Re: [yang-doctors] [Lsr] Yangdoctors last call review of draft-ietf-ospf-yang-09

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

Hi Rob,

From: Rob Shakir <[e-mail]>
Date: Monday, March 19, 2018 at 5:22 AM
To: Acee Lindem <[e-mail]>
Cc: Martin Bjorklund <[e-mail]>, "[e-mail]" <[e-mail]>, YANG Doctors <[e-mail]>, Ladislav Lhotka <[e-mail]>, "[e-mail]" <[e-mail]>
Subject: Re: [Lsr] [yang-doctors] Yangdoctors last call review of draft-ietf-ospf-yang-09

Hi Acee,

For the descriptions, there are tools that use these to build documentation automatically for a YANG model. We have found that such documentation is particularly useful for engineers that are actually consuming the models to generate config.

We are going through another revision prior to WG last call so feel free to improvements to data leafs that are lacking.


Going forward, if we expect YANG modelled data to be the way that we interact with network elements, then such generated documentation is likely to replace a bunch of CLI manuals, so it is worth ensuring the descriptions are useful in such a context IMHO.

This is direction supported by confd with CLI prompt text being either the YANG description or the text specified in te  tailf:info YANG extension dependent on the confdc compile options.

Thanks,
Acee



Just my $0.02,
r.
On Fri, Mar 16, 2018 at 17:31 Acee Lindem (acee) <[e-mail]<mailto:[e-mail]>> wrote:
Hi Martin,

On 3/14/18, 3:30 AM, "Martin Bjorklund" <[e-mail]<mailto:[e-mail]>> wrote:

    Hi,

    "Acee Lindem (acee)" <[e-mail]<mailto:[e-mail]>> wrote:
    > Hi Martin,
    > We believe that https://datatracker.ietf.org/doc/draft-ietf-ospf-yang/
    > satisfies your comments. Please take a look.
    > Thanks,
    > Acee
    >
    >     On 12/6/17, 6:46 AM, "Martin Bjorklund" <[e-mail]<mailto:[e-mail]>> wrote:
    >
    >         Ladislav Lhotka <[e-mail]<mailto:[e-mail]>> wrote:
    >         > Reviewer: Ladislav Lhotka
    >         > Review result: Ready with Issues
    >         >
    >         > The data model defined in this document is a massive piece of work:
    >         > it
    >         > consists of 11 YANG modules and defines around 1200 schema nodes. The
    >
    >         11 YANG modules?  Isn't there just one?
    >
    >
    >         I would like to add two quick comments to Lada's review.
    >
    >         o  Remove all "revision" statements except the one that says "initial
    >            revision".   The idea is to have one revision statement per
    >            published version (i.e., RFC).

    This is now addressed.


    >
    >         o  Many of the nodes have quite rudimentary descriptions, and the
    >            "reference" statement is rarely used.  For example:
    >
    >                  leaf lsa-id {
    >                    type yang:dotted-quad;
    >                    mandatory true;
    >                    description "LSA ID.";
    >                  }
    >
    >            It seems as the description is put there just to keep the tools
    >            quiet.  I know that it is painful to write good descriptions, but
    >            it does help the consumer of the data model.

    I don't think this was addressed; many descriptions are still on this
    form (including the lsa-id).  But if the authors and the WG believe
    that this is clear to the reader this is fine.

Note that I did beef up the descriptions and references for a number of data leaves. This is a pretty fundamental concept in OSPF and one could argument that someone who doesn’t understand it won't benefit from looking at the YANG model. However, we will expand the abbreviation in the first occurrence and indicate that LSAs are uniquely identified by the <lsa-type, lsa-id, adv-router> tuple in the various database description text.


    Just a few additional comments:

    o  In section 3, before the module, add:

       This module augments [I-D.ietf-netmod-rfc8022bis], imports a
       grouping from [I-D.ietf-bfd-yang], and references [RFC1765],
       [RFC4552], [RFC5082], [RFC5286], [RFC5329], [RFC5443], [RFC5631],
       [RFC5714], [RFC5880], [RFC5881], [RFC6021], [RFC6860], [RFC6987],
       [RFC7490], [RFC7684], [RFC7777], [RFC8291], and
       [I-D.ietf-rtgwg-backoff-algo].


      and add these documents to the references.

