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Internet Engineering Task Force (IETF)                       JP. VasseurRequest for Comments: 7102                           Cisco Systems, Inc.Category: Informational                                     January 2014ISSN: 2070-1721Terms Used in Routing for Low-Power and Lossy NetworksAbstract   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; seeSection 2 of RFC 5741.   Information about the current status of this document, any errata,   and how to provide feedback on it may be obtained athttp://www.rfc-editor.org/info/rfc7102.Vasseur                       Informational                     [Page 1]

RFC 7102                    LLN Routing Terms               January 2014Copyright Notice   Copyright (c) 2014 IETF Trust and the persons identified as the   document authors.  All rights reserved.   This document is subject toBCP 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   carefully, as they describe your rights and restrictions with respect   to this document.  Code Components extracted from this document must   include Simplified BSD License text as described in Section 4.e of   the Trust Legal Provisions and are provided without warranty as   described in the Simplified BSD License.Table of Contents1. Introduction ....................................................22. Terminology .....................................................33. Security Considerations .........................................74. Acknowledgements ................................................75. Informative References ..........................................71.  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.Vasseur                       Informational                     [Page 2]

RFC 7102                    LLN Routing Terms               January 2014   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.2.  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.Vasseur                       Informational                     [Page 3]

RFC 7102                    LLN Routing Terms               January 2014   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.Vasseur                       Informational                     [Page 4]

RFC 7102                    LLN Routing Terms               January 2014   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 ([RFC4461]and [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.Vasseur                       Informational                     [Page 5]

RFC 7102                    LLN Routing Terms               January 2014   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.Vasseur                       Informational                     [Page 6]

RFC 7102                    LLN Routing Terms               January 20143.  Security Considerations   Since this document specifies terminology and does not specify new   procedures or protocols, it raises no new security issues.4.  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.5.  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",RFC5826, 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.Vasseur                       Informational                     [Page 7]

RFC 7102                    LLN Routing Terms               January 2014Author's Address   JP. Vasseur   Cisco Systems, Inc.   1414 Massachusetts Avenue   Boxborough, MA  01719   US   EMail: jpv@cisco.comVasseur                       Informational                     [Page 8]