message

      securityLevel:As defined by IEEE802.15.4e std.

2.4.10.2.  Receive.data

   The command is invoked whenever a packet is received and inserted
   into a reception queue.  The method acts as a callback function to
   notify to the upper layers the received message.  Upper layers MUST
   provide an implementation for that method.

   The function has the following parameters:

      src address: L2 source address

      dest address: L2 unicast or broadcast destination address

      priority: packet priority, usually is consistent with queue
      priority

      message length: the length of the message.

      message: control message or data message

2.4.10.3.  Data Command Behavior




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   The following table describes the behavior of 6top upon reception of
   the Data Communication Configuration management commands.

   Data Communication Management Operations behavior

   +---------------------------------+---------------------------------+
   |            6top commands        |             6top behavior       |
   +---------------------------------+---------------------------------+
   | Send.data(src,dest,prio,        | The message is inserted in the  |
   |           len,msg,seclevel)     | the queue corresponding to the  |
   |                                 | required priority. Fails if the |
   |                                 | queue is full. Fails if the     |
   |                                 | destination address is not a    |
   |                                 | L2 neighbor of the node.        |
   +---------------------------------+---------------------------------+
   | Receive.data(src,dest,prio,len, | The method is invoked whenever a|
   |  msg)                           | message is inserted in the queue|
   |                                 | after successful reception.     |
   +---------------------------------+---------------------------------+

                                 Figure 4

2.4.11.  Label Switching Commands

2.4.11.1.  LabelSwitching.map

   The command used by upper layers to map one input cell or a bundle of
   input cells to an output cell or a bundle of output cells. 6top
   stores this mapping and makes sure that the packets are forwarded at
   the specific output cell/bundle.  Label Switching is enabled by the
   specified bundle as soon as the mapping is installed.

   The required parameters are:

      input cells: list of input cells (one or more cells in a bundle).
      Each input cells is described by an unique tuple (time slot,
      frequency offset, destination address).

      output cells: list of output cells (one or more cells in a
      bundle).  Each output cells is described by an unique tuple (time
      slot, frequency offset, destination address).

      load balancing policy: A policy for load balance cell usage.  The
      policy is out of the scope of this document, however an example
      can be use ROUND ROBIN policy within the cells of the same bundle.

2.4.11.2.  LabelSwitching.unmap




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   The command used by upper layers to unmap one input cell or a bundle
   of input cells to an output cell or a bundle of output cells.  The
   mapping is removed from the state kept by 6top.

   The required parameters are:

      input cells: list of input cells (one or more cells in a bundle).
      Each input cells is described by an unique tuple (time slot,
      frequency offset, destination address).

      output cells: list of output cells (one or more cells in a
      bundle).  Each output cells is described by an unique tuple (time
      slot, frequency offset, destination address).

2.4.11.3.  Label Switching Command Behavior

   The following table describes the behavior of 6top sublayer upon
   reception of the Label Switching Commands.

   Data Communication Management Operations behavior

   +---------------------------------+---------------------------------+
   |            6top commands        |           6top behavior         |
   +---------------------------------+---------------------------------+
   | LabelSwitching.map(src,dest,    | The 6top sublayer label mapping |
   |                    policy)      | table is configured with the    |
   |                                 | input and output cells bindings.|
   |                                 | According to the policy a       |
   |                                 | monitoring mechanism is started |
   |                                 | so load balancing can be        |
   |                                 | enforced.                       |
   +---------------------------------+---------------------------------+
   | LabelSwitching.unmap(src,dest)  | The src and dst cells are       |
   |                                 | removed from the mapping table  |
   |                                 | and any load balancing policy   |
   |                                 | is disabled.                    |
   +---------------------------------+---------------------------------+

                                 Figure 5

2.5.  Message Formats

   6top has to negotiate the scheduling of soft cells with neighbor
   nodes.  This negotiation happens through 6top-specific TSCH
   Information Elements, the format of which is defined in this section.
   This section also details the formats of the IEs defined in
   [IEEE802154e] and reused without modification.




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   6top messages can contain one or more IEs.  Section 2.5.1 defines the
   different IEs used by 6top, both the ones used without modification
   from [IEEE802154e], and the new ones defined by 6top.  Section 2.5.2
   shows how those IEs are assembled to form the different packets used
   by 6top.

2.5.1.  Information Elements

   IEEE802.15.4e defines Information elements (IEs) which are formatted
   data objects consisting of an ID, a length, and a data payload used
   to pass data between layers or devices.  IEEE802.15.4e defines Header
   IEs and Payload IEs; 6top only uses Payload IEs.  A Payload IE
   includes one or more IEs, and ends with a termination IE (ID = 0xf,
   see [IEEE802154e]).

   6top uses the following Information Elements, some defined in
   IEEE802.15.4e, others introduced in this document.

      Defined in [IEEE802154e] and used by 6top without modification:



         TSCH Synchronization IE (Section 2.5.1.1)

         TSCH Slotframe and Cell IE (Section 2.5.1.2)

         TSCH Timeslot Template IE (Section 2.5.1.3)

         TSCH Channel Hopping IE (Section 2.5.1.4)

      Defined by 6top:



         6top Opcode IE (Section 2.5.1.5)

         6top Bandwidth IE (Section 2.5.1.6)

         6top TrackID IE (Section 2.5.1.7)

         6top Generic Schedule IE (Section 2.5.1.8)

2.5.1.1.  TSCH Synchronization IE

   A Synchronization IE (SyncIE) contains Information allowing a node to
   synchronize to a TSCH network, including the current ASN and a join
   priority.  Synchronization IE must be included in all TSCH Enhanced
   Beacons.



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   6top re-uses this IE as defined in [IEEE802154e].

   Format of a TSCH Synchronization IE (SyncIE).

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Length      |    SubID    |T|          ASN                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                 ASN                           | Join Priority |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 6

   Length=6

   SubID=0x1a

   T=0, i.e. short type

   ASN (5 octets) contains the Absolute Slot Number corresponding to the
   timeslot in which the TSCH Enhanced Beacon is sent.

   The Join Priority can be used by a joining device to select among
   beaconing devices when multiple beacons are heard.  The PAN
   coordinator's join priority is zero.  A lower value of join priority
   indicates that the device is the preferred one to connect to.  The
   beaconing device's join priority is the lowest join priority heard
   when it joined the network plus one.