      NOTE: the list above is probably not complete, please ensure that
      all references in the YANG module are covered in this list, except
      the ones that are already present in the text body of the document
      (like RFC 8177).

Thanks - actually I knew about these many were a result of the above done right before the IETF cut-off. I was fully expecting a comment from Tom Petch by now... We'll make sure we add all these in the next revision.


      Also add RFC editor notes to the "RFC XXXX" strings you have that
      refer to current I-Ds (as opposed to the current document).

Right - a few of these are in the AUTH48 hours and will be updated to the actual numbers in the next revision.


    o  Remove the statement

         reference "RFC XXXX";

       on the top-level (before the revision statement).

       (The revision statement references this RFC).

Sure.


    o  I suggest you remove the "end comments" like:

          } // list link-scope-lsas

       It is not really clear why some end brackets have them and some do
       not.  Also they are not consistent, and sometimes don't match the
       "other end" (probably half of the ones I quickly checked were not
       correct).

       If you decide to keep them, please ensure that they are consistent
       and correct.

I agree - let me discuss with my co-authors.

Thanks,
Acee





    /martin


    >
    >
    >         /martin
    >
    >
    >         > "ietf-ospf@2017-10-30" module is compatible with the NMDA
    >         > architecture.
    >         >
    >         > **** Comments
    >         >
    >         > 1. Unless there is a really compelling reason not to do so, the
    >         >    "ietf-ospf" should declare YANG version 1.1. For one,
    >         >    "ietf-routing" that is being augmented by "ietf-ospf" already
    >         >    declares this version. Some of my suggestions below also assume
    >         >    version 1.1.
    >         >
    >         > 2. The "ietf-ospf" can work only with the new NMDA-compatible
    >         >    revisions of some modules, such as "ietf-interfaces" and
    >         >    "ietf-routing". I understand it is not desirable to import such
    >         >    modules by revision, but at least it should be mentioned in a
    >         >    description attached to every such import.
    >         >
    >         > 3. Maybe the draft could mention that implementations should supply a
    >         >    default routing domain as a system-controlled resource.
    >         >
    >         > 4. In "when" expressions, the module uses literal strings for
    >         >    identities. This is known to be problematic, the XPath functions
    >         >    derived-from() or derived-from-or-self() should be used instead.
    >         >
    >         > 5. Some enumerations, such as "packet-type" and "if-state-type"
    >         >    define enum identifiers with uppercase letters and/or underscores,
    >         >    for example "Database-Description" or "LONG_WAIT". RFC6087bis
    >         >    recommends that only lowercase letters, numbers and dashes. I
    >         >    think
    >         >    this convention should be observed despite the fact that the
    >         >    current names are traditionally used in OSPF specs. The
    >         >    "ietf-routing" module also defines "router-id" even though the
    >         >    documents use "Router ID".
    >         >
    >         > 6. The types of LSA headers are modelled as integers. While OSPF
    >         > gurus
    >         >    probably know these numbers by heart, it is not very
    >         >    reader-frienly. So at least some references to documents defining
    >         >    these numbers should be provided, but my suggestion is to consider
    >         >    implementing them with identities. It seems it might also be
    >         >    useful
    >         >    to define some "abstract" identities for these types. For example,
    >         >    if "opaque-lsa" is defined, then the definition of container
    >         >    "opaque" could simply use
    >         >
    >         >      when "derived-from(../../header/type, 'ospf:opaque-lsa')";
    >         >
    >         >    instead of
    >         >
    >         >       when "../../header/type = 9 or "
    >         >               + "../../header/type = 10 or "
    >         >               + "../../header/type = 11";
    >         >
    >         > 7. The title of sec. 2.9 should be "OSPF Notifications" rather than
    >         >    "OSPF notification".
    >         >
    >         >
    >         > _______________________________________________
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    >         >
    >
    >
    >
    >


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