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Versions: (draft-martocci-roll-building-routing-reqs) 00 01 02 03 04 05 06 07 08 09 RFC 5867

Networking Working Group                                J. Martocci, Ed.
Internet-Draft                                     Johnson Controls Inc.
Intended status: Informational                            Pieter De Mil
Expires: July 14, 2009                            Ghent University IBCN
                                                           W. Vermeylen
                                                    Arts Centre Vooruit
                                                           Nicolas Riou
                                                     Schneider Electric
                                                        January 14, 2009


      Building Automation Routing Requirements in Low Power and Lossy
                                 Networks
                 draft-ietf-roll-building-routing-reqs-02


Status of this Memo

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   This Internet-Draft will expire on July 14, 2009.

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Abstract

   The Routing Over Low power and Lossy network (ROLL) Working Group has
   been chartered to work on routing solutions for Low Power and Lossy
   networks (LLN) in various markets: Industrial, Commercial (Building),
   Home and Urban. Pursuant to this effort, this document defines the
   routing requirements for building automation.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC-2119.

Table of Contents

   1. Terminology....................................................4
   2. Introduction...................................................4
      2.1. Facility Management System (FMS) Topology.................5
         2.1.1. Introduction.........................................5
         2.1.2. Sensors/Actuators....................................6
         2.1.3. Area Controllers.....................................6
         2.1.4. Zone Controllers.....................................7
      2.2. Installation Methods......................................7
         2.2.1. Wired Communication Media............................7
         2.2.2. Device Density.......................................7
         2.2.3. Installation Procedure...............................9
   3. Building Automation Applications..............................10
      3.1. Locking and Unlocking the Building.......................10
      3.2. Building Energy Conservation.............................10
      3.3. Inventory and Remote Diagnosis of Safety Equipment.......11
      3.4. Life Cycle of Field Devices..............................11
      3.5. Surveillance.............................................11
      3.6. Emergency................................................12
      3.7. Public Address...........................................12
   4. Building Automation Routing Requirements......................12
      4.1. Installation.............................................13
         4.1.1. Zero-Configuration installation.....................13
         4.1.2. Sleeping devices....................................13
         4.1.3. Local Testing.......................................14
         4.1.4. Device Replacement..................................14
      4.2. Scalability..............................................15
         4.2.1. Network Domain......................................15
         4.2.2. Peer-to-peer Communication..........................15
      4.3. Mobility.................................................15
         4.3.1. Mobile Device Association...........................15
      4.4. Resource Constrained Devices.............................16


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         4.4.1. Limited Processing Power Sensors/Actuators..........16
         4.4.2. Limited Processing Power Controllers................16
      4.5. Addressing...............................................16
         4.5.1. Unicast/Multicast/Anycast...........................16
      4.6. Manageability............................................17
         4.6.1. Firmware Upgrades...................................17
         4.6.2. Diagnostics.........................................17
         4.6.3. Route Tracking......................................17
      4.7. Compatibility............................................17
         4.7.1. IPv4 Compatibility..................................18
         4.7.2. Maximum Packet Size.................................18
      4.8. Route Selection..........................................18
         4.8.1. Path Cost...........................................18
         4.8.2. Path Adaptation.....................................18
         4.8.3. Route Redundancy....................................18
         4.8.4. Route Discovery Time................................18
         4.8.5. Route Preference....................................19
         4.8.6. Path Persistence....................................19
   5. Traffic Pattern...............................................19
   6. Open issues...................................................20
   7. Security Considerations.......................................20
   8. IANA Considerations...........................................20
   9. Acknowledgments...............................................20
   10. References...................................................20
      10.1. Normative References....................................20
      10.2. Informative References..................................21
   11. Appendix A: Additional Building Requirements.................21
      11.1. Additional Commercial Product Requirements..............21
         11.1.1. Wired and Wireless Implementations.................21
         11.1.2. World-wide Applicability...........................21
         11.1.3. Support of the BACnet Building Protocol............21
         11.1.4. Support of the LON Building Protocol...............21
         11.1.5. Energy Harvested Sensors...........................22
         11.1.6. Communication Distance.............................22
         11.1.7. Automatic Gain Control.............................22
         11.1.8. Cost...............................................22
      11.2. Additional Installation and Commissioning Requirements..22
         11.2.1. Device Setup Time..................................22
         11.2.2. Unavailability of an IT network....................22
      11.3. Additional Network Requirements.........................22
         11.3.1. TCP/UDP............................................22
         11.3.2. Data Rate Performance..............................23
         11.3.3. High Speed Downloads...............................23
         11.3.4. Interference Mitigation............................23
         11.3.5. Real-time Performance Measures.....................23
         11.3.6. Packet Reliability.................................23
         11.3.7. Merging Commissioned Islands.......................23


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         11.3.8. Adjustable System Table Sizes......................24
      11.4. Prioritized Routing.....................................24
         11.4.1. Packet Prioritization..............................24
      11.5. Constrained Devices.....................................24
         11.5.1. Proxying for Constrained Devices...................24
      11.6. Reliability.............................................24
         11.6.1. Device Integrity...................................24





1. Terminology

   For description of the terminology used in this specification, please
   see the Terminology ID referenced in Section 10.1.



