Elwyn, thanks for your review. Christian, thanks for your responses. I think 
all of Elwyn’s comments have been addressed in the latest version. I entered a 
DISCUSS ballot on a different point related to the “IETF standard” tags.

Alissa

> On Mar 7, 2019, at 8:02 PM, Christian Hopps <[email protected]> wrote:
> 
> 
> 
>> On Mar 7, 2019, at 17:50, Elwyn Davies <[email protected] 
>> <mailto:[email protected]>> wrote:
>> 
>> Hi, Christian.
>> 
>> Thanks for the quick response.
>> 
>> I understand your intent, but the intent and the specification appear to be 
>> in conflict.
>> 
>> The pattern for tags is
>>          pattern '[a-zA-Z_][a-zA-Z0-9-_]*:[S ]+';  
>> 
>> This REQUIRES two character strings separated by a colon unless I have 
>> totally forgotten how to read such patterns. Thus all tags have a prefix of 
>> the form [a-zA-Z_][a-zA-Z0-9-_]* and a part after the colon that is 
>> essentially unconstrained.
> 
> Your right the pattern was wrong and needs to be fixed.
> 
>> S2 limits the values of the prefixes to those defined in the IANA registry 
>> of s7.1.. Further the values of the second part are constrained by the s7.2 
>> registry if the prefix is ietf:.
>> 
>> So, what should a YANG parser do when building datastores as per RFC 8342 if 
>> a tag prefix is not one of the ones in the s7.1 registry? Likewise if the 
>> prefix is ietf: and the whole tag is not in the s7.2 registry?
> 
> A YANG server should never place any restrictions on the tag values. There’s 
> need for this limiting and well known justification not to (applying Postel’s 
> Law/Robustness principle here).
> 
>> If you want to make the presence of the prefix a SHOULD then I think you 
>> need to adapt the pattern to make the whole prefix part optional.  However 
>> that doesn't get away from describing what the parser should do if it finds 
>> a prefix it doesn't know about. 
> 
> Assuming the pattern is fixed, do we really have to call out the fact that 
> something marked as a SHOULD should not be treated as a MUST? That seems like 
> what your asking for, perhaps I’m missing the point though. Are you just 
> asking for a blurb saying parsers must not restrict tag values? That seems 
> like restating but if it moves things forward I’m amiable. :)
> 
>> Additionally, I am not clear how the parser knows which tags should be 
>> marked as 'system' in the datastore as mentioned in the YANG module 
>> comments. 
> 
> B/c it (the server) put them there, not the user.
> 
>> Maybe it is that the ietf prefix and s7.2 value leads the tags to be marked 
>> as system tags but what should happen if it isn't in the s7.2 list?  Should 
>> the parser ignore such tags, throw a fault and refuse to parse the module or 
>> maybe treat them as user tags even if they are ietf prefixed?  
>> 
>> Also if new prefixes are defined by other SDOs, as envisaged in the last 
>> paragraph of s7.1, could or would these also be system tags?  Should there 
>> then be a flag or value in the registry to flag that tags with this prefix 
>> should be marked as system or otherwise?
>> 
>> Thus also brings up another issue for the s7.1 registry.  If another 
>> organisation is defining a prefix there really need to be contact and 
>> reference fields in the registry to specify the organisation maintaining 
>> this prefix, especially if such a prefix had its own equivalent of the s7.2 
>> registry, and the document that introduces the prefix.
>> 
>> I suggest the authors discuss the appropriate status for the three RFCs that 
>> I suggested should be normative and you disagreed with your AD.  It is a 
>> rather odd situation where a standards ltrack document is updating an 
>> informational or BCP document, and also needing knowledge of items described 
>> in BCPs.  With the revised policy on downrefs, this can be handled I believe.
> 
> We are updating the BCP guidelines (RFC8407) , but nothing is relying on them 
> that I see. I would have thought text that updates informative text is 
> treated as informative, this could be my ignorance showing.
> 
> RFC8340 being informative is what all the other yang documents (including 
> RFCs) I’ve seen do as well.
> 
> RFC8199 is informative, the values themselves are normative only in the sense 
> that they are being reserved. Again, maybe I’m wrong. I’d prefer to be told 
> so and then I’ll just move the reference.
> 
> I guess I don’t understand things well enough is all. Can you be specific 
> about the objections with each of the 3 references?
> 
> Thanks,
> Chris.
> 
>> 
>> Cheers,
>> Elwyn
>> 
>> Sent from Samsung tablet.
>> 
>> -------- Original message --------
>> From: Christian Hopps <[email protected] <mailto:[email protected]>>
>> Date: 06/03/2019 22:55 (GMT+00:00)
>> To: Elwyn Davies <[email protected] <mailto:[email protected]>>
>> Cc: [email protected] <mailto:[email protected]>, Christian Hopps 
>> <[email protected] <mailto:[email protected]>>, 
>> [email protected] 
>> <mailto:[email protected]>, "<[email protected] 
>> <mailto:[email protected]>>" <[email protected] <mailto:[email protected]>>, 
>> [email protected] <mailto:[email protected]>
>> Subject: Re: [Gen-art] [netmod] Genart last call review of 
>> draft-ietf-netmod-module-tags-06
>> 
>> [I covered this in the previous reply I just sent, and updated the model 
>> text in response too..]
>> 
>> The intent here is to not restrict users of tags where we don't have to. The 
>> prefix is only intended to avoid collision between disconnected groups 
>> (designers, implementers and users), since users are the final group to 
>> add/modify/use the tags we don't need to restrict them (and so we shouldn't).
>> 
>> Thanks,
>> Chris.
