RFC7102

Internet Engineering Task Force (IETF) JP. Vasseur Request for Comments: 7102 Cisco Systems, Inc. Category: Informational January 2014 ISSN: 2070-1721

     Terms Used in Routing for Low-Power and Lossy Networks

Abstract

This document provides a glossary of terminology used in routing requirements and solutions for networks referred to as Low-Power and Lossy Networks (LLNs). An LLN is typically composed of many embedded devices with limited power, memory, and processing resources interconnected by a variety of links. There is a wide scope of application areas for LLNs, including industrial monitoring, building automation (e.g., heating, ventilation, air conditioning, lighting, access control, fire), connected home, health care, environmental monitoring, urban sensor networks, energy management, assets tracking, and refrigeration.

Status of This Memo

This document is not an Internet Standards Track specification; it is published for informational purposes.

This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741.

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7102.

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Introduction

This document provides a glossary of terminology used in routing requirements and solutions for networks referred to as Low-Power and Lossy Networks (LLNs).

LLNs are typically composed of many embedded devices with limited power, memory, and processing resources interconnected by a variety of links, such as IEEE 802.15.4 or low-power Wi-Fi. There is a wide scope of application areas for LLNs, including industrial monitoring, building automation (heating, ventilation, air conditioning, lighting, access control, fire), connected home, health care, environmental monitoring, urban sensor networks, energy management, assets tracking, and refrigeration.

Since these applications are usually highly specific (for example, industrial automation, building automation, etc.), it is not uncommon to see a number of disparate terms used to describe the same device or functionality. Thus, in order to avoid confusion or discrepancies, this document specifies the common terminology to be used in all ROLL working group documents. The terms defined in this document are used in RFC5548, RFC5673, RFC5826, and RFC5867.

Terminology specific to a particular application is out of the scope of this document.

It is expected that all routing documents defining requirements or specifying solutions for LLN will use the common terminology specified in this document. This document should be listed as an informative reference.

Terminology

Actuator: A field device that controls a set of equipment. For

  example, an actuator might control and/or modulate the flow of a
  gas or liquid, control electricity distribution, perform a
  mechanical operation, etc.

AMI: Advanced Metering Infrastructure. Makes use of Smart Grid

  technologies.  A canonical Smart Grid application is smart-
  metering.

Channel: Radio frequency sub-band used to transmit a modulated signal

  carrying packets.

Channel Hopping: A procedure by which field devices synchronously

  change channels during operation.

Commissioning Tool: Any physical or logical device temporarily added

  to the network for the express purpose of setting up the network
  and device operational parameters.  The commissioning tool can
  also be temporarily added to the LLN for scheduled or unscheduled
  maintenance.

Closed Loop Control: A procedure whereby a device controller controls

  an actuator based on input information sensed by one or more field
  devices.

Controller: A field device that can receive sensor input and

  automatically change the environment in the facility by
  manipulating digital or analog actuators.

DA: Distribution Automation. Part of Smart Grid. Encompasses

  technologies for maintenance and management of electrical
  distribution systems.

DAG: Directed Acyclic Graph. A directed graph with no directed

  cycles (a graph formed by a collection of vertices and directed
  edges where each edge connects one vertex to another, such that
  there is no way to start at some vertex v and follow a sequence of
  edges that eventually loops back to vertex v again).

Data sink: A device that collects data from nodes in an LLN.

Downstream: Data direction traveling from outside of the LLN (e.g.,

  traffic coming from a LAN, WAN, or the Internet) via an LLN Border
  Router (LBR), or in general, "deeper" in the Directed Acyclic
  Graph computed by the routing protocol.

Field Device: A field device is a physical device placed in the

  network's operating environment (e.g., plant, urban area, or
  home).  Field devices include sensors and actuators as well as
  routers and Low-Power and Lossy Network Border Routers (LBRs).  A
  field device is usually (but not always) a device with constrained
  CPU, memory footprint, storage capacity, bandwidth, and sometimes
  power (battery operated).  At the time of writing, for the sake of
  illustration, a typical sensor or actuator would have a few
  Kilobytes of RAM, a few dozens of Kilobytes of ROM/Flash memory, a
  8-/16-/32-bit microcontroller, and communication capabilities
  ranging from a few kbits/s to a few hundred kbits/s.  Although
  continuous improvement of hardware and software technologies is
  expected, such devices will likely continue to be seen as
  resource-constrained devices compared to computers and routers
  used in the rest of the Internet.

Flash Memory: non-volatile memory that can be re-programmed.

FMS: Facility Management System. A global term applied across all

  the vertical designations within a building, including heating,
  ventilation, and air conditioning (also referred to as HVAC),
  fire, security, lighting, and elevator control.

HART: Highway Addressable Remote Transducer. A group of

  specifications for industrial process and control devices
  administered by the HART Foundation (see [HART]).  The latest
  version for the specifications is HART7, which includes the
  additions for WirelessHART.

HVAC: Heating, Ventilation, and Air Conditioning. A term applied to

  mechanisms used to maintain the comfort level of an internal
  space.

ISA: International Society of Automation. An ANSI accredited

  standards-making society.  ISA100 is an ISA committee whose
  charter includes defining a family of standards for industrial
  automation.  [ISA100.11a] is a working group within ISA100 that is
  working on a standard for monitoring and non-critical process-
  control applications.

LAN: Local Area Network.

LBR: Low-Power and Lossy Network Border Router. A device that

  connects the Low-Power and Lossy Network to another routing domain
  such as a LAN, a WAN, or the Internet where a different routing
  protocol may be in operation.  The LBR acts as a routing device
  and may possibly host other functions such as data collector or
  aggregator.

