6TiSCH Q. Wang, Ed.
Internet-Draft Univ. of Sci. and Tech. Beijing
Intended status: Informational X. Vilajosana
Expires: January 5, 2015 Universitat Oberta de Catalunya
T. Watteyne
Linear Technology
July 4, 2014
6TiSCH Operation Sublayer (6top) Interface
draft-ietf-6tisch-6top-interface-01
Abstract
This document defines a generic data model for the 6TiSCH Operation
Sublayer (6top), using the YANG data modeling language. This data
model can be used for future network management solutions defined by
the 6TiSCH working group. This document also defines a list commands
internal to the 6top sublayer.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in RFC
2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 5, 2015.
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Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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to this document. Code Components extracted from this document must
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. 6TiSCH Operation Sublayer (6top) Overview . . . . . . . . . . 3
2.1. Cell Model . . . . . . . . . . . . . . . . . . . . . . . 4
2.1.1. hard cells . . . . . . . . . . . . . . . . . . . . . 6
2.1.2. soft cells . . . . . . . . . . . . . . . . . . . . . 6
2.2. Data Transfer Model . . . . . . . . . . . . . . . . . . . 6
3. Generic Data Model . . . . . . . . . . . . . . . . . . . . . 8
3.1. YANG model of the 6top MIB . . . . . . . . . . . . . . . 8
3.2. YANG model of the IEEE802.15.4 PIB . . . . . . . . . . . 24
4. Commands . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.1. Normative References . . . . . . . . . . . . . . . . . . 33
5.2. Informative References . . . . . . . . . . . . . . . . . 33
5.3. External Informative References . . . . . . . . . . . . . 34
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 34
1. Introduction
This document defines a generic data model for the 6TiSCH Operation
Sublayer (6top), using the YANG data modeling language defined in
[RFC6020]. This data model can be used for future network management
solutions defined by the 6TiSCH working group. This document also
defines a list commands internal to the 6top sublayer. This data
model gives access to metrics (e.g. cell state), TSCH configuration
and control procedures, and support for the different scheduling
mechanisms described in [I-D.ietf-6tisch-architecture]. The 6top
sublayer addresses the set of management information and
functionalities described in [I-D.ietf-6tisch-tsch].
For example, network formation in a TSCH network is handled by the
use of Enhanced Beacons (EB). EBs include information for joining
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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 decentralized, centralized or
hybrid scheduling solutions. 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 [morell04label], due to the slotted nature of a TSCH
network, 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. 6TiSCH Operation Sublayer (6top) Overview
6top is a sublayer which is the next-higher layer for TSCH
(Figure 1), as detailed in [I-D.ietf-6tisch-architecture]. 6top
offers both management and data interfaces to an upper layer, and
includes monitoring and statistics collection, both of which are
configurable through its management interface. The detail of 6top-
sublayer is described in [I-D.wang-6tisch-6top-sublayer]
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Protocol Stack
+-----------------------------------+
| PCEP | CoAP | | 6LoWPAN | |
| PCC | DTLS | PANA | ND |RPL |
+------------------------------------------+
| TCP | UDP | ICMP | RSVP |
+------------------------------------------+
| IPv6 |
+------------------------------------------+
| 6LoWPAN HC |
+------------------------------------------+
| 6top |
+------------------------------------------+
| IEEE802.15.4e TSCH |
+------------------------------------------+
| IEEE802.15.4 |
+------------------------------------------+
Figure 1
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 2.1.
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 2.2.
Section 3 contains a generic data model for the 6top sublayer,
described in the YANG data modeling language.
The commands of the management and data interfaces are listed in
Section 4. This set of commands is designed to support
decentralized, centralized and hybrid scheduling solutions.
2.1. Cell Model
[IEEE802154e] 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 MLME-SET-LINK.request
command defined in [IEEE802154e] 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
slotOffset and channelOffset, in a specific slotframe.
In addition, 6top allows an upper layer to schedule a certain amount
of bandwidth to a neighbor, without having to specify the exact
slotOffset(s) and channelOffset(s). Once bandwidth is reserved, 6top
is in charge of ensuring that this requirement is continuously
satisfied. 6top dynamically reallocates cells if needed, and over-
provisions if required.
6top allows an upper layer to associate a 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 initializes 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.
6top allows an upper layer to ask a node to manage a portion of a
slotframe, which is named as chunk. Chunks can be delegated
explicitly by the PCE to a node, or claimed automatically by any node
that participates to the distributed cell scheduling process. The
resource in a chunk can be appropriated by the node, i.e. the owner
of the chunk.