2.5.1.2.  TSCH Slotframe and Cell IE

   The Slotframe and Cell IE (FrameAndCellIE) contains one or more
   slotframes and their respective cells that a beaconing device
   advertises to allow other devices to join the network.

   6top re-uses this IE as defined in [IEEE802154e].















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   Format of a TSCH Slotframe and Cell IE (FrameAndCellIE).

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Length      |    SubID    |T|  NumFrame     |               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+               |
   |                                                               |
   //               Slotframe and cell information                //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 7

   Length=variable

   SubID=0x1b

   T=0, i.e. short type

   NumFrame is set to the total number of slotframe descriptors
   contained in the TSCH Enhanced Beacon.

   Format of a slotframe descriptor.

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   FrameID      |            FrameLen          |   NumCell     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //          Cell information for each cell (5x NumCell)        //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 8

   The FrameID field shall be set to the slotframeHandle that uniquely
   identifies the slotframe.

   The FrameLen field shall be set to the size of the slotframe in
   number of timeslots.

   The NumCell field shall be set to the number of cells that belong to
   the specific slotframe identified by the slotframeHandle.

   Format of a Cell information.






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    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        SlotOffset             |        ChannelOffset          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  LinkOption   |
   +-+-+-+-+-+-+-+-+

                                 Figure 9

   SlotOffset shall be set to the timeslot of this cell.

   ChannelOffset shall be set to the logic channel of this cell.

   LinkOption indicates whether this cell is a TX cell, an RX cell, or a
   SHARED TX cell, whether the device to which it is being linked is to
   be used for clock synchronization, and whether this cell is hard
   cell.

2.5.1.3.  TSCH Timeslot Template IE

   Timeslot Template IE (SlotTemplateIE) defines Timeslot template being
   used by the TSCH device.

   6top re-uses this IE as defined in [IEEE802154e].

   Format of a TSCH Timeslot Template IE (SlotTemplateIE).

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Length      |    SubID    |T|  TemplateID   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 10

   Length=1

   SubID=0x1c

   T=0, i.e. short type

   TemplateID shall be set to a Timeslot template handle.  The full
   time-slot template, which contains the macTimeslotTemplate of TSCH
   (total 25 octets), may be included.(see IEEE802.15.4e).

2.5.1.4.  TSCH Channel Hopping IE

   Channel Hopping IE (ChHoppingIE) defines the Hopping Sequence being
   used by the TSCH device.



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   6top re-uses this IE as defined in [IEEE802154e].

   Format of a TSCH Channel Hopping IE (ChHoppingIE).

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      Length         | SubID |T| HopSequenceID |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 11

   Length=1

   SubID=0x09

   T=1, i.e. long type

   HopSequenceID shall be set to a Hopping Sequence handle.  The full
   Hopping Sequence information may be included. (see IEEE802.15.4e).

2.5.1.5.  6top Opcode IE

   6top Opcode IE (OpcodeIE) defines operation codes of packets in 6top
   sublayer.

   This IE is not present in [IEEE802154e] and is defined by 6top.

   Format of a 6top Opcode IE (OpcodeIE).

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Length      |    SubID    |T|   OpcodeID    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 12

   Length=1

   SubID=0x41

   T=0, i.e. short type

   OpcodeID field shall be set to one of the following codes.

      0x00: Reserve Soft Cell Request

      0x01: Reserve Soft Cell Response




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      0x02: Remove Soft Cell Request

      0x03: Reserve Hard Cell Request

      0x04: Remove Hard Cell Request

2.5.1.6.  6top Bandwidth IE

   Bandwidth IE (BwIE) defines the number of cells to be reserved or
   actually be reserved.

   This IE is not present in [IEEE802154e] and is defined by 6top.

   Format of a 6top Bandwidth IE (BwIE).

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Length      |    SubID    |T|    FrameID    |   NumCell     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 13

   Length=2

   SubID=0x42

   T=0, i.e. short type

   FrameID may be set to the SlotFrameHandle to identify the slotframe
   from which cells are reserved.  FrameID field may be set to NOP,
   which means no specific slotframe is associated.

   NumCell shall be set to the number of cells.  When BwIE is combined
   with the OpecodeID of Reserve Soft Cell Request, NumCell presents how
   many cells are required to reserve; and when BwIE is combined with
   the OpecodeID of Reserve Soft Cell Response, NumCell presents how
   many cells are reserved successfully.

2.5.1.7.  6top TrackID IE

   TrackID IE (TrackIdIE) describes the track which the reserved/removed
   cell(s) are associated with.

   This IE is not present in [IEEE802154e] and is defined by 6top.

   Format of a 6top TrackID IE (TrackIdIE).





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    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Length      |    SubID    |T|OwnerInstID|rev|               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+               |
   //                                                              //
   |                   TrackOwnerAddr                              |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 14

   Length=3 or 7.  When length=3, TrackOwnerAddr is 2 bytes short
   address, and when length=7, TrackOwnerAddr is 6 bytes long address.

   SubID=0x43

   T=0, i.e. short type

   The combination of TrackOwnerAddr and OwnerInstId represents a
   specific TrackID.

2.5.1.8.  6top Generic Schedule IE

   Generic Schedule IE (ScheduleIE) describes cell sets.  In different
   packets, ScheduleIE represents different information.  See
   Section 2.5.2 for more detail.

   This IE is not present in [IEEE802154e] and is defined by 6top.

   Format of a 6top Generic Schedule IE (ScheduleIE).

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Length      |    SubID    |T|                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
   |                                                               |
   //                   Schedule Body                             //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 15

   Length=variable

   SubID=0x44

   T=0, i.e. short type




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   Schedule Body carries one or more schedule object.  An object may
   carry a TLV, which may itself comprise other TLVs.  TLV format is as
   follows.  Type: 1 byte, Length: 1 byte, Value: variable

   The following are some examples of schedule object TLV.

   Example 1.  Cell Set TLV

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Type=1      |    Length     |     FrameID   |  NumCell    |F|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                        CellObjects                          //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 16

   FrameID shall be set to the slotframeHandle that uniquely identifies
   the slotframe.