>> 
>> > On Mar 6, 2019, at 2:39 PM, Elwyn Davies <[email protected] 
>> > <mailto:[email protected]>> wrote:
>> > 
>> > Hi.
>> > 
>> > After completing my review, I realized that there was a further minor 
>> > issue related to the possible values of tag prefixes, possible values of 
>> > standardized prefixes and behaviour of implementations in the face of tag 
>> > prefixes or values that are not in the relevant registries.
>> > 
>> > I think that the text in s2 should be reinforced to emphasise that the 
>> > only prefixes that should be expected are those in the IANA registry 
>> > defined in s7.1.
>> > 
>> > Either a new section or possibly in s3 text should be added to define the 
>> > behaviour of YANG implementations that encounter tags with prefixes that 
>> > are not in the s7.1 registry and tags with prefix ietf: that are not in 
>> > the s7.2 registry.
>> > 
>> > Regards,
>> > Elwyn Davies
>> > 
>> > 
>> > 
>> > 
>> > 
>> > Sent from Samsung tablet.
>> > 
>> > -------- Original message --------
>> > From: Datatracker on behalf of Elwyn Davies 
>> > <[email protected] <mailto:[email protected]>>
>> > Date: 06/03/2019 00:26 (GMT+00:00)
>> > To: [email protected] <mailto:[email protected]>
>> > Cc: [email protected] 
>> > <mailto:[email protected]>, [email protected] 
>> > <mailto:[email protected]>, [email protected] <mailto:[email protected]>
>> > Subject: [Gen-art] Genart last call review of   
>> > draft-ietf-netmod-module-tags-06
>> > 
>> > Reviewer: Elwyn Davies
>> > Review result: Almost Ready
>> > 
>> > I am the assigned Gen-ART reviewer for this draft. The General Area
>> > Review Team (Gen-ART) reviews all IETF documents being processed
>> > by the IESG for the IETF Chair.  Please treat these comments just
>> > like any other last call comments.
>> > 
>> > For more information, please see the FAQ at
>> > 
>> > <https://trac.ietf.org/trac/gen/wiki/GenArtfaq 
>> > <https://trac.ietf.org/trac/gen/wiki/GenArtfaq>>.
>> > 
>> > Document: draft-ietf-netmod-module-tags-06
>> > Reviewer: Elwyn Davies
>> > Review Date: 2019-03-05
>> > IETF LC End Date: 2019-03-03
>> > IESG Telechat date: Not scheduled for a telechat
>> > 
>> > Summary:
>> > Almost ready.  There are a couple of minor issues and a small number of 
>> > nits.
>> > Apologies for the slightly late delivery of the review.
>> > 
>> > Major issues:
>> > None
>> > 
>> > Minor issues:
>> > Abstract/s1: I would judge that RFC 8407 ought to be normative since it is
>> > updated.
>> > 
>> > S4.2: using the Netmod working group as contact point for the module is not
>> > future proof.  I am  not sure what the correct contact ought to be: IESG?
>> > 
>> > S7.2: [This is a thought that occurred to me...] ought there to be an ietf:
>> > security tag?
>> > 
>> > S9: I would consider RFCs 8199, 8340, 8342 and 8407 to be normative
>> > 
>> > Nits/editorial comments:
>> > Abstract: s/modules/module's/
>> > 
>> > Abstract:
>> > OLD:
>> > This document also provides guidance to future model writers, as such, this
>> > document updates RFC8407.
>> > 
>> > NEW:
>> > This document also provides guidance to future model writers; as such, this
>> > document updates RFC8407.
>> > 
>> > ENDS
>> > 
>> > S1.1, title: s/use cases of/use cases for/
>> > 
>> > S1.1, para 1: s/documents progression/document's development/
>> > 
>> > S1.1, paras 2, 3 and 5: Suggest s/E.g./For example/
>> > 
>> > S1.1, para 4: s/e.g./e.g.,/
>> > 
>> > S2, para 1:
>> >    > All tags SHOULD begin with a prefix indicating who owns their 
>> > definition.
>> > 
>> > If I read correctly, the YANG definition in s4.2 REQUIRES that all tags 
>> > have a
>> > prefix.  For clarity, it would better if this read:
>> >    All tags MUST begin with a prefix; it is intended that this prefix 
>> > SHOULD
>> >    [or maybe 'should'] indicate
>> >  the ownership or origination of the definition.
>> > 
>> > S2, para 1: s/yang type/YANG type/ (I think)
>> > 
>> > S2.2: s/follwing/following/
>> > 
>> > S3.1, para 2:
>> > OLD:
>> > If the module definition is IETF standards track, the tags MUST also be 
>> > Section
>> > 2.1. Thus, new modules can drive the addition of new standard tags to the 
>> > IANA
>> > registry, and the IANA registry can serve as a check against duplication.
>> > 
>> > NEW:
>> > If the module is defined in an IETF standards track document, the tags 
>> > MUST use
>> > the prefix defined in Section 2.1. Thus, definitions of new modules can 
>> > drive
>> > the addition of new standard tags to the IANA registry defined in Section 
>> > 7.2,
>> > and the IANA registry can serve as a check against duplication.
>> > 
>> > ENDS
>> > 
>> > S3.2: s/standard/IETF Standard/
>> > 
>> > S3.3: It would be useful to introduce the term 'masking' used later in the 
>> > YANG
>> > module definition.
>> > 
>> > S4.1: I think this usage of RFC 8340 makes it normative.
>> > 
>> > S4.2, extension module-tag definition: This should contain a pointer to RFC
>> > 8342 which discusses the system origin concept.
>> > 
>> > Major issues:
>> > 
>> > Minor issues:
>> > 
>> > Nits/editorial comments:
>> > 
>> > 
>> > _______________________________________________
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