Given this mechanism, 6top defines hard cells (which have been
requested specifically) and soft cells (which can be reallocated
dynamically). The hard/soft flag is introduced by the 6top sublayer
named as CellType, 0: soft cell, 1: hard cell. This option is
mandatory; all cells are either hard or soft.
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2.1.1. hard cells
A hard cell is a cell that cannot be dynamically reallocated by 6top.
The CellType MUST be set to 1. The cell is installed by 6top given
specific slotframe ID, slotOffset, and channelOffset.
2.1.2. soft cells
A soft cell is a cell that can be reallocated by 6top dynamically.
The CellType 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
[I-D.wang-6tisch-6top-sublayer].
2.2. Data Transfer Model
Once a TSCH schedule is established, 6top is responsible for feeding
the data 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.
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6top Data Transfer Model
|
| (DestAddr, Priority, Fragment)
|
+---------------------------------------+
| I-MUX |
+---------------------------------------+
| | | | .... |
| | | | |
+---+ +---+ +---+ +---+ +---+
| | | | | | | | | |
|Q1 | |Q2 | |Q3 | |Q4 | |Qn |
| | | | | | | | | |
+---+ +---+ +---+ +---+ +---+
| | | | |
| | | | |
+---------------------------------------+
| MUX |
+---------------------------------------+
|
|
+---+
|PDU|
+---+
|
| TSCH MAC-payload
|
Figure 2
In Figure 2, Qi represents a queue, which is either broadcast or
unicast, and has an assigned 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, all of the tracks can be used, or a subset of the
tracks can be used.
When 6top receives a packet to transmit through a Send.data command
(Section 4), 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 matching 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. The
following rules are a typical example:
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.
3. Generic Data Model
This section presents the generic data model of the 6top sublayer,
using the YANG data modeling langage. This data model can be used
for future network management solutions defined by the 6TiSCH working
group. The data model consists of the MIB (management information
base) defined in 6top, and part of the PIB (personal area network
information base) defined in [IEEE802154e] and [IEEE802154].
3.1. YANG model of the 6top MIB
list CellList {
key "CellID";
description
"List of scheduled cells of a node with all of its neighbors,
in all of its slotframes.";
leaf CellID {
type uint16;
description
"Equal to Linkhandle in the linkTable of TSCH";
reference
"IEEE802154e";
}
leaf SlotframeID {
type uint8;
description
"SlotframeID, one in SlotframeList, indicates the slotframe
the cell belongs to.";
reference
"IEEE802154e";
}
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leaf SlotOffset {
type uint16;
description
"Defined in IEEE802154e.";
reference
"IEEE802154e";
}
leaf ChannelOffset {
type uint8;
description
"Defined in IEEE802154e. Value range is 0..15";
reference
"IEEE802154e";
}
leaf LinkOption {
type bits {
bit Transmit {
position 0;
}
bit Receive {
position 1;
}
bit Share {
position 2;
}
bit Timekeeping {
position 3;
}
bit Reserved1 {
position 4;
}
bit Reserved2 {
position 5;
}
bit Reserved3 {
position 6;
}
bit Reserved4 {
position 7;
}
}
description
"Defined in IEEE802154e.";
reference
"IEEE802154e";
}
leaf LinkType {
type enumeration {
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enum NORMAL;
enum ADVERTISING;
}
description
"Defined in IEEE802154";
reference
"IEEE802154";
}
leaf CellType {
type enumeration {
enum SOFT;
enum HARD;
}
description
"Defined in 6top";
}
leaf TargetNodeAddress {
type uint64;
description
"Defined by 6top, but being constrained by TSCH
macNodeAddress size, 2-octets. If using TSCH as MAC,
higher 6-octets should be filled with 0, and lowest
2-octets is neighbor address";
}
leaf TrackID {
type uint16;
description
"A TrackID is one in the TrackList, pointing to a tuple
(TrackOwnerAddr,InstanceID) , where TrackOwnerAddr is the
address of the node which initializes 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.";
}
container Statistic {
leaf NumOfStatistic {
type uint8;
description
"Number of statistics collected on the cell";
}
list MeasureList {
key "StatisticsMetricsID";
leaf StatisticsMetricsID{
type uint16;
description
"An index of StatisticsMetricList, which defines how
to collect data and get the statistice value";
}
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leaf StatisticsValue{
type uint16;
config false;
description
"updated by 6top according to the statistics methed
specified by StatisticsMetricsID";
}
}
}
}
list SlotframeList {
key "SlotframeID";
description