   NumCell shall be set to the number of cells that belong to the
   specific slotframe identified by the slotframeHandle.

   F=1 means the specified cells equals to what are listed in
   CellObjects, and F=0 means the specified cells equals to what are not
   listed in CellObjects.

   CellObjects carries the information for one or more cells, including
   SlotOffset, ChannelOffset, LinkOption (Figure 9).

   Example 2.  Schedule Matrix TLV

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Type=2      |    Length     |  FrameID      |StartSlotOffset|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |StartSLotOffset|    NumSlot    |                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
   |                                                               |
   //                 SlotBitMap (2x NumSlot)                     //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 17





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   FrameID field shall be set to the slotframeHandle that uniquely
   identifies the slotframe.

   StartSlotOffset field (2 octets) shall be set to the slotoffset in
   the specific slotframe identified by the slotframeHandle.

   NumSlot field shall be set to the number of slots from
   StartSlotOffset in the specific slotframe identified by the
   slotframeHandle.

   SlotBitMap (per slot) indicates for the given slot which channels are
   specified.  For the 16 channels in 2.4GHz band, 2-octets are used to
   indicate which channel is specified.  For example, given a slot and a
   SlotBitmap with value (10001000,00010000); the bitmap represents that
   ChannelOffset-0, ChannelOffset-4, ChannelOffset-11 are specified.

2.5.2.  Packet Formats

   This section describes the packets used in 6top to form a network,
   reserve/maintain bandwidth using soft cells, and reserve/remove hard
   cells in both Tx side and Rx side.  Each of these packets use one or
   more IEs defined in Section 2.5.1.

2.5.2.1.  TSCH Enhanced Beacon

   The TSCH Enhanced Beacon is used to announce the presence of the
   network and allows new nodes to join.  It is an IEEE802.15.4e
   Enhanced Beacon packet with the following Payload IEs:

      TSCH Synchronization IE (Section 2.5.1.1)

      TSCH Timeslot Template IE (Section 2.5.1.3)

      TSCH Channel Hopping IE (Section 2.5.1.4)

      TSCH Slotframe and Cell IE (Section 2.5.1.2)

   Payload IE of TSCH Enhanced Beacon Packet













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    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Length        |GroupID|T|             SyncIE            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        SyncIE                                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         SyncIE                |      SlotTemplateIE           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |SlotTemplateIE |               ChHoppingIE                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                        FrameAndCellIE                       //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 18

   Length=variable

   GroupID=0x1, i.e. MLME IE

   T=1, i.e. payload IE

   See Section 2.5.1.1, Section 2.5.1.3, Section 2.5.1.4,Section 2.5.1.2
   for SyncIE, SlotTemplateIE, ChHoppingIE and FrameAndCellIE.

2.5.2.2.  Soft Cell Reservation Request

   A Soft Cell Reservation Request packet is an IEEE802.15.4e data
   packet with the following payload IE.

   Payload IE of Soft Cell Reservation Request

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Length        |GroupID|T|          OpcodeIE             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | OpcodeIE      |                  BwIE                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    BwIE       |                                               |
   +-+-+-+-+-+-+-+-+                                               |
   //                          ScheduleIE                         //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 19

   Length=variable



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   GroupID=0x1, i.e. MLME IE

   T=1, i.e. payload IE

   The OpcodeID field in the 3-octet OpcodeIE should be set to 0x00,
   indicates Reserve Soft Cell Request operation.

   The NumCell field in 4-octet BwIE should be set to the number of
   cells needed to be reserved.

   The ScheduleIE specifies a candidate cell set, from which the cells
   should be reserved.  ScheduleIE may be empty, means there is no
   constrain on which cells should not be reserved.

   In addition, TrackIdIE can be added in the packet to associate the
   reserved soft cells to a specific TrackID.

2.5.2.3.  Soft Cell Reservation Response

   Soft Cell Reservation Response is an IEEE802.15.4e data packet with
   the following payload IE.

   Payload IE of Soft Cell Reservation Response

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Length        |GroupID|T|          OpcodeIE             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | OpcodeIE      |                  BwIE                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    BwIE       |                                               |
   +-+-+-+-+-+-+-+-+                                               |
   //                          ScheduleIE                         //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 20

   Length=variable

   GroupID=0x1, i.e. MLME IE

   T=1, i.e. payload IE

   The OpcodeID field in the 3-octet OpcodeIE should be set to 0x01,
   indicates Reserve Soft Cell Response operation.





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   The NumCell field in 4-octet BwIE should be set to the number of
   cells which have been reserved successfully.

   The ScheduleIE should specify all of the cells which have been
   reserved successfully.

   In addition, TrackIdIE can be added in the packet to associate the
   reserved soft cells to a specific TrackID.

2.5.2.4.  Soft Cell Remove Request

   Soft Cell Remove Request is an IEEE802.15.4e data packet with the
   following payload IE.

   Payload IE of Soft Cell Remove Request

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Length        |GroupID|T|          OpcodeIE             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | OpcodeIE      |                                               |
   +-+-+-+-+-+-+-+-+                                               |
   //                          ScheduleIE                         //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 21

   Length=variable

   GroupID=0x1, i.e. MLME IE

   T=1, i.e. payload IE

   The OpcodeID field in the 3-octet OpcodeIE should be set to 0x02,
   indicates Remove Soft Cell Request operation.

   The ScheduleIE should specify all the cells that need to be removed.

2.5.2.5.  Hard Cell Reservation Request

   Hard Cell Reservation Request packet is an IEEE802.15.4e data packet
   with the following payload IE.

   Payload IE of Hard Cell Reservation Request






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    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Length        |GroupID|T|          OpcodeIE             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | OpcodeIE      |                                               |
   +-+-+-+-+-+-+-+-+                                               |
   //                          ScheduleIE                         //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 22

   Length=variable

   GroupID=0x1, i.e. MLME IE

   T=1, i.e. payload IE

   The OpcodeID field in the 3-octet OpcodeIE should be set to 0x03,
   indicates Reserve Hard Cell Request operation.

   The ScheduleIE should specify all the cell that need to be reserved.

   In addition, TrackIdIE can be added in the packet to associate the
   reserved hard cells to a specific TrackID.

2.5.2.6.  Hard Cell Remove Request

   Hard Cell Remove Request is an IEEE802.15.4e data packet with the
   following payload IE.

