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RFC 7548

Informational
Pages: 26
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Management of Networks with Constrained Devices: Use Cases

 


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Internet Engineering Task Force (IETF)                     M. Ersue, Ed.
Request for Comments: 7548                                Nokia Networks
Category: Informational                                     D. Romascanu
ISSN: 2070-1721                                                    Avaya
                                                        J. Schoenwaelder
                                                               A. Sehgal
                                                Jacobs University Bremen
                                                                May 2015


       Management of Networks with Constrained Devices: Use Cases

Abstract

   This document discusses use cases concerning the management of
   networks in which constrained devices are involved.  A problem
   statement, deployment options, and the requirements on the networks
   with constrained devices can be found in the companion document on
   "Management of Networks with Constrained Devices: Problem Statement
   and Requirements" (RFC 7547).

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/rfc7548.

Page 2 
Copyright Notice

   Copyright (c) 2015 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
   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 Contents

   1. Introduction ....................................................3
   2. Access Technologies .............................................4
      2.1. Constrained Access Technologies ............................4
      2.2. Cellular Access Technologies ...............................5
   3. Device Life Cycle ...............................................6
      3.1. Manufacturing and Initial Testing ..........................6
      3.2. Installation and Configuration .............................6
      3.3. Operation and Maintenance ..................................7
      3.4. Recommissioning and Decommissioning ........................7
   4. Use Cases .......................................................8
      4.1. Environmental Monitoring ...................................8
      4.2. Infrastructure Monitoring ..................................9
      4.3. Industrial Applications ...................................10
      4.4. Energy Management .........................................12
      4.5. Medical Applications ......................................14
      4.6. Building Automation .......................................15
      4.7. Home Automation ...........................................17
      4.8. Transport Applications ....................................18
      4.9. Community Network Applications ............................20
      4.10. Field Operations .........................................22
   5. Security Considerations ........................................23
   6. Informative References .........................................24
   Acknowledgments ...................................................25
   Contributors ......................................................26
   Authors' Addresses ................................................26

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1.  Introduction

   Constrained devices (also known as sensors, smart objects, or smart
   devices) with limited CPU, memory, and power resources can be
   connected to a network.  Such a network of constrained devices itself
   may be constrained or challenged, e.g., with unreliable or lossy
   channels, wireless technologies with limited bandwidth and a dynamic
   topology, needing the service of a gateway or proxy to connect to the
   Internet.  In other scenarios, the constrained devices can be
   connected to a unconstrained network using off-the-shelf protocol
   stacks.  Constrained devices might be in charge of gathering
   information in diverse settings including natural ecosystems,
   buildings, and factories and sending the information to one or more
   server stations.

   Network management is characterized by monitoring network status,
   detecting faults (and inferring their causes), setting network
   parameters, and carrying out actions to remove faults, maintain
   normal operation, and improve network efficiency and application
   performance.  The traditional network management application
   periodically collects information from a set of managed network
   elements, it processes the collected data, and it presents the
   results to the network management users.  Constrained devices,
   however, often have limited power, have low transmission range, and
   might be unreliable.  Such unreliability might arise from device
   itself (e.g., battery exhausted) or from the channel being
   constrained (i.e., low-capacity and high-latency).  They might also
   need to work in hostile environments with advanced security
   requirements or need to be used in harsh environments for a long time
   without supervision.  Due to such constraints, the management of a
   network with constrained devices offers different types of challenges
   compared to the management of a traditional IP network.

   This document aims to understand use cases for the management of a
   network in which constrained devices are involved.  It lists and
   discusses diverse use cases for management from the network as well
   as from the application point of view.  The list of discussed use
   cases is not an exhaustive one since other scenarios, currently
   unknown to the authors, are possible.  The application scenarios
   discussed aim to show where networks of constrained devices are
   expected to be deployed.  For each application scenario, we first
   briefly describe the characteristics followed by a discussion on how
   network management can be provided, who is likely going to be
   responsible for it, and on which time-scale management operations are
   likely to be carried out.

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   A problem statement, deployment and management topology options as
   well as the requirements on the networks with constrained devices can
   be found in the companion document [RFC7547].

   This documents builds on the terminology defined in [RFC7228] and
   [RFC7547].  [RFC7228] is a base document for the terminology
   concerning constrained devices and constrained networks.  Some use
   cases specific to IPv6 over Low-Power Wireless Personal Area Networks
   (6LoWPANs) can be found in [RFC6568].

2.  Access Technologies

   Besides the management requirements imposed by the different use
   cases, the access technologies used by constrained devices can impose
   restrictions and requirements upon the Network Management System
   (NMS) and protocol of choice.

   It is possible that some networks of constrained devices might
   utilize traditional unconstrained access technologies for network
   access, e.g., local area networks with plenty of capacity.  In such
   scenarios, the constrainedness of the device presents special
   management restrictions and requirements rather than the access
   technology utilized.

   However, in other situations, constrained or cellular access
   technologies might be used for network access, thereby causing
   management restrictions and requirements to arise as a result of the
   underlying access technologies.

   A discussion regarding the impact of cellular and constrained access
   technologies is provided in this section since they impose some
   special requirements on the management of constrained networks.  On
   the other hand, fixed-line networks (e.g., power-line communications)
   are not discussed here since tend to be quite static and do not
   typically impose any special requirements on the management of the
   network.

2.1.  Constrained Access Technologies

   Due to resource restrictions, embedded devices deployed as sensors
   and actuators in the various use cases utilize low-power, low-data-
   rate wireless access technologies such as [IEEE802.15.4], Digital
   Enhanced Cordless Telecommunication (DECT) Ultra Low Energy (ULE), or
   Bluetooth Low-Energy (BT-LE) for network connectivity.

   In such scenarios, it is important for the NMS to be aware of the
   restrictions imposed by these access technologies to efficiently
   manage these constrained devices.  Specifically, such low-power, low-

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   data-rate access technologies typically have small frame sizes.  So
   it would be important for the NMS and management protocol of choice
   to craft packets in a way that avoids fragmentation and reassembly of
   packets since this can use valuable memory on constrained devices.

   Devices using such access technologies might operate via a gateway
   that translates between these access technologies and more
   traditional Internet protocols.  A hierarchical approach to device
   management in such a situation might be useful, wherein the gateway
   device is in-charge of devices connected to it, while the NMS
   conducts management operations only to the gateway.