"List of all of the slotframes used by the node.";
leaf SlotframeID {
type uint8;
description
"Equal to SlotframeHandle defined in TSCH";
reference
"IEEE802154e";
}
leaf NumOfSlots {
type uint16;
description
"indicates how many timeslots in the slotframe";
}
}
list MonitoringStatusList {
key "MonitoringStatusID";
description
"List of the monitoring configuration and results per
slotframe and neighbor. Basically, it is used for Monitoring
Function of 6top to re-allocate softcells or initial the
softcell negotiation process to increase/decrease number of
softcells. Upper layer can use it also.";
leaf MonitoringStatusID {
type uint16;
}
leaf SlotframeID {
type uint8;
description
"SlotframeID, one in SlotframeList, indicates the slotframe
being monitored";
reference
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"IEEE802154e";
}
leaf TargetNodeAddress {
type uint64;
description
"Defined by 6top, but being constrained by TSCH
macNodeAddress size, 2-octets. If using TSCH as MAC,
higher 6-octets should be filled with 0, and lowest
2-octets is neighbor address. It indicates the communication
link being mornitored";
}
leaf EnforcePolicy {
type enumeration {
enum DISABLE;
enum BESTEFFORT;
enum STRICT;
enum OVERPROVISION;
}
description
"Currently enforced QoS policy. DISABLE-no QoS;
BESTEFFORT- best effort policy is used; STRICT- Strict
Priority Queueing; OVERPROVISION- cell overprovision";
}
leaf AllocatedHard {
type uint16;
config false;
description
"Number of hard cells allocated";
}
leaf AllocatedSoft {
type uint16;
config false;
description
"Number of soft cells allocated";
}
leaf OverProvision {
type uint16;
config false;
description
"Overprovisioned cells. 0 if EnforcePolicy is
DISABLE";
}
leaf QoS {
type uint16;
config false;
description
"Current QoS including overprovisioned cells, i.e. the
bandwidth obtained including the overprovisioned cells.";
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}
leaf NQoS {
type uint16;
config false;
description
"Real QoS without over provisioned cells, i.e. the actual
bandwidth without taking into account the overprovisioned
cells.";
}
}
list StatisticsMetricsList {
key "StatisticsMetricsID";
description
"List of Statistics Metrics used in the node.";
leaf StatisticsMetricsID {
type uint16;
}
leaf SlotframeID {
type uint16;
description
"SlotframeID, one in SlotframeList, specifies the slotframe to
which the statistics metrics applies to. If empty, applies to
all slotframes";
reference
"IEEE802154e";
}
leaf SlotOffset {
type uint16;
description
"Specific slotOffset to which the statistics metrics applies
to. If empty, applies to all timeslots";
reference
"IEEE802154e";
}
leaf ChannelOffset {
type uint8;
description
"Specific channelOffset to which the statistics metrics applies
to. If empty, applies to all channels";
reference
"IEEE802154e";
}
leaf TargetNodeAddress {
type uint64;
description
"Specific neighbor nodes to which the statistics metrics
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applies to. If empty, applies to all neighbor nodes.";
}
leaf Metrics {
type enumeration {
enum PDR;
enum ETX;
enum RSSI;
enum LQI;
}
description
"The metric to be monitored.";
}
leaf Window {
type uint16;
description
"measurement period, in Number of the slotframe size";
}
leaf Enable {
type enumeration {
enum DISABLE;
enum ENABLE;
}
description
"indicates the StatisticsMetric is active or not";
}
}
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list EBList {
key "EbID";
description
"List of information related with the EBs used by the node";
leaf EbID {
type uint8;
}
leaf CellID {
type uint16;
description
"CellID, one in CellList, indicates the cell used to send
EB";
}
leaf Peroid {
type uint16;
description
"The EBs period, in seconds, indicates the interval between
two EB sendings";
}
leaf Expiration {
type enumeration {
enum NEVERSTOP;
enum EXPIRATION;
}
description
"NEVERSTOP- the period of the EB never stops; EXPIRATION-
when the Period arrives, the EB will stop.";
}
leaf Priority {
type uint8;
description
"The joining priority model that will be used for
advertisements. Joining priority MAY be for example
SAME_AS_PARENT, RANDOM, BEST_PARENT+1 or
DAGRANK(rank).";
}
}
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container TimeSource {
description
"specify the timesource selection policy and some relative
statistics.";
leaf policy {
type enumeration {
enum ALLPARENT;
enum BESTCONNECTED;
enum LOWESTJOINPRIORITY;
}
description
"indicates the policy to choose timesource. ALLPARENT- choose
from all parents; BESTCONNECTED- choose the best-connected
node; LOWESTJOINPRIORITY- choose the node with lowest priority
in its EB.";
}
leaf TargetNodeAddress {
type uint64;
description
"Address of the time source neighbor";
}
