Internet Engineering Task Force IRTF, 29 Nov 2021

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From YouTube: T2TRG Interim Meeting, 2021-11-29

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T2TRG Interim Meeting, 2021-11-29

A

Good and then any questions or comments on the proposed agenda.

A

Okay, then perhaps perhaps we we get get going um so sebastian, I don't know if you had anything prepared for the previous meeting, you would like to um get going directly or is it easier to start with an overview of what is the latest in the td and tm happening of things?

A

How do you think it's the best way to run this.

B

Well, um I have some slides, which gives a quick overview about why thing model and what kind of features we have so far.

B

I can quickly go over the slides and after that we can make discussion on relation to sdf. So we have some experience on plugfest about this. So typical we have a lot of sdf samples which are transformed to thing models or two to a single description, um so um yeah. It's. uh I put my proposal to start with with this approach, yeah. So to give you a quick update uh about what's going on at w3c, and then we can move on to comparison and questions and so on.

A

Sounds very good.

C

A

Stop sharing and you can take the screen.

B

Yeah um does it looks good.

D

Sorry, you can see the title slide.

E

B

What do you see now? I should have seen your movie okay, then. Maybe let's go this way, I'm not going to presentation mode, okay, well um right! So um yeah. Thank you for uh having me here and giving the chance to give you the latest about the thing model.

B

um So this are some slides which I use for my lecture. So ah so they are, I would say, a very detailed full with a lot of examples, but maybe it's quite um quite nice to have all the good feeling for what you can use some approaches here, and so that's the reason why I have so many examples here in this slide. So um right just to give you a quick motivation. Why was this now introduced?

B

Also in web of things, the scene model approach and, as you know, um we have two different life cycle aspects of iot equipment and um and starting from from designing iot devices until it's installed by the customer and deployed by the customer, you have different phase, which different kind of yeah, I would say, meter information are available and, as you know, the thing description is a description of a device that is really active.

B

It's online or accessible uh you prov, you're, getting all the detailed information, that's inscription how to yeah to uh get to specific uh information from the device, and it also means you have all the metadata like um ip address and also the security meter data so that you know what kind of security mode you must apply to have a very successful connection to uit equipment and yeah, and the situation is sometimes that you have things designed, which maybe you have a different setup regarding.

B

I don't know um protocols or security modes and so on and and of course, you have sometimes also not all the information required to some specific point like how is the ip address which is in the future, used yeah. So, as you know, ip trust typical provided in the thing description.

B

However, um when you buy this equipment here like in here, then your typical ip address is not uh known yet because it's then just known when it's uh installed by the customer and you're assigned an ip address right and the question is, if there's a way how we can design already, I would say only the capabilities of the thing.

B

Without going into the details of communication, data metadata and and serial key security meter data- and that was, for example, one of the motivation here to have something which giving us the opportunity for doing so and another aspect which we like to have- and this is what, for example, also sdf having on board is the opportunity to adapt already existing definition or basic definition from other models yeah. So, let's, let's assume we have some different kind of lamps here, um one of them. You can change the colors and you can dim and all the stuff.

B

And then you have basic lamps, which is providing basic information like um the status or you have the functionality to switch on and off, and- and this is typical, but the basic functionality which you always have also also in the smart lamps here, which you have more functionality yeah and the question is how you can simply adapt existing definition from some basic thing: models uh or thin definitions and adapted to do not again this redefinition right.

B

So there was the request: how we can simply reuse existing knowledge and capabilities in new thing models, yeah and yeah, and the answer is that we have to find the thing model approach um so maybe to to give you just a background um about the history. So in the 1.0 version of the thing description we had had already this approach uh compiled in there. However, it was called differently. We called this thing description template that time.

B

However, since uh td 1.1, we have it called zing model, because the term makes more sense than this template approach and yeah.

B

We have also more or less a formal definition uh here, so I think the script I think model is a description for a class of things that have the same capabilities, describes the properties actually events and common metadata that are shared for entire group of things compared to I think description model does not contain enough information to identify or interact with your thing instance as well, especially last sentence make very clear that the thing model is, I would say, a uncompleted thing description since typically, you will not find very specific communication metadata in there to make interaction with the thing um right.

