Last Call Review of draft-ietf-netmod-nmda-diff-06
review-ietf-netmod-nmda-diff-04-yangdoctors-lc-rahman-2020-09-06-01

Hi Alex,

Thank you for addressing my comments.

I checked rev-06, and I believe the XML and JSON output in the example is
broken: there is a single “edit” element with multiple “edit-id” elements. I
believe there should be multiple “edit” elements.

The only “nit” is that leaf-xpath-filter references 6021 instead of 6991 (as
you correctly pointed out in your response).
           leaf xpath-filter {
             if-feature nc:xpath;
             type yang:xpath1.0;
             description
               "This parameter contains an XPath expression
                identifying the portions of the target
                datastore to retrieve.";
             reference "RFC 6021: Common YANG Data Types";
           }

> Issues
>             1.            YANG model P8, for “leaf xpath-filter”, add
reference to RFC6021. There should also be a normative reference to RFC6021 (as
per RFC8407) <ALEX> Thanks.  Adding reference to 6991 (as 6021 is obsoleted).
</ALEX>

Regards,
Reshad.

From: Alexander L Clemm <ludwig@clemm.org>
Date: Friday, September 18, 2020 at 3:48 PM
To: "Reshad Rahman (rrahman)" <rrahman@cisco.com>, "yang-doctors@ietf.org"
<yang-doctors@ietf.org> Cc: "last-call@ietf.org" <last-call@ietf.org>,
"netmod@ietf.org" <netmod@ietf.org>, "draft-ietf-netmod-nmda-diff.all@ietf.org"
<draft-ietf-netmod-nmda-diff.all@ietf.org> Subject: Re: [yang-doctors] [netmod]
Yangdoctors last call review of draft-ietf-netmod-nmda-diff-04

Thank you!

I just uploaded rev -06.

--- Alex
On 9/18/2020 12:47 PM, Reshad Rahman (rrahman) wrote:
Hi Alex,

This addresses my comment/concern.

Regards,
Reshad.

From: Alexander L Clemm <ludwig@clemm.org><mailto:ludwig@clemm.org>
Date: Friday, September 18, 2020 at 3:43 PM
To: "Reshad Rahman (rrahman)" <rrahman@cisco.com><mailto:rrahman@cisco.com>,
"yang-doctors@ietf.org"<mailto:yang-doctors@ietf.org>
<yang-doctors@ietf.org><mailto:yang-doctors@ietf.org> Cc:
"last-call@ietf.org"<mailto:last-call@ietf.org>
<last-call@ietf.org><mailto:last-call@ietf.org>,
"netmod@ietf.org"<mailto:netmod@ietf.org>
<netmod@ietf.org><mailto:netmod@ietf.org>,
"draft-ietf-netmod-nmda-diff.all@ietf.org"<mailto:draft-ietf-netmod-nmda-diff.all@ietf.org>
<draft-ietf-netmod-nmda-diff.all@ietf.org><mailto:draft-ietf-netmod-nmda-diff.all@ietf.org>
Subject: Re: [yang-doctors] [netmod] Yangdoctors last call review of
draft-ietf-netmod-nmda-diff-04

Hi Reshad,

okay, so let's add the following then to section 4, in the explanation of the
"differences" output parameter:

"When a datastore node in the source of the comparison is not present in the
target of the comparison, this can be indicated either as a "delete" or as a
"remove" in the patch as there is no differentiation between those operations
for the purposes of the comparison.  "

And update the description as follows:

         container differences {
          description
           "The list of differences, encoded per RFC8072 with an
             augmentation to include source values where
             applicable.  When a datastore node in the source is
             not present in the target, this can be indicated either
             as a 'delete' or as a 'remove' as there is no difference
             between them for the purposes of the comparison.";
...

I will post this in a -06 shortly.  Please let us know if this addresses your
concerns or if there is anything else.

Thanks!