2. Introduction

   Commercial buildings have been fitted with pneumatic and subsequently
   electronic communication pathways connecting sensors to their
   controllers for over one hundred years.  Recent economic and
   technical advances in wireless communication allow facilities to
   increasingly utilize a wireless solution in lieu of a wired solution;
   thereby reducing installation costs while maintaining highly reliant
   communication.

   The cost benefits and ease of installation of wireless sensors allow
   customers to further instrument their facilities with additional
   sensors; providing tighter control while yielding increased energy
   savings.

   Wireless solutions will be adapted from their existing wired
   counterparts in many of the building applications including, but not
   limited to Heating, Ventilation, and Air Conditioning (HVAC),
   Lighting, Physical Security, Fire, and Elevator systems. These
   devices will be developed to reduce installation costs; while
   increasing installation and retrofit flexibility, as well as
   increasing the sensing fidelity to improve efficiency and building
   service quality.



   Sensing devices may be battery or mains powered.  Actuators and area
   controllers will be mains powered.


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   Facility Management Systems (FMS) are deployed in a large set of
   vertical markets including universities; hospitals; government
   facilities; Kindergarten through High School (K-12); pharmaceutical
   manufacturing facilities; and single-tenant or multi-tenant office
   buildings. These buildings range in size from 100K sqft structures (5
   story office buildings), to 1M sqft skyscrapers (100 story
   skyscrapers) to complex government facilities such as the Pentagon.
   The described topology is meant to be the model to be used in all
   these types of environments, but clearly must be tailored to the
   building class, building tenant and vertical market being served.

   The following sections describe the sensor, actuator, area controller
   and zone controller layers of the topology.  (NOTE: The Building
   Controller and Enterprise layers of the FMS are excluded from this
   discussion since they typically deal in communication rates requiring
   WLAN communication technologies).



2.1. Facility Management System (FMS) Topology

 2.1.1. Introduction

   To understand the network systems requirements of a facility
   management system in a commercial building, this document uses a
   framework to describe the basic functions and composition of the
   system. An FMS is a hierarchical system of sensors, actuators,
   controllers and user interface devices based on spatial extent.
   Additionally, an FMS may also be divided functionally across alike,
   but different building subsystems such as HVAC, Fire, Security,
   Lighting, Shutters and Elevator control systems as denoted in Figure
   1.

   Much of the makeup of an FMS is optional and installed at the behest
   of the customer.  Sensors and actuators have no standalone
   functionality. All other devices support partial or complete
   standalone functionality.  These devices can optionally be tethered
   to form a more cohesive system.  The customer requirements dictate
   the level of integration within the facility.  This architecture
   provides excellent fault tolerance since each node is designed to
   operate in an independent mode if the higher layers are unavailable.



              +------+ +-----+ +------+ +------+ +------+ +------+

Bldg App'ns   |      | |     | |      | |      | |      | |      |


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              |      | |     | |      | |      | |      | |      |

Building Cntl |      | |     | |   S  | |   L  | |   S  | |  E   |

              |      | |     | |   E  | |   I  | |   H  | |  L   |

Area Control  |  H   | |  F  | |   C  | |   G  | |   U  | |  E   |

              |  V   | |  I  | |   U  | |   H  | |   T  | |  V   |

Zone Control  |  A   | |  R  | |   R  | |   T  | |   T  | |  A   |

              |  C   | |  E  | |   I  | |   I  | |   E  | |  T   |

Actuators     |      | |     | |   T  | |   N  | |   R  | |  O   |

              |      | |     | |   Y  | |   G  | |   S  | |  R   |

Sensors       |      | |     | |      | |      | |      | |      |

              +------+ +-----+ +------+ +------+ +------+ +------+

                  Figure 1: Building Systems and Devices



 2.1.2. Sensors/Actuators

   As Figure 1 indicates an FMS may be composed of many functional
   stacks or silos that are interoperably woven together via Building
   Applications.  Each silo has an array of sensors that monitor the
   environment and actuators that effect the environment as determined
   by the upper layers of the FMS topology.   The sensors typically are
   the fringe of the network structure providing environmental data into
   the system.  The actuators are the sensors counterparts modifying the
   characteristics of the system based on the input sensor data and the
   applications deployed.