2.2.  Cellular Access Technologies

   Machine-to-machine (M2M) services are increasingly provided by mobile
   service providers as numerous devices, home appliances, utility
   meters, cars, video surveillance cameras, and health monitors are
   connected with mobile broadband technologies.  Different
   applications, e.g., in a home appliance or in-car network, use
   Bluetooth, Wi-Fi, or ZigBee locally and connect to a cellular module
   acting as a gateway between the constrained environment and the
   mobile cellular network.

   Such a gateway might provide different options for the connectivity
   of mobile networks and constrained devices:

   o  a smartphone with 3G/4G and WLAN radio might use BT-LE to connect
      to the devices in a home area network,

   o  a femtocell might be combined with home gateway functionality
      acting as a low-power cellular base station connecting smart
      devices to the application server of a mobile service provider,

   o  an embedded cellular module with LTE radio connecting the devices
      in the car network with the server running the telematics service,

   o  an M2M gateway connected to the mobile operator network supporting
      diverse Internet of Things (IoT) connectivity technologies
      including ZigBee and Constrained Application Protocol (CoAP) over
      6LoWPAN over IEEE 802.15.4.

   Common to all scenarios above is that they are embedded in a service
   and connected to a network provided by a mobile service provider.
   Usually, there is a hierarchical deployment and management topology
   in place where different parts of the network are managed by
   different management entities and the count of devices to manage is
   high (e.g., many thousands).  In general, the network is comprised of
   manifold types and sizes of devices matching to different device

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   classes.  As such, the managing entity needs to be prepared to manage
   devices with diverse capabilities using different communication or
   management protocols.  In the case in which the devices are directly
   connected to a gateway, they most likely are managed by a management
   entity integrated with the gateway, which itself is part of the NMS
   run by the mobile operator.  Smartphones or embedded modules
   connected to a gateway might themselves be in charge of managing the
   devices on their level.  The initial and subsequent configuration of
   such a device is mainly based on self-configuration and is triggered
   by the device itself.

   The gateway might be in charge of filtering and aggregating the data
   received from the device as the information sent by the device might
   be mostly redundant.

3.  Device Life Cycle

   Since constrained devices deployed in a network might go through
   multiple phases in their lifetime, it is possible for different
   managers of networks and/or devices to exist during different parts
   of the device lifetimes.  An in-depth discussion regarding the
   possible device life cycles can be found in [IOT-SEC].

3.1.  Manufacturing and Initial Testing

   Typically, the life cycle of a device begins at the manufacturing
   stage.  During this phase, the manufacturer of the device is
   responsible for the management and configuration of the devices.  It
   is also possible that a certain use case might utilize multiple types
   of constrained devices (e.g., temperature sensors, lighting
   controllers, etc.) and these could be manufactured by different
   entities.  As such, during the manufacturing stage, different
   managers can exist for different devices.  Similarly, during the
   initial testing phase, where device quality-assurance tasks might be
   performed, the manufacturer remains responsible for the management of
   devices and networks that might comprise them.

3.2.  Installation and Configuration

   The responsibility of managing the devices must be transferred to the
   installer during the installation phase.  There must exist procedures
   for transferring management responsibility between the manufacturer
   and installer.  The installer may be the customer or an intermediary
   contracted to set up the devices and their networks.  It is important
   that the NMS that is utilized allows devices originating at different
   vendors to be managed, ensuring interoperability between them and the
   configuration of trust relationships between them as well.

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   It is possible that the installation and configuration
   responsibilities might lie with different entities.  For example, the
   installer of a device might only be responsible for cabling a
   network, physically installing the devices, and ensuring initial
   network connectivity between them (e.g., configuring IP addresses).
   Following such an installation, the customer or a subcontractor might
   actually configure the operation of the device.  As such, during
   installation and configuration multiple parties might be responsible
   for managing a device and appropriate methods must be available to
   ensure that this management responsibility is transferred suitably.

3.3.  Operation and Maintenance

   At the outset of the operation phase, the operational responsibility
   of a device and network should be passed on to the customer.  It is
   possible that the customer, however, might contract the maintenance
   of the devices and network to a subcontractor.  In this case, the NMS
   and management protocol should allow for configuring different levels
   of access to the devices.  Since different maintenance vendors might
   be used for devices that perform different functions (e.g., HVAC,
   lighting, etc.), it should also be possible to restrict management
   access to devices based on the currently responsible manager.

3.4.  Recommissioning and Decommissioning

   The owner of a device might choose to replace, repurpose, or even
   decommission it.  In each of these cases, either the customer or the
   contracted maintenance agency must ensure that appropriate steps are
   taken to meet the end goal.

   In case the devices needs to be replaced, the manager of the network
   (customer or contractor responsible) must detach the device from the
   network, remove all appropriate configuration, and discard the
   device.  A new device must then be configured to replace it.  The NMS
   should allow for the transferring of the configuration and replacing
   an existing device.  The management responsibility of the operation/
   maintenance manager would end once the device is removed from the
   network.  During the installation of the new replacement device, the
   same responsibilities would apply as those during the Installation
   and Configuration phases.

   The device being replaced may not have yet reached end-of-life, and
   as such, instead of being discarded, it may be installed in a new
   location.  In this case, the management responsibilities are once
   again resting in the hands of the entities responsible for the
   Installation and Configuration phases at the new location.

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   If a device is repurposed, then it is possible that the management
   responsibility for this device changes as well.  For example, a
   device might be moved from one building to another.  In this case,
   the managers responsible for devices and networks in each building
   could be different.  As such, the NMS must not only allow for
   changing configuration but also the transferring of management
   responsibilities.

   In case a device is decommissioned, the management responsibility
   typically ends at that point.

4.  Use Cases

4.1.  Environmental Monitoring

   Environmental monitoring applications are characterized by the
   deployment of a number of sensors to monitor emissions, water
   quality, or even the movements and habits of wildlife.  Other
   applications in this category include earthquake or tsunami early-
   warning systems.  The sensors often span a large geographic area;
   they can be mobile; and they are often difficult to replace.
   Furthermore, the sensors are usually not protected against tampering.

   Management of environmental-monitoring applications is largely
   concerned with monitoring whether the system is still functional and
   the roll out of new constrained devices in case the system loses too
   much of its structure.  The constrained devices themselves need to be
   able to establish connectivity (autoconfiguration), and they need to
   be able to deal with events such as losing neighbors or being moved
   to other locations.

