Dual stack IPv6 for IPv4 depletion

Wed Jul 15 15:58:19 UTC 2015

> On Jul 15, 2015, at 03:43 , Baldur Norddahl <baldur.norddahl at gmail.com> wrote:
> 
> On 15 July 2015 at 01:34, Owen DeLong <owen at delong.com> wrote:
> 
>> For one thing a /32 is nowhere near enough for anything bigger than a
>> modest ISP today. Many will need /28, /24, or even larger. The biggest ones
>> probably need /16 or even /12 in some cases.
>> 
> 
> What is the definition of a modest and a large ISP?
> 
> In the RIPE region even the smallest ISP can get a /29 with no
> documentation necessary. But likely that is all they will ever get because
> policy requires that you use that /29 at about 30% efficiency if you do /48
> allocations to end users.

Which is fine… 30% of a /29 at /48 is 524,288 end-sites served. For a
residential provider, I’d say that’s a medium-sized provider.

A large provider would be one that serves several million end-sites. There
are at least a handful of providers in the US for example, that have 10,000,000+
customers. A /29 wouldn’t be enough for them.

RIPEs policy ignores the inefficiencies created by topology and that’s kind
of unfortunate in my opinion, but so far it doesn’t appear too egregious, so
I haven’t taken the time to propose better policy.

> You would need more than a million users to get a /24.

Sure. Many ISPs have more than a million end-sites (note end-sites != users).

In many cases customer and end-site are synonymous, but in many cases, a
single customer may have many end-sites. For example, a business which
has several buildings in a campus may treat each building as an end-site.

A multi-tenant building would likely treat each tenant as a separate end-site.

etc.

> I do not think the RIPE region has an ISP large enough to apply for a /16
> or anything near it.

Perhaps. There are at least 2 ISPs in the US that I know of with 20,000,000+
customers. Since the NA in NANOG stands for North America, I kind of figured
that the situation in North America ought to be considered somewhat relevant.

> Therefore we can conclude that if ARIN manages to use up all the /3 address
> space currently reserved for allocation, we will still be able to get
> address space in Europe for the next thousands years :-). It is thought
> that RIPE will not use up the /12 that IANA allocated to RIPE - ever.

I doubt even with our current policy, ARIN is unlikely to use up the /12 in my
lifetime or even in the lifetime of the IPv6 protocol. Even if we do, I doubt we
will use more than 2 or 3 /12s ever.

> Personally I believe the ARIN policy is the sane one. But we need to abide
> by the rules in the region we live in.

I agree with you, but as the author of the current ARIN ISP IPv6 policy, I
may be biased. ;-)

Owen