 2.1.3. Area Controllers

   An area describes a small physical locale within a building,
   typically a room.  HVAC (temperature and humidity) and Lighting (room
   lighting, shades, solar loads) vendors oft times deploy area
   controllers. Area controls are fed by sensor inputs that monitor the
   environmental conditions within the room.  Common sensors found in
   many rooms that feed the area controllers include temperature,
   occupancy, lighting load, solar load and relative humidity.  Sensors


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   found in specialized rooms (such as chemistry labs) might include air
   flow, pressure, CO2 and CO particle sensors.  Room actuation includes
   temperature setpoint, lights and blinds/curtains.

 2.1.4. Zone Controllers

   Zone Control supports a similar set of characteristics as the Area
   Control albeit to an extended space.  A zone is normally a logical
   grouping or functional division of a commercial building.  A zone may
   also coincidentally map to a physical locale such as a floor.

   Zone Control may have direct sensor inputs (smoke detectors for
   fire), controller inputs (room controllers for air-handlers in HVAC)
   or both (door controllers and tamper sensors for security).  Like
   area/room controllers, zone controllers are standalone devices that
   operate independently or may be attached to the larger network for
   more synergistic control.



2.2. Installation Methods

 2.2.1. Wired Communication Media

   Commercial controllers are traditionally deployed in a facility using
   twisted pair serial media following the EIA-485 electrical standard
   operating nominally at 38400 to 76800 baud.  This allows runs to 5000
   ft without a repeater.  With the maximum of three repeaters, a single
   communication trunk can serpentine 15000 ft.  EIA-485 is a multi-drop
   media allowing upwards to 255 devices to be connected to a single
   trunk.

    Most sensors and virtually all actuators currently used in
   commercial buildings are "dumb", non-communicating hardwired devices.
   However, sensor buses are beginning to be deployed by vendors which
   are used for smart sensors and point multiplexing.   The Fire
   industry deploys addressable fire devices, which usually use some
   form of proprietary communication wiring driven by fire codes.

 2.2.2. Device Density

   Device density differs depending on the application and as dictated
   by the local building code requirements.  The following sections
   detail typical installation densities for different applications.





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2.2.2.1. HVAC Device Density

   HVAC room applications typically have sensors/actuators and
   controllers spaced about 50ft apart.  In most cases there is a 3:1
   ratio of sensors/actuators to controllers.  That is, for each room
   there is an installed temperature sensor, flow sensor and damper
   actuator for the associated room controller.

   HVAC equipment room applications are quite different.  An air handler
   system may have a single controller with upwards to 25 sensors and
   actuators within 50 ft of the air handler.  A chiller or boiler is
   also controlled with a single equipment controller instrumented with
   25 sensors and actuators.  Each of these devices would be
   individually addressed since the devices are mandated or optional as
   defined by the specified HVAC application.  Air handlers typically
   serve one or two floors of the building.  Chillers and boilers may be
   installed per floor, but many times service a wing, building or the
   entire complex via a central plant.

   These numbers are typical.  In special cases, such as clean rooms,
   operating rooms, pharmaceuticals and labs, the ratio of sensors to
   controllers can increase by a factor of three.  Tenant installations
   such as malls would opt for packaged units where much of the sensing
   and actuation is integrated into the unit.  Here a single device
   address would serve the entire unit.

2.2.2.2. Fire Device Density

   Fire systems are much more uniformly installed with smoke detectors
   installed about every 50 feet.  This is dictated by local building
   codes.  Fire pull boxes are installed uniformly about every 150 feet.
   A fire controller will service a floor or wing.  The fireman's fire
   panel will service the entire building and typically is installed in
   the atrium.

2.2.2.3. Lighting Device Density

   Lighting is also very uniformly installed with ballasts installed
   approximately every 10 feet.  A lighting panel typically serves 48 to
   64 zones.  Wired systems typically tether many lights together into a
   single zone.  Wireless systems configure each fixture independently
   to increase flexibility and reduce installation costs.

2.2.2.4. Physical Security Device Density

   Security systems are non-uniformly oriented with heavy density near
   doors and windows and lighter density in the building interior space.


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   The recent influx of interior and perimeter camera systems is
   increasing the security footprint.  These cameras are atypical
   endpoints requiring upwards to 1 megabit/second (Mbit/s) data rates
   per camera as contrasted by the few Kbits/s needed by most other FMS
   sensing equipment.  Previously, camera systems had been deployed on
   proprietary wired high speed network. More recent implementations
   utilize wired or wireless IP cameras integrated to the enterprise
   LAN.

2.2.3. Installation Procedure

   Wired FMS installation is a multifaceted procedure depending on the
   extent of the system and the software interoperability requirement.
   However, at the sensor/actuator and controller level, the procedure
   is typically a two or three step process.

