Re: [Roll] Benjamin Kaduk's Discuss on draft-ietf-roll-turnon-rfc8138-14: (with DISCUSS and COMMENT)

[Benjamin Kaduk <[e-mail]>]

Hi Pascal, all,

Thanks for the updated drafts; I'm happy to see that useofrplinfo is
marking MOP 7 as "special" with respect to the flags registry.

That said, and my apologies for a hazy memory coming back to this after a
couple months, in a year or N from now when mopex is finalized, how will
someone looking at mopex know to use RFC8138 on links where 6LoWPAN Header
Compression applies (and not use it otherwise)?  We are claiming in the -14
of this document that:

                              For a MOP value of 7, [RFC8138] MUST be
   used on Links where 6LoWPAN Header Compression [RFC6282] applies and
   MUST NOT be used otherwise.

but I am not sure (or have forgotten) what the chain of references is
supposed to lead someone who is implementing RPL plus MOP=7 to the
requirement to use RFC 8138.  I don't think we should just rely on the
mopex text to do so, since we are trying to impose the requirement with
this document (which predates mopex by some time), and there's not anything
(other than our collective memories, of course) requiring mopex to remain
consistent with that requirement.

Thanks,

Ben

On Wed, Sep 30, 2020 at 04:25:10PM +0000, Pascal Thubert (pthubert) wrote:
> Hello Alvaro
> 
> I uploaded both draft with the suggested update, please see
> 
> https://tools.ietf.org/rfcdiff?url2=draft-ietf-roll-turnon-rfc8138-17.txt
> https://www.ietf.org/rfcdiff?url2=draft-ietf-roll-unaware-leaves-21.txt
> 
> Keep safe
> 
> Pascal
> 
> > -----Original Message-----
> > From: Alvaro Retana <[e-mail]>
> > Sent: jeudi 24 septembre 2020 17:49
> > To: Pascal Thubert (pthubert) <[e-mail]>
> > Cc: Benjamin Kaduk <[e-mail]>; The IESG <[e-mail]>; draft-ietf-
> > [e-mail]; Martin Duke <[e-mail]>;
> > Routing Over Low power and Lossy networks <[e-mail]>; roll-
> > [e-mail]; Michael Richardson <[e-mail]>
> > Subject: Re: [Roll] Benjamin Kaduk's Discuss on draft-ietf-roll-turnon-rfc8138-
> > 14: (with DISCUSS and COMMENT)
> > 
> > On September 24, 2020 at 8:13:09 AM, Pascal Thubert wrote:
> > 
> > 
> > Pascal:
> > 
> > Hi!
> > 
> > > Following the meeting last Monday and subsequent the update of
> > > useofrplinfo by Michael (thanks Michael!) I published a new version of
> > > the turnon RFC
> > > 8138 draft.
> > >
> > > The major changes are
> > > - removed the formal update to RFC 6550
> > > - refer to useofrplinfo as the justification why the flag is not
> > > defined for MOP 7
> > > - defined the operation in MOP 7 as compression on iff the Link uses
> > > 6LoPWAN HC.
> > 
> > Thanks for these changes.
> > 
> > Because we have to cycle useofrplinfo back through (when the WG is done
> > with it), I asked Ben/Martin to wait for that before coming back to this
> > document.  It'll make it easier than tracking multiple changes. :-)
> > 
> > 
> > OTOH, I do have comments on the recent change:
> > 
> > OLD>
> >    Section 4.3 of [USEofRPLinfo] updates [RFC6550] to indicate that the
> >    definition of the Flags applies to Mode of Operation (MOP) values
> >    zero (0) to six (6) only, leaving the flags reserved for MOP value
> >    seven (7).  For a MOP value of 7, the bit in position 2 is considered
> >    unallocated and [RFC8138] MUST be used on Links where 6LoWPAN Header
> >    Compression [RFC6282] applies and MUST NOT be used otherwise.
> > 
> > NEW>
> > 
> >    Section 4.3 of [USEofRPLinfo] updates [RFC6550] to indicate that the
> >    definition of the Flags applies to Mode of Operation (MOP) values zero (0)
> >    to six (6) only.  For a MOP value of 7, [RFC8138] MUST be used on Links
> >    where 6LoWPAN Header Compression [RFC6282] applies and MUST NOT be
> > used
> >    otherwise.
> > 
> > 
> > Thanks!
> > 
> > Alvaro.