Subject: [Roll] review of draft-ietf-roll-applicability-ami

From: Jari Arkko <[email-masked]>
Date: Fri, 29 Jul 2011 09:46:58 -0400

I have reviewed this document, and had some comments:

First off, I was one of the IESG members who have been asking for the 
ROLL working group to produce applicability statement(s) about RPL. 
Thank you for working on this! However, I think we are still not quite 
there. What at least I was asking for was more about experience, 
measurements, and analysis about how well RPL works in various types of 
networks. The current document is more descriptive (talks about the RPL 
design goals, for instance) and contains some profiling. While those 
parts are very useful as well, I feel that the core part of the 
contribution that this applicability statement should be making is 
missing. Perhaps the working should make an open call for the 
experience/measurements/analysis that is needed. Some may already exist, 
I'm sure.

Some additional more detailed comments:

The gas and water metering part discusses cases where the meters can or 
can not rely on the networks that electricity measurement devices have 
created. I think this description is not quite right. My experience is 
that gas and water meters tend to exist in places with power easily 
available. In Finland, for instance, water/heat pipe meters have been a 
standard for new homes dating back at least 2004, and they all run from 
mains power. So I think power will be available, and the ability to use 
another measuring network is kind of a secondary issue (and reuse of 
other networks may be more about administrative borders than about 
technology anyway).

Both the electricity and gas/water sections appear to take it almost for 
granted that multi-hop routing is necessary in these applications. 
That's certainly one way of building the networks, and the reason for 
the existence of this working group. But I would have expected that an 
applicability statement talked about the situations where this works 
best versus situations where some other solutions might work better. I 
see a lot of one-hop commercial deployment in this space, for instance, 
the metering systems in Finland are cellular-based. Is there something 
that you could say about when the different approaches are best 
applicable? Or is that purely a business issue, i.e., both work well and 
the only question is equipment/provider cost?

> As a result, all smart metering traffic
> typically goes through the LBRs, with the vast majority of traffic
> flowing from smart meter devices to the head-end servers, i.e., in a
> Multipoint-to-Point (MP2P) fashion.
>   

I'm not so sure about this. Pure metering implementations may have 
initiation on either side of the connection, and a request is likely to 
be a small packet but so are responses. As you note yourself later, 
there are firmware updates and other extraneous traffic cases that may 
balance the small response - slightly bigger response equation. In any 
case, its pretty useless of for me or you to guess -- but I'm guessing 
some actual operators have real data about the traffic mix and 
directionality. Can that be cited?

Jari

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From: JP Vasseur <[email-masked]>
Date: Fri, 29 Jul 2011 10:22:05 -0400

Thanks Jari,

See in line.

On Jul 29, 2011, at 9:46 AM, Jari Arkko wrote:

> First off, I was one of the IESG members who have been asking for the ROLL working group to produce applicability statement(s) about RPL. Thank you for working on this!

Thanks for your support, and yes we're not there yet, still lots of work to be done.
Good to see discussion, suggestions and comments.

> However, I think we are still not quite there. What at least I was asking for was more about experience, measurements, and analysis about how well RPL works in various types of networks. The current document is more descriptive (talks about the RPL design goals, for instance) and contains some profiling. While those parts are very useful as well, I feel that the core part of the contribution that this applicability statement should be making is missing. Perhaps the working should make an open call for the experience/measurements/analysis that is needed. Some may already exist, I'm sure.
> 

From what I heard there is some data coming from deployed networks, not yet at a large scale, but you are right that those are useful.

> The gas and water metering part discusses cases where the meters can or can not rely on the networks that electricity measurement devices have created. I think this description is not quite right. My experience is that gas and water meters tend to exist in places with power easily available. In Finland, for instance, water/heat pipe meters have been a standard for new homes dating back at least 2004, and they all run from mains power. So I think power will be available, and the ability to use another measuring network is kind of a secondary issue (and reuse of other networks may be more about administrative borders than about technology anyway).
> 

Interesting, thanks. I'll leave it the authors who worked on this section.

> Both the electricity and gas/water sections appear to take it almost for granted that multi-hop routing is necessary in these applications. That's certainly one way of building the networks, and the reason for the existence of this working group. But I would have expected that an applicability statement talked about the situations where this works best versus situations where some other solutions might work better. I see a lot of one-hop commercial deployment in this space, for instance, the metering systems in Finland are cellular-based. Is there something that you could say about when the different approaches are best applicable? Or is that purely a business issue, i.e., both work well and the only question is equipment/provider cost?

This is an excellent point and should be addressed in the next revision. 
Authors, could you look at this ?

> I'm not so sure about this. Pure metering implementations may have initiation on either side of the connection, and a request is likely to be a small packet but so are responses. As you note yourself later, there are firmware updates and other extraneous traffic cases that may balance the small response - slightly bigger response equation. In any case, its pretty useless of for me or you to guess -- but I'm guessing some actual operators have real data about the traffic mix and directionality. Can that be cited?

Yes it must be.

Thanks for the constructive comments.

JP.

> 
> Jari
> 
> _______________________________________________
> Roll mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/roll

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From: "Popa, Daniel" <[email-masked]>
Date: Fri, 29 Jul 2011 07:55:26 -0700

Hi Jari, 

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On Behalf Of
> Jari Arkko
> Sent: Friday, July 29, 2011 9:47 AM
> To: [email-masked]
> Subject: [Roll] review of draft-ietf-roll-applicability-ami
> 
> 

DP> Definitely, there is no single communication link-layer technology that will be able to satisfy the Smart Grid/Metering requirements. There are use cases where one technology shows its limits and so you have to use another one, generally more expensive, that can help you achieve the requirements.  

> directionality. Can that be cited?

DP> Based on our experience, the traffic generated by the Metering Application is highly asymmetric (much more up than down). However, new applications (other than metering) can eventually change this ratio, but please keep in mind that AMI networks are mainly deployed for Metering Applications! So we expect traffic to remain asymmetric. 
DP> Lot of noise is in the air about potential new applications - other than metering apps - that can use the AMI networks, but nothing really concrete or useful about those applications. 
DP> Do you think that ISPs will provide their traffic matrix? :)