   Most FMS equipment is 24 VAC equipment that can be installed by a
   low-voltage electrician.  He/she arrives on-site during the
   construction of the building prior to the sheet wall and ceiling
   installation.  This allows him/her to allocate wall space, easily
   land the equipment and run the wired controller and sensor networks.
   The Building Controllers and Enterprise network are not normally
   installed until months later.  The electrician completes his task by
   running a wire verification procedure that shows proper continuity
   between the devices and proper local operation of the devices.

   Later in the installation cycle, the higher order controllers are
   installed, programmed and commissioned together with the previously
   installed sensors, actuators and controllers.  In most cases the IP
   network is still not operable.  The Building Controllers are
   completely commissioned using a crossover cable or a temporary IP
   switch together with static IP addresses.

   Once the IP network is operational, the FMS may optionally be added
   to the enterprise network.  The wireless installation process must
   follow the same work flow.  The electrician will install the products
   as before and run local functional tests between the wireless device
   to assure operation before leaving the job.   The electrician does
   not carry a laptop so the commissioning must be built into the device
   operation.



   The wireless installation process must follow the same work flow.
   The electrician will install the products as before and run local
   functional tests between the wireless devices to assure operation



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   before leaving the job.   The electrician does not carry a laptop so
   the commissioning must be built into the device operation.



3. Building Automation Applications

   Vooruit is an arts centre in a restored monument which dates from
   1913.  This complex monument consists of over 350 different rooms
   including a meeting rooms, large public halls and theaters serving as
   many as 2500 guests.  A number of use cases regarding Vooruit are
   described in the following text.  The situations and needs described
   in these use cases can also be found in all automated large
   buildings, such as airports and hospitals.

3.1. Locking and Unlocking the Building

   The member of the cleaning staff arrives first in the morning
   unlocking the building (or a part of it) from the control room.  This
   means that several doors are unlocked; the alarms are switched off;
   the heating turns on; some lights switch on, etc.  Similarly, the
   last person leaving the building has to lock the building.  This will
   lock all the outer doors, turn the alarms on, switch off heating and
   lights, etc.

   The ''building locked'' or ''building unlocked'' event needs to be
   delivered to a subset of all the sensors and actuators. It can be
   beneficial if those field devices form a group (e.g. ''all-sensors-
   actuators-interested-in-lock/unlock-events). Alternatively, the area
   and zone controllers could form a group where the arrival of such an
   event results in each area and zone controller initiating unicast or
   multicast within the LLN.

   This use case is also described in the home automation, although the
   requirement about preventing the "popcorn effect" draft [I-D.ietf-
   roll-home-routing-reqs] can be relaxed a little bit in building
   automation. It would be nice if lights, roll-down shutters and other
   actuators in the same room or area with transparent walls execute the
   command around (not 'at') the same time (a tolerance of 200 ms is
   allowed).

3.2. Building Energy Conservation

   A room that is not in use should not be heated, air conditioned or
   ventilated and the lighting should be turned off.  In a building with
   a lot of rooms it can happen quite frequently that someone forgets to
   switch off the HVAC and lighting.  This is a real waste of valuable


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   energy.  To prevent this from happening, the janitor can program the
   building according to the day's schedule.  This way lighting and HVAC
   is turned on prior to the use of a room, and turned off afterwards.
   Using such a system Vooruit has realized a saving of 35% on the gas
   and electricity bills.

3.3. Inventory and Remote Diagnosis of Safety Equipment

   Each month Vooruit is obliged to make an inventory of its safety
   equipment.  This task takes two working days.  Each fire extinguisher
   (100), fire blanket (10), fire-resistant door (120) and evacuation
   plan (80) must be checked for presence and proper operation.  Also
   the battery and lamp of every safety lamp must be checked before each
   public event (safety laws).  Automating this process using asset
   tracking and low-power wireless technologies would reduce a heavy
   burden on working hours.

   It is important that these messages are delivered very reliably and
   that the power consumption of the sensors/actuators attached to this
   safety equipment is kept at a very low level.



3.4. Life Cycle of Field Devices

   Some field devices (e.g. smoke detectors) are replaced periodically.
   The ease by which devices are added and deleted from the network is
   very important to support augmenting sensors/actuators during
   construction.

   A secure mechanism is needed to remove the old device and install the
   new device.  New devices need to be authenticated before they can
   participate in the routing process of the LLN. After the
   authentication, zero-configuration of the routing protocol is
   necessary.

3.5. Surveillance

   Ingress and egress are real-time applications needing response times
   below 500msec, for example for cardkey authorization.  It must be
   possible to configure doors individually to restrict use on a per
   person basis with respect to time-of-day and person entering.  While
   much of the surveillance application involves sensing and actuation
   at the door and communication with the centralized security system,
   other aspects, including tamper, door ajar, and forced entry
   notification, are to be delivered to one or more fixed or mobile user
   devices within 5 seconds.