B

um This is a very small example of a thing description um on our lamp, uh so you find your simple interaction: affordance, that the lamp is providing here. So you find a property status and action toggle and event overheating, and, as you can see here, there's no additional information provided about communication, metadata yeah, so typical we would only. I would also have forms in here to get information what I have to do to set up the the network interface and to make the right uh request here for the status, as example.

B

So this is, for example, missing here and also not required in sync models.

B

The same is also true for security meter data and so on so um yeah- and this is a valid thing- this testing model here um just a comparison to a thin description. I like this kind of illustration here, so the model a typical uh kind of stamp. We are missing information.

B

Typical in there and when we want to create a valid thing description out of the thing with the model, then all the missing information have to provided there to uh to the thing model to have done by the thing description, yeah, and this also shows a thing. What is also kind of, I would say, class definition of things yeah, where you can instantiate multiple thing: descriptions based on the number of devices you created for this specific class system.

B

um Right how we do into five thing models. uh We have introduced a new ad type in the thing description, which is simple, saying um tm, so tm is the prefix, so that also means we have our own name space for the theme mode of it, which has covered all the uh vocabularies only addressing the theme models.

B

So we are using this value here to identify what is the thing model and yeah, and then we have a couple of design tools um to yeah design um thing models um with other thing models: here's books on the use case if you like to extend uh existing thing model. So, let's assume we have here a basic thing model definition like this on off and then we would use the links container to say: okay, we are pointing to existing thing model here and um and say simple extended.

B

That means that the instances of the thing model so when it comes to the thing description, build and also in have india the property on off. um In addition to this dim property here, and then we have also this reference. This is actually the same approach. What you have in sdf as well, so you make a simple reference to to a place of a existing definition somewhere.

B

So you simply say where's the location of this document and then you're using json pointer to say please copy or clone everything what is defined somewhere else or like in here. So you say you want to reuse the definition of the dim definition here in this new property, which is called dimming and uh and what is also possible that you are able to override existing definition.

B

So that means that you simply override the maximum here and you add, extend all the additional values like the unit term here, so you you're, providing additional information here, and we have also a kind of restriction of this overriding approach, and this is explained in this slide that you should be also careful about this overwriting topic, because here's the request that all the instances of the new definition should be valid also to the old definition yeah. So let me take this dimming property, which is uh copied from from this.

B

This example here and you see the maximum is overwritten by 120 yeah. So now is the danger that instances can be higher than 120 so like 110, and this will be then valid regarding this definition. However, it will be not valid regarding to the to the source definition or to the to the origin definition anymore, and that's the reason why it's not allowing to this in that array.

B

uh We have also the restriction of the typing yeah, so we feel for override types.

B

Then yes, for example, also to risk that you have some, for example, some floating values here and- um and if this is the case like 20.5, then this will be not valid regarding this integer, which expects some discrete values in here right um well and this example will be correct. So this extends this existing definition. However, overwrites this dim approach or the stim definition.

B

However, it is in the range of this source definition, so that means all the um instances that are created here out of this um new definition. Here they are definitely valid to the to the source definition.

B

um Then we have also this composition. This is also a very uh useful approach to yeah to say, um I'm like to create a new system based on.

B

Existing definitions, so a good example of here is, for example, to say: okay, I like to design a new smart ventilation system and the smart ventilation is based on the definition of ventilation and has also some fancy leds on on that, and then you have already led thing model defined somewhere and you have also a ventilation thing model defined somewhere, and then you can express this.

B

This composition, simple by this links container, you say: okay, this new system, swatch ventilation, consists of um ventilation, thing model and on this led sting model, and what you should also provide here is a instance name. So this is a way to give a kind of identifier of this thing model. So this is, for example, useful for doing so.

B

If you, for example, have a system which uses a multiple different kind of sub models, uh multiple same ventilation or same led lamps, and then you can provide a own instance name for each model of the led to make a differentiation of them in the application later on.

B

Personally, I'm not very happy about the instance name term. Maybe uh it's still, maybe it's getting renamed in the future, but at the moment this is the working assumption well and then we have also provided a uh algorithm. How you can generate things description out of this thing: model approaches um yeah. I don't want to jump over each step here, what you have to do there, but there are some replacing process needed, and then you have to replace the placeholder identifier. I will show you what this is about actually and so on.

