Re: [netmod] Query on Announcing Conformance Information in the <hello> Message

[Robert Varga <[e-mail]>]

On 02/05/17 10:25, Martin Bjorklund wrote:
> Robert Varga <[e-mail]> wrote:
>> On 20/04/17 18:35, Andy Bierman wrote:
>>>
>>> Yes -- it looks correct.
>>> The structure is defined in RFC 6020:
>>> https://tools.ietf.org/html/rfc6020#section-5.6.4
>>>
>>
>> Hello Andy,
>>
>> One thing that is not quite clear in RFC6020 due to not being clear what
>> 'supported module' means.
> 
> Right; specifically the difference between "implement" and "support
> for import", which is clarified in RFC 7950 and RFC 7895.
> 
>> Should deviations be applied in case a module is advertised, but is not
>> mentioned in a deviations parameter like this:
> 
> No.
> 
>>    <hello xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
>>        <capability>
>>          http://example.com/syslog?module=syslog
>>        </capability>
>>        <capability>
>>          http://example.com/my-deviations?module=my-devs
>>        </capability>
>>      </hello>
>>
>> If not, does this imply that any deviation statement targeting an
>> external module, which does not have a matching deviations parameter
>> should silently be ignored?
> 
> Yes.  Just like a grouping can be defined without ever being used.
> 
> For example, a device might put all its deviations in a
> single module, but then list it in the deviations parameter for a
> subset of all potential modules.

Thanks Martin,

this does make sense, but there seems to be little implied about this in
the text of https://tools.ietf.org/html/rfc7950#section-7.20.3.

Furthermore https://tools.ietf.org/html/rfc7950#section-7.20.3.3 is a
bit misleading, as it states:

   A server would advertise both modules "example-base" and
   "example-deviations".

Based on your reply, it is not sufficient to advertise both modules as
'implement', but rather for 'deviation' statements to be effective,
'example-deviations' needs to also be present in example-base's
advertised deviation list.

Maybe 7.20.3 could use a paragraph describing interplay with
advertisement and the text in 7.20.3.3 could be made more explicit?

Regards,
Robert