leaf MinTimeCorrection {
type uint16;
config false;
description
"measured in microsecond";
}
leaf MaxTimeCorrection {
type uint16;
config false;
description
"measured in microsecond";
}
leaf AveTimeCorrection {
type uint16;
config false;
description
"measured and computed in microsecond";
}
}
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typedef asntype {
description
"The type to store ASN. String of 5 bytes";
type string {
length "0..5";
}
}
list NeighborList {
key "TargetNodeAddress";
description
"statistics per communication link.";
leaf TargetNodeAddress {
type uint64;
description
"Address of the time source neighbor";
}
leaf RSSI {
type uint8;
config false;
description
"The received signal strength";
}
leaf LinkQuality {
type uint8;
config false;
description
"The LQI metric";
}
leaf ASN {
type asntype;
config false;
description
"The 5 ASN bytes, indicates the most recent timeslot when a
packet from the neighbor was received";
}
}
list QueueList {
key "QueueId";
description
"List of Queues, including configuration and statistics.";
leaf QueueId {
type uint8;
description
"Queue Identifier";
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}
leaf TxqLength {
type uint8;
description
"The TX queue length in number of packets";
}
leaf RxqLength {
type uint8;
description
"The RX queue length in number of packets";
}
leaf NumrTx {
type uint8;
description
"Number of allowed retransmissions.";
}
leaf Age {
type uint16;
description
"In seconds. Discard packet according to its age
on the queue. 0 if no discards are allowed.";
}
leaf RTXbackoff {
type uint8;
description
"retransmission backoff in number of slotframes.
0 if next available timeslot wants to be used.";
}
leaf StatsWindow {
type uint16;
description
"In second, window of time used to compute stats.";
}
leaf QueuePriority {
type uint8;
description
"The priority for this queue.";
}
list TrackIds {
key "TrackID";
leaf TrackID{
type uint16;
description
"The TrackID, one in TrackList, indicates the Track is
associated with the Queue.";
}
}
leaf MinLenTXQueue {
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type uint8;
config false;
description
"Statistics, lowest TX queue length registered in the window.";
}
leaf MaxLenTXQueue {
type uint8;
config false;
description
"Statistics, largest TX queue length registered in the
window.";
}
leaf AvgLenTXQueue {
type uint8;
config false;
description
"Statistics, avg TX queue length registered in the window.";
}
leaf MinLenRXQueue {
type uint8;
config false;
description
"Statistics, lowest RX queue length registered in the window.";
}
leaf MaxLenRXQueue {
type uint8;
config false;
description
"Statistics, largest RX queue len registered in the window.";
}
leaf AvgLenRXQueue {
type uint8;
config false;
description
"Statistics, avg RX queue length registered in the window.";
}
leaf MinRetransmissions {
type uint8;
config false;
description
"Statistics, lowest number of retransmissions registered in
the window.";
}
leaf MaxRetransmissions {
type uint8;
config false;
description
"Statistics, largest number of retransmissions registered
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in the window.";
}
leaf AvgRetransmissions {
type uint8;
config false;
description
"Statistics, average number of retransmissions registered
in the window.";
}
leaf MinPacketAge {
type uint16;
config false;
description
"Statistics, in seconds, minimum time a packet stayed in
the queue during the observed window.";
}
leaf MaxPacketAge {
type uint16;
config false;
description
"Statistics, in seconds, maximum time a packet stayed
in the queue during the observed window.";
}
leaf AvgPacketAge {
type uint16;
config false;
description
"Statistics, in seconds, average time a packet stayed in
the queue during the observed window.";
}
leaf MinBackoff {
type uint8;
config false;
description
"Statistics, in number of slotframes, minimum Backoff
for a packet in the queue during the observed window.";
}
leaf MaxBackoff {
type uint8;
config false;
description
"Statistics, in number of slotframes, maximum Backoff
for a packet in the queue during the observed window.";
}
leaf AvgBackoff {
type uint8;
config false;
description
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"Statistics, in number of slotframes, average Backoff
for a packet in the queue during the observed window.";
}
}
list LabelSwitchList {
key "LabelSwitchID";
description
"List of Label switch' configuration on the node";
leaf LabelSwitchID {
type uint16;
}
list InputCellIds {
key "CellID";
leaf CellID{
type uint16;
description
"The CellID, indicates the Rx cell on which the packet will
come in.";
}
}
list OutputCellIds {
key "CellID";
leaf CellID{
type uint16;
description
"The CellID, indicates the Tx cell on which the received