   Management responsibility typically rests with the organization
   running the environmental-monitoring application.  Since these
   monitoring applications must be designed to tolerate a number of
   failures, the time scale for detecting and recording failures is, for
   some of these applications, likely measured in hours and repairs
   might easily take days.  In fact, in some scenarios it might be more
   cost- and time-effective not to repair such devices at all.  However,
   for certain environmental monitoring applications, much tighter time
   scales may exist and might be enforced by regulations (e.g.,
   monitoring of nuclear radiation).

   Since many applications of environmental-monitoring sensors are
   likely to be in areas that are important to safety (flood monitoring,
   nuclear radiation monitoring, etc.), it is important for management
   protocols and NMSs to ensure appropriate security protections.  These
   protections include not only access control, integrity, and

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   availability of data, but also provide appropriate mechanisms that
   can deal with situations that might be categorized as emergencies or
   when tampering with sensors/data might be detected.

4.2.  Infrastructure Monitoring

   Infrastructure monitoring is concerned with the monitoring of
   infrastructures such as bridges, railway tracks, or (offshore)
   windmills.  The primary goal is usually to detect any events or
   changes of the structural conditions that can impact the risk and
   safety of the infrastructure being monitored.  Another secondary goal
   is to schedule repair and maintenance activities in a cost-effective
   manner.

   The infrastructure to monitor might be in a factory or spread over a
   wider area (but difficult to access).  As such, the network in use
   might be based on a combination of fixed and wireless technologies,
   which use robust networking equipment and support reliable
   communication via application-layer transactions.  It is likely that
   constrained devices in such a network are mainly C2 devices [RFC7228]
   and have to be controlled centrally by an application running on a
   server.  In case such a distributed network is widely spread, the
   wireless devices might use diverse long-distance wireless
   technologies such as Worldwide Interoperability for Microwave Access
   (WiMAX) or 3G/LTE.  In cases, where an in-building network is
   involved, the network can be based on Ethernet or wireless
   technologies suitable for in-building use.

   The management of infrastructure monitoring applications is primarily
   concerned with the monitoring of the functioning of the system.
   Infrastructure monitoring devices are typically rolled out and
   installed by dedicated experts, and updates are rare since the
   infrastructure itself does not change often.  However, monitoring
   devices are often deployed in unsupervised environments; hence,
   special attention must be given to protecting the devices from being
   modified.

   Management responsibility typically rests with the organization
   owning the infrastructure or responsible for its operation.  The time
   scale for detecting and recording failures is likely measured in
   hours and repairs might easily take days.  However, certain events
   (e.g., natural disasters) may require that status information be
   obtained much more quickly and that replacements of failed sensors
   can be rolled out quickly (or redundant sensors are activated
   quickly).  In case the devices are difficult to access, a self-
   healing feature on the device might become necessary.  Since
   infrastructure monitoring is closely related to ensuring safety,

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   management protocols and systems must provide appropriate security
   protections to ensure confidentiality, integrity, and availability of
   data.

4.3.  Industrial Applications

   Industrial Applications and smart manufacturing refer to tasks such
   as networked control and monitoring of manufacturing equipment, asset
   and situation management, or manufacturing process control.  For the
   management of a factory, it is becoming essential to implement smart
   capabilities.  From an engineering standpoint, industrial
   applications are intelligent systems enabling rapid manufacturing of
   new products, dynamic response to product demands, and real-time
   optimization of manufacturing production and supply-chain networks.
   Potential industrial applications (e.g., for smart factories and
   smart manufacturing) are:

   o  Digital control systems with embedded, automated process controls;
      operator tools; and service information systems optimizing plant
      operations and safety.

   o  Asset management using predictive maintenance tools, statistical
      evaluation, and measurements maximizing plant reliability.

   o  Smart sensors detecting anomalies to avoid abnormal or
      catastrophic events.

   o  Smart systems integrated within the industrial energy-management
      system and externally with the smart grid enabling real-time
      energy optimization.

   Management of Industrial Applications and smart manufacturing may, in
   some situations, involve Building Automation tasks such as control of
   energy, HVAC, lighting, or access control.  Interacting with
   management systems from other application areas might be important in
   some cases (e.g., environmental monitoring for electric energy
   production, energy management for dynamically scaling manufacturing,
   vehicular networks for mobile asset tracking).  Management of
   constrained devices and networks may not only refer to the management
   of their network connectivity.  Since the capabilities of constrained
   devices are limited, it is quite possible that a management system
   would even be required to configure, monitor, and operate the primary
   functions for which a constrained device is utilized, besides
   managing its network connectivity.

   Sensor networks are an essential technology used for smart
   manufacturing.  Measurements, automated controls, plant optimization,
   health and safety management, and other functions are provided by a

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   large number of networked sectors.  Data interoperability and
   seamless exchange of product, process, and project data are enabled
   through interoperable data systems used by collaborating divisions or
   business systems.  Intelligent automation and learning systems are
   vital to smart manufacturing, but they must be effectively integrated
   with the decision environment.  The NMS utilized must ensure timely
   delivery of sensor data to the control unit so it may take
   appropriate decisions.  Similarly, the relaying of commands must also
   be monitored and managed to ensure optimal functioning.  Wireless
   sensor networks (WSNs) have been developed for machinery Condition-
   based Maintenance (CBM) as they offer significant cost savings and
   enable new functionalities.  Inaccessible locations, rotating
   machinery, hazardous areas, and mobile assets can be reached with
   wireless sensors.  Today, WSNs can provide wireless link reliability,
   real-time capabilities, and quality-of-service and they can enable
   industrial and related wireless sense and control applications.

   Management of industrial and factory applications is largely focused
   on monitoring whether the system is still functional, real-time
   continuous performance monitoring, and optimization as necessary.
   The factory network might be part of a campus network or connected to
   the Internet.  The constrained devices in such a network need to be
   able to establish configuration themselves (autoconfiguration) and
   might need to deal with error conditions as much as possible locally.
   Access control has to be provided with multi-level administrative
   access and security.  Support and diagnostics can be provided through
   remote monitoring access centralized outside of the factory.