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3.6. Emergency

   In case of an emergency it is very important that all the visitors be
   evacuated as quickly as possible.  The fire and smoke detectors set
   off an alarm and alert the mobile personnel on their user device
   (e.g. PDA).  All emergency exits are instantly unlocked and the
   emergency lighting guides the visitors to these exits.  The necessary
   sprinklers are activated and the electricity grid monitored if it
   becomes necessary to shut down some parts of the building. Emergency
   services are notified instantly.

   A wireless system could bring in some extra safety features.
   Locating fire fighters and guiding them through the building could be
   a life-saving application.

   These life critical applications ought to take precedence over other
   network traffic.  Commands entered during these emergencies have to
   be properly authenticated by device, user, and command request.



3.7. Public Address

   It should be possible to send audio and text messages to the visitors
   in the building.  These messages can be very diverse, e.g. ASCII text
   boards displaying the name of the event in a room, audio
   announcements such as delays in the program, lost and found children,
   evacuation orders, etc.

   The control network is expected be able to readily sense the presence
   of an audience in an area and deliver applicable message content.





4. Building Automation Routing Requirements

   Following are the building automation routing requirements for a
   network used to integrate building sensor actuator and control
   products.  These requirements have been limited to routing
   requirements only.  These requirements are written not presuming any
   preordained network topology, physical media (wired) or radio
   technology (wireless).  See Appendix A for additional requirements
   that have been deemed outside the scope of this document yet will
   pertain to the successful deployment of building automation systems.



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4.1. Installation

   Building control systems typically are installed and tested by
   electricians having little computer knowledge and no network
   knowledge whatsoever.  These systems are often installed during the
   building construction phase before the drywall and ceilings are in
   place.  For new construction projects, the building enterprise IP
   network is not in place during installation of the building control
   system.

   In retrofit applications, pulling wires from sensors to controllers
   can be costly and in some applications (e.g. museums) not feasible.

   Local (ad hoc) testing of sensors and room controllers must be
   completed before the tradesperson can complete his/her work.  This
   testing allows the tradesperson to verify correct client (e.g. light
   switch) and server (e.g. light ballast) before leaving the jobsite.
   In traditional wired systems correct operation of a light
   switch/ballast pair was as simple as flipping on the light switch.
   In wireless applications, the tradesperson has to assure the same
   operation, yet be sure the operation of the light switch is
   associated to the proper ballast.

   System level commissioning will later be deployed using a more
   computer savvy person with access to a commissioning device (e.g. a
   laptop   computer).  The completely installed and commissioned
   enterprise IP network may or may not be in place at this time.
   Following are the installation routing requirements.

 4.1.1. Zero-Configuration installation

   It MUST be possible to fully commission network devices without
   requiring any additional commissioning device (e.g. laptop). The
   device MAY support up to sixteen integrated switches to uniquely
   identify the device on the network.

 4.1.2. Sleeping devices

   Sensing devices will, in cases, utilize battery power or energy
   harvesting techniques for power and will operate in a mostly sleeping
   mode to maintain power consumption within a modest budget.  Routing
   MUST recognize the constraints associated the power budget of such
   low duty cycle devices.  If such devices provide routing, rather than
   merely host connectivity, the energy costs associated with such
   routing need to fit within the power budget.  If the mechanisms for


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   duty cycling dictate very long response times or specific temporal
   scheduling, routing and forwarding will need to take such constraints
   into account.

   Communication to these mostly sleeping devices MUST be bidirectional.
   Typically, batteries need to be operational for at least 5 years when
   the sensing device is transmitting its data(e.g. 64 bytes) once per
   minute.  This requires that sleeping devices must have minimal link
   on time when they awake and transmit onto the network. Moreover,
   maintaining the ability to receive inbound data must be accomplished
   with minimal link on time.

   In many cases, proxies with unconstrained power budgets are used to
   cache the inbound data for a sleeping device until the device
   awakens.  In such cases, routing MUST recognize the selected proxy
   for the sleeping device.



 4.1.3. Local Testing

   The local sensors and requisite actuators and controllers must be
   testable within the locale (e.g. room) to assure communication
   connectivity and local operation without requiring other systemic
   devices.  Routing must allow for temporary ad hoc paths to be
   established that are updated as the network physically and
   functionally expands.

 4.1.4. Device Replacement

   Replacement devices need to be plug-and-play with no additional setup
   compared to what is normally required for a new device.  Devices
   referencing data in the replaced device must be able to reference
   data in its replacement without being reconfigured to refer to the
   new device.  Thus, such a reference cannot be a hardware identifier,
   such as the MAC address, nor a hardcoded route.  If such a reference
   is an IP address, the replacement device must be assigned the IP
   addressed previously bound to the replaced device.  Or if the logical
   equivalent of a hostname is used for the reference, it must be
   translated to the replacement IP address.









