Re: [Gen-art] Gen-ART review of draft-ietf-dime-app-design-guide-19

[Jouni Korhonen <[e-mail]>]

Martin,

Thanks for the detailed review. I'll let the authors respond to these if they
have further questions or clarifications to ask.

- Jouni



On Sep 14, 2013, at 3:13 AM, Martin Thomson <[e-mail]> wrote:

> I am the assigned Gen-ART reviewer for this draft. For background on
> Gen-ART, please see the FAQ at
> 
> <http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>.
> 
> Please resolve these comments along with any other Last Call comments
> you may receive.
> 
> Document: draft-ietf-dime-app-design-guide-19
> Reviewer: Martin Thomson
> Review Date: 2013-09-13
> IETF LC End Date: unknown, early review
> IESG Telechat date: (if known)
> 
> Summary: This document is ready, with some minor issues and nits.
> 
> Minor issues:
> I would find it a lot easier to read this document if it did as the
> goals state (the first objective from the introduction) and clarify
> what the extensibility rules in Diameter say with respect to each of
> the described extensions.  It's not easy to glean this information
> from RFC 6733, which makes reviewing this a little tricky.
> 
> For instance, Section 4.1 doesn't really say what the expectations are
> with respect to implementations that receive unknown or unsupported
> commands.  I think that I could guess, but I'd rather not.  (I just
> read the relevant parts of 6733, and it turns out that my guess was
> wrong.)
> 
> The same applies to Section 4.2, presumably through applying the same
> principles.  The question here is: what would be the expected behavior
> if a node was operating on the new application definition and that
> node received a deleted command?  (The old implementation presumably
> has no problem with the absence of the command if it's being removed.)
> 
> The same applies to Section 5.
> 
> Sections 4.4.2 and particularly 5.6 lead me to infer that the
> extensibility for enumerated types is fundamentally broken, so maybe
> those properties need to be expanded upon a little here too.
> 
> The placement of the guidance in Section 5.6 seems fairly important
> for Section 4, lest that important information be lost to someone just
> looking to tweak a command.
> 
> Section 4.3.1, perhaps add to the M-bit criteria: Would the presence
> or value of the AVP alter the interpretation of the command (or any
> other AVP) in any way?  (nit: s/AVPs/AVP on second bullet here.)
> 
> I didn't find the list in  Section 6 particularly compelling.  It
> seemed a little like motherhood statements.  The description of what
> it was this was talking about: good; the description of how these
> "often" (always?) manifest is also useful.  I wonder though whether
> it's safe to generalize when you only see generic protocols extensions
> as optional AVPs.  Perhaps you need to refocus on exactly that, and
> leave the other forms of extension to speculation.
> 
> Nits/editorial comments:
> The last paragraph of Section 3 is confusing to me.  Firstly, the
> subject of the reminder is missing from the first sentence.  I think
> that the intent of that sentence is to say that extending by adding
> applications or commands is to be avoided, but then subsequent
> sentences make it clear that doing so is easy.  The last sentence
> seems to be talking about something else entirely, which is the value
> that IANA registries provide.  I am going to have to suggest that this
> be reworded entirely.
> 
> In Section 4.1, I'd like to see the note turned into real text.  The
> size and complexity of an application seems to be a fairly significant
> factor in determining whether a new application imports commands, or
> whether separate applications are defined.
> 
> I read the first bullet in Section 4.3.2 as a sentence, several times,
> before realizing that it's a title.  Please reconsider the formatting
> of this list.  At a very minimum, remove the period.
> 
> --Martin
> 
> p.s., I'm on vacation starting approximately ...now, since I'm out of
> time for this review... so apologies for any slow responses to the
> review.