Re: Yangdoctors last call review of draft-ietf-bfd-rfc9127-bis-01

[Mahesh Jethanandani <[e-mail]>]

Hi Jan,

Thanks first of all for the review.

> On Feb 3, 2022, at 3:22 AM, Jan Lindblad via Datatracker <[e-mail]> wrote:
> 
> Reviewer: Jan Lindblad
> Review result: Ready with Issues
> 
> This is the last call YANG Doctor review of draft-ietf-bfd-rfc9127-bis.
> Browsing the mail archives, this has been a long story. Realizing that the
> context of the bis is to fix a particular issue, I have focused only on the
> diffs from RFC 9127. I feel any additional nitpicks I might find in a complete
> review would not be welcome at this stage.
> 
> I have reviewed the diffs, and find them fulfill the desired technical goals.
> Since this update breaks backwards compatibility as defined in RFC 6020 sec 10
> and RFC 7950 sec 11, the process for approving this change has been discussed
> at length. One argument that has been put forward for going ahead is that the
> previous version of this module was released only a short time ago, so there is
> no proliferation of impacted systems in the field.
> 
> Another argument has been that the YANG Versioning Design Team is working on
> updated backwards compatibility rules. The Ver-DT proposed updates to the
> compatibility rules would indeed allow a change of this kind under certain
> conditions. A key condition for allowing such a break with the backwards
> compatibility is that the module revision history announces this break clearly
> to all readers. This is not the case in the -01 version of the modules.
> 
>   revision 2022-01-04 {
>       description
>         "Updates to add client configuration parameters feature.";
> 
> In my YANG Doctor opinion, updating the revision statement to clearly state
> that this version is not backwards compatible with the previous version is an
> absolute requirement. I think it would also be fair to module readers to add a
> few sentences explaining what's going on here.

How does this sound?

OLD:
      "Updates to add client configuration parameters feature.";

NEW:
      "Updates to add client configuration parameters feature.
       This update breaks backward compatability with earlier
       version of the model. The new feature prevents up to 
       three client configuration parameters from being
       included, where they were not needed.";


Thanks.


Mahesh Jethanandani
[e-mail]