Re: [spring] Éric Vyncke's Abstain on draft-ietf-spring-sr-yang-29: (with COMMENT)

["Acee Lindem (acee)" <[e-mail]>]

HI Eric, 

See inline.

On 1/14/21, 8:46 AM, "Éric Vyncke via Datatracker" <[e-mail]> wrote:

    Éric Vyncke has entered the following ballot position for
    draft-ietf-spring-sr-yang-29: Abstain

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

    Thank you for the work put into this document even if I am balloting ABSTAIN,
    this is useful piece and it should really be improved to fix my ABSTAIN reasons
    so that I could actively support it. Read my ABSTAIN ballot as "I oppose this
    document but understand that others differ and am not going to stand in the way
    of the others" per https://www.ietf.org/standards/process/iesg-ballots/ .

    Please note that I am neither a YANG expert nor a segment routing one (hence my
    ABSTAIN rather than a DISCUSS).

    Based on title, I was expecting this document to be generic and to see
    companion YANG models for the MPLS and IPv6 data planes but it seems that this
    document also augments *only* the MPLS one. The asymmetry does not look good to
    me... Are the authors/WG sure that the IPv6 YANG model can also be specified by
    augmenting this model (draft-ietf-spring-srv6-yang-00 is still a -00 ...) and
    relying on types defined in ietf-segment-routing-common ? Especially when
    noting that the authors are different ?

Yingzhen and I have had several meetings with the SRv6 YANG model editors and are confident that there is alignment. 

    The YANG model for SR is really short (mostly meaningless except for one more
    tag in the namespace tree):
       "module: ietf-segment-routing
         augment /rt:routing:
           +--rw segment-routing"

    To be honest, I strongly dislike the fact that there is no common element
    between the YANG modules for MPLS and IPv6 data planes inside
    ietf-segment-routing. I admit that I am not an SR expert but I would have
    expected more common elements: policies, routing protocols, SID, link bundles,

There are many ways to factor the IETF YANG models and this one includes the base segment routing support. It seems you are not in touch with the other routing and segment routing models. For example, the routing protocol segment routing extensions are augmentations to the routing protocol models (in alignment with the vendor implementations). 

Thanks,
Acee


    ... even if the leaves could be instantiated as generic types to be augmented
    later.

    One additional regret is that the document shepherd write-up is really really
    short. But it includes the most important element (to my eyes): the WG feedback
    & consensus.

    Regards,

    -éric