   Payload IE of Hard Cell Remove Request

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Length        |GroupID|T|          OpcodeIE             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | OpcodeIE      |                                               |
   +-+-+-+-+-+-+-+-+                                               |
   //                          ScheduleIE                         //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                 Figure 23

   Length=variable

   GroupID=0x1, i.e. MLME IE



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   T=1, i.e. payload IE

   The OpcodeID field in the 3-octet OpcodeIE should be set to 0x04,
   indicates Remove Hard Cell Request operation.

   The ScheduleIE should specify all the cells that need to be removed.

2.6.  Time Sequence

   6top neighbors exchange 6top-specific packets in the following cases,
   each detailed in a subsection.

      Network formation is detailed in Section 2.6.1.

      Creating soft cells is detailed in Section 2.6.2.

      Deleting soft cells is detailed in Section 2.6.3.

      Maintaining soft cells is detailed in Section 2.6.4.

      Creating hard cells is detailed in Section 2.6.5.

      Deleting hard cells is detailed in Section 2.6.6.

2.6.1.  Network Formation

   Network formation consists of two processes: joining and maintenance.

2.6.1.1.  Joining

   A node already in the network sends out TSCH Enhanced Beacons
   periodically.

   When a node is joining an existing network, it listens for TSCH
   Enhanced Beacons.  After collecting one or more TSCH Enhanced BEACONs
   (the format of which is detailed in Section 2.5.2.1), the joining
   node must do the following.

      Initialize a neighbor table.  Establish a neighbor table and
      record all of the information described in the TSCH Enhanced
      BEACONs as its initial schedule with those neighbors.

      Select a time source neighbor.  According to the Joining Priority
      described by SyncIEs, the joining node chooses one or more of the
      advertisers as its time source neighbors. 6top does not specify
      the criteria to choose time source neighbors from the Enhanced
      BEACONs.




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      Select cells for Enhanced Beacons.  The joining node selects one
      or more cells to broadcast its own Enhanced Beacons, which may be
      same as the cells used by its neighbors for Enhanced Beacon
      broadcast, and record those cell(s) into the TSCH schedule with
      LinkType=ADVERTISING.

      From its Enhanced Beacons, including the cell(s) for its Enhanced
      Beacon, which LinkOption should be set to "Receive" and
      "Timekeeping", telling its neighbors that the cell is used for
      broadcast.

      Start broadcasting Enhanced Beacon and communicate with neighbors.

2.6.1.2.  Maintenance

   Nodes may broadcast Enhance Beacons on the cells marked with
   LinkType=ADVERTISING, and listen for Enhanced Beacons from neighbors
   on the cells with LinkOption = "Receive" and "Timekeeping".  If a
   cell with both LinkType=ADVERTISING has both the "Receive" and
   "Timekeeping" LinkOption, it is shared by neighbors and itself to
   broadcast, then broadcast Enhanced Beacon has higher priority.

   Whenever a node receives an Enhanced Beacon, it must update its
   schedule if there is a difference.

2.6.2.  Creating soft cells

   The upper layer instructs 6top to schedule one or more soft cells by
   calling the Create soft cell command.  This command can also be
   called by the monitoring process internal to 6top.





















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   When receiving a Create soft cell command, Node A's 6top sublayer
   forms a Soft Cell Reservation Request packet which includes BwIE and
   ScheduleIE.  The BwIE includes the number of cells needed to be
   reserved (N1), and ScheduleIE includes a candidate cell set from
   which the new cells should be selected.  If the ScheduleIE is empty,
   Node A indicates there is no constraint on cell selection.  The Soft
   Cell Reservation Request is then sent to the neighbor (Node B) with
   whom new cells need to be added.  After receiving the Soft Cell
   Reservation Request, Node B selects the cells from the candidate cell
   set defined by the ScheludeIE in the Soft Cell Reservation Request,
   and forms a Soft Cell Reservation Response packet, in which BwIE
   indicates the number of cells actually being reserved (N2), and
   ScheduleIE indicates those reserved cells.  If N2 is smaller than N1,
   node B indicates to node A that there are not enough qualified cells
   to be reserved.  Node B must record the reserved cells into its local
   schedule while sending out Soft Cell Reservation Response.  After
   receiving the Soft Cell Reservation Response, Node A must record the
   reserved cells into its local schedule.

   The policy to build a candidate cell set and the policy to select
   cells from the candidate cell set to reserve is flexiable.  For
   example, the candidate cell set can be all of the cells not used by
   Node A, and Node B can randomly choose N1 cells, which are not used
   by Node B, from the candidate cell set.

   The expression of Schedule Body is flexible.  For example, Node A can
   use Cell Set TLV defined in Figure 16 with field 'F' set to '0', and
   the CellObjects includes all of the cells being used by Node A. In
   another word, the cell candidate set is all of the cells not being
   included in the list defined by CellObjects.

   The policy to deal with the failure or not fully satisfaction in a
   soft cell Reservation process is flexible.  For example, Node A may
   initiate another soft cell reservation procedure, or simply report to
   upper layer.

2.6.3.  Deleting soft cells

   The upper layer instructs 6top to delete one or more soft cells by
   calling the Delete soft cell command.  This command can also be
   called by the monitoring process internal to 6top.

   When receiving a Delete soft cell command, Node A's 6top sublayer
   selects cells to be removed from its local schedule, and creates a
   Soft Cell Remove Request, including a ScheduleIE.  The ScheduleIE
   indicates which specific cells to remove with a neighbor (Node B).
   The cells specified in the ScheduleIE should be removed from local
   schedule of Node A while the Soft Cell Remove Request is sent to Node



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   B. When receiving the Soft Cell Remove Request, the cells specified
   in the ScheduleIE should be removed from the local schedule of Node
   B.

   The policy to select cells corresponding to a Delete soft cell
   command is out of scope.

2.6.4.  Maintaining soft cells

   The monitoring process internal to 6top (Section 2.8) is responsible
   for monitoring and re-scheduling soft cells to meet some QoS
   requirements.  The monitoring process may issue a soft cell
   Maintenance command, which indicate a set of cells to be moved in the
   TSCH schedule.

