W3C

WoT Architecture

17 Sep 2020

Agenda

Attendees

Present
Kaz_Ashimura, Michael_Lagally, Michael_McCool, Sebastian_Kaebisch, Ryuichi_Matsukura, Tomoaki_Mizushima, Zoltan_Kis
Regrets
Chair
Lagally
Scribe
McCool

Contents


<scribe> scribenick: McCool

Minutes review sept 10

<kaz> Sep-10

presentation by Matsukura-san on ITU-T home use case

need for discovery section; McCool mention tool now used for sequence diagrams in Discovery doc

and need to improve language in that section

discussed CHIP, agriculture-greenhouse use case

discussion of components

Lagally: shall we approve?

all: no objections

Lagally: minutes are approved

Export/legal restrictions

Sebastian: new regulations that has impact on standards work

forbidden to get involved in projects with non-public technology discussion that has use in US

McCool: for example, we have non-public (Member-only) mailing lists

so can't have technical discussions on those non-public mailing lists, but github is ok

proposal: not use non-public mailing lists for technical discussions or meeting minutes, draft minutes included

RESOLUTION: do not use non-public mailing lists for technical discussions or meeting minutes, draft minutes included

Legal compliance

in general, for people complying with the law... it's obvious and implied, do we have to say anything?

eg compliance with auditing, privacy, safety, etc. requirements

my preference is to declare it out of scope

we could declare it out of scope, or add a disclaimer under conformance

something like "We do not specifically address any legal requirements that may apply to your application or location."

I think we should check with W3M if this is a reasonable thing to do.

Link relation types

McCool/Lagally: let's brainstorm, link them to use cases later

Lagally: describe a topology; relationships between entities

McCool: suggest we list relations we want first, later on look for names or a spec we can adopt
... and even if we adopt an existing set of definitions, we should identify particular ones that should be used for specific purposes in WoT

Lagally: right, we have to be a bit more selective
... and there are some overlaps

McCool: and in a profile we also need to limit link relation types to a finite, static subset

<mlagally__> https://www.iana.org/assignments/link-relations/link-relations.xhtml

Sebastian: there is also a possibility of when to use a link relation type and when to use a semantic relation

Lagally: when you think about how you model things in UML: inheritance, implementation, aggregation

McCool: let's also list the entities we care about
... thing model, thing description, directory
... what we want to know is where a TD was sourced from, so that (for example) a consumer can subscribe to update it
... also need to deal with bidirectional links
... "implements" may also have inclusive and exclusive variants
... eg can a TD implement more than one TM (for sub-APIs)
... need to clarify when to use links and when to use semantic relations; suggest to use "dereferenceable"

Lagally: aggregation

McCool: is aggregation "member of a set"

Lagally: same or different types?

McCool: "like" is a fuzzy concept

Sebastian: do we need explicit entity types or will contentTypes cover that?

McCool: I was thinking of entity types more as a way to structure the requirements discussion

Lagally: note that inheritance etc. raises various naming issues

McCool: another general category of link types is "metadata"
... manufacturer, author, documentation, etc.

Lagally: let's review iana spec...

<mlagally__> https://www.iana.org/go/rfc8288 Link relations: https://www.iana.org/assignments/link-relations/link-relations.xhtml

Lagally: (group looks at iana spec, update docs)

<mlagally__> https://github.com/w3c/wot-architecture/edit/master/REQUIREMENTS/link-relation-types.md

Contributions and new requirements

Zoltan: made a PR

<mlagally__> https://github.com/w3c/wot-architecture/pull/539

Zoltan: reviews diff
... added introduction, background of work, state names
... didn't want to make this section too long
... this section however is mostly interested in state names, data that is involved
... separate section for data (information lifecycle)
... also system, thing lifecycles
... need to explain why we have three, what the use cases are
... eg. using devices that are already provisioned, provisioning new devices directly to work with WoT, etc.
... "provisioning service" may or may not be a concrete service, is handled in different ways
... similar to T2TRG model, but we need to add some more detail, "opening up" some of the T2TRG states
... eg. we add more detail to "bootstrapping"
... there are also examples mapping terminology to other specs that call these states by different names
... e.g. bootstrapping/onboarding/initial provisioning
... is this normative or informative?
... can make the names normative, but hard to make transitions normative
... different in different systems

Lagally: can't really mandate that certain transitions are supported by different devices

Zoltan: feedback that came up what that other people have worked already on this
... so why should we be different?

Lagally: some states are not defined in other systems, eg. maintenance

Zoltan: some always appear, some are optional

Lagally: can we use end-of-life?

Zoltan/McCool: have to ensure that definitions are equivalent though

McCool: I also want to note that you can always destroy something, the question is whether you can do it through the protocol

Lagally: example of cash card that used flash so you could only burn cells to decrease the value; once discharged, cannot be recharged; eol
... suggest that we keep it as a PR and everyone does a review

Zoltan: would like to create pictures, need to use the same terms

McCool: (I really wish we could use SVG rather than software-specific files like ppt or drawio but whatever)

Lagally: let's use SVG as the master; drawio can read and write SVG, so...
... need to not have both svg and drawio in github, confusing which is the master, so will remove .drawio file

Zoltan: is there a style guide?

(Sebastian leaves)

McCool: for the record I do like the simpler style that Michael brought; lots of detail in each state gets pretty confusing, and it's harder to edit; we can put that detail in the text

Zoltan: suggest we take the current diagram and take out the detail and create a simpler version
... what about actors, etc?

Lagally: I would put that in text too

Zoltan: ok, then we agree, let me go and draft something

Lagally: everyone, then please review

Profiles

<kaz> wot-profile issues

Lagally: several issues for standardized capabilities, units etc

<inserted> Issue 30

McCool: all subsets of "limit to specific extension vocabularies"

Lagally: want to discuss more specific issue of organizing PRs to address each issue

McCool: suggest we add a single paragraph that just says "you are allowed to use these semantic extensions and ONLY these"

Lagally: probably should go in to section 5.1.1, at the top, discuss vocabulary

<kaz> WoT Profile draft - 5.1.1 General

McCool: I think we should also specify the prefix, it will make parsing easier
... may also need protocol vocabulary; but we still need to discuss how to handle/mandate protocols
... but WHEN we allow use of a specific protocol, also need to allow those protocol's vocab

<kaz> Newly created issue 34

Lagally: for units...

McCool: issue #29

<kaz> Issue 29

McCool: units mandatory vs. use of unit system is mandatory
... most of the discussion was around the latter
... pretty hard to make units mandatory, some things are unitless
... probably just a strong requirement

Lagally: could make them mandatory, but provide an "unspecified"

McCool: and since "cm" is easier to type than "unspecified" it's easier to do it right...

<kaz> [adjourned]

Summary of Action Items

Summary of Resolutions

  1. do not use non-public mailing lists for technical discussions or meeting minutes, draft minutes included
[End of minutes]

Minutes manually created (not a transcript), formatted by David Booth's scribe.perl version (CVS log)
$Date: 2020/09/29 15:47:45 $