Re: [secdir] Secdir last call review of draft-ietf-lsr-isis-fast-flooding-07

["Les Ginsberg (ginsberg)" <[e-mail]>]

Bruno/Barry -

In regards to:

> > — Section 4.4 —
> >
>    > Length: Indicates the length in octets (1-8) of the Value field.  The
>    > length SHOULD be the minimum required to send all bits that are set.
> >
> > The SHOULD seems very odd: what would be a good reason to make it
> longer than necessary?  Is there a real reason not to straightforwardly say,
> “The length is the minimum required…”?
> 
> [Bruno] To be honest, that's just verbatim copy from
> https://datatracker.ietf.org/doc/html/rfc8919#name-application-identifier-
> bit-
> At the time, I had assumed that copying an already agreed upon sentence
> from an RFC was simplifier and safer. Looks like I was only 50% right 😉.
> You have a good point. I can't find a legitimate reason.
> I used your proposed wording (although my natural inclination would have
> used a "MUST")
> 
[LES:] The reason RFC 8919 uses SHOULD - and why this draft should do the same - is that sending additional bits unnecessarily is not incorrect - it is simply inefficient.
If you use "MUST" you are stating that receivers are obligated to reject a correct advertisement simply because it is unnecessarily long.
This is unwise and counterproductive.
As a WG member and co-author I object to this change.

HTH

   Les