--- Alex

On 9/18/2020 5:57 AM, Reshad Rahman (rrahman) wrote:
Hi Alex,

I think the only “problem” with using both “remove” and “delete” is that it
could be confusing (when should one be used and not the other). Adding some
text to say they’re the same for the diff operation is good enough for me.

Regards,
Reshad.

From: Alexander L Clemm <ludwig@clemm.org><mailto:ludwig@clemm.org>
Date: Tuesday, September 15, 2020 at 7:31 PM
To: "Reshad Rahman (rrahman)" <rrahman@cisco.com><mailto:rrahman@cisco.com>,
"yang-doctors@ietf.org"<mailto:yang-doctors@ietf.org>
<yang-doctors@ietf.org><mailto:yang-doctors@ietf.org> Cc:
"last-call@ietf.org"<mailto:last-call@ietf.org>
<last-call@ietf.org><mailto:last-call@ietf.org>,
"netmod@ietf.org"<mailto:netmod@ietf.org>
<netmod@ietf.org><mailto:netmod@ietf.org>,
"draft-ietf-netmod-nmda-diff.all@ietf.org"<mailto:draft-ietf-netmod-nmda-diff.all@ietf.org>
<draft-ietf-netmod-nmda-diff.all@ietf.org><mailto:draft-ietf-netmod-nmda-diff.all@ietf.org>
Subject: Re: [yang-doctors] [netmod] Yangdoctors last call review of
draft-ietf-netmod-nmda-diff-04

Hi Reshad,

re: question 1: As you indicate, there may be no distinction between indicating
a "remove" or a "delete" in the patch.  Right now it would be acceptable to
return either.  If we want to eliminate this freedom, which one would you
prefer be used?  Shall we remove the possibility for "delete" and just cover it
using "remove"?

Note that the place where this is specified in the model is as part of a
condition that specifies when the source value should be included.   If we want
to rule out that diff can return either "remove" or "delete" (indeed they are
synonymous), we would need to add text to the container description that when a
data object is present in the target of the comparison but not the source, that
"remove" should be used to indicate that.

The model would be changed follows.  Please confirm if this looks good to you &
we'll incorporate it.

OLD

           container differences {

             description

               "The list of differences, encoded per
               RFC8072<https://tools.ietf.org/html/rfc8072> with an

                augmentation to include source values where

                applicable.";

             uses ypatch:yang-patch {

               augment "yang-patch/edit" {

                 description

                   "Provide the value of the source of the patch,

                    respectively of the comparison, in addition to

                    the target value, where applicable.";

                 anydata source-value {

                   when "../operation = 'delete'"

                     + "or ../operation = 'merge'"

                     + "or ../operation = 'move'"

                     + "or ../operation = 'replace'"

                     + "or ../operation = 'remove'";

                   description

                     "The anydata 'value' is only used for 'delete',

                      'move', 'merge', 'replace', and 'remove'

                      operations.";

                 }

                 reference "RFC 8072<https://tools.ietf.org/html/rfc8072>: YANG
                 Patch Media Type";

               }

             }

           }

NEW:

           container differences {

             description

               "The list of differences, encoded per
               RFC8072<https://tools.ietf.org/html/rfc8072> with an

                augmentation to include source values where

                applicable.  Where a difference include a data object

                in the target that is not present in the source,

                this shall be indicated as a 'remove' operation

                in the patch, not as a 'delete' operation.";

             uses ypatch:yang-patch {

               augment "yang-patch/edit" {

                 description

                   "Provide the value of the source of the patch,

                    respectively of the comparison, in addition to

                    the target value, where applicable.";

                 anydata source-value {

                   when "../operation = 'merge'"

                     + "or ../operation = 'move'"

                     + "or ../operation = 'replace'"

                     + "or ../operation = 'remove'";

                   description

                     "The anydata 'value' is only used for 'merge',

                      'move','replace', and 'remove' operations.";

                 }

                 reference "RFC 8072<https://tools.ietf.org/html/rfc8072>: YANG
                 Patch Media Type";

               }

             }

           }

Thanks
--- Alex

On 9/15/2020 4:04 PM, Reshad Rahman (rrahman) wrote:

Hi Alex,

I will review the latest version.