   When a receiving a soft cell Maintenance command, 6top initializes a
   Soft Cell Remove Request (Section 2.6.3) with the neighbor in
   question, followed by a Soft Cell Reservation Request
   (Section 2.6.2).

2.6.5.  Creating hard cells

   The upper layer instructs 6top to create one or more hard cells by
   calling the Create hard cell command.

   When receiving a Create hard cell command, Node A's 6top sublayer
   creates a Hard Cell Reservation Request, including a ScheduleIE.  The
   ScheduleIE indicates which specific cells with a neighbor (Node B) to
   be added.  The cells specified in the ScheduleIE should be added in
   local schedule of Node A while the Hard Cell Reserve Request is sent
   to Node B. When receiving the Hard Cell Reserve Request, the cells
   specified in the ScheduleIE should be added in the local schedule of
   Node B.

2.6.6.  Deleting hard cells

   The upper layer instructs 6top to delete one or more hard cells by
   calling the Delete hard cell command.

   When receiving a Delete hard cell command, Node A's 6top sublayer
   creates a Hard Cell Remove Request, including a ScheduleIE.  The
   ScheduleIE indicates which specific cells with a neighbor (Node B) to
   be removed.  The cells specified in the ScheduleIE should be removed
   from local schedule of Node A while the Hard Cell Remove Request is
   sent to Node B. When receiving the Hard Cell Remove Request, the
   cells specified in the ScheduleIE should be removed from the local
   schedule of Node B.




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2.7.  Statistics

   The 6top Statistics Fuction (SF) is responsible for collecting
   statistics, which it can provide to an upper layer and the Monitoring
   Function (Section 2.8).

2.7.1.  Statistics Metrics

   6top is in charge of keeping statistics from a set of metrics
   gathered from the behavior of the TSCH layer.

   The statistics data related to node states and cell metrics should be
   provided to upper layer for management, e.g. for RPL to calculate
   Rank or to GMPLS to determine whether the link in a multi-hop path is
   meeting the required bandwidth.  The specific algorithm to generate
   the statistics is implementation dependent and hence out of the scope
   of this document.  However, the statistics component should include
   the following metrics:

   1.  LinkThroughput: associated with a link, Node A->Node B. For
       example, LinkThroughput can be calculated with:
       SUM(NumOfCell(i)*NumOfBytePerPacket)/(FrameLen(i)*SlotDuration)
       where NumOfCell(i) is the total number of cells from Node A to
       Node B in Slotframe-i, FrameLen(i) is the length of Slotframe-i.

   2.  Latency: associated with a link, Node A->Node B. For example,
       latency can be expressed as Minimum and Maximum Latency.  Minimum
       Latency = Min(MinNumOfSlot(i),i=1..) * SlotDuration and Maximum
       Latency = Max(MaxNumOfSlot(i),i=1..) * SlotDuration where,
       MinNumOfSlot(i) and MaxNumOfSlot(i) are the minimum or maximum
       number of slots between two dedicated cells from Node A to Node B
       in Slotframe-i, respectively.

   3.  LinkQuality.  For example, average LQI, ETX;

   4.  TafficLoad.  For example, Queue Full Rate, Queue Empty Rate;

   5.  NodeEnergy.  For example, E_E=E_bat / [E_0 (T-t)/T].

2.7.2.  Statistics Configuration

   Statistics Function should be configurable.  The configuration
   parameters should include:

      LinkQualityStatisticsEn.

      TafficLoadStatisticsEn.




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      DeviceStatisticsEn.

   6top statistics function is enabled/disabled and configured by the
   commands defined in Section 2.4.4

2.8.  Monitoring

   The 6top Monitoring Fuction (MF) is responsible for monitoring cell
   quality, traffic load, and issuing soft cell Maintenance command, or
   Create/Delete soft cell command.  The data provided by Statistics
   Function may be used as a input of MF in making monitoring decision.

2.8.1.  Monitor Configuration

   Monitoring Function should be configurable.  The configuration
   parameters should include:

      MaintainCellEn.

      CreateDeleteCellEn.

      QosLevel.  QosLevel should associate with specific neighbor
      address.  QosLevel may reflect the latency constraint, cell
      quality constraint, and so on.  The value of QosLevel works as the
      bandwidth redundancy coefficient.

   6top monitoring function is enabled/disabled and configured by the
   commands defined in Section 2.4.3

2.8.2.  Actuation

   The cell quality statistics may be used to generate soft cell
   Maintenance command, which leads to a soft cell Maintenance procedure
   (see Section 2.6.4).  The traffic load statistics may be used to
   generate internal Create/Delete soft cell commands, which leads to a
   soft cell Reservation process or a soft cell Remove process,
   respectively. (see Section 2.6.2 and Section 2.6.3)

   The policy to generate the soft cell Maintenance command and the
   policy to generate Create/Delete soft cell commands is out of the
   scope.

   The policy to generate Create/Delete soft cell commands may take
   QosLevel into account.  For example, there are two slotframes
   existing, Slotframe-1 consists of 32 slots, Slotframe-2 consists of
   96 slots; Slot duration is 10ms; QosLevel=1.5.  If, from the traffic
   load statistics, MF figures out 2 packet/second should be added, then
   it leads to a Create soft cell command, where FrameID=2, NumCell=3.



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2.9.  Label Switching

   Label Switching Fuction (LS) in 6top is responsible for maintaining
   the mapping of input cells and output cells in the same track in a
   particular node.  By keeping that mapping, layer 3 routing can be
   avoided as packets are forwarded by the 6top sublayer according to
   the input cells they were received on.  The selected output cell is
   one of the cells that forward the packet to the subsequent hop in the
   track.  As cells can be grouped in bundles, 6top can maintain
   mappings from input bundles to output bundles and provide a policy to
   select the output cell according to the input cell.

3.  Using 6top

   This part describes how 6top gives support to specific upper layers.

3.1.  RPL on 6top

   6top provides a set of functionalities so higher layers can obtain
   information about the status of the network and take advantage of the
   slotted structure to improve metric calculation and objective
   function optimization.  The following sections describe how RPL can
   make use of 6top sublayer.

