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

Martin Duke <martin.h.duke@gmail.com> Fri, 18 September 2020 21:03 UTC

Return-Path: <martin.h.duke@gmail.com>
X-Original-To: roll@ietfa.amsl.com
Delivered-To: roll@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 714393A10EB; Fri, 18 Sep 2020 14:03:05 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.097
X-Spam-Level:
X-Spam-Status: No, score=-2.097 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.com
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 25MTKyVqhyDe; Fri, 18 Sep 2020 14:03:03 -0700 (PDT)
Received: from mail-il1-x135.google.com (mail-il1-x135.google.com [IPv6:2607:f8b0:4864:20::135]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 815F73A10E6; Fri, 18 Sep 2020 14:03:03 -0700 (PDT)
Received: by mail-il1-x135.google.com with SMTP id y9so7707876ilq.2; Fri, 18 Sep 2020 14:03:03 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=w+L95Qw014844WjUBbiKDb/ePmMuJVTn+y2SJB6SyaI=; b=IAIW3H7C3a9eZR31V15H1C3O4AFrA/kSC4Dh+iKaGg2ULGKD2TedIpeOYPxZFwnzf5 aqt0ejSBio6sJxXw4thA9W/dBFH/8zV467Y3qqXTpuS7jnmmx3aQffJUKpGq3eruIoez 9+Js07Vf3bsHfDsB1ojhwyMUYkhTDXjzm5d0FyLgM4NHln45cEZ5vW39ewRDign8/sHN A/CZfO2IX1aLgB2Rkk4s2PVCSknIdF4ZYRljsol8TAb5RUNO1Ymntfbt0fSaBWwMfYFl G/4WBnboEZc3oyRywy/v4zIvz5DnsemDi/TfaK6b0ayzACzf3zXZsUyz2THMQtnyGLLY jwsQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=w+L95Qw014844WjUBbiKDb/ePmMuJVTn+y2SJB6SyaI=; b=OnJSerEhp3kdh5oVcmv4UMJiLPdD76ofX28Bnos3e7b05dcdX0nXk0FV4TbasXrMpH 4Ri8jRfkYkISWpFl/ycs/7VjDenFCNIAClBmzmhCqm0ejFNs8RBBNNPE46pwFRVU5lzR G0kaCEWVWcz0Crr776ZaS6/aFiFot5MrbV2bmyTLPXBnzcF3Bh43xnpaifWWB2+NOWpj SoQLNV5rshLk96ssGBlj4oGSBcq9ljUBjFKCoGN2u2AKtHnlkJ/4A0hRnWeswa7BZKpw K71xw76eMFf0faTqaKW1EJ2wrmzAadbQcT50UDrZQVugwCc+AvOlC77NRV1P29j9Er2A +aLg==
X-Gm-Message-State: AOAM53257WnQBqxDHS9aGHXhcLTqxZYDE14EwDnP+ykX127Lcmqz7dG+ eS+A8JQsYhUyKVqJlY/Tfvp1VfjCnTvJmoVAjv0=
X-Google-Smtp-Source: ABdhPJzWw5/CCWwaalbAHR7L3lMLCHeeIBzgxBy88EvOaBS26CJ79HyerYvNPl0E+sFqXDTf5MmkAG0Xnrn+YPLgqlQ=
X-Received: by 2002:a92:c60d:: with SMTP id p13mr26032145ilm.272.1600462982611; Fri, 18 Sep 2020 14:03:02 -0700 (PDT)
