I've read the text in -29, and I do think it's much better. Thank you. The "counterpart" sentence is followed immediately by "There are important differences", and maybe that's good enough. (Still concerned about this one sentence being taken out of context, but I'll just have to remain vigilant and point out the missing context if/when I see such things). Thank you.
Cleared my discuss. Thanks for your patience and effort! On Thu, Oct 1, 2020 at 4:06 AM Toerless Eckert <[email protected]> wrote: > On Wed, Sep 30, 2020 at 02:14:25PM +0000, Eric Vyncke (evyncke) wrote: > > About ULA, why not simply keeping: > > > > " ULA: (Global ID prefix) A "Unique Local Address" (ULA) is an IPv6 > > address in the block fc00::/7, defined in [RFC4193]." > > > > And nothing else of the existing paragraph. IMHO, there is no need to > justify the choice > > Eric: If we can not agree on a simple sentence comparing what we have in > IPv6 > with what we had in IPv4, we should stop writing RFCs or using IPv6. > > Eliot: Thanks for the "analog" suggestion, but i think "analog" is > semantically > close to "counterpoint", aka: suggesting a closer functional equivalence > with > rfc1918 than there actual is, so IMHO it would not resolve Eriks concern. > > Cheers > Toerless > > > > -éric > > > > ???-----Original Message----- > > From: Anima <[email protected]> on behalf of Toerless Eckert < > [email protected]> > > Date: Wednesday, 30 September 2020 at 15:55 > > To: Erik Kline <[email protected]> > > Cc: "[email protected]" <[email protected]>, " > [email protected]" < > [email protected]>, The IESG < > [email protected]>, "[email protected]" <[email protected]>, Sheng Jiang < > [email protected]> > > Subject: Re: [Anima] Erik Kline's Discuss on > draft-ietf-anima-autonomic-control-plane-28: (with DISCUSS and COMMENT) > > > > Inline > > > > On Sun, Sep 27, 2020 at 02:52:17PM -0700, Erik Kline wrote: > > > Toerless, > > > > > > Thanks for taking the time to go through all this. Generally > LGTM, but I > > > would like to iterate on the ULA text (nothing major). > > > > > > > > > > > [ section 2 ] > > > > > > > > > > * "It is the approximate IPv6 counterpart of the IPv4 private > address > > > > > ([RFC1918])." > > > > > > > > > > I understand the intent but I don't think this statement is > complete. I > > > > > think we shouldn't let this sentence out into the wild as is > since it > > > > could > > > > > be read without any context nor even any pretense of > interest in > > > > nuance. > > > > > > > > > > May I suggest: > > > > > > > > > > "It is often thought of as the approximate IPv6 counterpart > of the IPv4 > > > > > private address space ([RFC1918]), though it is in fact > meaningfully > > > > > different in important and subtle ways [and upon which this > document > > > > relies]." > > > > > > > > Thanks for not trying to talk me out of the comparison, which i > > > > successfully > > > > used to explain ULA to many customers. Your proposal is a bit > too verbose > > > > for > > > > the terminoloy section, so it's now: > > > > > > > > It is often thought of as the approximate IPv6 counterpart of > the IPv4 > > > > private address (<xref target="RFC1918" format="default"/>). > There are > > > > important differences though that are beneficial for and > exploited by the > > > > ACP, such as the ULA Global ID prefix, which are the first > 48-bits of a ULA > > > > address. In this document it is abbreviated as "ULA prefix". > > > > > > > > > > It's a statement of fact that this is how people unfamiliar with > this space > > > view this space. It's apparently also a statement of fact that > people are > > > still actively being told this. ;-) > > > > > > But I still think it's not quite right. For one, the real > counterpart to > > > 1918 in IPv6 is the deprecated site-local prefix. > > > > > > Also, to say it's "often > > > thought of" in an IETF document implies more IETF folks think of > this way, > > > when in reality I'm not sure that's the case. > > > > *cough* *cough* > > > > |> [ section 2 ] > > |> > > |> * "It is the approximate IPv6 counterpart of the IPv4 private > address > > |> ([RFC1918])." > > |> ... > > |> May I suggest: > > |> "It is often thought of as the approximate IPv6 counterpart of > the IPv4 > > |> private address space ([RFC1918]), though it is in fact > meaningfully > > |> different in important and subtle ways ... > > > > Aka: It is now your text that you would like to see revisited ! > > > > > If you really