packet should be sent out.";
}
}
leaf LoadBalancingPolicy {
type enumeration {
enum ROUNDROBIN;
enum OTHER;
}
description
"The load-balancing policy. ROUNDROBIN- Round robin algorithm
is used for forwarding scheduling.";
}
}
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list TrackList {
key "TrackId";
description
"List of the tracks through the node.";
leaf TrackId {
type uint16;
description
"Track Identifier, named locally. It is used to refer to the
tuple (TrackOwnerAddr, InstanceID).";
}
leaf TrackOwnerAddr {
type uint64;
description
"The address of the node which initializes the process of
creating the track, i.e., the owner of the track;";
}
leaf InstanceID {
type uint16;
description
"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.";
}
}
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list ChunkList {
key "ChunkId";
description
"List of the chunks assigned to the node.";
leaf ChunkId{
type uint16;
description
"The identifier of a chunk";
}
leaf SlotframeId{
type uint8;
description
"SlotframeID, one in SlotframeList, indicates the
slotframe to which the chunk belongs";
}
leaf SlotBase {
type uint16;
description
"the base slotOffset of the chunk in the slotframe";
}
leaf SlotStep {
type uint8;
description
"the slot incremental of the chunk";
}
leaf ChannelBase {
type uint8;
description
"the base channelOffset of the chunk";
}
leaf ChannelStep {
type uint8;
description
"the channel incremental of the chunk";
}
leaf ChunkSize {
type uint8;
description
"the number of cells in the chunk. The chunk is the set
of (slotOffset(i), channelOffset(i)),
i=0..Chunksize-1,
slotOffset(i)= (slotBase + i * slotStep) % slotframeLen,
channelOffset(i) = (channelBase + i * channelStep) % 16";
}
}
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list ChunkCellList {
key "SlotOffset ChannelOffset";
description
"List of all of the cells assigned to the node via the
assignment of chunks.";
leaf SlotOffset{
type uint16;
description
"The slotoffset of a cell which belongs to a Chunk";
}
leaf ChannelOffset{
type uint16;
description
"The channeloffset of a cell which belongs to a chunk.";
}
leaf ChunkId {
type uint16;
description
"Identifier of the chunk the cell belongs to";
}
leaf CellID{
type uint16;
description
"Initial value of CellID is 0xFFFF. When the cell is
scheduled, the value of CellID is same as that in
CellList";
}
leaf ChunkCellStatus {
type enumeration {
enum UNSCHEDULED;
enum SCHEDULED;
}
}
}
3.2. YANG model of the IEEE802.15.4 PIB
This section describes the YANG model of the part of PIB
([IEEE802154] and [IEEE802154e]) used by 6top, such as security
related attributes, TSCH related attributes. This part of data will
be accessed through the MLME-GET and MLME-SET primitive [IEEE802154]
directly, instead of using 6top comannds.
TODO the security related attributes will be added after 6TiSCH WG
has consensus on the security scheme of 6top
container TSCHSpecificPIBAttributes {
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description
"TSCH specific MAC PIB attributes.";
reference
"table 52b in IEEE802.15.4e-2012.";
leaf macMinBE {
type uint8;
description
"defined in Table 52b of IEEE802.15.4e-2012,
The minimum value of the backoff exponent (BE) in the
CSMA-CA algorithm or the TSCH-CA algorithm. default:
3-CSMA-CA, 1-TSCH-CA";
}
leaf macMaxBE {
type uint8;
description
"defined in Table 52b of IEEE802.15.4e-2012,
The maximum value of the backoff exponent (BE) in the
CSMA-CA algorithm or the TSCH-CA algorithm. default:
5-CSMA-CA, 7-TSCH-CA";
}
leaf macDisconnectTime {
type uint16;
description
"defined in Table 52b of IEEE802.15.4e-2012,
Time (in Timeslots) to send out Disassociate frames
before disconnecting, default: 0x00ff";
}
leaf macJoinPriority {
type uint8;
description
"defined in Table 52b of IEEE802.15.4e-2012,
The lowest join priority from the TSCH Synchronization
IE in an Enhanced beacon, default: 1";
}
leaf macASN {
type asntype;
description
"defined in Table 52b of IEEE802.15.4e-2012,
The Absolute Slot Number, i.e., the number of slots
that ha elapsed since the start of the network.";
}
leaf macNoHLBuffers {
type enumeration {
enum TRUE;
enum FALSE;
}
description
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"defined in Table 52b of IEEE802.15.4e-2012,
If the value is TRUE, the higher layer receiving the
frame payload cannot buffer it, and the device should
acknowledge frames with a NACK; If FALSE, the higher
layer can accept the frame payload. default: FALSE";
}
}
list TSCHmacTimeslotTemplate {
key "macTimeslotTemplateId";
description
"List of all timeslot templates used in the node.";
reference
"table 52e in IEEE802.15.4e-2012.";
leaf macTimeslotTemplateId {
type uint8;
description
"defined in Table 52e of IEEE802.15.4e-2012.
