Re: [netmod] Comments on draft-ietf-netmod-schema-mount-09

Hi,

-----Original Message-----
From: Robert Wilton [mailto:rwilton@cisco.com] 
Sent: Thursday, March 29, 2018 5:32 PM
To: Yemin (Amy) <amy.yemin@huawei.com>; otilibil@eurecom.fr; netmod@ietf.org
Subject: Re: [netmod] Comments on draft-ietf-netmod-schema-mount-09

Hi Amy,

On 29/03/2018 08:09, Yemin (Amy) wrote:
> Hi Rob,
>
> Thanks for clarification.
> By using the deviation, I can remove the containers I don't need, and I could also remove some data nodes within the container, right?
Yes.

>
> BTW, your reply provides a good guideline. Is it possible to include those text into the draft?
I'll leave this to the authors to decide.

A more realistic example may be helpful given that mine was slightly contrived.
[Amy] A concrete example would be even better!

Thanks,
Rob

>
> BR,
> Amy
> -----Original Message-----
> From: Robert Wilton [mailto:rwilton@cisco.com]
> Sent: Tuesday, March 27, 2018 6:33 PM
> To: Yemin (Amy) <amy.yemin@huawei.com>; otilibil@eurecom.fr; 
> netmod@ietf.org
> Subject: Re: [netmod] Comments on draft-ietf-netmod-schema-mount-09
>
> Hi Amy,
>
>
> On 27/03/2018 04:47, Yemin (Amy) wrote:
>> Hi all,
>>
>> I also have a question/comment regarding this draft, maybe if it's discussed already.
>>
>> If there a model A, which I would like to use just part of model A in another model B, what should I do?
>> The draft states that "This document allows mounting of complete data models only.  Other specifications may extend this model by defining additional mechanisms such as mounting sub-hierarchies of a module."
>> It seems that the current schema mount doesn't support such usage.
> That is correct.
>
>>    
>>
>> Then I'm thinking that using deviation to create a new sub-module A', then mount the sub-module A' in model B.
>> Will it be a possible way out?
> If you have a module A, then you could create another module, A-deviations, that used deviation delete statements to remove parts of A's schema.
>
> Then a server could mount both modules A and A-deviations, hence excluding parts of module A at the mount point.
>
> However, this approach would not allow you to only mount a descendant subtree in A.  E.g. You couldn't just directly mount the "interfaces/interface/statistics" container from RFC 8343, but you could mount the ietf-interfaces module and then deviate delete all nodes except for the interfaces/interface/statistics container.
>
> Thanks,
> Rob
>
>
>> BR,
>> Amy
>> -----Original Message-----
>> From: netmod [mailto:netmod-bounces@ietf.org] On Behalf Of 
>> otilibil@eurecom.fr
>> Sent: Monday, March 26, 2018 7:18 PM
>> To: netmod@ietf.org
>> Subject: [netmod] Comments on draft-ietf-netmod-schema-mount-09
>>
>> Hi members,
>>
>> I comment on that draft:
>>
>> * Instead of "it is often necessary that an existing module (or a set 
>> of modules) is added to the data model starting at a non-root 
>> location", this would read better: "it is often necessary that an 
>> existing module (or a set of modules) be added to the data model at 
>> locations other than the root." (Section 1)
>>
>> * 'The "mount-point" statement MUST NOT be used in a YANG version 1 
>> module' Why this documents keeps YANG 1 off from its scope? (Section
>> 3.1)
>>
>> * 'Specifically, a server that doesn?t support the NMDA, MAY 
>> implement revision 2016-06-21 of "ietf-yang-library" [RFC7950] under 
>> a mount point' [RFC7895] defines "ietf-yang-library", not [RFC7950] 
>> (Section
>> 6)
>>
>> * Why not "Tree Diagram" instead of "Data Model"? The wording has 
>> become a Best Practice (Section 8)
>>
>> * Idem, "This document...has the following diagram" captures better the Best Practice than "This document...has the following structure"
>> (Section 8)
>>
>> * Same remark on restricting to YANG 1.1: "The ?mount-point? 
>> statement MUST NOT be used in a YANG version 1 module, neither 
>> explicitly nor via a ?uses? statement (description of the extension 
>> "mount-point")
>>
>> * Should this sentence refers only to [RFC6020]? "This document registers a YANG module in the YANG Module Names registry [RFC6020]"
>> (Section 10)
>>
>> * The document cites /schema-mounts as "The schema defined by this 
>> state data provides detailed information about a server 
>> implementation may help an attacker identify the server capabilities 
>> and server implementations with known bugs" I think this section 
>> should warn also
>> on:
>>       ** Section 2.1.2 and 4 of [RFC7895] (the list 'module' contains the leaf 'schema': from which anyone may retrieve a YANG module)
>>       ** Section 3 of [RFC6022] (it defines the RPC 'get-schema'; with which anyone may get a YANG module)
>>       ** and Section 5 of [RFC8341] (reminding administrators to set user rights accordingly, and giving their defaults values).
>>
>> Regards,
>> Ariel
>>
>> [RFC6020] https://tools.ietf.org/html/rfc6020
>> [RFC7895] https://tools.ietf.org/html/rfc7895
>> [RFC7950] https://tools.ietf.org/html/rfc7950
>> [RFC8341] https://tools.ietf.org/html/rfc8341
>>
>>
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