want to leave this notion in (removing the sentence > > > altogether is good by me), perhaps we can wordsmith it a bit > more. If I > > > may propose: > > > > How about: > > > > ULA: (Global ID prefix) A "Unique Local Address" (ULA) is an > IPv6 > > address in the block fc00::/7, defined in [RFC4193]. ULA is > the > > IPv6 successor of the IPv4 private address space ([RFC1918]). > > ULA have important differences over IPv4 private addresses > that > > are beneficial for and exploited by the ACP, such as the > Locally > > Assigned Global ID prefix, which are the first 48-bits of a > ULA > > address [RFC4193 section 3.2.1]. In this document this > prefix is > > abbreviated as "ULA prefix". > > > > Successor is hopefully more correct word. Sure, site local prefixes > > where a successor too, but i hope i do not have to write > > > > "ULA is the (only surviving) IPv6 successor..." > > > > > OLD: > > > > > > ULA: (Global ID prefix) A "Unique Local Address" (ULA) is an > IPv6 > > > address in the block fc00::/7, defined in [RFC4193]. It is > often > > > thought of as the approximate IPv6 counterpart of the IPv4 > private > > > address ([RFC1918]). There are important differences though > that > > > are beneficial for and exploited by the ACP, such as the ULA > > > Global ID prefix, which are the first 48-bits of a ULA > address. > > > In this document it is abbreviated as "ULA prefix". > > > > > > NEW: > > > > > > ULA: (Global ID prefix) A "Unique Local Address" (ULA) is an > IPv6 > > > address in the block fc00::/7, defined in [RFC4193]. > Sometimes > > > thought of as the approximate IPv6 counterpart of the IPv4 > private > > > address ([RFC1918]), there are important differences that are > > > beneficial for and exploited by the ACP. In this document, > the > > > "ULA prefix" refers to Locally Assigned Global ID prefixes, > which > > > are the first 48-bits of the ULA address [RFC4193 section > 3.2.1]. > > > > Beside the counterpart wordsmithing, > > i do not like the removal of pointing out that the ULA prefix is the > > new benefit of ULA that we exploit with ACP. That was at the core of > the > > explanation. > > > > > (I didn't think it was worth trying to get into the fc00::/8 vs > fd00::/8 > > > distinction in this glossary text.) > > > > I agree, but i do not see neither the glossary or the rest of the > text > > doing that. The spec part just specifies use of fd00:/8 without > > discussion and the glossary just uses the ::/7 as thats what rfc4193 > say.. > > Am i missing something ? > > > > > > [ section 8.1.3 ] > > > > > > > > > > * Why is an RIO for ::/0 with a lifetime of 0 required? > Doesn't it > > > > suffice > > > > > it set the default router lifetime to 0? Separately, are > all nodes > > > > required > > > > > to be Type C? > > > > > > > > Check the new text, i hope it explains everything. > > > > > > > > Yes, type A and B do not support per-prefix auto selection of > router, > > > > The lifetime of 0 is used so only Type C hosts will invalidate > the > > > > default route for the ACP edge node, but not Type A/B hosts. > Maybe there > > > > is another parameter combination that achieves this goal, but > this was > > > > the easiest for me to assess/describe. > > > > > > > > > > This looks better, thank you. > > > > > > To be honest, I don't know what the point of Type A/B hosts is > anymore (and > > > if it were possible to declare these anima deployments greenfield > I would > > > recommend saying the default router lifetime MUST be zero in the > RA header > > > to force clients to use a stack that works -- but that's just me). > > > > I would guess that A and B have been seen in the wild before 4191 was > > released and so the RFC was written to be inclusive. No idea. > > > > I have no idea how prevalent these types are, and the current > described > > method may be a tiny bit more convoluted but seems to be more > compatible. > > > > Given my deployment experience of enterprises withholding from > adopting > > new network technology when it wasn't compatible with their oldest > > NMS equipment, i am a bit burned in promoting "hard cut" solutions, > and > > this ben an OPS area draft instead of e.g.: RTG is a good excuse for > that > > approach ;-)) > > > > Cheers > > Toerless > > > > _______________________________________________ > > Anima mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/anima > > > > -- > --- > [email protected] >
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