   In order to optimize the combination of RPL and TSCH, 6top provides
   specific support to RPL in the following aspects:

      RPL Neighbor Discovery and Parent Selection

      RPL Rank Computation

      RPL Control Messages Broadcast

      QoS

3.1.1.  Support to Neighbor Discovery and Parent Selection

   The Section 2.4.7 defines a set of commands so the neighbor table can
   be managed and queried by RPL.  An entry to the neighbor table is
   inserted whenever an EBs is received at L2.  The EB causes the 6top
   sublayer to create an entry to the neighbors table.  A neighbor table
   entry contains a set of statistics with respect to that specific
   neighbor such as the ASN when the last packet has been received from
   that neighbor, a set of cell quality metrics (RSSI, LQI), number of
   packets sent to it or number of packets received from it amongst
   others. 6top updates that table upon sending or reception of a packet
   from/to a neighbor.  RPL can query at any time the neighbor table to
   retrieve information about a particular neighbor.  This information



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   can be used to compute the routing objective function as for example
   the inverse of the Probability Delivery Ratio (PDR).  Parent
   selection can also be driven by the information contained on the
   neighbor table as well as complemented with the cells statistics
   defined in Section 2.4.4 and Section 2.7.

   6top enables RPL to configure EB periodicity.  By controlling the EBs
   periodicity, RPL can configure how network dynamism and support to
   mobility are addressed, as more frequent beacons the more prone to
   cope with mobility.  Section 2.4.5 enables to configure how the
   network is formed and EBs periodicity.

   RPL may want to select the policy to determine the time source
   neighbor, this can be interesting when time source neighbors can be
   aligned to the routing topology, i.e., the selected time source
   neighbor can be the node's favorite parent in a specific DODAG.
   Section 2.4.6 describes the 6top command to set up the desired
   policy.  The policy is selected by RPL and enforced by the 6top
   sublayer.

   The rule for 6top to select and maintain time source neighbors is as
   follows:

      The time source neighbor of a node should be a member of the
      node's neighbor set.

      Time source neighbors should be the neighbors which have a
      relatively lower join priority in the neighbor set.  A lower join
      priority indicates that the neighbor is closer to the TSCH PAN
      coordinator.

      The link between a node and one of its time source neighbors
      should be a good link quality.

3.1.2.  Support of Rank Computation

   The RPL objective function is computed using a set of metrics.  The
   specific metrics and how the objective function is calculated are out
   of the scope of the present document, however, 6top builds a set of
   functionalities to provide more accurate statistics of the underlying
   layer so the objective function can be accommodated to the nature of
   a TSCH MAC layer.

   6top provides statistics for rank computation as described in
   sections Section 2.4.4 and Section 2.7.  The function used to compute
   the rank based on those statistics is out of scope of 6top, however
   the provided metrics are aligned to the behavior of the TSCH MAC
   layer.



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3.1.3.  Support of Control Messages Broadcast

   In RPL, some control messages, e.g. DIO and DAO in storing mode, need
   to be broadcast to all neighbor nodes.  The broadcast channel
   requirement has to be addressed by 6top by configuring TSCH to
   provide such a channel.

   In order to decouple the upper (RPL) layer from TSCH, instead of
   carrying DIO messages in Enhance Beacons, 6top introduces a mechanism
   to establish broadcast cells.

   In TSCH schedule, every cell has the LinkType attribute.  If
   LinkType=ADVERTISING, indicates that the cell may be used to send an
   Enhanced Beacon.  When a node forms its Enhanced Beacon, the cell,
   with LinkType=ADVERTISING, should be included in the FrameAndCellIE,
   and its LinkOption field should be set to the combination of
   "Receive" and "Timekeeping".  The receiver of the Enhanced Beacon may
   listen to at the cell to get the Enhanced Beacon ([IEEE802154e]).
   6top takes this way to establish broadcast channel, which not only
   allows TSCH broadcast Enhanced Beacon, but also allows an upper layer
   like RPL broadcast.

   To support DIO and DAO broadcast, 6top uses the payload of a Data
   Packet to carry the DIO or DAO.  The message is inserted into the
   queue associated with the cells which LinkType is set to ADVERTISING.
   Then, taking advantage of the broadcast cell feature established with
   FrameAndCellIE as described above, the data packet with DIO or DAO in
   payload can be received by neighbors, which leads to the maintenance
   of DODAG.

   The LinkOption of combining "Receive" and "Timekeeping" let the
   receivers of the Enhanced Beacon understand that the cell is used as
   broadcast cell.  But the frequency of sending Enhance Beacon or other
   broadcast messages by upper layer is determined by the timers
   associated with the messages, e.g. Enhance Beacon is triggered by the
   timer in 6top, and the DIO message is triggered by the trickle timer
   of RPL.  Therefore, for energy efficiency, receivers can have some
   policy to wake up at the broadcast cell, but it is implementation
   dependent.

3.1.4.  Support to QoS

   TSCH MAC layer is decoupled from the upper layers and its interaction
   with them is asynchronous.  This means that the MAC layer executes a
   schedule and checks at each slot according to the type of cell
   whether there is something to send or receive.  If that is the case
   the packet is sent and the MAC layer continues its operation.  When
   an upper layer sends a packet, this packet is pushed into a queue



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   waiting to the MAC layer to read it and sent it in a particular slot
   according to is destination and priority (Section 2.3). 6top provides
   a set of queue management operations which enable upper layers to
   create different queues and determine their priorities.  In that
   sense different classes of traffic can be handled by the routing
   layer, i.e inserting a packet to a specific queue according to its
   priority.

   6top provides at least a Broadcast Queue, a Transmit Queue, and a
   Receive Queue.  RPL can configure the queues with Internal Queueing
   Command (Section 2.4.8.1).  Broadcast Queue are associated with cells
   with LinkType=ADVERTISING in sender's schedule, and
   LinkOption="Receive" and "Timekeeping" in all neighbors' schedule.
   That indicates the cells can be used for broadcast from the sender to
   its neighbors.  Transmit Queues are associated with the dedicated
   Transmit cells or Shared Cells.  RPL can benefit from having
   different priority queues in order to improve latency or provide
   integrated services with different priorities, i.e different traffic
   classes.

   Data Communication Command (Section 2.4.10) can be used to send
   control messages and data messages.  The operation is used to insert
   a message to an specific queue.