LLN: Low-Power and Lossy Network. Typically composed of many

  embedded devices with limited power, memory, and processing
  resources interconnected by a variety of links, such as IEEE
  802.15.4 or low-power Wi-Fi.  There is a wide scope of application
  areas for LLNs, including industrial monitoring, building
  automation (HVAC, lighting, access control, fire), connected home,
  health care, environmental monitoring, urban sensor networks,
  energy management, assets tracking, and refrigeration.

MP2P: Multipoint-to-Point. Used to describe a particular traffic

  pattern (e.g., MP2P flows collecting information from many nodes
  flowing upstream towards a collecting sink or an LBR).

MAC: Medium Access Control. Refers to algorithms and procedures used

  by the data link layer to coordinate use of the physical layer.

Non-Sleepy Node: A node that always remains in a fully powered-on

  state (i.e., always awake) where it has the capability to perform
  communication.

Open Loop Control: A process whereby a plant operator manually

  manipulates an actuator over the network where the decision is
  influenced by information sensed by field devices.

PER: Packet Error Rate. A ratio of the number of unusable packets

  (not received at all or received in error, even after any
  applicable error correction has been applied) to the total number
  of packets that would have been received in the absence of errors.

P2P: Point To Point. Refers to traffic exchanged between two nodes

  (regardless of the number of hops between the two nodes).

P2MP: Point-to-Multipoint. Refers to traffic between one node and a

  set of nodes.  This is similar to the P2MP concept in Multicast or
  MPLS Traffic Engineering (RFC4461and RFC4875).  A common use
  case for the Routing Protocol for Low-Power and Lossy Networks
  (RPL) involves P2MP flows from or through a DAG root outward
  towards other nodes contained in the DAG.

RAM: Random Access Memory. A volatile memory.

RFID: Radio Frequency IDentification.

ROM: Read-Only Memory.

ROLL: Routing Over Low-Power and Lossy Networks.

RPL: An IPv6 Routing Protocol for Low-Power and Lossy Networks that

  provides a mechanism whereby multipoint-to-point traffic from
  devices inside the LLN towards a central control point as well as
  point-to-multipoint traffic from the central control point to the
  devices inside the LLN are supported.  RPL also supports point-to-
  point traffic between any arbitrary nodes in the LLN.

RPL Domain: A collection of RPL routers under the control of a single

  administration.  The boundaries of routing domains are defined by
  network management by setting some links to be exterior, or inter-
  domain, links.

Schedule: An agreed execution, wake-up, transmission, reception,

  etc., timetable between two or more field devices.

Sensor: A device that measures a physical quantity and converts it to

  an analog or digital signal that can be read by a program or a
  user.  Sensed data can be of many types: electromagnetic (e.g.,
  current, voltage, power, or resistance), mechanical (e.g.,
  pressure, flow, liquid density, or humidity), chemical (e.g.,
  oxygen or carbon monoxide), acoustic (e.g., noise or ultrasound),
  etc.

Sleepy Node: A node that may sometimes go into a sleep mode (i.e., go

  into a low-power state to conserve power) and temporarily suspend
  protocol communication.  When not in sleep mode, the sleepy node
  is in a fully powered-on state where it has the capability to
  perform communication.

Smart Grid: A broad class of applications to network and automate

  utility infrastructure.

Timeslot: A fixed time interval that may be used for the transmission

  or reception of a packet between two field devices.  A timeslot
  used for communications is associated with a slotted-link.

Upstream: Data direction traveling from the LLN via the LBR to

  outside of the LLN (LAN, WAN, or Internet) or generally closer to
  the root of the DAG computed by the routing protocol.

WAN: Wide Area Network.

Security Considerations

Since this document specifies terminology and does not specify new procedures or protocols, it raises no new security issues.

Acknowledgements

The authors would like to thank Christian Jacquenet, Tim Winter, Pieter De Mil, David Meyer, Mukul Goyal, and Abdussalam Baryun for their valuable feedback.

Informative References

[HART] HART Communication Foundation, <http://www.hartcomm.org>.

[ISA100.11a]

         ISA, "Wireless systems for industrial automation: Process
         control and related applications", ISA 100.11a, May 2008,
         <http://www.isa.org/Community/
         SP100WirelessSystemsforAutomation>.

RFC4461 Yasukawa, S., Ed., "Signaling Requirements for Point-to-

         Multipoint Traffic-Engineered MPLS Label Switched Paths
         (LSPs)", RFC 4461, April 2006.

RFC4875 Aggarwal, R., Ed., Papadimitriou, D., Ed., and S. Yasukawa,

         Ed., "Extensions to Resource Reservation Protocol - Traffic
         Engineering (RSVP-TE) for Point-to-Multipoint TE Label
         Switched Paths (LSPs)", RFC 4875, May 2007.

RFC5548 Dohler, M., Ed., Watteyne, T., Ed., Winter, T., Ed., and D.

         Barthel, Ed., "Routing Requirements for Urban Low-Power and
         Lossy Networks", RFC 5548, May 2009.

RFC5673 Pister, K., Ed., Thubert, P., Ed., Dwars, S., and T.

         Phinney, "Industrial Routing Requirements in Low-Power and
         Lossy Networks", RFC 5673, October 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., Ed., De Mil, P., Riou, N., and W. Vermeylen,

         "Building Automation Routing Requirements in Low-Power and
         Lossy Networks", RFC 5867, June 2010.

Author's Address

JP. Vasseur Cisco Systems, Inc. 1414 Massachusetts Avenue Boxborough, MA 01719 US

EMail: [email protected]