   Factory-automation tasks require that continuous monitoring be used
   to optimize production.  Groups of manufacturing and monitoring
   devices could be defined to establish relationships between them.  To
   ensure timely optimization of processes, commands from the NMS must
   arrive at all destination within an appropriate duration.  This
   duration could change based on the manufacturing task being
   performed.  Installation and operation of factory networks have
   different requirements.  During the installation phase, many
   networks, usually distributed along different parts of the factory/
   assembly line, coexist without a connection to a common backbone.  A
   specialized installation tool is typically used to configure the
   functions of different types of devices, in different factory
   locations, in a secure manner.  At the end of the installation phase,
   interoperability between these stand-alone networks and devices must
   be enabled.  During the operation phase, these stand-alone networks
   are connected to a common backbone so that they may retrieve control
   information from and send commands to appropriate devices.

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   Management responsibility is typically owned by the organization
   running the industrial application.  Since the monitoring
   applications must handle a potentially large number of failures, the
   time scale for detecting and recording failures is, for some of these
   applications, likely measured in minutes.  However, for certain
   industrial applications, much tighter time scales may exist, e.g., in
   real-time, which might be enforced by the manufacturing process or
   the use of critical material.  Management protocols and NMSs must
   ensure appropriate access control since different users of industrial
   control systems will have varying levels of permissions.  For
   example, while supervisors might be allowed to change production
   parameters, they should not be allowed to modify the functional
   configuration of devices like a technician should.  It is also
   important to ensure integrity and availability of data since
   malfunctions can potentially become safety issues.  This also implies
   that management systems must be able to react to situations that may
   pose dangers to worker safety.

4.4.  Energy Management

   The EMAN working group developed an energy-management framework
   [RFC7326] for devices and device components within or connected to
   communication networks.  This document observes that one of the
   challenges of energy management is that a power distribution network
   is responsible for the supply of energy to various devices and
   components, while a separate communication network is typically used
   to monitor and control the power distribution network.  Devices in
   the context of energy management can be monitored for parameters like
   power, energy, demand and power quality.  If a device contains
   batteries, they can be also monitored and managed.

   Energy devices differ in complexity and may include basic sensors or
   switches, specialized electrical meters, or power distribution units
   (PDU), and subsystems inside the network devices (routers, network
   switches) or home or industrial appliances.  The operators of an
   energy-management system are either the utility providers or
   customers that aim to control and reduce the energy consumption and
   the associated costs.  The topology in use differs and the deployment
   can cover areas from small surfaces (individual homes) to large
   geographical areas.  The EMAN requirements document [RFC6988]
   discusses the requirements for energy management concerning
   monitoring and control functions.

   It is assumed that energy management will apply to a large range of
   devices of all classes and networks topologies.  Specific resource
   monitoring, like battery utilization and availability, may be
   specific to devices with lower physical resources (device classes C0
   or C1 [RFC7228]).

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   Energy management is especially relevant to the Smart Grid.  A Smart
   Grid is an electrical grid that uses data networks to gather and act
   on energy and power-related information in an automated fashion with
   the goal to improve the efficiency, reliability, economics, and
   sustainability of the production and distribution of electricity.

   Smart Metering is a good example of an energy-management application
   based on Smart Grid.  Different types of possibly wireless small
   meters all together produce a large amount of data, which is
   collected by a central entity and processed by an application server,
   which may be located within the customer's residence or off site in a
   data center.  The communication infrastructure can be provided by a
   mobile network operator as the meters in urban areas will most likely
   have a cellular or WiMAX radio.  In case the application server is
   located within the residence, such meters are more likely to use
   Wi-Fi protocols to interconnect with an existing network.

   An Advanced Metering Infrastructure (AMI) network is another example
   of the Smart Grid that enables an electric utility to retrieve
   frequent electric usage data from each electric meter installed at a
   customer's home or business.  Unlike Smart Metering, in which case
   the customer or their agents install appliance-level meters, an AMI
   is typically managed by the utility providers and could also include
   other distribution automation devices like transformers and
   reclosers.  Meters in AMI networks typically contain constrained
   devices that connect to mesh networks with a low-bandwidth radio.
   Usage data and outage notifications can be sent by these meters to
   the utility's headend systems, via aggregation points of higher-end
   router devices that bridge the constrained network to a less
   constrained network via cellular, WiMAX, or Ethernet.  Unlike meters,
   these higher-end devices might be installed on utility poles owned
   and operated by a separate entity.

   It thereby becomes important for a management application not only to
   be able to work with diverse types of devices, but also to work over
   multiple links that might be operated and managed by separate
   entities, each having divergent policies for their own devices and
   network segments.  During management operations, like firmware
   updates, it is important that the management systems perform robustly
   in order to avoid accidental outages of critical power systems that
   could be part of AMI networks.  In fact, since AMI networks must also
   report on outages, the management system might have to manage the
   energy properties of battery-operated AMI devices themselves as well.

   A management system for home-based Smart Metering solutions is likely
   to have devices laid out in a simple topology.  However, AMI network
   installations could have thousands of nodes per router, i.e., higher-
   end device, which organize themselves in an ad hoc manner.  As such,

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   a management system for AMI networks will need to discover and
   operate over complex topologies as well.  In some situations, it is
   possible that the management system might also have to set up and
   manage the topology of nodes, especially critical routers.
   Encryption-key management and sharing in both types of networks are
   also likely to be important for providing confidentiality for all
   data traffic.  In AMI networks, the key may be obtained by a meter
   only after an end-to-end authentication process based on
   certificates.  The Smart Metering solution could adopt a similar
   approach or the security may be implied due to the encrypted Wi-Fi
   networks they become part of.

   The management of such a network requires end-to-end management of
   and information exchange through different types of networks.
   However, as of today, there is no integrated energy-management
   approach and no common information model available.  Specific energy-
   management applications or network islands use their own management
   mechanisms.

4.5.  Medical Applications

   Constrained devices can be seen as an enabling technology for
   advanced and possibly remote health-monitoring and emergency-
   notification systems, ranging from monitors for blood pressure and
   heart rate to advanced devices capable of monitoring implanted
   technologies, such as pacemakers or advanced hearing aids.  Medical
   sensors may not only be attached to human bodies, they might also
   exist in the infrastructure used by humans such as bathrooms or
   kitchens.  Medical applications will also be used to ensure
   treatments are being applied properly, and they might guide people
   losing orientation.  Fitness and wellness applications, such as
   connected scales or wearable heart monitors, encourage consumers to
   exercise and empower self-monitoring of key fitness indicators.
   Different applications use Bluetooth, Wi-Fi, or ZigBee connections to
   access the patient's smartphone or home cellular connection to access
   the Internet.