   For example a suitable configuration can include two Broadcast Queues
   with priority High and Low, respectively; three Transmit Queues, with
   priority High, Mid, and Low, respectively; and one Receive Queue.

   When DestAddr is a broadcast address, its related MAC layer packets
   will be pushed into the Broadcast Queue with the corresponding
   priority. 6top is responsible for feeding these packets to TSCH at
   broadcast cells.

   When DestAddr is unicast address, its related MAC layer packets will
   be push into the Transmit Queue with corresponding priority. 6top is
   responsible for feeding these packets to TSCH at Transmit cells or
   Shared Cells.

   6top conducts a QoS policy, which is out of scope.  Here is an
   example.  Packets in higher priority queue MUST be sent out before
   the packets in lower priority queue.  Then, when there is an
   available broadcast/unicast cell, 6top checks the broadcast/unicast
   queue with higher priority first, if there is a packet, then feed it
   to TSCH at the cell, otherwise checks broadcast/unicast queue with
   lower priority further.  Repeat the process, until find a broadcast/
   unicast packet to feed to TSCH or find all of broadcast/unicast
   queues are empty.




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3.2.  GMPLS on 6top

   GMPLS is a 2.5 layer service that is used to forward packets based on
   the concept of generalized label.  Labels are determined by a
   reservation protocol during the formation of a multi-hop path.  As
   defined by [RFC3471],[RFC3473] and [RFC4606] a generalized label
   identifies a flow of data through a set of nodes that conform to a
   multi-hop path.  Instead of being appended to each packet as is the
   case in MPLS [RFC3031], the generalized label it is kept at each node
   in the form of a table.  The table can be used to map input cells to
   output cells so routing decisions can be taken at that layer.

   In order to optimize the combination of GMPLS and TSCH, 6top provides
   specific support to GMPLS in the following aspects:

      Cell Reservation Support

      QoS

3.2.1.  Cell Reservation Support for GMPLS on 6top

   The GMPLS control plane is used to send path reservation requests and
   reservation confirmations.  When reservation confirmations are
   received, GMPLS needs to configure the underlying MAC layer to
   provide the required bandwidth. 6top provides a set of commands to
   deal with bandwidth allocation, i.e. cell allocation.  Section 2.4.1
   describes the operations that GMPLS layer may use for cell
   configuration.  Note that 6top supports different types of
   reservations: soft cell and hard cell.  How the reservation
   requirements are expressed is out of scope of this document, but 6top
   is able to handle a reservation done as a specific bandwidth
   requirement, done through specifying exact cells.

   GMPLS can also give different priorities to its control plane and
   data plane.  It can for example be interesting to have a higher
   priority for control messages so the network adapts to new bandwidth
   requirements quickly.  In contrast, data plane messages can be given
   a higher priority when they need to meet higher throughput or lower
   latency. 6top provides commands (Section 2.4.8) to manage MAC layer
   queues and assign different priorities to them.

3.2.2.  Supporting QoS

   GMPLS can use 6top statistics to determine whether some QoS
   requirement is met.  Metrics defined in Section 2.7 and operations
   defined in Section 2.4.4.4 can be used by GMPLS to trigger new
   bandwidth allocation, or to map different input bundles to output
   bundles.



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4.  References

4.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

4.2.  Informative References

   [RFC2205]  Braden, B., Zhang, L., Berson, S., Herzog, S., and S.
              Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
              Functional Specification", RFC 2205, September 1997.

   [RFC2464]  Crawford, M., "Transmission of IPv6 Packets over Ethernet
              Networks", RFC 2464, December 1998.

   [RFC3031]  Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
              Label Switching Architecture", RFC 3031, January 2001.

   [RFC3036]  Andersson, L., Doolan, P., Feldman, N., Fredette, A., and
              B. Thomas, "LDP Specification", RFC 3036, January 2001.

   [RFC3471]  Berger, L., "Generalized Multi-Protocol Label Switching
              (GMPLS) Signaling Functional Description", RFC 3471,
              January 2003.

   [RFC3473]  Berger, L., "Generalized Multi-Protocol Label Switching
              (GMPLS) Signaling Resource ReserVation Protocol-Traffic
              Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.

   [RFC3819]  Karn, P., Bormann, C., Fairhurst, G., Grossman, D.,
              Ludwig, R., Mahdavi, J., Montenegro, G., Touch, J., and L.
              Wood, "Advice for Internet Subnetwork Designers", BCP 89,
              RFC 3819, July 2004.

   [RFC4606]  Mannie, E. and D. Papadimitriou, "Generalized Multi-
              Protocol Label Switching (GMPLS) Extensions for
              Synchronous Optical Network (SONET) and Synchronous
              Digital Hierarchy (SDH) Control", RFC 4606, August 2006.

   [RFC4919]  Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6
              over Low-Power Wireless Personal Area Networks (6LoWPANs):
              Overview, Assumptions, Problem Statement, and Goals", RFC
              4919, August 2007.

   [RFC4944]  Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
              "Transmission of IPv6 Packets over IEEE 802.15.4
              Networks", RFC 4944, September 2007.



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   [RFC5548]  Dohler, M., Watteyne, T., Winter, T., and D. Barthel,
              "Routing Requirements for Urban Low-Power and Lossy
              Networks", RFC 5548, May 2009.

   [RFC5826]  Brandt, A., Buron, J., and G. Porcu, "Home Automation
              Routing Requirements in Low-Power and Lossy Networks", RFC
              5826, April 2010.

   [RFC5867]  Martocci, J., De Mil, P., Riou, N., and W. Vermeylen,
              "Building Automation Routing Requirements in Low-Power and
              Lossy Networks", RFC 5867, June 2010.

   [RFC5673]  Pister, K., Thubert, P., Dwars, S., and T. Phinney,
              "Industrial Routing Requirements in Low-Power and Lossy
              Networks", RFC 5673, October 2009.

   [RFC6282]  Hui, J. and P. Thubert, "Compression Format for IPv6
              Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
              September 2011.

   [RFC6550]  Winter, T., Thubert, P., 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, March 2012.

   [RFC6568]  Kim, E., Kaspar, D., and JP. Vasseur, "Design and
              Application Spaces for IPv6 over Low-Power Wireless
              Personal Area Networks (6LoWPANs)", RFC 6568, April 2012.