B

There's some very simple processing steps: how to generate out of thing models, thing description, um yeah! This is the example which also shows we have also this tm required what you also have in sdf- and this simple says: okay, if you have some required properties, definitely that defined then this should be definitely showing also show up in the single description instance.

B

Then right and as you can see here, this is not a valid thing description regarding this thing model, since it's expecting two interactions here, namely the property status and the action toggle, and here only the status is present, and here we have a valid one and the next one is also valid, because um this is optional. This event- and this also means it can be simple- also reflected by this in description.

B

uh So it would be also valid to have it here well and then we have the placeholder concept. The placeholder concept is um simple uh approach to give in the thing model, some yeah, I would say some places, which should be then replaced when it comes to generate thing description instances.

B

So, for example, here you want to give a specific pattern of the title, then you say you can say your thermostat number data, so the tester then replaced also. What you can, of course, do is to provide first information of the protocol metadata, so you can provide a scheme value here. However, you have done here to replace this.

B

This part, with the ip address of the program that you're going to use and so on, then you have also other places where you can provide this placeholder and if you want to uh generate thing description out of the theme model with the placeholder, then you should have this kind of placeholder map um can be any kind of a map approach here. So the specification does not force to use this in a json format. You can do it also and that's different format, but this is just example how this can look like.

B

um So there's a simple lookup uh of this identifier and it's a simple, replacing then the parts with the value that is provided in the map. So what I p addressed: the maximum value, the observable uh situation and so on- and this is, I think, a very cool approach when it comes to mass deployment that you provide a specific um batch of placeholder maps for specific.

B

Assets so that you can have the individual thing description which are providing specific information.

B

Well- and this is the last slide, um so we have also a tool which calls editor, which helps you also designing thing models, and it also shows nicely the dependencies of the thing models.

B

So if you have to find some dependencies um like to your extension models or you have a composition and so on, then you can simply also this here is a nice graph here, uh but in general it is a tool which um gives you opportunity to edit your file in the text form or, if you like it more, I would say track and drop or more on this assistance diet, and you can also call this a graphical approach here and design your thing description or seeing models, if you like it.

B

um Well, that's the last slide um yeah. Now I'm open for questions and discussions.

A

We're very good thanks a lot sebastian. This was this was great um first obvious question: can we get a copy of the slides.

B

Yeah sure sure yeah awesome.

A

Thank you and I I it's I'm glad to see you know, there's kind of good cross-pollination of features between sdf and and otm. I think that's going to be helping us to move between those two formats, so it's nice to be actually designing this boat. At the same time,.

D

It's a good question.

D

Oh sorry, I I thought you were done.

A

Yeah yeah yeah: I'm good go ahead.

D

Can a thing model have a form um you showed your example without forms, but what, if I wanted a form that had like for, I think about bacnet, for example, where you have things like the you know: object id and things like that that are fixed on the device, but you just don't have the ip address so with bacnet. I'd want a form that would have separate properties for things like object id and all that when I generated a td I'd want to generate the url for for the bacnet from that.

D

So can I do that with thing model? Yes,.

B

Yes sure so there is, I mean not this limitation on on what is not allowed, I would say yeah, so you can of course also have forms in there, and so you can simply have this and then uh place it here and to remove this, and then you can say. Okay, I have an entry.

D

B

D

Put the you have to indicate it with a placeholder, so it gets put in the map, and so it can be worked on.

B

It and then and then you can provide a placeholder here, yeah.

D

Yeah, so I I guess: I'd want to point out that in sdf we just use json pointer, so we don't really, but that's what you would when you do, the transform you would. You would put placeholders in that that map would reference the json pointers that are in what we call the mapping file or mapping information. But it seems like that's what the equivalent in sdf would be just the use of json pointers.

B

Yeah I mean you can do this the same here right. You can also use the tm ref right and you can also copy the stuff in there right on this level yeah, but this would also work and what was also work is that you have something like that. um Did you say you have a placeholder on this on this level? You had to say, okay, here, um that you need some forms info yeah, which provided by the mapping file. Somehow right would be also possible, so you can.