See below for questions/responses.

On 2020-09-15, 5:19 PM, "yang-doctors on behalf of Alexander L Clemm"
<yang-doctors-bounces@ietf.org on behalf of
ludwig@clemm.org><mailto:yang-doctors-bounces@ietf.orgonbehalfofludwig@clemm.org>
wrote:

    Hello Reshad, hello YANG Doctors,

    thank you for your review!  Please find my replies inline, <ALEX>.  We

    have also just posted -05 (thanks, Yingzhen, for doublechecking my

    updates).

    --- Alex on behalf of coauthors

    On 9/7/2020 7:06 AM, Reshad Rahman (rrahman) wrote:

    > <Here's the same message with hopefully more readable formatting>

    >

    > Review of rev -04 by Reshad Rahman

    >

    > The document is clear and well-written. While some issues have been
    identified, they can be resolved quickly.

    >

<snip>

    > Questions

    >    1.      YANG model: does the operation “delete” make sense for a diff
    operation? If it is kept, it’d be good to have some text explaining that
    for a diff operation, “delete” and “replace” are the same? If they’re not
    the same, please also add some text….

<RR> I actually meant "delete" and "remove".

    <ALEX> Here we are simply referring to the basic YANG-patch edit

    operations per https://tools.ietf.org/html/rfc8072#page-11.  Those are

    in turn derived from <edit-config> operations per

    https://tools.ietf.org/html/rfc6241#page-37.  I am not sure we need add

    to explain those, as we are directly referring to YANG-patch.

    </ALEX>

<RR> The operations are indeed well defined in RFC8072 (copied below), but they
are defined from the perspective of YANG-Patch. So for YANG-Patch "delete" and
"remove" are different operations, but from a diff comparison I believe they
are the same (the resource must exist since it's being returned in a diff)

   +-----------+-----------------------------------------------------------------+

   | delete    | delete a data resource if it already exists; if it    |

   |                | does not exist, return an error                          
       |

   |                |                                                          
                              |

   | remove | remove a data resource if it already exists           |

   +-----------+-----------------------------------------------------------------+

    >    3.      YANG model P9, for the “uses path:yang-patch”, why not have a 
    reference to RFC8072 (is it because the description above mentions RFC8072)?

    <ALEX> We are clearly referencing RFC 8072; are you suggesting to put a

    reference substatement below the uses statement?   It looks a little

    strange to me but sure, we will add it.

<RR> Not needed.

    >    4.      Section 7 mentions rate limiting requests per client. Should
    there be a “global” rate-limiting too, i.e not client-specific?

    <ALEX> I am not sure this is really needed as I think the number of

    management clients will in general be fairly limited to begin with, but

    we can certainly add it.  How about the following text:

    OLD:

    One possibility for an implementation to mitigate against such a

    possibility is to limit the number of requests that is served to a

    client in any one time interval, rejecting requests made at a higher

    frequency than the implementation can reasonably sustain.

    NEW:

    One possibility for an implementation to mitigate against such a

    possibility is to limit the number of requests that is served to a

    client, or to any number of clients, in any one time interval, rejecting

    requests made at a higher frequency than the implementation can

    reasonably sustain.

<RR> Good with me.

    </ALEX>

    >    5.      Wondering if section 8 should be in an Appendix (or even
    removed)? Also, the method suggested doesn’t seem to guarantee that the
    difference persisted for the “dampening” time.

    <ALEX> Personally, I do think it makes sense to include a brief

    discussion of possible further extensions.  I suggest to keep the

    section if it's okay with you, or perhaps leave it to the chair whether

    they have a preference to remove it.

    </ALEX>

<RR>Whatever the WG/chairs decide is fine with me.

Regards,

Reshad.