Re: [Roll] Remaining issues on draft-ietf-roll-nsa-extension

[Ines Robles <[e-mail]>]

Hi Aris,

On Tue, Mar 10, 2020 at 6:24 PM Remous-Aris Koutsiamanis <[e-mail]>
wrote:

> Two small issues remain:
>
> a) Compression of the PS IPv6 addresses.
> Rahul brought this up in his review, we mentioned that this was proposed
> before, implemented and then re-removed because of the plan to have a draft
> that performs compression on all RPL control traffic packets (following
> Pascal's and Dominique's advice).
> *Question: is there any chance this has changed and we might want to
> perform compression on the PS field specifically after all?*
>

I think the compression can take place in a separate draft.

>
> b) Change of the context of the PS NSA object from a constraint to a
> metric.
> Following  Dominique's suggestion we changed it from a constraint to a
> recorded (R=1), partial (P=1) metric (C=0).
> The issue is that we are extending MRHOF and MRHOF supports the use of a
> single metric for computing the rank.
> It is true that the PS NSA object is not used for rank calculation, and we
> have clarified this.
> However, there might be still a conflict or a point to be clarified.
> See in MRHOF Section 2 Terminology
> <https://www.rfc-editor.org/rfc/rfc6719.html#section-2>:
> "Selected metric:  The metric chosen for path selection by the network
> operator.  MRHOF supports using a single metric for path selection."
>

Maybe you could add this to the section 4 and explain how the extending
MRHOF address this point.

>
> VS our draft Section 5.1 "Usage"
> <https://tools.ietf.org/html/draft-ietf-roll-nsa-extension-07#section-5.1>
> :
> "It is important that the PS does not affect the calculation of the rank
> through candidate neighbors.  It is only used with the CA OF to remove
> nodes which do not fulfill the CA OF criteria from the candidate neighbor
> list."
> *Question: Is this sufficient in terms of explanation?*
>

Section 5 is clear to me.

Thank you,

Ines.

>
>
> We would really appreciate answers on these, if possible of course, before
> the ROLL meeting so that we can update/finalize the drafts.
>
> Kind regards,
> Aris & Georgios
>
>
>