   Constrained devices that are part of medical applications are managed
   either by the users of those devices or by an organization providing
   medical (monitoring) services for physicians.  In the first case,
   management must be automatic and/or easy to install and set up by
   laypeople.  In the second case, it can be expected that devices will
   be controlled by specially trained people.  In both cases, however,
   it is crucial to protect the safety and privacy of the people who use
   medical devices.  Security precautions to protect access
   (authentication, encryption, integrity protections, etc.) to such
   devices may be critical to safeguarding the individual.  The level of
   access granted to different users also may need to be regulated.  For

Top      ToC       Page 15 
   example, an authorized surgeon or doctor must be allowed to configure
   all necessary options on the devices; however, a nurse or technician
   may only be allowed to retrieve data that can assist in diagnosis.
   Even though the data collected by a heart monitor might be protected,
   the pure fact that someone carries such a device may need protection.
   As such, certain medical appliances may not want to participate in
   discovery and self-configuration protocols in order to remain
   invisible.

   Many medical devices are likely to be used (and relied upon) to
   provide data to physicians in critical situations in which the
   patient might not be able to report such data themselves.  Timely
   delivery of data can be quite important in certain applications like
   patient-mobility monitoring in nursing homes.  Data must reach the
   physician and/or emergency services within specified limits of time
   in order to be useful.  As such, fault detection of the communication
   network or the constrained devices becomes a crucial function of the
   management system that must be carried out with high reliability and,
   depending on the medical appliance and its application, within
   seconds.

4.6.  Building Automation

   Building automation comprises the distributed systems designed and
   deployed to monitor and control the mechanical, electrical, and
   electronic systems inside buildings with various destinations (e.g.,
   public and private, industrial, institutions, or residential).
   Advanced Building Automation Systems (BASs) may be deployed
   concentrating the various functions of safety, environmental control,
   occupancy, and security.  Increasingly, the deployment of the various
   functional systems is connected to the same communication
   infrastructure (possibly IP-based), which may involve wired or
   wireless communication networks inside the building.

   Building automation requires the deployment of a large number (10 to
   100,000) of sensors that monitor the status of devices, parameters
   inside the building, and controllers with different specialized
   functionality for areas within the building or the totality of the
   building.  Inter-node distances between neighboring nodes vary from 1
   to 20 meters.  The NMS must, as a result, be able to manage and
   monitor a large number of devices, which may be organized in multi-
   hop meshed networks.  Distances between the nodes, and the use of
   constrained protocols, means that networks of nodes might be
   segmented.  The management of such network segments and nodes in
   these segments should be possible.  Contrary to home automation, in
   building management the devices are expected to be managed assets and
   known to a set of commissioning tools and a data storage, such that
   every connected device has a known origin.  This requires the

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   management system to be able to discover devices on the network and
   ensure that the expected list of devices is currently matched.
   Management here includes verifying the presence of the expected
   devices and detecting the presence of unwanted devices.

   Examples of functions performed by controllers in building automation
   are regulating the quality, humidity, and temperature of the air
   inside the building as well as regulating the lighting.  Other
   systems may report the status of the machinery inside the building
   like elevators or inside the rooms like projectors in meeting rooms.
   Security cameras and sensors may be deployed and operated on separate
   dedicated infrastructures connected to the common backbone.  The
   deployment area of a BAS is typically inside one building (or part of
   it) or several buildings geographically grouped in a campus.  A
   building network can be composed of network segments, where a network
   segment covers a floor, an area on the floor, or a given
   functionality (e.g., security cameras).  It is possible that the
   management tasks of different types of some devices might be
   separated from others (e.g, security cameras might operate and be
   managed via a network separate from that of the HVAC in a building).

   Some of the sensors in BASs (for example, fire alarms or security
   systems) register, record, and transfer critical alarm information;
   therefore, they must be resilient to events like loss of power or
   security attacks.  A management system must be able to deal with
   unintentional segmentation of networks due to power loss or channel
   unavailability.  It must also be able to detect security events.  Due
   to specific operating conditions required from certain devices, there
   might be a need to certify components and subsystems operating in
   such constrained conditions based on specific requirements.  Also, in
   some environments, the malfunctioning of a control system (like
   temperature control) needs to be reported in the shortest possible
   time.  Complex control systems can misbehave, and their critical
   status reporting and safety algorithms need to be basic and robust
   and perform even in critical conditions.  Providing this monitoring,
   configuration and notification service is an important task of the
   management system used in building automation.

   In some cases, building automation solutions are deployed in newly
   designed buildings; in other cases, it might be over existing
   infrastructures.  In the first case, there is a broader range of
   possible solutions, which can be planned for the infrastructure of
   the building.  In the second case, the solution needs to be deployed
   over an existing infrastructure taking into account factors like
   existing wiring, distance limitations, and the propagation of radio
   signals over walls and floors, thereby making deployment difficult.
   As a result, some of the existing WLAN solutions (e.g., [IEEE802.11]
   or [IEEE802.15]) may be deployed.  In mission-critical or security-

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   sensitive environments and in cases where link failures happen often,
   topologies that allow for reconfiguration of the network and
   connection continuity may be required.  Some of the sensors deployed
   in building automation may be very simple constrained devices for
   which C0 or C1 [RFC7228] may be assumed.

   For lighting applications, groups of lights must be defined and
   managed.  Commands to a group of light must arrive within 200 ms at
   all destinations.  The installation and operation of a building
   network has different requirements.  During the installation, many
   stand-alone networks of a few to 100 nodes coexist without a
   connection to the backbone.  During this phase, the nodes are
   identified with a network identifier related to their physical
   location.  Devices are accessed from an installation tool to connect
   them to the network in a secure fashion.  During installation, the
   setting of parameters of common values to enable interoperability may
   be required.  During operation, the networks are connected to the
   backbone while maintaining the network identifier to physical
   location relation.  Network parameters like address and name are
   stored in the DNS.  The names can assist in determining the physical
   location of the device.