MIME-Version: 1.0
References: <159968972884.1065.3876077471852624744@ietfa.amsl.com> <MN2PR11MB35659A0710E687A7C9995E6ED8270@MN2PR11MB3565.namprd11.prod.outlook.com> <20200910200744.GE89563@kduck.mit.edu> <17053.1599841430@localhost> <20200911162617.GQ89563@kduck.mit.edu> <8F19C753-DCA0-4A32-BA3B-A124B2F7F745@cisco.com> <MN2PR11MB3565F2602A0DC55DE9FF3604D83F0@MN2PR11MB3565.namprd11.prod.outlook.com> <CAM4esxQBL+4wNzJTZ_+QKMCGuo4fgyxZKxr3xmFDVEAn9J7HLQ@mail.gmail.com> <E8B2CE91-7FEE-4728-A280-935B69EF3E91@cisco.com>
In-Reply-To: <E8B2CE91-7FEE-4728-A280-935B69EF3E91@cisco.com>
From: Martin Duke <martin.h.duke@gmail.com>
Date: Fri, 18 Sep 2020 14:02:50 -0700
Message-ID: <CAM4esxQpcWROj9mMd3iUXr1EF8kvoF8Zmq-w4BPFVW+BtDU93w@mail.gmail.com>
To: "Pascal Thubert (pthubert)" <pthubert@cisco.com>
Cc: "Pascal Thubert (pthubert)" <pthubert=40cisco.com@dmarc.ietf.org>, Benjamin Kaduk <kaduk@mit.edu>, Alvaro Retana <aretana.ietf@gmail.com>, "roll-chairs@ietf.org" <roll-chairs@ietf.org>, Michael Richardson <mcr+ietf@sandelman.ca>, Routing Over Low power and Lossy networks <roll@ietf.org>, Ines Robles <mariainesrobles@googlemail.com>, "draft-ietf-roll-turnon-rfc8138@ietf.org" <draft-ietf-roll-turnon-rfc8138@ietf.org>, The IESG <iesg@ietf.org>, Alvaro Retana <aretana.ietf@yahoo.com>
Content-Type: multipart/alternative; boundary="0000000000008e089d05af9cd30d"
Archived-At: <https://mailarchive.ietf.org/arch/msg/roll/uwyOmbWqJ1GlOlYEV6UTmhuKomU>
X-Mailman-Approved-At: Fri, 18 Sep 2020 22:32:26 -0700
Subject: Re: [Roll] Benjamin Kaduk's Discuss on draft-ietf-roll-turnon-rfc8138-14: (with DISCUSS and COMMENT)
X-BeenThere: roll@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Routing Over Low power and Lossy networks <roll.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/roll>, <mailto:roll-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/roll/>
List-Post: <mailto:roll@ietf.org>
List-Help: <mailto:roll-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/roll>, <mailto:roll-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 18 Sep 2020 21:03:06 -0000