B

Provide as much many information you would like to have, or does it make sense to to to to be generic enough and the only thing which will say uh what not makes sense to provide in the same model this which this goes more in this instance specific information yeah so like the ip address or or ids of something or like something like that. So if this is a more or less not not required, and everything is possible right.

D

So um also that was my final comment was your use of the word instance.

D

Even you have an instance, but it doesn't have an ip address yet that that's sort of my take away from that. So you can have instances that of thing models that don't have ip addresses and you're still calling them instances.

D

B

Well, the thing description is the instance or what you might mean so so.

D

You had a thing in your one of the slides. You had a thing model construct. Yeah you mean the composition hang on. I think.

E

B

E

D

B

Yeah, this is the composition uh thing here that you, uh you have six existing things, yeah like lamps and uh engine, I don't know, and you want to create out of them a new system right.

D

Yeah you're calling that an instance, but yet you could still generate a number of different tvs, differentiated tvs from those instances. They could have different addresses and they can have.

B

Exactly yeah, so um that's the question if the instance name is taking over. I don't know in the in the uh title of the thing description. I don't know.

D

The context is we're having a currently having a discussion in the sdf about, what's an instance and- and so this seems to be um another example of people using the word instance to describe something that isn't really um network accessible. Yet um yeah.

F

D

Want to get too deep into that discussion, but I wanted to kind of plant a flag there.

B

So you would like prefer to have a url identifier.

D

F

Oh, I see okay.

D

It has to do with how we use the word instance yeah.

F

D

So maybe so I don't say that we only use instance when we have a url, I'm just saying that it's very confusing to use the word instance. I don't want to try to define it here, but.

F

D

Is that is what you said is kind of the part of the question is: should we only use the word instance when it's something that has a url and can be accessed on a network, and I'm not sure about that? But that's that's our that's our discussion, yeah. I wasn't trying to make a conclusion, though,.

B

Yeah yeah yeah sure.

A

A very challenging topic- and I think it's going to be useful- to have also some kind of alignment across organizations here so yeah.

B

A

B

A discussion- I I don't know how you name this. You have just name right or your.

B

I don't know, what's do or do I have a.

D

Definition that uses another definition and then we can. We can have what I've been calling successive refinement or you can have several layers. I can define what what a bacnet object is and then I can define an analog input object and then I can define a a a temperature measurement. That's an analog input and all three of those can be defined by saying more about adding more constraints like units and things like that. My first one doesn't have any units. The second you know I only add units at the third stage.

D

I only add number constraints at the second stage, and none of those are instances yet really or you could say that each one is an instance of the previous definition. So we don't really see the bright line between class and instance, or some of us don't.

A

So sebastian, what do you think are the main features you will be developing going further here or do you think now you have the set you need for the for your use cases of the of the thing model.

B

So the composition is the very newest one there. This was a request from bosch to have this, so um so they would. They had a lot a lot of use cases, and I see also this a lot of potential of uh of use cases or scenarios, and so the composition is very the last one and at the moment um we don't have further feature requests.

B

So at the moment I would say it's kind of stable and so yeah, I would say um it's now put in the 1.1 version of the thing description. Maybe what is awesome.

B

Makes sense to say here we will maybe in a new charter, move the section what we have as a thing model move to our own specification document, because I think it makes sense to to consider the thing model more separately from the theme description and not being a part of the thing description itself, uh because it's getting more and more intention uh to work with the single model approach, since it's quite interesting um from the life cycle aspect uh to to to have something at the designing approach which can be used from the very beginning and and and the part uh how to generate things, description or singing models.

B

Then yeah. Another aspect to be considered. But at the moment I would say yeah it's to call uh to to test the thing model approach as it is to provide comments. So we have still time uh until march for going the candidate recommendation.

B

So we have still time to yeah to to modify or optimize approaches what you what I have shown here. But at the moment, uh from the point of view of features, I would say it's everything is covered now.

B

Or, do you miss something.

A

And no, no, no, I was wondering like like, if we, for example, uh would build more codes to get going between stf and tds. Now is the moment I sorry between sdf and tm. It's like now it's the moment to look at the spec and see like how how features map are we missing? Something should something maybe that's made easier.

A

I guess what you're saying that now it is stable, uh spec.