   It is also important for a building automation NMS to take safety and
   security into account.  Ensuring privacy and confidentiality of data,
   such that unauthorized parties do not get access to it, is likely to
   be important since users' individual behaviors could be potentially
   understood via their settings.  Appropriate security considerations
   for authorization and access control to the NMS is also important
   since different users are likely to have varied levels of operational
   permissions in the system.  For example, while end users should be
   able to control lighting systems, HVAC systems, etc., only qualified
   technicians should be able to configure parameters that change the
   fundamental operation of a device.  It is also important for devices
   and the NMS to be able to detect and report any tampering they might
   find, since these could lead to potential user safety concerns, e.g.,
   if sensors controlling air quality are tampered with such that the
   levels of carbon monoxide become life threatening.  This implies that
   an NMS should also be able to deal with and appropriately prioritize
   situations that might potentially lead to safety concerns.

4.7.  Home Automation

   Home automation includes the control of lighting, heating,
   ventilation, air conditioning, appliances, entertainment and home
   security devices to improve convenience, comfort, energy efficiency,
   and safety.  It can be seen as a residential extension of building
   automation.  However, unlike a BAS, the infrastructure in a home is
   operated in a considerably more ad hoc manner.  While in some

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   installations it is likely that there is no centralized management
   system akin to a BAS available, in other situations outsourced and
   cloud-based systems responsible for managing devices in the home
   might be used.

   Home-automation networks need a certain amount of configuration
   (associating switches or sensors to actuators) that is either
   provided by electricians deploying home-automation solutions, by
   third-party home-automation service providers (e.g., small
   specialized companies or home-automation device manufacturers) or by
   residents by using the application user interface provided by home-
   automation devices to configure (parts of) the home-automation
   solution.  Similarly, failures may be reported via suitable
   interfaces to residents or they might be recorded and made available
   to services providers in charge of the maintenance of the home-
   automation infrastructure.

   The management responsibility either lies with the residents or is
   outsourced to electricians and/or third parties providing management
   of home-automation solutions as a service.  A varying combination of
   electricians, service providers, or the residents may be responsible
   for different aspects of managing the infrastructure.  The time scale
   for failure detection and resolution is, in many cases, likely
   counted in hours to days.

4.8.  Transport Applications

   "Transport application" is a generic term for the integrated
   application of communications, control, and information processing in
   a transportation system.  "Transport telematics" and "vehicle
   telematics" are both used as terms for the group of technologies that
   support transportation systems.  Transport applications running on
   such a transportation system cover all modes of the transport and
   consider all elements of the transportation system, i.e. the vehicle,
   the infrastructure, and the driver or user, interacting together
   dynamically.  Examples for transport applications are inter- and
   intra-vehicular communication, smart traffic control, smart parking,
   electronic toll-collection systems, logistic and fleet management,
   vehicle control, and safety and roadside assistance.

   As a distributed system, transport applications require an end-to-end
   management of different types of networks.  It is likely that
   constrained devices in a network (e.g., a moving in-car network) have
   to be controlled by an application running on an application server
   in the network of a service provider.  Such a highly distributed
   network including cellular devices on vehicles is assumed to include
   a wireless access network using diverse long-distance wireless
   technologies such as WiMAX, 3G/LTE, or satellite communication, e.g.,

Top      ToC       Page 19 
   based on an embedded hardware module.  As a result, the management of
   constrained devices in the transport system might be necessary to
   plan top-down and might need to use data models obliged from and
   defined on the application layer.  The assumed device classes in use
   are mainly C2 [RFC7228] devices.  In cases, where an in-vehicle
   network is involved, C1 devices [RFC7228] with limited capabilities
   and a short-distance constrained radio network, e.g., IEEE 802.15.4
   might be used additionally.

   All Transport Applications will require an IT infrastructure to run
   on top of, e.g., in public-transport scenarios like trains, buses, or
   metro networks infrastructure might be provided, maintained, and
   operated by third parties like mobile-network or satellite-network
   operators.  However, the management responsibility of the transport
   application typically rests within the organization running the
   transport application (in the public-transport scenario, this would
   typically be the public-transport operator).  Different aspects of
   the infrastructure might also be managed by different entities.  For
   example, the in-car devices are likely to be installed and managed by
   the manufacturer, while the local government or transportation
   authority might be responsible for the on-road vehicular
   communication infrastructure used by these devices.  The backend
   infrastructure is also likely to be maintained by third-party
   operators.  As such, the NMS must be able to deal with different
   network segments (each being operated and controlled by separate
   entities) and enable appropriate access control and security.

   Depending on the type of application domain (vehicular or stationary)
   and service being provided, it is important for the NMS to be able to
   function with different architectures, since different manufacturers
   might have their own proprietary systems relying on a specific
   management topology option, as described in [RFC7547].  Moreover,
   constituents of the network can either be private, belong to
   individuals or private companies, or be owned by public institutions
   leading to different legal and organization requirements.  Across the
   entire infrastructure, a variety of constrained devices is likely to
   be used, and they must be individually managed.  The NMS must be able
   to either work directly with different types of devices or have the
   ability to interoperate with multiple different systems.

   The challenges in the management of vehicles in a mobile-transport
   application are manifold.  The up-to-date position of each node in
   the network should be reported to the corresponding management
   entities, since the nodes could be moving within or roaming between
   different networks.  Secondly, a variety of troubleshooting
   information, including sensitive location information, needs to be
   reported to the management system in order to provide accurate
   service to the customer.  Management systems dealing with mobile

Top      ToC       Page 20 
   nodes could possibly exploit specific patterns in the mobility of the
   nodes.  These patterns emerge due to repetitive vehicular usage in
   scenarios like people commuting to work and supply vehicles
   transporting shipments between warehouses, etc.  The NMS must also be
   able to handle partitioned networks, which would arise due to the
   dynamic nature of traffic resulting in large inter-vehicle gaps in
   sparsely populated scenarios.  Since mobile nodes might roam in
   remote networks, the NMS should be able to provide operating
   configuration updates regardless of node location.

   The constrained devices in a moving transport network might be
   initially configured in a factory, and a reconfiguration might be
   needed only rarely.  New devices might be integrated in an ad hoc
   manner based on self-management and self-configuration capabilities.
   Monitoring and data exchange might be necessary via a gateway entity
   connected to the backend transport infrastructure.  The devices and
   entities in the transport infrastructure need to be monitored more
   frequently and may be able to communicate with a higher data rate.
   The connectivity of such entities does not necessarily need to be
   wireless.  The time scale for detecting and recording failures in a
   moving transport network is likely measured in hours, and repairs
   might easily take days.  It is likely that a self-healing feature
   would be used locally.  On the other hand, failures in fixed
   transport-application infrastructure (e.g., traffic lights, digital-
   signage displays) are likely to be measured in minutes so as to avoid
   untoward traffic incidents.  As such, the NMS must be able to deal
   with differing timeliness requirements based on the type of devices.