   [RFC6606]  Kim, E., Kaspar, D., Gomez, C., and C. Bormann, "Problem
              Statement and Requirements for IPv6 over Low-Power
              Wireless Personal Area Network (6LoWPAN) Routing", RFC
              6606, May 2012.

   [RFC6755]  Campbell, B. and H. Tschofenig, "An IETF URN Sub-Namespace
              for OAuth", RFC 6755, October 2012.

   [I-D.watteyne-6tsch-tsch-lln-context]
              Watteyne, T., Palattella, M., and L. Grieco, "Using
              IEEE802.15.4e TSCH in an LLN context: Overview, Problem
              Statement and Goals", draft-watteyne-6tsch-tsch-lln-
              context-02 (work in progress), May 2013.

   [I-D.thubert-6tsch-architecture]
              Thubert, P., Assimiti, R., and T. Watteyne, "An
              Architecture for IPv6 over Time Slotted Channel Hopping",
              draft-thubert-6tsch-architecture-01 (work in progress),
              April 2013.



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   [I-D.palattella-6tsch-terminology]
              Palattella, M., Thubert, P., Watteyne, T., and Q. Wang,
              "Terminology in IPv6 over Time Slotted Channel Hopping",
              draft-palattella-6tsch-terminology-00 (work in progress),
              March 2013.

   [I-D.vilajosana-6tsch-basic]
              Vilajosana, X., "Minimal 6TSCH Configuration", draft-
              vilajosana-6tsch-basic-00 (work in progress), June 2013.

   [I-D.ohba-6tsch-security]
              Chasko, S., Das, S., Lopez, R., Ohba, Y., Thubert, P., and
              A. Yegin, "Security Framework and Key Management Protocol
              Requirements for 6TSCH", draft-ohba-6tsch-security-01
              (work in progress), July 2013.

   [I-D.thubert-roll-forwarding-frags]
              Thubert, P. and J. Hui, "LLN Fragment Forwarding and
              Recovery", draft-thubert-roll-forwarding-frags-01 (work in
              progress), February 2013.

   [I-D.tsao-roll-security-framework]
              Tsao, T., Alexander, R., Daza, V., and A. Lozano, "A
              Security Framework for Routing over Low Power and Lossy
              Networks", draft-tsao-roll-security-framework-02 (work in
              progress), March 2010.

   [I-D.thubert-roll-asymlink]
              Thubert, P., "RPL adaptation for asymmetrical links",
              draft-thubert-roll-asymlink-02 (work in progress),
              December 2011.

   [I-D.ietf-roll-terminology]
              Vasseur, J., "Terminology in Low power And Lossy
              Networks", draft-ietf-roll-terminology-12 (work in
              progress), March 2013.

   [I-D.ietf-roll-p2p-rpl]
              Goyal, M., Baccelli, E., Philipp, M., Brandt, A., and J.
              Martocci, "Reactive Discovery of Point-to-Point Routes in
              Low Power and Lossy Networks", draft-ietf-roll-p2p-rpl-17
              (work in progress), March 2013.

   [I-D.ietf-roll-trickle-mcast]
              Hui, J. and R. Kelsey, "Multicast Protocol for Low power
              and Lossy Networks (MPL)", draft-ietf-roll-trickle-
              mcast-04 (work in progress), February 2013.




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   [I-D.thubert-6lowpan-backbone-router]
              Thubert, P., "6LoWPAN Backbone Router", draft-thubert-
              6lowpan-backbone-router-03 (work in progress), February
              2013.

   [I-D.sarikaya-core-sbootstrapping]
              Sarikaya, B., Ohba, Y., Moskowitz, R., Cao, Z., and R.
              Cragie, "Security Bootstrapping Solution for Resource-
              Constrained Devices", draft-sarikaya-core-
              sbootstrapping-04 (work in progress), April 2012.

   [I-D.gilger-smart-object-security-workshop]
              Gilger, J. and H. Tschofenig, "Report from the 'Smart
              Object Security Workshop', 23rd March 2012, Paris,
              France", draft-gilger-smart-object-security-workshop-00
              (work in progress), October 2012.

   [I-D.phinney-roll-rpl-industrial-applicability]
              Phinney, T., Thubert, P., and R. Assimiti, "RPL
              applicability in industrial networks", draft-phinney-roll-
              rpl-industrial-applicability-02 (work in progress),
              February 2013.

   [I-D.ietf-core-coap]
              Shelby, Z., Hartke, K., and C. Bormann, "Constrained
              Application Protocol (CoAP)", draft-ietf-core-coap-18
              (work in progress), June 2013.

4.3.  External Informative References

   [IEEE802154e]
              IEEE standard for Information Technology, "IEEE std.
              802.15.4e, Part. 15.4: Low-Rate Wireless Personal Area
              Networks (LR-WPANs) Amendament 1: MAC sublayer", April
              2012.

   [IEEE802154]
              IEEE standard for Information Technology, "IEEE std.
              802.15.4, Part. 15.4: Wireless Medium Access Control (MAC)
              and Physical Layer (PHY) Specifications for Low-Rate
              Wireless Personal Area Networks", June 2011.

   [OpenWSN]  , "Berkeley's OpenWSN Project Homepage", ,
              <http://www.openwsn.org/>.

   [label-switching-154e]
              Morell, A., Vilajosana, X., Lopez-Vicario, J., and T.
              Watteyne, "Label Switching over IEEE802.15.4e Networks.



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Internet-Draft                 6tsch-6top                      July 2013


              Transactions on Emerging Telecommunications Technologies",
              June 2013.

Authors' Addresses

   Qin Wang (editor)
   Univ. of Sci. and Tech. Beijing
   30 Xueyuan Road
   Beijing, Hebei  100083
   China

   Phone: +86 (10) 6233 4781
   Email: wangqin@ies.ustb.edu.cn


   Xavier Vilajosana
   Universitat Oberta de Catalunya
   156 Rambla Poblenou
   Barcelona, Catalonia  08018
   Spain

   Phone: +34 (646) 633 681
   Email: xvilajosana@uoc.edu


   Thomas Watteyne
   Linear Technology
   30695 Huntwood Avenue
   Hayward, CA  94544
   USA

   Phone: +1 (510) 400-2978
   Email: twatteyne@linear.com


















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