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4.2. Scalability

   Building control systems are designed for facilities from 50000 sq.
   ft. to 1M+ sq. ft.  The networks that support these systems must
   cost-effectively scale accordingly.  In larger facilities
   installation may occur simultaneously on various wings or floors, yet
   the end system must seamlessly merge.  Following are the scalability
   requirements.

 4.2.1. Network Domain

   The routing protocol MUST be able to support networks with at least
   1000 routers and 1000 hosts.  Subnetworks (e.g. rooms, primary
   equipment) within the network must support upwards to 255 sensors
   and/or actuators.

   .

 4.2.2. Peer-to-peer Communication

   The data domain for commercial FMS systems may sprawl across a vast
   portion of the physical domain.  For example, a chiller may reside in
   the facility's basement due to its size, yet the associated cooling
   towers will reside on the roof.  The cold-water supply and return
   pipes serpentine through all the intervening floors.  The feedback
   control loops for these systems require data from across the
   facility.

   A network device must be able to communicate in a peer-to-peer manner
   with any other device on the network. Thus, the routing protocol MUST
   provide routes between arbitrary hosts within the appropriate
   administrative domain.



4.3. Mobility

   Most devices are affixed to walls or installed on ceilings within
   buildings.  Hence the mobility requirements for commercial buildings
   are few.  However, in wireless environments location tracking of
   occupants and assets is gaining favor.

 4.3.1. Mobile Device Association

   Mobile devices SHOULD be capable of unjoining (handing-off) from an
   old network joining onto a new network within 15 seconds.



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4.4. Resource Constrained Devices

   Sensing and actuator device processing power and memory may be 4
   orders of magnitude less (i.e. 10,000x) than many more traditional
   client devices on an IP network.  The routing mechanisms MUST
   therefore be tailored to fit these resource constrained devices.

 4.4.1. Limited Processing Power Sensors/Actuators

   The software stack requirements for sensors and actuators MUST be
   implementable in 8-bit devices with no more than 128KB of flash
   memory (including at least 32KB for the application code) and no more
   than 8KB of RAM (including at least 1KB RAM available for the
   application).

 4.4.2. Limited Processing Power Controllers

   The software stack requirements for room controllers SHOULD be
   implementable in 8-bit devices with no more than 256KB of flash
   memory (including at least 32KB for the application code) and no more
   than 8KB of RAM (including at least 1KB RAM available for the
   application)



4.5. Addressing

   Facility Management systems require different communication schema to
   solicit or post network information. Broadcasts or anycasts need be
   used to resolve unresolved references within a device when the device
   first joins the network.

   As with any network communication, broadcasting should be minimized.
   This is especially a problem for small embedded devices with limited
   network bandwidth.  In many cases a global broadcast could be
   replaced with a multicast since the application knows the application
   domain.  Broadcasts and multicasts are typically used for network
   joins and application binding in embedded systems.

 4.5.1. Unicast/Multicast/Anycast

   Routing MUST support anycast, unicast, multicast and broadcast
   services (or IPv6 equivalent).


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4.6. Manageability

   In addition to the initial installation of the system (see Section
   4.1), it is equally important for the ongoing maintenance of the
   system to be simple and inexpensive.

 4.6.1. Firmware Upgrades

   To support high speed code downloads, routing MUST support transports
   that provide parallel downloads to targeted devices yet guarantee
   packet delivery.

 4.6.2. Diagnostics

   To improve diagnostics, the network layer SHOULD be able to be placed
   in and out of 'verbose' mode.  Verbose mode is a temporary debugging
   mode that provides additional communication information including at
   least total number of packets sent, packets received, number of
   failed communication attempts, neighbor table and routing table
   entries.

 4.6.3. Route Tracking

   Route diagnostics SHOULD be supported providing information such as
   path quality; number of hops; available alternate active paths with
   associated costs.



4.7. Compatibility

   The building automation industry adheres to application layer
   protocol standards to achieve vendor interoperability.  These
   standards are BACnet and LON.  It is estimated that fully 80% of the
   customer bid requests received world-wide will require compliance to
   one or both of these standards.  ROLL routing will therefore need to
   dovetail to these application protocols to assure acceptance in the
   building automation industry.  These protocols have been in place for
   over 10 years.  Many sites will require backwards compatibility with
   the existing legacy devices.





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 4.7.1. IPv4 Compatibility

   The routing protocol MUST support intercommunication among IPv4 and
   IPv6 devices..

 4.7.2. Maximum Packet Size

   Routing MUST support packet sizes to 1526 octets (to be backwards
   compatible with 802.3 subnetworks)



4.8. Route Selection

   Route selection determines reliability and quality of the
   communication paths among the devices. Optimizing the routes over
   time resolve any nuances developed at system startup when nodes are
   asynchronously adding themselves to the network.  Path adaptation
   will reduce latency if the path costs consider hop count as a cost
   attribute.