   Since transport applications of the constrained devices and networks
   deal with automotive vehicles, malfunctions and misuse can
   potentially lead to safety concerns as well.  As such, besides access
   control, privacy of user data, and timeliness, management systems
   should also be able to detect situations that are potentially
   hazardous to safety.  Some of these situations could be automatically
   mitigated, e.g., traffic lights with incorrect timing, but others
   might require human intervention, e.g., failed traffic lights.  The
   management system should take appropriate actions in these
   situations.  Maintaining data confidentiality and integrity is also
   an important security aspect of a management system since tampering
   (or malfunction) can also lead to potentially dangerous situations.

4.9.  Community Network Applications

   Community networks are comprised of constrained routers in a multi-
   hop mesh topology, communicating over lossy, and often wireless,
   channels.  While the routers are mostly non-mobile, the topology may
   be very dynamic because of fluctuations in link quality of the
   (wireless) channel caused by, e.g., obstacles, or other nearby radio

Top      ToC       Page 21 
   transmissions.  Depending on the routers that are used in the
   community network, the resources of the routers (memory, CPU) may be
   more or less constrained -- available resources may range from only a
   few kilobytes of RAM to several megabytes or more, and CPUs may be
   small and embedded, or more powerful general-purpose processors.
   Examples of such community networks are the FunkFeuer network
   (Vienna, Austria), FreiFunk (Berlin, Germany), Seattle Wireless
   (Seattle, USA), and AWMN (Athens, Greece).  These community networks
   are public and non-regulated, allowing their users to connect to each
   other and -- through an uplink to an ISP -- to the Internet.  No fee,
   other than the initial purchase of a wireless router, is charged for
   these services.  Applications of these community networks can be
   diverse, e.g., location-based services, free Internet access, file
   sharing between users, distributed chat services, social networking,
   video sharing, etc.

   As an example of a community network, the FunkFeuer network comprises
   several hundred routers, many of which have several radio interfaces
   (with omnidirectional and some directed antennas).  The routers of
   the network are small-sized wireless routers, such as the Linksys
   WRT54GL, available in 2011 for less than 50 euros.  Each router, with
   16 MB of RAM and 264 MHz of CPU power, is mounted on the rooftop of a
   user.  When a new user wants to connect to the network, they acquire
   a wireless router, install the appropriate firmware and routing
   protocol, and mount the router on the rooftop.  IP addresses for the
   router are assigned manually from a list of addresses (because of the
   lack of autoconfiguration standards for mesh networks in the IETF).

   While the routers are non-mobile, fluctuations in link quality
   require an ad hoc routing protocol that allows for quick convergence
   to reflect the effective topology of the network (such as
   Neighborhood Discovery Protocol (NHDP) [RFC6130] and Optimized Link
   State Routing version 2 (OLSRv2) [RFC7181] developed in the MANET
   WG).  Usually, no human interaction is required for these protocols,
   as all variable parameters required by the routing protocol are
   either negotiated in the control traffic exchange or are only of
   local importance to each router (i.e. do not influence
   interoperability).  However, external management and monitoring of an
   ad hoc routing protocol may be desirable to optimize parameters of
   the routing protocol.  Such an optimization may lead to a topology
   that is perceived to be more stable and to a lower control traffic
   overhead (and therefore to a higher delivery success ratio of data
   packets, a lower end-to-end delay, and less unnecessary bandwidth and
   energy use).

Top      ToC       Page 22 
   Different use cases for the management of community networks are
   possible:

   o  A single NMS, e.g., a border gateway providing connectivity to the
      Internet, requires managing or monitoring routers in the community
      network, in order to investigate problems (monitoring) or to
      improve performance by changing parameters (managing).  As the
      topology of the network is dynamic, constant connectivity of each
      router towards the management station cannot be guaranteed.
      Current network management protocols, such as SNMP and Network
      Configuration Protocol (NETCONF), may be used (e.g., use of
      interfaces such as the NHDP-MIB [RFC6779]).  However, when routers
      in the community network are constrained, existing protocols may
      require too many resources in terms of memory and CPU; and more
      importantly, the bandwidth requirements may exceed the available
      channel capacity in wireless mesh networks.  Moreover, management
      and monitoring may be unfeasible if the connection between the NMS
      and the routers is frequently interrupted.

   o  Distributed network monitoring, in which more than one management
      station monitors or manages other routers.  Because connectivity
      to a server cannot be guaranteed at all times, a distributed
      approach may provide a higher reliability, at the cost of
      increased complexity.  Currently, no IETF standard exists for
      distributed monitoring and management.

   o  Monitoring and management of a whole network or a group of
      routers.  Monitoring the performance of a community network may
      require more information than what can be acquired from a single
      router using a network management protocol.  Statistics, such as
      topology changes over time, data throughput along certain routing
      paths, congestion, etc., are of interest for a group of routers
      (or the routing domain) as a whole.  As of 2014, no IETF standard
      allows for monitoring or managing whole networks instead of single
      routers.

4.10.  Field Operations

   The challenges of configuring and monitoring networks operated in the
   field by rescue and security agencies can be different from the other
   use cases since the requirements and operating conditions of such
   networks are quite different.

   With technology advancements, field networks operated nowadays are
   becoming large and can consist of a variety of different types of
   equipment that run different protocols and tools that obviously
   increase complexity of these mission-critical networks.  In many
   scenarios, configurations are, most likely, manually performed.

Top      ToC       Page 23 
   Furthermore, some legacy and even modern devices do not even support
   IP networking.  A majority of protocols and tools developed by
   vendors that are being used are proprietary, which makes integration
   more difficult.

   The main reason for this disjoint operation scenario is that most
   equipment is developed with specific task requirements in mind,
   rather than interoperability of the varied equipment types.  For
   example, the operating conditions experienced by high altitude
   security equipment is significantly different from that used in
   desert conditions.  Similarly, equipment used in fire rescue has
   different requirements than flood-relief equipment.  Furthermore,
   interoperation of equipment with telecommunication equipment was not
   an expected outcome or (in some scenarios) may not even be desirable.