B

Yeah I mean we have this transformation code, I mean uh also in the testing folder. We have a plenty of examples of um sdf and thing model, um for example, again has a couple of provided, whereas it's.

B

Is not the latest one.

B

B

So this are, for example, thing models that I used, one of them last um test fest and here's, this converter tool, which we used or which I used that time. So a student of mine have developed it as a tool to transform sdf.

B

Definitions to think models right and- and then here I provided some examples here- how this can look like yeah, so I used here the slight red m and then light control um example and so on.

B

I don't know if, if it makes sense to have a look in each of them or.

A

B

A

I guess we don't have time to look at these, but thanks a lot for the for the update and um actually a colleague of mine made a bit of a demo. Where also integrates your. I think it's your tool uh with the other translator tools, so we can go with from sdf to all the other ecosystems and and back um so I think we are that that sounds sounds very good like now. Is the right time to look at also the details of like what? What are we potentially missing there.

D

A

D

A

D

With uh sdf, where I I made a an extension to sdf that that uses thing, description and thing model elements like data, schemas and forms, and so basically in the workflow, you can say what elements of data schema you want to bind to a thing using a mapping file and also what form you can bind to a an sdf definition. And then, when you generate the thing model or thing description, it uses that information, as as hints or as as guidance in the construction.

D

So I'd like to stay in sync with the in terms of the tool flow also.

D

We have proposed extensions for sdf as a the mechanism for how you do that, but also the content um in terms of being able to use vocabulary from uh thing description or like, for example, I use the modbus vocabulary to generate the thing description from that it has to come from somewhere and in one workflow envisioned workflow. It comes from the sdf file as an extension.

A

Okay, very good, I mean now looking at the time of this being super interesting. I think we only have a bit more than 15 minutes till the end of the session, so I think sebastian. We definitely need to catch up uh later later again on on more of this um so yeah, and I think in particular I want one part that we didn't have a no chance to discuss. Is this: uh how do we go from uh sdf into yeah?

A

I hate to use the word instance, but you know something like you would use a td to describe of, um and I guess, if you go for td, then maybe sdf into tm and then tm into uh td uh might be the right approach.

A

um Then the question is like: where do we get that extra piece of information and um like by the addresses and and such and now we've been discussing it, whether it's a mapping, file or something else- and I think like using what you guys have learned here on going between tm and td, probably makes a lot of sense.

A

um So maybe we should have a look at that together, someday.

B

Yeah sure yeah um I mean, um and as I mentioned, I am still everything is quite open uh in in terms of definition, and maybe it's not very practical to have it that way um and uh yeah. I would be happy to to close exchange with you uh and it would be very cool that we are definitely uh looked at sdf and thing model are working very smoothly together, yeah, so that that there should be not a conflict in in from the design uh point of view.

B

So, uh however, I am um the the student uh which I asked to make this tool and you make also it is comparison and- and it sees this- and there was actually not really a plotting point in anything uh that seems to not uh to walk to each other. So everything should be yeah everything. What you define sdf should be also reflectable in the thing model and vice versa. Yeah I mean unless uh something is new defined in sdf, so maybe I'm not ever aware of of all the new features.

B

What you have maybe designed in a couple of weeks or months, then maybe you need a new look on this, but my experience is- and I don't know michael. uh You also had also also always a look on this I've, not a feeling, there's some contradictionary contradiction or some problematic definitions somewhere, which may be resolved some problems when, when you like to convert from one format to another.

D

No there there, I don't. I don't think there are any any show stoppers that there were probably some things that um you know that we'd like to align like uh read-only for readable and this sort of thing, uh and also you know to to really nail the structure part, because what it's all about composition, I don't have any really any use for anything that does isn't composed. That's just the they're, the basic elements, but they have to get composed before you can really use them in the system.

D

So um I think those that's really where we need to focus on how we build systems and how the workflow um works. When we build systems but yeah, I agree with you. There's no there's no main show stopper it's it's just. um There are just different ways of doing a few different ways to do things and we need to sort of figure out. What's you know whether it matters and where it matters pick a good way.

B

And maybe one thing which, um when you mention how to generate thing description, I mean one thing I have not explained to you is how to generate things description out of a composition uh definition and in the td spec. There are two approaches provided for doing so. One approach is that you keep the structure as it is so so you have for each thing model uh um then, especially the thing description representation of that.

