Subject: Re: [Roll] Moving forward with the protocol work

From: <[email-masked]>
Date: Fri, 31 Jul 2009 09:10:35 +0200

Hi Jerry, all,

Thanks for the detailed description of the Building Automation setting.
I'm wondering if you could propose an estimate of how many multi-hop P2P
routes an average node would sit on? So that we can gauge the
consequences of potential P2P routing algorithms on nodes' memory/energy
limits...
As suggested by somebody else (sorry I lost track who it was), it would
seem that many P2P flows in a given "room" are direct connections with
no (control plane)routing involved. Am I totally mistaken on this?
Regards,

Dominique

----------------------- 
Date: Thu, 30 Jul 2009 14:12:10 -0500
From: [email-masked]
Subject: Re: [Roll] Moving forward with the protocol work
To: "Julien Abeille (jabeille)" <[email-masked]>
Cc: ROLL WG <[email-masked]>, [email-masked]
Message-ID:
	
<[email-masked]>
Content-Type: text/plain; charset="us-ascii"

Hi Julien,

Section 3 of the Building Requirements ID describes the typical devices
and device densities in a commercial building; Section 6 describes the
traffic flow.  Let me try to reiterate here ...

The building control application domain includes Heating Ventilation and
Air Conditioning (aka HVAC), Physical Security, Lighting, Elevator and
Fire control.  While each has its nuances, they all fall roughly onto
the same topology.  The leaf layer for these systems are the sensors.
There's a plethora of them including temperature sensors, humidity
sensors, pressure sensors, tamper switches, C02, C0, smoke detectors,
occupancy sensors, light switches, and the list goes on.  In a room, you
might expect a temp sensor, a humidity sensor, an occupancy sensor,
solar sensor, smoke detector and light switches. 

Now along with the room sensors, there are room actuators and room
controllers.  The controllers receive the environmental data from the
sensors, and determine the necessary control based on conditions, system
overrides, time-of-day, etc and then control the environment by tweaking
the actuators accordingly.  The HVAC system will modulate the airflow
and augment heating/cooling.  The shade controller will sense solar load
and adjust the shades.  The lighting will be adjusted as requested by
the presentation mode.  When I talk about a room, I am not meaning
necessarily only a closed door meeting room.  This would also apply to
public spaces such as an attria, hallways, ballrooms.etc.  The key
ingredient in this is that each of these areas has a self contained
sensor/controller/actuator subsystem.

Now, the next layer of controllers are the zone and area controllers. 
These are higher level devices that supply the facility with more global
control systems.  HVAC will have air handlers that supply fresh air to
the rooms.  Chillers that support cold air to the rooms, boilers that
supply heat.  Lighting panels will control whole floors rather than
simply rooms. 
 The point being that these higher order devices are also LLN devices
incorporating another whole set of sensors such as outdoor air temp,
relative humidity, etc.

With regards to your question about layer 2, at present these devices
are not IP devices.  They typically reside on an EIA-485 network.

Hope this helps,

Jerry

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From: JP Vasseur <[email-masked]>
Date: Fri, 31 Jul 2009 18:20:53 +0200

I do not want to stop that excellent discussion. Just please change  
the thread title.

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