Re: [netmod] Fwd: New Version Notification for draft-lengyel-netmod-yang-instance-data-01.txt

Robert Wilton <> Tue, 26 June 2018 15:44 UTC

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To: Balazs Lengyel <>, "" <>
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From: Robert Wilton <>
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Date: Tue, 26 Jun 2018 16:44:16 +0100
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Subject: Re: [netmod] Fwd: New Version Notification for draft-lengyel-netmod-yang-instance-data-01.txt
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Note, adding it to the meta-data YANG definition does not mean that 
everyone has to populate this, it just ensures that it has a consistent 
name and semantics for clients/servers that do want to use it.


On 26/06/2018 16:38, Balazs Lengyel wrote:
> Any opinions on Rob's suggestion about a free-text versioning string?
> I am neutral on this.
> regards Balazs
> On 6/26/2018 5:31 PM, Robert Wilton wrote:
>> On 26/06/2018 16:20, Balazs Lengyel wrote:
>>> On 6/26/2018 4:07 PM, Robert Wilton wrote:
>>>>>>>> 7) It might want to include a semantic version number for an
>>>>>>>>        instance-data-set, depending on whether the YANG 
>>>>>>>> versioning discussions
>>>>>>>>        ends up.
>>>>>>>>      BALAZS: Yes I would like to. However I am not exactly 
>>>>>>>> clear on what does
>>>>>>>>      backwards compatibility mean for instance data.
>>>>>>>>      Data MAY NOT be removed or changed only added. ???
>>>>>>>>      Who would use the semver numbers ???
>>>>>>> What does the version number mean? Every change of instance data 
>>>>>>> in an
>>>>>>> instacne-data-set leads to a new version number? What is a bug 
>>>>>>> fix in
>>>>>>> this sense? What is a non-backwards compatible change of 
>>>>>>> instance data?
>>>>>>> I am left a bit puzzled.
>>>>>> Probably I don't mean semantic version.  But often files have 
>>>>>> versioning, or
>>>>>> revision, information associated with them.  This can be muxed 
>>>>>> into the file
>>>>>> name/path, but it also seems like potentially useful metadata, 
>>>>>> and being
>>>>>> able to handle this generically in a consistent way might be 
>>>>>> beneficial.
>>>>>> As an example, perhaps the capability information related to S/W 
>>>>>> release
>>>>>> 1.2.4, etc.
>>>>> We need to separate a version number of the instance data from the a
>>>>> version number (or version context) that may be needed in order to
>>>>> understand what a YANG (module, path) tuple means if we move to a
>>>>> different YANG versioning scheme. The later I agree would be needed,
>>>>> the former I am less sure of - at least if we talk semantic version
>>>>> numbers.
>>>> Yes, I agree with the need for the latter, that may entail listing 
>>>> the versions of the modules in the meta-data.
>>>> But what I was actually referring to was the former, and thinking 
>>>> more of it is just being a string field in the meta-data with a 
>>>> well defined name, that is optional to populate.  Actually, I see 
>>>> the current definition already has a revision with a date and 
>>>> description string.  This is roughly along the lines of what I was 
>>>> thinking of for versioning (although I'm not sure why this should 
>>>> be a list rather than just a pair of leaves).
>>>> Thanks,
>>>> Rob
>>> BALAZS:  IMHO if we want to use versioning (semver) to version the 
>>> instance-data-set itself we first need to understand what backwards 
>>> compatibility means for an instance data set.
>> So, I'm suggesting versioning, but not semver.  Just a string version 
>> field.  E.g. for XR I would just put in the XR release number 
>> "R4.5.1" or similar.
> Balazs Lengyel                       Ericsson Hungary Ltd.
> Senior Specialist
> Mobile: +36-70-330-7909      
> .