B

So here we have the smart ventilation again, and then we have the model for the ventilation tm and the led tm and when it comes to generating descriptions. So if you do it only for one for one device, then you have one thing: description for yeah for the top level uh thing model yeah, then you have to see description of this sub uh system, the ventilation, and then you have the td for the led subsystem and often they are linked to each other right.

B

So you can have a look in the links container and then you can see where I'm coming from or where I'm related to yeah. Everything is defined in the links container.

B

um There's also, another approach is to describe what I call self-contained description, where you have all the information provided in a single thing description, and there can be, however, the risk of name, collision or name clashes and to avoiding this by using simple. Then the instance name what we have provided in the links container of the composition as a kind of prefix um of um of the of the properties which coming from the subsystem right.

B

So these are the property from the ventilation and and then we have this actions uh from the led and we're using simple the instance name as a kind of prefix and underscore yeah. So this was one approach or one idea how you can also define a single thing, description on a composed definition yeah. So this is the instance name, and this is then used as a prefix when it's when you like to have the thing description in the in the single file right.

D

Well, my takeaway is still that we, we have a lot of different ways of doing things, and it looks like what that you're looking at a few different ways too. I don't know if we're looking to kind of settle on a best practice or to allow a bunch of different ways, depending on the use case any anyway, that's kind of where the discussion going.

B

D

B

Yeah, okay, I will stop sharing.

A

Okay, very good thanks a lot sebastian. That was a good update and good, and I think we have a good way forward here to explore the synergies and opportunities there together good. So then it's no more final questions comments there. Let me do spend uh the remaining five to ten minutes on the on the last um topic, the connecting ipso devices to ddr applications, hacking so yeah.

A

So here the idea was to uh take the challenge that we discussed with the with the dddl team and actually did some practical hacking uh on providing the device is described with sdf, for example, an ipso device into the ddl platform via the transformation that we can do enabled by by sdf, and um here we would need to do a a bit of planning, perhaps to kick off our hacking, hacking activity and like let's, we could either have a specific hackathon day on it or we could do some work, work, offline and gather later on, but maybe the first things would be to document a little.

A

uh What do we want want to achieve here?

A

um So with cars kirsten? You were actually the one who proposed this grand challenge originally. Do you want to say a few words of introduction? um What what do you have in mind here.

C

Yeah, basically, the idea was that we take an existing sdf model and if so, is probably a good one, because we have lots of experience with the the underlying uh mechanisms and uh build an actual dtga, based instance of that in in the asia system.

C

So we're not just doing some theoretically valid translation, but we actually go ahead and build something that can be put into the microsoft implementation. And then we make sure that the the operations you might be able to do.

C

Original ipso instances are possible in some form on the azure ddl instances and well, of course, the the top achievement would be to do this completely automatically.

C

So you, you actually can look like an episode instance through a converter that talks to the dtd uh instance, and that's, of course, just just one concrete form of uh doing what we we want to do in this semantic converter approach.

C

But given that we have some some specific proposal for help from microsoft for setting up an actual instance, I think that would be an interesting approach to pursue.

A

Hey thanks carsten um any questions comments here before we go on the practical way forward.

D

Questions are about the way forward, use real.

F

D

That kind of thing so yeah, let's go ahead and keep going.

A

Yeah, well, actually, that's that's. That's a very good point. Probably I would um start the easy way around use, something like the you know. The eclipse slash on uh demo live with them, client that you know works out of the box and- and you can have um you- can have a few simulated sensors uh exposed um and then and then perhaps um put that on on the lesson uh live with the management server and through the management server apis.

A

uh You would expose these um using sdf semantics and and then you bring the sdf models to there. um So you convert the aesthetic models to ddl and then from dtdl provide a a binding towards deletion apis, and you would then need to build on, of course, on the population, something that understands the stf semantics, but that should be pretty much the same content as we have in the mapping files uh for the uh ipsum rules.

A

So but probably the next step would be building these boxes. How I just explained and and make make it up, speak more clear, but that's something what I had initially in mind.