 4.8.1. Path Cost

   The routing protocol MUST support a metric of route quality and
   optimize path selection according to such metrics within constraints
   established for links along the paths. These metrics SHOULD reflect
   metrics such as signal strength, available bandwidth, hop count,
   energy availability and communication error rates.

 4.8.2. Path Adaptation

   Communication paths MUST adapt toward the chosen metric(s) (e.g.
   signal quality) optimality in time.

 4.8.3. Route Redundancy

   The network layer SHOULD be configurable to allow secondary and
   tertiary paths to be established and used upon failure of the primary
   path.

 4.8.4. Route Discovery Time

   Mission critical commercial applications (e.g. Fire,Security) require
   reliable communication and guaranteed end-to-end delivery of all
   messages in a timely fashion.  Application layer time-outs must be
   selected judiciously to cover anomalous conditions such as lost
   packets and/or path discoveries; yet not be set too large to over


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   damp the network response.  Route discovery occurring during packet
   transmission MUST not exceed 120 msecs.

 4.8.5. Route Preference

   The route discovery mechanism SHOULD allow a source node (sensor) to
   dictate a configured destination node (controller) as a preferred
   routing path.

 4.8.6. Path Persistence

   To eliminate high network traffic in power-fail or brown-out
   conditions previously established routes SHOULD be remembered and
   invoked prior to establishing new routes for those devices reentering
   the network.



5. Traffic Pattern

   The independent nature of the automation systems within a building
   plays heavy onto the network traffic patterns.  Much of the real-time
   sensor data stays within the local environment.  Alarming and other
   event data will percolate to higher layers.

   Systemic data may be either polled or event based.  Polled data
   systems will generate a uniform packet load on the network.  This
   architecture has proven not scalable.  Most vendors have developed
   event based systems which passes data on event.  These systems are
   highly scalable and generate low data on the network at quiescence.
   Unfortunately, the systems will generate a heavy load on startup
   since all the initial data must migrate to the controller level.
   They also will generate a temporary but heavy load during firmware
   upgrades.  This latter load can normally be mitigated by performing
   these downloads during off-peak hours.

   Devices will need to reference peers occasionally for sensor data or
   to coordinate across systems.  Normally, though, data will migrate
   from the sensor level upwards through the local, area then
   supervisory level.  Bottlenecks will typically form at the funnel
   point from the area controllers to the supervisory controllers.








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6. Open issues

   Other items to be addressed in further revisions of this document
   include:

   All known open items completed



7. Security Considerations

   Security policies, especially wireless encryption and overall device
   authentication need to be considered.  These issues are out of scope
   for the routing requirements, but could have an impact on the
   processing capabilities of the sensors and controllers.

   As noted above, the FMS systems are typically highly configurable in
   the field and hence the security policy is most often dictated by the
   type of building to which the FMS is being installed.



8. IANA Considerations

   This document includes no request to IANA.



9. Acknowledgments

   J. P. Vasseur, Ted Humpal and Zach Shelby are gratefully acknowledged
   for their contributions to this document.

   This document was prepared using 2-Word-v2.0.template.dot.



10. References

10.1. Normative References

   draft-ietf-roll-home-routing-reqs-03

   draft-ietf-roll-terminology-00.txt





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10.2. Informative References

   ''RS-485 EIA Standard: Standard for Electrical Characteristics of
   Generators and Receivers for use in Balanced Digital Multipoint
   Systems'', April 1983

   ''BACnet: A Data Communication Protocol for Building and Automation
   Control Networks'' ANSI/ASHRAE Standard 135-2004'', 2004

   ''LON: OPEN DATA COMMUNICATION IN BUILDING AUTOMATION, CONTROLS AND
   BUILDING MANAGEMENT - BUILDING NETWORK PROTOCOL - PART 1: PROTOCOL
   STACK'', 11/25/2005



11. Appendix A: Additional Building Requirements

   Appendix A contains additional building requirements that were deemed
   out of scope for the routing document yet provided ancillary
   informational substance to the reader.  The requirements will need to
   be addressed by ROLL or other WGs before adoption by the building
   automation industry will be considered.

11.1. Additional Commercial Product Requirements

11.1.1.  Wired and Wireless Implementations

   Solutions must support both wired and wireless implementations.

11.1.2. World-wide Applicability

   Wireless devices must be supportable at the 2.4Ghz ISM band.
   Wireless devices should be supportable at the 900 and 868 ISM bands
   as well.

11.1.3.  Support of the BACnet Building Protocol

   Devices implementing the ROLL features should support the BACnet
   protocol.

11.1.4.  Support of the LON Building Protocol

   Devices implementing the ROLL features should support the LON
   protocol.