Again, I don't understand the protocol evolution model here, but isn't the
coder *already* in a fix if she encounters an unknown MOP?

On Fri, Sep 18, 2020, 13:48 Pascal Thubert (pthubert) <pthubert@cisco.com>
wrote:

> It’s not an easy one Martin
>
> With this bit we cover a transition after which we reclaim the bits. So we
> want a time bomb.
>
> After the transition the thing signaled by the bit will be always on.
>
> For a number of reasons there will be a RPLv2 and that one we decided will
> have MOP7.
>
> The leaves 5 and 6 that can still be defined with the bits meaningful.
> Those may never be defined.
>
> The question is what the cider does today in his code for those value of
> MOP. We need to tell him something...
>
> Keep safe.
>
> Pascal
>
> Le 18 sept. 2020 à 19:44, Martin Duke <martin.h.duke@gmail.com> a écrit :
>
> 
> So I think this update somewhat clarifies the meaning of the original
> text, but I am still somewhat concerned about that meaning. Perhaps I just
> don't understand how DIO versioning works.
>
> Are the MOP codepoints meant to represent different ways of parsing the
> DIO base object? It seems very odd to me that this document is describing
> behavior in any way for MOP 5 and up, as there is no IETF consensus on what
> these codepoints are going to represent. Is the intent of this language to
> avoid having to write in every future specification "nodes using this MOP
> MUST use RFC 8138 and the T bit is reserved."?
>
> On Fri, Sep 18, 2020 at 7:15 AM Pascal Thubert (pthubert) <pthubert=
> 40cisco.com@dmarc.ietf.org> wrote:
>
>> Hello Benjamin and Alvaro
>>
>> I published the latest to have a fresh reference point.
>>
>> There seems to be an agreement that
>> 1) we need to tell the implementer what to do when MOP ==7
>> 2) The changes are updating RFC 6550 formally.
>>
>> This is reflected in draft 15 as published.
>>
>> Please let me know if I mossed something!
>>
>> Take care,
>>
>> Pascal
>>
>> Pascal
>>
>> > -----Original Message-----
>> > From: Pascal Thubert (pthubert)
>> > Sent: vendredi 11 septembre 2020 21:17
>> > To: Benjamin Kaduk <kaduk@mit.edu>
>> > Cc: Michael Richardson <mcr+ietf@sandelman.ca>ca>; Routing Over Low power
>> > and Lossy networks <roll@ietf.org>rg>; roll-chairs@ietf.org; Alvaro Retana
>> > <aretana.ietf@yahoo.com>om>; Ines Robles <mariainesrobles@googlemail.com>om>;
>> > draft-ietf-roll-turnon-rfc8138@ietf.org; The IESG <iesg@ietf.org>
>> > Subject: Re: [Roll] Benjamin Kaduk's Discuss on
>> draft-ietf-roll-turnon-rfc8138-
>> > 14: (with DISCUSS and COMMENT)
>> >
>> > Now I’m unsure Michael and I agree anymore.
>> >
>> > What will today’s developer code?
>> >
>> > We ask him to test if mop is < 7
>> >
>> > What value will the developer place in his code if the test returns
>> false?
>> >
>> > If there is no code the Boolean will be uninitialized and the result
>> will depend
>> > on the type of variable and the compiler.
>> >
>> > Whatever the developer does the code will end up having a behavior,
>> > compression or not.
>> >
>> >  Leaving it to the implementation will have some people choose true and
>> > others false. This is not what we want.
>> >
>> > We want to control what the code does so we can expect it in the future
>> and
>> > build our backward compatibility based on that sure knowledge.
>> >
>> > Before the draft the default was no compression. Quite naturally since
>> initially
>> > it did not exist.
>> >
>> > Also we discussed on the ML that for RPLv2 all implementations MUST
>> support
>> > the compression.
>> >
>> > In which case it is a better default for a coder today to decide to use
>> the
>> > compression for mop 7, isn’t it?
>> >
>> > I hope I make the case right. Just think you’re coding it!
>> >
>> > Take care,
>> >
>> > Pascal
>> >
>> > > Le 11 sept. 2020 à 18:26, Benjamin Kaduk <kaduk@mit.edu> a écrit :
>> > >
>> > > On Fri, Sep 11, 2020 at 12:23:50PM -0400, Michael Richardson wrote:
>> > >>
>> > >> Benjamin Kaduk <kaduk@mit.edu> wrote:
>> > >>> to MOPs 0..6; but the situation for MOP 7 seems slightly different.
>> > >>> If we were *just* leaving the bit undefined/free for reuse in that
>> > >>> situation, that is probably also something that we can do in a
>> > >>> normal "allocate a bit from an IANA registry" document without need
>> for
>> > Updates.
>> > >>
>> > >> Up to here, we agree.
>> > >>
>> > >>> But that's not
>> > >>> all we're doing; we're also saying that if you see MOP==7, then you
>> > >>> have to use the 8138
>> > >>> header/compression/whatever-we-end-up-calling-it.  Yet we are
>> > >>> *not* allocating MOP==7.
>> > >>
>> > >> Tthat's exactly what we don't want to do.
>> > >>
>> > >> We are saying NOTHING about rfc8138 when MOP==7.
>> > >> Nor are we saying that the T-bit exists (or doesn't exist).
>> > >
>> > > That's not how I read:
>> > >
>> > >       For a MOP value of 7, the compression MUST be used by default
>> > >   regardless of the setting of the "T" flag.
>> > >
>> > >
>> > >> What behaviour is default and what behaviour is negotiated, and how
>> > >> it it negotiated, and how the results are turned on, would be up to a
>> > >> document that specifies MOP=7 (or larger mopex)
>> > >
>> > > What you describe here is more along the lines of what I expected.
>> > >
>> > > -Ben
>> > >
>> > >> As an analogy, when we did the ToS->DSCP + bits-that-became-ECN
>> > >> change, we did this for IP_version==4 and IP_version==6.
>> > >> We specifically did not change it for IP_version==7 or 8.
>> > >>
>> > >> --
>> > >> Michael Richardson <mcr+IETF@sandelman.ca>   . o O ( IPv6 IøT
>> consulting )
>> > >>           Sandelman Software Works Inc, Ottawa and Worldwide
>> > >>
>> > >
>> > >
>>
>