Re: [Lsr] Robert Wilton's No Objection on draft-ietf-lsr-yang-isis-reverse-metric-04: (with COMMENT)

["Rob Wilton (rwilton)" <[e-mail]>]

Hi Acee,

I don't disagree, but I believe that your comment generally applies to all AD review comments received during a telechat.

But notwithstanding, when reviewing this draft, and YANG model, I found aspects of its behaviour potentially unclear that I think could raise questions/problems to those implementing it, hence why I raised the comments that I did.  I would rather that those are clarified now, if necessary, before it becomes an RFC.  But at the end of the day, I considered balloting discuss, but decided to ballot no-obj on this draft, leaving it to the authors to consider the points that I raised and decide whether or not to act on them.

It is also the case that I have not read/reviewed the base ISIS YANG model, and some of my questions may be implicit in the design of that YANG model that this one is augmenting.

Thanks,
Rob


-----Original Message-----
From: Acee Lindem (acee) <[e-mail]> 
Sent: 29 November 2021 14:36
To: Rob Wilton (rwilton) <[e-mail]>; The IESG <[e-mail]>
Cc: [e-mail]; [e-mail]; [e-mail]; [e-mail]
Subject: Re: Robert Wilton's No Objection on draft-ietf-lsr-yang-isis-reverse-metric-04: (with COMMENT)

Hi Rob, 
Seems it would be better to get modeling suggestions earlier in the cycle than IESG telechat. 
Thanks,
Acee

On 11/29/21, 6:05 AM, "Robert Wilton via Datatracker" <[e-mail]> wrote:

    Robert Wilton has entered the following ballot position for
    draft-ietf-lsr-yang-isis-reverse-metric-04: No Objection

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    ----------------------------------------------------------------------
    COMMENT:
    ----------------------------------------------------------------------

    Hi Chris,

    Thanks for this YANG module.

    Nit:
    - Copyright statement in the YANG module should presumably be updated to 2021,
    to match the revision entry.

    A few comments on the YANG model:
    - For the interface config, reverse-metric turns up twice in the path.  You
    could perhaps drop it from the
      grouping so that it only appears once?
    - Would it be helpful to make the top level reverse-metric container have
    presence?  This might make more
      sense if constraints are ever added to validate that a metric is specified at
      the top level, or under at least one of the levels.
    - Am I right in assuming that that the level-1/level-2 config is effectively
    hierarchical and would override
      the config under the reverse-metric grouping?  E.g., is it allowed to specify
      a metric at the top level, and the whole-lan flag only under the level-1?  If
      so, would it be helpful to document this hierarchical behaviour in the
      description for the fields?
    - There is a default assigned to exclude-te-metric, but no default assigned to
    whole-lan and allow-unreachable.
      If the config is not hierarchical, then should these all have defaults? If
      the config is hierarchical then perhaps they should not have any defaults,
      and the use statement for the top level reverse-metric grouping should refine
      them with default values?  Assuming that the descriptions make their
      hierarchical nature clear?

    Security Considerations:
    Would it also be helpful to include a reference back to the security
    considerations of the base ISIS YANG module, since the concerns that apply to
    metrics there would seem to mostly also apply here.

    References:
    - Probably need to add XML and JSON references or otherwise change the requests
    to edit-config or RESTCONF requests. - XML reference can be as per RFC 8342,
    JSON should probably be to RFC 7951.

    A.1.  Example Enable XML
    Suggest retitling to: Enablement Example Using XML YANG Instance Data"

    A.2.  Example Use XML
    Suggest retitling to: "Usage Example using XML YANG Instance Data"

    A.3.  Example JSON
    Suggest retitling to: "Usage Example using JSON YANG Instance Data"

    Thanks,
    Rob