Re: [Softwires] [Softwire] draft-ietf-softwire-map-00 does NOT reflect the consensus from the WG

[Wojciech Dec <[e-mail]>]

Hi,

taking a step back to discuss some items in more detail, and hopefully move
this discussion forward:

1. Domain size
The MAP architecture does not prescribe the size of a domain, and neither
does it prescribe the number of rules to be used. There is nothing in the
technology, except vendor implementation limits or practical sense (or
both), to prevent MAP domains from defining 1 domain = 1 CPE. This was a
day 1 characteristic of MAP drafts.
Choosing to deploy or implement MAP with a configuration supporting 1 rule,
100 rules or 100k rules or domains is a vendor's and/or operator's choice.
Nobody is stating that deployment is to be limited to X rules, nor that a
near infinite number of rules is reasonable. These are general points that
apply to DS-lite state as well as the "Light Weight 4 over 6" or "stateless
deterministic NAT", and pretty much any technology for that matter.

2. Stateless DOES NOT mean configuration-less
There appears to be confusion between the concept of stateless and
configuration-less. MAP domains are based on configured rules, that are
provisioned/applied through means that are currently outside the scope of
Softwire drafts - this is configuration state, and this was and continues
to be a characteristic of MAP.
Further more, unlike some of the other proposals, MAP allows to optimize
the amount of configuration needed in cases where this is viable. In other
words, MAP does NOT exclusively force 1:1 rule configuration, but also
allows N:1.

3. Stateless has no data plane induced state
A major difference between stateless (eg MAP) and stateful (eg Carrier
Grade NAT44/Ds-Lite) solutions is that the latter are characterised by
dynamic core node forwarding state that is directly driven by user
data-plane traffic (eg new IP flows). MAP does not rely on such dynamic
state, never did.

4. No change of MAP spec
The updated MAP draft does not change the MAP architecture nor its
technical underpinnings. In fact there are no changes, bar editorial to the
normative parts of MAP, something that is proven by existing
implementations prior to this draft supporting the current draft. A few
individuals appear to object to new descriptive text which highlights the
usage of MAP, eg in 1:1. Removing that text will not change the matter that
MAP allows such usage. Prohibiting such use by specification would actually
require a spec change, besides being unreasonable.

5. What is the problem?
We're  pleased to see a growing understanding of MAP's applicability to
solve problems, incl v4-v6 address independence, when needed. Given that
the emails on this thread do not appear to bring forward any technical
issues with the MAP solution, could we know WHY we need other solutions to
the problem, or what is the problem that remains to be solved?

Taking the liberty to speak on behalf of the other MAP authors, I would
like to say that we all remain open for collaboration with all WG members
in terms of arriving at a minimal set of reasonable solutions that solve
problems that the community cares about. We also trust that our renewed WG
leadership will finally help us all in getting there.

Regards,
Woj.

On 25 June 2012 08:51, Qi Sun <[e-mail]> wrote:

> **
> Hi Satoru,
>
> In MAP 1:1 mode, if there are 10000000 subscribers, there would be
> 10000000 MAP domains which a BR has to manage. I think that will create a
> huge mapping table on the BR, which is called 'state' that stateful
> solutions deal with.
>
> Best Regards!
>
> ------------------------------
> Qi Sun
>
>  *From:* Satoru Matsushima <[e-mail]>
> *Date:* 2012-06-25 10:27
> *To:* Lee, Yiu <[e-mail]>
> *CC:* [e-mail]; Yong Cui <[e-mail]>
> *Subject:* Re: [Softwires] [Softwire] draft-ietf-softwire-map-00 does NOT
> reflect the consensus from the WG
>  Hi Yiu,
>
> No, that's a misunderstanding.
>
> Current MAP specify the case for ea-len is 'zero'. It is 'per-subscriber mapping' in stateless manner, not to introduce 'per-flow NAT binding' or 'per-subscriber state on demand'.
>
> cheers,
> --satoru
>
> On 2012/06/25, at 2:32, Lee, Yiu wrote:
>
> > Dear Satoru and MAP-DT
> >
> > I echo what Peng and Qiong said. When the WG agreed working on the
> > stateless solution, it was very clear stated that the solution would not
> > maintain states in the network. If the 1:1 mode changed this, this no
> > longer matched the requirements stated in the stateless motivation draft,
> > thus, it would disqualify MAP as a solution for the motivation draft.
> >
> > AFAIK, the MAP Design Team could propose a change, but such a dramatic
> > change by introducing states in the network would require WG approval. I
> > would like the chairs to clarify this.
> >
> > Thanks,
> > Yiu
> >
> >
> > On 6/24/12 12:21 PM, "Peng Wu" <[e-mail]> wrote:
> >
> >> Hi Qiong, Satoru and all,
> >>
>
> >> I should thank Qiong for pointing this out. I gotta say I'm a bit shocked.
> >> If I understand the procedures of IETF correctly, a WG document should
> >> reflect the consensus of the WG. MAP is approved by the WG as a
> >> stateless solution. As a participator in Softwire, I didn't get the
> >> information anywhere that the MAP WG document would cover the
> >> so-called 1:1, in fact per-user stateful mode before it was released,
> >> not to say discuss in the WG. Don't the WG need to approve such big
> >> change anymore?
> >>
> >> Now let me provide my impression as an outsider of the MAP DT. You
> >> guys make great effort to build the solution, The address composition,
> >> the GMA algorithm, the different types of address mapping rules.
> >> should be quite difficult to pull together such sophisticated ideas. I
> >> guess that's what it takes to achieve the benifits of statelessness.
> >> And I admire that, bravo. Then, all of a sudden, you guys are saying,
> >> let's apply this sophisticated method to the different problem, by
> >> dropping quite some comlexity and twistting the mechanism a bit, seems
> >> it may work. Considering the problem are now solved in a more pure and
> >> clear way, I'm sorry but I CANNOT follow the logic here.
> >>
> >> On Sun, Jun 24, 2012 at 2:00 PM, Satoru Matsushima
> >> <[e-mail]> wrote:
> >>> Hi Qiong,
> >>>
> >>> I'm disagree with your opinion.
> >>>
> >>> 1. Recent changes in draft-ietf-softwire-map-00 has been discussed in
> >>> the DT.
> >>> 2. MAP just covers so called '1:1 mode' with most granular mapping rule
> >>> for CEs provisioning, which is as one of its characteristics.
> >>> 3. The motivation draft does not restrict that as you stated, just
> >>> 'assumed', it's neither 'MUST' nor 'SHOULD'.
> >>>
> >>> Best regards,
> >>> --satoru
> >>>
> >>>
> >>> On 2012/06/24, at 14:35, Qiong wrote:
> >>>
> >>>> Hi all,
> >>>>
> >>>> As we all know, once an individual draft is adopted as a WG draft, it
> >>>> is owned by the whole WG, rather than just the editors. Just as Remi
> >>>> said, the normal procedure to follow is to reach WG consensus _before_
> >>>> posting a newly edited version.
> >>>>
> >>>> From draft-mdt-softwire-mapping-address-and-port-03 to
> >>>> draft-ietf-softwire-map-00, there are several changes between them. In
> >>>> particular, the newly introduced "1:1 mode", which decouples IPv4 and
> >>>> IPv6 addressing, has never been discussed openly in the WG mailing
> >>>> list, or even in the MAP design team either.
> >>>>
> >>>> Actually, this "1:1 mode" is against the stateless-4v6-motivation
> >>>> draft. The motivation draft has clearly defines the "Stateless 4/6
> >>>> solution" as follows:
> >>>>
> >>>> Stateless 4/6 solution denotes a solution which does not require any
> >>>> per-user state (see Section 2.3 of [RFC1958]) to be maintained by any
> >>>> IP address sharing function in the Service Provider's network. This
> >>>> category of solutions assumes a dependency between an IPv6 prefix and
> >>>> IPv4 address.
> >>>>
> >>>> AFAIK what the WG has adopted MAP related draft is
> >>>> draft-mdt-softwire-mapping-address-and-port-03, NOT
>
> >>>> draft-ietf-softwire-map-00. And the stateless solution should ³response
>
> >>>> to the solution motivation document² according to the Softwire charter.
>
> >>>> That means draft-ietf-softwire-map-00 IS NOT QUALIFIED to be a WG draft.
> >>>>
> >>>> We can all recall that our softwire WG has worked on stateless
> >>>> solutions for more than one and a half years, and we have achieved a
>
> >>>> lot of work which has been documented in charter, stateless motivation,
> >>>> 4rd-varients, MAP-03, etc. AFAIK all the authors have kept the basic
> >>>> "stateless" principle and the MAP design team is also working on it
> >>>> together to find a better algorithm, address format, etc. So it is
>
> >>>> really not appropriate to make such changes when MAP is adopted as a WG
> >>>> item in such a short time.
> >>>>
> >>>> From this perspective, draft-ietf-softwire-map-00 can only be regarded
> >>>> as draft-XX-softwire-mapping-address-and-port-04. It is not even the
> >>>> output of MAP design team.
> >>>>
> >>>> Best wishes
> >>>>
> >>>> ==============================================
> >>>> Qiong Sun
> >>>> China Telecom Beijing Research Institude
> >>>>
> >>>>
> >>>> Open source code:
> >>>> lightweight 4over6: http://sourceforge.net/projects/laft6/
> >>>> PCP-natcoord: http://sourceforge.net/projects/pcpportsetdemo/
> >>>> ===============================================
> >>>>
> >>>>
> >>>> _______________________________________________
> >>>> Softwires mailing list
> >>>> [e-mail]
> >>>> https://www.ietf.org/mailman/listinfo/softwires
> >>>
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