Re: [Roll] I-D Action: draft-ietf-roll-nsa-extension-02.txt

"Georgios Z. Papadopoulos" <georgios.papadopoulos@imt-atlantique.fr> Mon, 01 July 2019 15:51 UTC

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From: "Georgios Z. Papadopoulos" <georgios.papadopoulos@imt-atlantique.fr>
In-Reply-To: <MN2PR11MB35659CC596E5F23ED47CFC9AD8F90@MN2PR11MB3565.namprd11.prod.outlook.com>
Date: Mon, 01 Jul 2019 17:51:40 +0200
Cc: "dominique.barthel@orange.com" <dominique.barthel@orange.com>, Routing Over Low power and Lossy networks <roll@ietf.org>, Aris <aris@ariskou.com>
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References: <156139562335.17453.10181644975970552720@ietfa.amsl.com> <CAK76Pr=cOTdAfnxyC9Bq2BPqEzwsH=2LvbZsGuSJjuV6uyvqrQ@mail.gmail.com> <20818_1561994784_5D1A2620_20818_214_5_D93FEF87.62BE1%dominique.barthel@orange.com> <MN2PR11MB35659CC596E5F23ED47CFC9AD8F90@MN2PR11MB3565.namprd11.prod.outlook.com>
To: "Pascal Thubert (pthubert)" <pthubert@cisco.com>
Archived-At: <https://mailarchive.ietf.org/arch/msg/roll/6Mue53u0bU-a0-hrtcxnwbIgIGM>
Subject: Re: [Roll] I-D Action: draft-ietf-roll-nsa-extension-02.txt
Precedence: list

Hello Pascal,

Below is the summarized discussion.

Basically, is it good idea to use capitalized "SHOULD”" or lower case “should” when talking about compressing the parent address list.
In the draft we suggest using a implementation similar to SRH-6LoRH for the IPv6 address (which we have implemented in Contiki btw).
However, its similar but not identical to the one in SRH-6LoRH.
Dominique says, if we use capitalized “SHOULD” then it might create problems in the WGLC, if we do not have have an explicit spec.
Thus, in the -3 version we have used lower case "should”.

What do you think?
Georgios and Aris

— — — 

Happy to contribute : )

Can someone summarize the discussion?

All the best,

Pascal

> On Jul 1, 2019, at 17:44, Pascal Thubert (pthubert) <pthubert@cisco.com> wrote:
> 
> Section 4.2: "Therefore, the PS IPv6 address(es) field SHOULD be compressed using the compression method for Source Routing Header 6LoRH (SRH-6LoRH)". I understand that a similar compression mechanism could be used. However, this requires defining a protocol element that does not exist today, unless I missed something. Therefore, the normative SHOULD is irrelevant. I guess this section is merely suggesting future work. 
> We do have this almost fully implemented (almost: only works in single root RPL instances).
> Would it make sense to spell out the exact specification of the compression even if it is largely a copy of the SRH-6LoRH compression method?
> I can lowercase the SHOULD, but using this kind of compression really makes big difference in practice.

> [DB] talk to Pascal about this, he looks pretty knowledgeable in SHOULDs. Anyway, if you capitalise SHOULD, then you have to explain the consequences of not following the recommendation. Whereas if you lowercase it, it's only free advice. You can stil explain why you think it is a good idea. My worry is that a capitalised SHOULD here will stop the draft later in the IESG processing because you are referring to a non-existent specification (formally speaking). Again, ask Pascal, I totally trust him on this question.

[Roll] I-D Action: draft-ietf-roll-nsa-extension-… internet-drafts
Re: [Roll] I-D Action: draft-ietf-roll-nsa-extens… Remous-Aris Koutsiamanis
Re: [Roll] I-D Action: draft-ietf-roll-nsa-extens… dominique.barthel
Re: [Roll] I-D Action: draft-ietf-roll-nsa-extens… Pascal Thubert (pthubert)
Re: [Roll] I-D Action: draft-ietf-roll-nsa-extens… Georgios Z. Papadopoulos
Re: [Roll] I-D Action: draft-ietf-roll-nsa-extens… dominique.barthel
Re: [Roll] I-D Action: draft-ietf-roll-nsa-extens… Pascal Thubert (pthubert)
Re: [Roll] I-D Action: draft-ietf-roll-nsa-extens… Remous-Aris Koutsiamanis