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  • 2019-07-18 OIMT Meeting notes

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  • Malcolm Betts
  • Kam Lam


  • Admin
    • September F2F meeting
      • Making the Core model open… progress
    • ITU-T Liaison
    • Feedback on Action item wiki page and work item wiki page
  • Vendor extensions (Chris Hartley)
  • Decorator pattern (Nigel Davis)
  • Co-routing constraint in the Core model… broader context (Andrea Mazzini, Nigel Davis, Karthik Sethuraman, Malcolm Betts)
  • Considering the next release of TR-512
    • Feature content backlog
    • Tool migration stalling
    • Model structure

Discussion items


Vendor extensionsChris

Vendor extension packet based examples

  • Not submitting at this point but will discuss
  • Decoration on decoration
  • Nigel noted that this was not the decorator pattern
  • Vendor extensions - no subclassing
  • Nigel mentioned the new augment stereotype
  • Chris went through a number of examples
  • Removes need for guesswork and "can you do" style negotiation as the capability is expressed up front
  • Augment is an embedding
  • Certification process
  • Nigel noted that we also need to substitute or redefine properties from the standard
  • Nigel noted that some TR-512.7 covers some of this in a looser form
  • Nigel emphasized that there are reasons why a product may support a subset


MEF and ONF differ in the use of decorator (GoF) v Chris' Decoration approach

  • Karthik has prepared some material for work in MEF (which was not discussed in detail as it is a MEF contribution)
  • Chris noted that he had prepared material previously but could not find it on the wiki page
  •  AI: Nigel Davis: Review Chris' document against other material on decorator and provide any additional input to Karthik

CoRouting ConstraintNigel/Andrea
  • {{Form last week }}Nigel/Andrea summarized the essential concern
    • An intent can be defined in terms of constraints where those constraints may identify specific entities. If the constraint is intended to be throughout the life of the entity then this puts a lifecycle dependency between the constrained thing and the constraining thing. There appear to be various possible dependencies but the constraint is not explicit as to which one is relevant.
    • It appears that this has not been covered in any known prior work
  • Nigel noted that the current intent statements do not allow for full lifecycle dependency constraints
  • Chris note that this relates to Malcolm's Lifecycle dependency
  •  AI: Nigel Davis: Discuss this challenge off-line with Malcolm
  • Nigel noted that
    • The issue occurs when there is a one way relationship to a thing that then gets deleted or changed
    • The issue only arises when there is persistent constraints
    • There should be some defined action for each Lifecycle change
  • Andrea noted that in some way relates to slicing
    • There are independent constraints
  • Andrea noted that
  • Nigel indicated that we simply need to state the legal behaviors
    • A null pointer may be completely valid under some circumstances and not other
  • Karthik indicated that Yang require-instance is true/false
  • Nigel pointed out that there are some constraints that do not have any obvious reason for their existence
  • Karthik noted that Bernd had covered a lot of this in the work on association dependencies related to the lifecycle strereotype.
  •  AI: Nigel Davis: Study the guidelines for statements on lifecycle dependency and requires-instance
  • We should consider providing a property with the constraints

Considering the next release of TR-512


AI: Hing-Kam Lam  Nigel Davis Add "next release of TR-512" to next week's agenda.

Action items