Identifier of Timeslot Template. default: 0";
}
leaf macTsCCAOffset {
type uint16;
description
"The time between the beginning of timeslot and start
of CCA operation, in microsecond. default: 1800";
}
leaf macTsCCA {
type uint16;
description
"Duration of CCA, in microsecond. default: 128";
}
leaf macTsTxOffset {
type uint16;
description
"The time between the beginning of the timeslot and
the start of frame transmission, in microsecond.
default: 2120";
}
leaf macTsRxOffset {
type uint16;
description
"Beginning of the timeslot to when the receiver shall
be listening, in microsecond. default: 1120";
}
leaf macTsRxAckDelay {
type uint16;
description
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"End of frame to when the transmitter shall listen for
Acknowledgment, in microsecond. default: 800";
}
leaf macTsTxAckDelay {
type uint16;
description
"End of frame to start of Acknowledgment, in
microsecond.
default: 1000";
}
leaf macTsRxWait {
type uint16;
description
"The time to wait for start of frame, in microsecond.
default: 2200";
}
leaf macTsAckWait {
type uint16;
description
"The minimum time to wait for start of an
Acknowledgment, in microsecond. default: 400";
}
leaf macTsRxTx {
type uint16;
description
"Transmit to Receive turnaround, in microsecond.
default: 192";
}
leaf macTsMaxAck {
type uint16;
description
"Transmission time to send Acknowledgment,in
microsecond. default: 2400";
}
leaf macTsMaxTx {
type uint16;
description
"Transmission time to send the maximum length frame,
in microsecond. default: 4256";
}
leaf macTsTimeslotLength {
type uint16;
description
"The total length of the timeslot including any unused
time after frame transmission and Acknowledgment,
in microsecond. default: 10000";
}
}
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list TSCHHoppingSequence {
key "macHoppingSequenceID";
description
"List of all channel hopping sequences used in the
nodes";
reference
"Table 52f of IEEE802.15.4e-2012";
leaf macHoppingSequenceID {
type uint8;
description
"defined in Table 52f of IEEE802.15.4e-2012.
Each hopping sequence has a unique ID. default: 0";
}
leaf macChannelPage {
type uint8;
description
"Corresponds to the 5 MSBs (b27, ..., b31) of a row
in phyChannelsSupported. Note this may not correspond
to the current channelPage in use.";
}
leaf macNumberOfChannels {
type uint16;
description
"Number of channels supported by the PHY on this
channelPage.";
}
leaf macPhyConfiguration {
type uint32;
description
"For channel pages 0 to 6, the 27 LSBs(b0, b1, ...,
b26) indicate the status (1 = to be used, 0 = not to
be used) for each of the up to 27 valid channels
available to the PHY. For pages 7 and 8, the 27 LSBs
indicate the configuration of the PHY, and the channel
list is contained in the extendedBitmap.";
}
leaf macExtendedBitmap {
type uint64;
description
"For pages 7 and 8, a bitmap of numberOfChannels bits,
where bk shall indicate the status of channel k for
each of the up to numberOfChannels valid channels
supported by that channel page and phyConfiguration.
Otherwise field is empty.";
}
leaf macHoppingSequenceLength {
type uint16;
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description
"The number of channels in the Hopping Sequence.
Does not necessarily equal numberOfChannels.";
}
list macHoppingSequenceList {
key "HoppingChannelID";
leaf HoppingChannelID {
type uint16;
description
"channels to be hopped over";
}
}
leaf macCurrentHop {
type uint16;
config false;
description
"Index of the current position in the hopping sequence
list.";
}
}
4. Commands
6top provides a set of commands as the interface with the higher
layer. Most of these commands are related to the management of
slotframes, cells and scheduling information. 6top also provides an
interface allowing an upper layer to retrieve status information and
statistics. The command set aims to facilitate 6top implementation
by describing the main operations that higher layers may use to
interact with 6top. The listed commands aim at providing semantics
to manipulate 6top MIB, IEEE802.15.4 PIB and IEEE802.15.4e PIB
programmatically.
