Re: draft-narten-ipv6-3177bis-48boundary-02.txt

[JORDI PALET MARTINEZ <jordi.palet@consulintel.es>]

Hi Thomas,

Below, in-line.

Regards,
Jordi

> De: Thomas Narten <narten@us.ibm.com>
> Responder a: <owner-v6ops@ops.ietf.org>
> Fecha: Thu, 13 Jul 2006 09:30:19 -0400
> Para: <jordi.palet@consulintel.es>
> CC: <ipv6@ietf.org>, <v6ops@ops.ietf.org>
> Asunto: Re: draft-narten-ipv6-3177bis-48boundary-02.txt
> 
> Hi Jordi.
> 
>> Hi all,
> 
>> I've reviewed this document and my comments are as follows.
> 
>> 1. Introduction
>> "giving out an excessive". I think we need to define excessive
>> and/or say if this is an objective or subjective perception.
> 
> I have two repsonses to this.
> 
> First. giving out a /48 to every home network (which today has at most
> a handful of machines, which means, one subnet would suffice) is

Part of the problem is what each of us considers enough, and this may depend
on knowledge about developments being cooked, which bring the need of more
than 256 subnets, even if you have only a handful of devices in each one.

> widely viewed as excessive. Even a /56 to such end sites seems more
> than enough space to meet needs for at least the next decade (and most
> people seem to be comfortable with that, even if it is a lot of
> space). You've been to RIR meetings. Surely you have noticed this

Yes, having been in probably all the RIR meetings in the last 3 years or so,
my perception is that people is divided in both sides, but there is not a
clear view that one or the other is good. In concrete regions this becomes
more balanced to one side or the other.

Moreover, most of the people talking about this has the view of "/48 is bad"
because they don't understand the scale of magnitude vs. IPv4, they are some
how "IPv4 old fashioned mind set".

The perception was even worst because the previous HD-ratio.

However, now that the HD-ratio change has been accepted in all the regions,
the perception of /48 being a waste, is not realistic.

I recall Tony Hain figures with the HD-ratio change of about 480 years or
so. I think even if we are mistaken by let's say 250-300 years, assuming
that our conservation principles need to account for that much time is
extra-conservation and that can be considered even worst than being
wasteful.

Do we really believe IP will still be sufficient at that time for our needs
?

> sentiment both in the hallway and in comments made (regularly) at the
> microphone.
> 
> But more to the point, the current text in the document actually says:
> 
>    There are a number of considerations that factor into address
>    assignment policies. For example, to provide for the long-term health
>    and scalability of the public routing infrastructure, it is important
>    that addresses aggregate well. Likewise, giving out an excessive
>    amount of address space could result in premature depletion.
> 
> How can you possibly object to the use of the word excessive in the
> above context?   

I think is subjective, as explained above with the perception of what is
wasteful and what not from different people.

However, as the text say, it is important that addresses aggregate well, so
I just noticed that this seems to be in favor of my argument, seems better a
balance between more addresses and less "address blocks" (so bigger blocks),
while we aren't wasting space, as it helps avoiding future deaggregation.

Note I'm not saying that RFC3177 is perfect anymore.

> 
>> A general comment/opinion. I don't think this document should be
>> published as is, because it provides a bad message to the market
>> about IPv6 assignment recommendations not being stable. I will be in
>> favor of a "smaller" revision of RFC3177, not so much disruptive as
>> this one, but in the other way around, discouraging /128 and /64
>> assignments.
> 
> As you know, policy proposals to move away from /48 are currently
> being discussed in the indvidual RIR regions. Indeed, ARIN has already
> adopted one
> (http://www.arin.net/policy/proposals/2005_8.html). Publishing this

Yes, and ARIN is the only one that approved it at the time being. At least
in three other regions, my recall is that has been rejected for further
discussion in the list, which will need probably an average of 1 year to be
again considered for approval.

> document will not stop the registries from moving away from
> /48. Indeed, a primary goal is to make it clear that making such a
> decision is for the RIRs to make (i.e., to acknowledge reality), and
> that from an IPv6 architectural perspective, this is fine.

I think we have a disagreement here. It is true that there is not a strict
technical reason for using something different than /48 which may affect
protocols, however, there are other operational reasons which are of the
same relevance.

That's why RFC3177 was not mandating, but providing guidelines, and this I
believe we still need to keep doing. This is what we do in v6ops and if we
don't provide operational guidelines or recommendations or whatever we want
to say for "ways to do the things and why, pros/cons", probably, we should
not have ops WGs at all.

The documents are not just read by RIRs but also by LIRs, enterprises, etc.
They need guidelines, and usually they will take their own decisions, but we
should not create extra-alarmist perceptions when they aren't proven.

> 
> So, to be clear, do you disagree with the statement that moving from
> /48 to /56 is fine from an architectural perspective? If not, please
> be specific.

Responded above already. Is fine from an architectural perspective, but not
from the operational perspective considerations.

> 
> I do agree there are operational issues with having varying prefix
> sizes. But that is something that the RIRs need to take into
> consideration as they discuss policy proposals. Indeed, this document
> tries to make clear that taking into consideration such operational
> considerations should be done.

Same as above, this is ops WG tasks and "open" suggestions may be even worst
than no suggestions at all.

> 
>> I think the motivations behind the /48 are still valid and one of
>> the main goals of IPv6 addressing space is to ensure enough space to
>> end-users, which is only ensured with a clear boundary
>> recommendation.
> 
> It is widely viewed that a /56 to everyone would achieve this
> adequately, whereas a /48 is "execessive" to achieve this goal.

I've the same trouble with "widely". This is somehow a subjective
appreciation. As Ralph suggested, let's make figures for everything and may
be we can get an objective view, otherwise, let's try to keep being
objective.

> 
>> Furthermore, the lack of a clear boundary disrupts the RFC3177 goal of
>> ensuring a consistent subnet to facilitate management and renumbering. In
>> practice receiving a new assignment from and ISP w/o a specific
>> recommendation will be a big source of troubles if different ISPs decide to
>> do different things. Take the case of a user moving from an existing ISP
>> with today provides a /48 to a new one.
> 
> The document says this. But in any case, this argument needs to be
> taken directly to the RIRs.
> 
>> In addition, as an end user, it provides a recommendation to ISPs to
>> provide a reduced service in terms of the number of subnets, instead
>> of the actual /48 recommendations (with a clear example for /56),
>> which I think is very bad, especially when it is based in a
>> subjective view of "excessive".
> 
>> I also think that the lack of clarity in stating that more than a
>> single /64 is required in most of the cases is going to be wrongly
>> taken as a "go for /64".
> 
> I see no evidence that RIR policies are going in that direction. My

No, I was not referring to RIRs here, but to ISPs.

> sense (this is based on following and participating in RIR discussions
> for the last few years) is that those communities understand very well
> that a /64 as default end site allocation unit is neither desirable
> nor necessary and that there is plenty of address space to make the
> default allocations much larger. But they (even from day one) have
> largely viewed a /48 as excessively large.
> 
> Thomas
> 




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