Re: [Roll] Moving forward with the protocol work

[Mischa Dohler <[e-mail]>]

Hi Jerry, my understanding of p2p was slightly different in that I 
thought you assumed a (flat) architecture where every node needs to talk 
to any other node. From your description - and what I also had in mind - 
it seems that some nodes (e.g. sensors) wish to communicate with an 
order of magnitude lower number of nodes (e.g. actuators, distributed 
central units). In my opinion, this difference in order of magnitude 
changes quite a bit in the protocol design. Mischa.

[e-mail] wrote:
> 
> 
> 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
> 
> 
> 
> 
> *"Julien Abeille (jabeille)" <[e-mail]>*
> 
> 07/30/2009 11:07 AM
> 
> 	
> To
> 	<[e-mail]>, "Mischa Dohler" <[e-mail]>
> cc
> 	"ROLL WG" <[e-mail]>, <[e-mail]>
> Subject
> 	RE: [Roll] Moving forward with the protocol work
> 
> 
> 	
> 
> 
> 
> 
> 
> Hi Jerald,
>  
> just to understand better the setup in commercial buildings: in a 
> typical scenario,  which devices / how many are present in a room, what 
> is the layer 2 topology and the p2p application flows?
>  
> Thank you,
> Julien
> 
> ------------------------------------------------------------------------
> *From:* [e-mail] [mailto:[e-mail]] *On Behalf 
> Of *[e-mail]*
> Sent:* jeudi 30 juillet 2009 17:58*
> To:* Mischa Dohler*
> Cc:* ROLL WG; [e-mail]*
> Subject:* Re: [Roll] Moving forward with the protocol work
> 
> 
> 
> Hi Mischa,
> 
> Nearly all communication in a commercial building facility management 
> system is point to point.  I'm surprised the other three requirements 
> don't also have a strong p2p requirement.  Back in the early 80's prior 
> to processor based sensors, we deployed 'dumb sensors' that would simply 
> upload their current environmental information to a centralized 
> minicomputer.  This centralized model was not scalable nor fault 
> tolerant.  That is if the minicomputer 'blew a gasket', the entire 
> building went out of control.
> 
> As soon as it was economically viable, we decentralized control by 
> moving it down into the rooms.  Now each room was controlled 
> independently with an array of room sensors and room controllers.  Now 
> if a controller failed, only the room might lose control, not the entire 
> complex.  The room controllers were then further controlled by higher 
> level controllers.  This distributed architecture has been in place for 
> 25 years and is the mainstay of building control.  
> 
> My point is that is the Commercial Market the LLN is not just a path for 
> moving data nortbound.  Most of the packets sent on the LLN are destined 
> to other nodes on the LLN.  They all require application ACKs.  About 
> 20% of the packets are destined to the LBR and onwards.  These are event 
> packets being sent to the higher layers for further analysis.
> 
> If we don't support a robust p2p protocol option in ROLL, we will knock 
> out the Building Market in its entirety which means at best you will 
> only solve 75% of the need.
> 
> 
> Jerry
> 
> 
> 
> *Mischa Dohler <[e-mail]>*
> Sent by: [e-mail]
> 
> 07/29/2009 04:18 PM
> 
> 	
> To
> 	JP Vasseur <[e-mail]>
> cc
> 	ROLL WG <[e-mail]>
> Subject
> 	Re: [Roll] Moving forward with the protocol work
> 
> 
> 
> 	
> 
> 
> 
> 
> 
> 
> JP, all,
> 
> We should use this early design stage to come up with one solution - one
> solution which is not necessarily optimum for all cases but for the
> (e.g.) 95% quantile. The PHY guys learned to live with such an approach.
> The MAC folks are getting there and we should take our chance now. 95%
> means clearly to concentrate on the core issues, of which loop
> detection/avoidance, p2p and security are somehow still open.
> 
> I do understand the concept of loops arising. I have doubts that with
> the dynamics of typical ROLL networks, these will give us headaches
> within this 95% application quantile. I have read tons of papers
> produced in the last decade on routing in ROLL-type networks. Loop
> detection and avoidance was clearly not something people (including
> those doing practical rollouts and running their companies today) were
> worried about too much. Unless somebody provides me with a convincing
> study, I propose to merely adopt some simple and possibly sub-optimum
> heuristics and then forget about it.
> 
> P2P seems to worry some of us (sorry, Jerry, for having forgotten about
> the p2p paragraph). However, again, are we talking about the 95%
> quantile here? Furthermore, how much p2p exactly are you talking about?
> Any node truly to any node? Are we back to pure ad hoc then? I guess if
> IETF couldn't provide us with a magic ultra low power solution for ad
> hoc networks in past years, then chances are slim that this will work
> out now. Unless somebody provides me with a convincing study that
> adopting a general p2p ROLL protocol will not jeopardize the efficiency
> of the 95% quantile applications, I propose to adopt some simple and
> possibly sub-optimum heuristics and then forget about it.
> 
> Security is an important issue.
> 
> Now that we are at it, I sampled quite a large number of companies at an
> M2M event in Paris a few months ago organized by Orange where we met
> with JP and others. The large majority of companies present there
> explicitly told me that - for a very varying set of reasons - they would
> never let IP run over their ROLL-type networks. The sheer majority did
> suprise me. We still have a lot of work ahead.
> 
> I am in favour of adopting draft-dt-roll-rpl-01 as a WG document.
> 
> Mischa.
> 
> 
> 
> 
> 
> 
> JP Vasseur wrote:
>  > Dear WG,
>  >
>  > First of all, thanks for all the time and energy you all have devoted
>  > during the past few weeks on the protocol work. There was excellent
>  > followup discussion at the physical WG meeting.
>  >
>  > To the question "Do you think that RPL provides an adequate foundation
>  > for the ROLL routing protocol work", there was clearly a good consensus
>  > in the WG meeting. It was also recognized there are still several open
>  > issues for which we WILL need help from many WG contributors, including
>  > the authors of other documents.
>  >
>  > Could you please confirm (or not) the adoption of draft-dt-roll-rpl-01
>  > as a WG document ?
>  >
>  > Then we will of course move to the next step.
>  >
>  > Thanks,
>  >
>  > JP and David
>  >
>  >
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