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, slotOffset, channelOffset). 6top
schedules the cell and marks it as a hard cell, indicating that it
cannot reschedule this cell. The return value is CellID and the
created cell is also filled in CellList(Section 3.1).
CREATE.softcell: To create soft cell(s). 6top is responsible for
picking the exact slotOffset and channelOffset in the schedule,
and ensure that the target node chooses the same cell and TrackID.
6top marks these cells as soft cell, indicating that it will
continuously monitor their performance and reschedule if needed.
The return value is CellID, and the created cell is also filled in
CellList (Section 3.1).
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READ.cell: Given a (slotframe ID, slotOffset, channelOffset),
retrieves the cell information. A read command can be issued for
any cell, hard or soft. 6top gets cell information from CellList
(Section 3.1).
UPDATE.cell: Update a hard cell, i.e., re-allocate it to a
different slotOffset and/or channelOffset. Fails if the cell does
not exist. CellList (Section 3.1) will be modified.
DELETE.hardcell: To remove a hard cell. This removes the hard
cell from the node's schedule, from CellList (Section 3.1).
DELETE.softcell: To remove a (number of) soft cell(s). This
command leads the pair of nodes figure out the specific cell(s) to
be removed. After that, the cell(s) will be removed from the
CellLists (Section 3.1) on both sides.
REALLOCATE.softcell: To force a re-allocation of a soft cell. The
reallocated cell will be installed in a different slotOffset,
channelOffset but slotframe and TrackID remain the same. Hard
cells MUST NOT be reallocated. This command will result in the
modificaition of CellLists (Section 3.1) on both sides.
CREATE.slotframe: Creates a new slotframe. Adds a entry to the
SlotframeList (Section 3.1).
READ.slotframe: Returns the information of a slotframe given its
slotframeID from SlotframeList (Section 3.1).
UPDATE.slotframe: Change the number of timeslots in a slotframe
given its slotframeID in SlotframeList (Section 3.1).
DELETE.slotframe: Deletes a slotframe, remove it from
SlotframeList (Section 3.1).
CONFIGURE.monitoring: Configures the level of QoS the Monitoring
process MUST enforce, i.e. config MonitoringStatusList
(Section 3.1).
READ.monitoring: Reads the current Monitoring status from
MonitoringStatusList (Section 3.1).
CONFIGURE.statistics: Configures the statistics process in
StatisticsMetricsList(Section 3.1). The CONFIGURE.statistics
enables flexible configuration and supports empty parameters that
will force 6top to conduct statistics on all members of that
dimension. For example, if ChannelOffset is empty and metric is
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set as PDR, then, 6top will conduct the statistics of PDR on all
of channels.
READ.statistics: Reads a metric for the specified dimension.
Information is aggregated according to the parameters from
CellList (Section 3.1).
RESET.statistics: Resets the gathered statistics in CellList
(Section 3.1).
CONFIGURE.eb: Configures EBs, i.e. configures EBlist
(Section 3.1).
READ.eb: Reads the EBs configuration from EBList (Section 3.1).
CONFIGURE.timesource: Configures the Time Source Neighbor
selection process, i.e. configure TimeSource (Section 3.1).
READ.timesource: Retrieves information about the time source
neighbors of that node from TimeSource (Section 3.1).
CREATE.neighbor: Creates an entry for a neighbor in the neighbor
table, i.e. NeighborList (Section 3.1).
READ.all.neighbor: Returns the list of neighbors of that node
according to NeighborList (Section 3.1).
READ.neighbor: Returns the information of a specific neighbor of
that node specified by its neighbor address according to
NeighborList (Section 3.1).
UPDATE.neighbor: Updates the last status for a given
TargetNodeAddress in the NeighborList (Section 3.1).
DELETE.neighbor: Deletes a neighbor given its address from
NeighborList (Section 3.1).
CREATE.queue: Creates and Configures a queue in QueueList
(Section 3.1).
READ.queue: Reads the queue configuration for given QueueId from
QueueList (Section 3.1).
READ.queue.stats: For a given QueueId, reads the queue statistics
information from the QueueList (Section 3.1).