   Currently, field networks operate with a fixed Network Operations
   Center (NOC) that physically manages the configuration and evaluation
   of all field devices.  Once configured, the devices might be deployed
   in fixed or mobile scenarios.  Any configuration changes required
   would need to be appropriately encrypted and authenticated to prevent
   unauthorized access.

   Hierarchical management of devices is a common requirement in such
   scenarios since local managers or operators may need to respond to
   changing conditions within their purview.  The level of configuration
   management available at each hierarchy must also be closely governed.

   Since many field operation devices are used in hostile environments,
   a high failure and disconnection rate should be tolerated by the NMS,
   which must also be able to deal with multiple gateways and disjoint
   management protocols.

   Multi-national field operations involving search, rescue, and
   security are becoming increasingly common, requiring interoperation
   of a diverse set of equipment designed with different operating
   conditions in mind.  Furthermore, different intra- and inter-
   governmental agencies are likely to have a different set of
   standards, best practices, rules and regulations, and implementation
   approaches that may contradict or conflict with each other.  The NMS
   should be able to detect these and handle them in an acceptable
   manner, which may require human intervention.

5.  Security Considerations

   This document discusses use cases for management of networks with
   constrained devices.  The security considerations described
   throughout the companion document [RFC7547] apply here as well.

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6.  Informative References

   [RFC6130]  Clausen, T., Dearlove, C., and J. Dean, "Mobile Ad Hoc
              Network (MANET) Neighborhood Discovery Protocol (NHDP)",
              RFC 6130, DOI 10.17487/RFC6130, April 2011,
              <http://www.rfc-editor.org/info/rfc6130>.

   [RFC6568]  Kim, E., Kaspar, D., and JP. Vasseur, "Design and
              Application Spaces for IPv6 over Low-Power Wireless
              Personal Area Networks (6LoWPANs)", RFC 6568,
              DOI 10.17487/RFC6568, April 2012,
              <http://www.rfc-editor.org/info/rfc6568>.

   [RFC6779]  Herberg, U., Cole, R., and I. Chakeres, "Definition of
              Managed Objects for the Neighborhood Discovery Protocol",
              RFC 6779, DOI 10.17487/RFC6779, October 2012,
              <http://www.rfc-editor.org/info/rfc6779>.

   [RFC6988]  Quittek, J., Ed., Chandramouli, M., Winter, R., Dietz, T.,
              and B. Claise, "Requirements for Energy Management",
              RFC 6988, DOI 10.17487/RFC6988, September 2013,
              <http://www.rfc-editor.org/info/rfc6988>.

   [RFC7181]  Clausen, T., Dearlove, C., Jacquet, P., and U. Herberg,
              "The Optimized Link State Routing Protocol Version 2",
              RFC 7181, DOI 10.17487/RFC7181, April 2014,
              <http://www.rfc-editor.org/info/rfc7181>.

   [RFC7228]  Bormann, C., Ersue, M., and A. Keranen, "Terminology for
              Constrained-Node Networks", RFC 7228,
              DOI 10.17487/RFC7228, May 2014,
              <http://www.rfc-editor.org/info/rfc7228>.

   [RFC7326]  Parello, J., Claise, B., Schoening, B., and J. Quittek,
              "Energy Management Framework", RFC 7326,
              DOI 10.17487/RFC7326, September 2014,
              <http://www.rfc-editor.org/info/rfc7326>.

   [RFC7547]  Ersue, M., Ed., Romascanu, D., Schoenwaelder, J., and U.
              Herberg, "Management of Networks with Constrained Devices:
              Problem Statement and Requirements", RFC 7547,
              DOI 10.17487/RFC7547, May 2015,
              <http://www.rfc-editor.org/info/rfc7547>.

   [IOT-SEC]  Garcia-Morchon, O., Kumar, S., Keoh, S., Hummen, R., and
              R. Struik, "Security Considerations in the IP-based
              Internet of Things", Work in Progress, draft-garcia-core-
              security-06, September 2013.

Top      ToC       Page 25 
   [IEEE802.11]
              IEEE, "Part 11: Wireless LAN Medium Access Control (MAC)
              and Physical Layer (PHY) Specifications", IEEE Standard
              802.11, March 2012,
              <http://standards.ieee.org/about/get/802/802.11.html>.

   [IEEE802.15]
              IEEE, "WIRELESS PERSONAL AREA NETWORKS (PANs)", IEEE
              Standard 802.15, 2003-2014,
              <https://standards.ieee.org/about/get/802/802.15.html>.

   [IEEE802.15.4]
              IEEE, "Part 15.4: Low-Rate Wireless Personal Area Networks
              (LR-WPANs)", IEEE Standard 802.15.4, September 2011,
              <https://standards.ieee.org/about/get/802/802.15.html>.

Acknowledgments

   The following persons reviewed and provided valuable comments during
   the creation of this document:

   Dominique Barthel, Carsten Bormann, Zhen Cao, Benoit Claise, Bert
   Greevenbosch, Ulrich Herberg, Ted Lemon, Kathleen Moriarty, James
   Nguyen, Zach Shelby, Peter van der Stok, and Martin Thomson.

   The authors would like to thank the reviewers and the participants on
   the Coman mailing list for their valuable contributions and comments.

   Juergen Schoenwaelder and Anuj Sehgal were partly funded by Flamingo,
   a Network of Excellence project (ICT-318488) supported by the
   European Commission under its Seventh Framework Programme.

Top      ToC       Page 26 
Contributors

   The following persons made significant contributions to and reviewed
   this document:

   o  Ulrich Herberg contributed Section 4.9, "Community Network
      Applications".

   o  Peter van der Stok contributed to Section 4.6, "Building
      Automation".

   o  Zhen Cao contributed to Section 2.2, "Cellular Access
      Technologies".

   o  Gilman Tolle contributed Section 4.4 "Energy Management".

   o  James Nguyen and Ulrich Herberg contributed to Section 4.10 "Field
      Operations".

Authors' Addresses

   Mehmet Ersue (editor)
   Nokia Networks

   EMail: mehmet.ersue@nokia.com


   Dan Romascanu
   Avaya

   EMail: dromasca@avaya.com


   Juergen Schoenwaelder
   Jacobs University Bremen

   EMail: j.schoenwaelder@jacobs-university.de


   Anuj Sehgal
   Jacobs University Bremen

   EMail: s.anuj@jacobs-university.de