D

So it sounds like the architecture that we that we're envisioning is very similar to the architecture that we've been talking about. When we were talking about the ocf to lightweight mtm stuff, that the semantic bridge translator converter, it seems like a similar architecture, you, you would have to create a model bridge and then have a binding.

A

A

And that's that's a good point, because we what we did discuss back in the days if we should use the what is the web of things, dd uh implementation, the yeah.

D

Maybe it could even be thing web um bing web.

F

D

No dot could even be a component, maybe depending on how it goes, and what kind of things you're interfacing to.

A

Yeah because I think yeah team web has a lot of these bindings already implemented, and if we can generate tds out of um out of this model all of these models, then we should be able to generate enough information for the team web implementation to actually.

D

So we say here here, um you know: lightweight m2m is sort of easier because you have this other sort of direct path of doing it or maybe not, but but also that, if you had a, I had to adapt to a lot of different protocols. This is easily usable. This node wad engine is easily usable to a bacnet and modbus and mqtt, and whatever.

A

Indeed- and I think was when we maybe maybe the next first steps would be set up a bit of an infrastructure um from from our side that we can point to with the with the ddl uh models, and then um they have a have a chat with that with the brian and and his team on like where, where, where do we? What is the easiest ways from from the ddl or or mark might or as your digital twins infrastructure to communicate?

A

um And whether would it make sense to have the node water in between you know not what could provide the http apis um or whether it's go to directly from there to the lesson management server apis and in particular it would be at the same time interesting to think about the how we can go between all three. You know ipso ddl and ocf, because that's maybe could be guiding our architecture. Our decisions here to think about three ecosystems at once.

D

But yeah this is just the.

F

Slides that describe.

D

The architecture and things like that you have a like any, maybe a next step- might be to create some. I mean trivial step but create some. You know like write down what we're just talking about.

A

Indeed, indeed, and actually maybe uh sebastian do you happen to know on the note, what has there been any development uh on the light with mdm site? I don't know it has a co-op uh implementation or from the beginning, but has anyone experiment like with them to them.

B

um I think there should be no problem to use it directly. I think there is only this situation that that you always get the full payload on the application side. So if you um requesting a property, then the lightweight mdm has our own uh predefined payload structure, right and- and this is a full path to the application um so which I think it's not very nice, but it would work yeah. So then you have to work on the um that's where.

D

I have worked on um what I was calling a semantic api, but what it actually is is a way of of extracting things from the payload based on um an annotated, json schema that has json path, pointers into it, and so that was like halfway to being able to to do the semantic. So what you're saying is node lot currently does the protocol translation, but we would have to build the semantic translation layer on top of that at least the payload translation.

B

Exactly so, this is not not not yeah, because it's very specific right and noteworth should be more independent of specific ecosystems or specific uh iot.

D

Systems but then again as part of tdd 2.0 investigative work to look at whether there should be a separation from the abstract data. um Yeah.

B

D

On the concrete data schema yeah.

B

Yeah yeah: this is uh what we uh quite often have this discussion. I think we have to work on this in the td 2.0, so to have a nice solution for this discussion.

B

um Unfortunately, when we yeah, unfortunately, I have to go to the next meeting um yeah, it was fun. I will send you the the slide and yeah. Then, let's see us in one of the next meetings right.

A

Very good thanks a lot sebastian. Definitely, let's continue the discussions later thanks a lot for joining today.

B

You thank you bye.

A

B

Thank you, bye, bye,.

A

Okay, yeah. Indeed we are over time, so I guess we had. This is a good time to conclude also or for the rest of us, but um and let's see, I guess- we're gonna have a another uh session on the on this topic.

A

um Let's see if we managed to have one before the christmas vacations, um but then we have a good time to hack over our christmas vacations and then get full packed full speed in january, okay, but let's take the uh over over the email and- and I and telegram the planning further for the next session.

A

Good, any more questions comments before we close for today.

D

It's a reminder about um one dm meeting later today and our design team meeting on wednesday.

C

Yeah, I will be late as always. um I hope I can get rid of this regular yang zebra thing soon, but right now it's conflicting.

D

Yeah yeah and we're going ahead with maintaining the schedule anyway, even though we we don't, you know we're not like fully in in in deep with the review board, yet.

C

Okay, talk to you later ready.

A

Talk to you in one hour.

C

A

Thank you, bye.