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11.1.5.  Energy Harvested Sensors

   RFDs should target for operation using viable energy harvesting
   techniques such as ambient light, mechanical action, solar load, air
   pressure and differential temperature.

11.1.6.  Communication Distance

   A source device may be upwards to 1000 feet from its destination.
   Communication may need to be established between these devices
   without needing to install other intermediate 'communication only'
   devices such as repeaters

11.1.7.  Automatic Gain Control

   For wireless implementations, the device radios should incorporate
   automatic transmit power regulation to maximize packet transfer and
   minimize network interference regardless of network size or density.

 11.1.8.   Cost

   The total installed infrastructure cost including but not limited to
   the media, required infrastructure devices (amortized across the
   number of devices); labor to install and commission the network must
   not exceed $1.00/foot for wired implementations.

   Wireless implementations (total installed cost) must cost no more
   than 80% of wired implementations.

11.2.    Additional Installation and Commissioning Requirements

 11.2.1.   Device Setup Time

   Network setup by the installer must take no longer than 20 seconds
   per device installed.

11.2.2.  Unavailability of an IT network

   Product commissioning must be performed by an application engineer
   prior to the installation of the IT network.

11.3.    Additional Network Requirements

 11.3.1.   TCP/UDP

   Connection based and connectionless services must be supported



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 11.3.2.   Data Rate Performance

   An effective data rate of 20kbits/s is the lowest acceptable
   operational data rate acceptable on the network.

 11.3.3.   High Speed Downloads

   Devices receiving a download MAY cease normal operation, but upon
   completion of the download must automatically resume normal
   operation.

11.3.4.  Interference Mitigation

   The network must automatically detect interference and seamlessly
   migrate the network hosts channel to improve communication.  Channel
   changes and nodes response to the channel change must occur within 60
   seconds.

11.3.5.  Real-time Performance Measures

   A node transmitting a 'request with expected reply' to another node
   must send the message to the destination and receive the response in
   not more than 120 msec.  This response time should be achievable with
   5 or less hops in each direction.  This requirement assumes network
   quiescence and a negligible turnaround time at the destination node.

 11.3.6.   Packet Reliability

   Reliability must meet the following minimum criteria :

   < 1% MAC layer errors on all messages; After no more than three
   retries

   < .1% Network layer errors on all messages;

   After no more than three additional retries;

   < 0.01% Application layer errors on all messages.

   Therefore application layer messages will fail no more than once
   every 100,000 messages.

 11.3.7.   Merging Commissioned Islands

   Subsystems are commissioned by various vendors at various times
   during building construction.  These subnetworks must seamlessly



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   merge into networks and networks must seamlessly merge into
   internetworks since the end user wants a holistic view of the system.

 11.3.8.   Adjustable System Table Sizes

   Routing must support adjustable router table entry sizes on a per
   node basis to maximize limited RAM in the devices.



11.4. Prioritized Routing

   Network and application routing prioritization is required to assure
   that mission critical applications (e.g. Fire Detection) cannot be
   deferred while less critical application access the network.

11.4.1. Packet Prioritization

   Routers must support quality of service prioritization to assure
   timely response for critical FMS packets.

11.5. Constrained Devices

   The network may be composed of a heterogeneous mix of full, battery
   and energy harvested devices.  The routing protocol must support
   these constrained devices.



11.5.1. Proxying for Constrained Devices

   Routing must support in-bound packet caches for low-power (battery
   and energy harvested) devices when these devices are not accessible
   on the network.

   These devices must have a designated powered proxying device to which
   packets will be temporarily routed and cached until the constrained
   device accesses the network.



11.6. Reliability

 11.6.1. Device Integrity

   Commercial Building devices must all be periodically scanned to
   assure that the device is viable and can communicate data and alarm


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   information as needed. Network routers should maintain previous
   packet flow information temporally to minimize overall network
   overhead.














































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Authors' Addresses


   Jerry Martocci
   Johnson Control
   507 E. Michigan Street
   Milwaukee, Wisconsin, 53202
   USA

   Phone: 414.524.4010
   Email: jerald.p.martocci@jci.com



   Nicolas Riou
   Schneider Electric
   Technopole 38TEC T3
   37 quai Paul Louis Merlin
   38050 Grenoble Cedex 9
   France

   Phone: +33 4 76 57 66 15
   Email: nicolas.riou@fr.schneider-electric.com



   Pieter De Mil
   Ghent University - IBCN
   G. Crommenlaan 8 bus 201
   Ghent  9050
   Belgium

   Phone: +32-9331-4981
   Fax:   +32--9331--4899
   Email: pieter.demil@intec.ugent.be




   Wouter Vermeylen
   Arts Centre Vooruit
   ???
   Ghent  9000
   Belgium

   Phone: ???
   Fax:   ???


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   Email: wouter@vooruit.be
















































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