UPDATE.queue: For a given QueueId, update its configuration in the
QueueList (Section 3.1).
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DELETE.queue: Deletes a Queue for a given QueueId from the
QueueList (Section 3.1).
LabelSwitching.map: Maps an input cell or a bundle of input cells
to an output cell or a bundle of output cells, i.e. adds a entry
to the LabelSwitchList (Section 3.1).
LabelSwitching.unmap: Unmap one input cell or a bundle of input
cells to an output cell or a bundle of output cells, i.e. modifies
the LabelSwitchList (Section 3.1).
CREATE.chunk: Creates a chunk which consists of one or more
unscheduled cells, i.e. add an entry to the ChunkList
(Section 3.1).
READ.chunk: Returns the information of a chunk given its ChunkID
from ChunkList (Section 3.1).
DELETE.chunk: For given ChunkId, removes a chunk from the
ChunkList (Section 3.1), which also causes all of the scheduled
cells in the chunk to be deleted from the TSCH schedule and
CellList (Section 3.1).
CREATE.hardcell.fromchunk: Creates one or more hard cells from a
chunk. 6top schedules the cell and marks it as a hard cell,
indicating that it cannot reschedule this cell. The cell will be
added into the CellList (Section 3.1). In addition, 6top will
change the attributes corresponding to the cell in the
ChunkCellList (Section 3.1), i.e. its CellID is changed to the
same CellID in the CellList, and its Status is changed to
SCHEDULED.
READ.chunkcell: Returns the information of all cells in a chunk
given its ChunkID from ChunkCellList (Section 3.1).
DELETE.hardcell.fromchunk: To remove a hard cell which comes from
a chunk. This removes the hard cell from the node's schedule and
CellList (Section 3.1). In addition, it changes the attributes
corresponding to the cell in the ChunkCellList (Section 3.1), i.e.
its CellID is changed back to 0xFFFF, and its Status is changed to
UNSCHEDULED.
5. References
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5.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
5.2. Informative References
[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the
Network Configuration Protocol (NETCONF)", RFC 6020,
October 2010.
[I-D.ietf-6tisch-tsch]
Watteyne, T., Palattella, M., and L. Grieco, "Using
IEEE802.15.4e TSCH in an LLN context: Overview, Problem
Statement and Goals", draft-ietf-6tisch-tsch-00 (work in
progress), November 2013.
[I-D.ietf-6tisch-architecture]
Thubert, P., Watteyne, T., and R. Assimiti, "An
Architecture for IPv6 over the TSCH mode of IEEE
802.15.4e", draft-ietf-6tisch-architecture-02 (work in
progress), June 2014.
[I-D.ietf-6tisch-terminology]
Palattella, M., Thubert, P., Watteyne, T., and Q. Wang,
"Terminology in IPv6 over the TSCH mode of IEEE
802.15.4e", draft-ietf-6tisch-terminology-01 (work in
progress), February 2014.
[I-D.ietf-6tisch-minimal]
Vilajosana, X. and K. Pister, "Minimal 6TiSCH
Configuration", draft-ietf-6tisch-minimal-01 (work in
progress), June 2014.
[I-D.ietf-6tisch-6top-interface]
Wang, Q., Vilajosana, X., and T. Watteyne, "6TiSCH
Operation Sublayer (6top) Interface", draft-ietf-6tisch-
6top-interface-00 (work in progress), March 2014.
[I-D.wang-6tisch-6top-sublayer]
Wang, Q., Vilajosana, X., and T. Watteyne, "6TiSCH
Operation Sublayer (6top)", draft-wang-6tisch-6top-
sublayer-00 (work in progress), February 2014.
[I-D.ietf-6tisch-coap]
Sudhaakar, R. and P. Zand, "6TiSCH Resource Management and
Interaction using CoAP", draft-ietf-6tisch-coap-00 (work
in progress), May 2014.
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5.3. 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) Amendment 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] Watteyne, T., Vilajosana, X., Kerkez, B., Chraim, F.,
Weekly, K., Wang, Q., Glaser, S., and K. Pister, "OpenWSN:
a Standards-Based Low-Power Wireless Development
Environment", Transactions on Emerging Telecommunications
Technologies , August 2012.
[morell04label]
Morell, A., Vilajosana, X., Lopez-Vicario, J., and T.
Watteyne, "Label Switching over IEEE802.15.4e Networks.
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
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Thomas Watteyne
Linear Technology
30695 Huntwood Avenue
Hayward, CA 94544
USA
Phone: +1 (510) 400-2978
Email: twatteyne@linear.com
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