Re: [Pce] Benjamin Kaduk's No Objection on draft-ietf-pce-stateful-flags-00: (with COMMENT)

["Adrian Farrel" <[e-mail]>]

> Thanks for this clear and well-written document!  I just have a couple
> of editorial comments that probably don't even need a response.

Thanks for reading, Ben.

Every review comment deserves a response.

> Section 4
>
>  There will remain an issue with compatibility between implementations
>  of RFC 8231 that might set any of the unassigned flags, and current
> (such as [RFC8281]) and future (such as
>  [I-D.ietf-pce-lsp-control-request]) specifications.  That problem
>  cannot be fixed in old implementations by any amount of
>  documentation, and can only be handled for future specifications by
>  obsoleting the Flags field and using a new technique.  Fortunately,
>  however, most implementations will have been constructed to set
>  unused flags to zero which is consistent with the behavior described
>  in this document.
>
> I had a little bit of trouble reading this, as I keep expecting the
> first sentence to be saying that there is a legitimately-allocated flag
> value that is set with intent to change behavior, but it doesn't really
> say anything specifically about a flag value getting allocated (or
> used).

How about this becomes...

  There will remain an issue with compatibility between implementations
  of RFC 8231 that might set any of the unassigned flags, and current
 (such as [RFC8281]) and future (such as
  [I-D.ietf-pce-lsp-control-request]) specifications that assign specific
  meanings to flags if set.

> W.r.t. obsoleting Flags vs. relying on "most implementations" to be
> consistent with this document's recommendations, is it worth being more
> clear about the conclusion that this document is drawing, namely that
> the risk of bad interactions is sufficiently small that there is no
> desire to incur the cost of obsoleting/replacing the Flags field?

How about
OLD
   Fortunately,
   however, most implementations will have been constructed to set
   unused flags to zero which is consistent with the behavior described
   in this document.
NEW
   Fortunately,
   however, most implementations will have been constructed to set
   unused flags to zero which is consistent with the behavior described
   in this document and so the risk of bad interactions is sufficiently
   small that there is no need to obsolete the existing Flags field.
END

Thanks,
Adrian