Re: Dual stack IPv6 for IPv4 depletion

[Mark Andrews <marka () isc org>]

In message <559DB604.8060901 () lugosys com>, "Israel G. Lugo" writes:
> On 07/05/2015 06:26 PM, Owen DeLong wrote:
> > > On Jul 4, 2015, at 23:51 , Valdis.Kletnieks () vt edu wrote:
> > >
> > > Put their IPv4 behind a NAT and a globally routed /56.
> > >
> > > There, FTFY. :)
> > Or better yet globally routed /48.
> >
> > /56 is still a bad idea.
> >
> > Owen
> I've read this many times and am aware it's the standard recommendation.
> Makes perfect sense for the customer side, as it would be hard for him
> to subnet properly otherwise.
>
> Doesn't seem to make sense at all for the ISP side, though. Standard
> allocation /32. Giving out /48s. Even if we leave out proper subnet
> organization and allocate fully densely, that's at most 65,536 subnets.
> Not a very large ISP.

/32 is not the standard allocation.  It is the *minimum* allocation
for a ISP.  ISPs are expected to ask for *more* addresses to meet their
actual requirements.

> You can say "get more blocks", or "get larger blocks". Sure, let's give
> each ISP a /24. That lets them have up to 16M customers (and that's
> still subnetting densely, which sucks rather a lot). Doesn't leave that
> many allocation blocks for the RIRs to hand out, though.

Which in part is why the minimum is a /32.
 
> People usually look at IPv6 and focus on the vast numbers of individual
> addresses. Naysayers usually get shot down with some quote mentioning
> the number of atoms in the universe or some such. Personally, I think
> that's a red herring; the real problem is subnets. At this rate I
> believe subnets will become the scarce resource sooner or later.

No.  People look at /48's for sites.  35,184,372,088,832 /48 sites out of the
1/8th of the total IPv6 space currently in use.  That is 35 trillion sites
and if we use that up we can look at using a different default size in the
next 1/8th.

> Sure, in the LAN side we'll never have to worry about address scarcity.
> But what's the point of having addresses to spare, if it just means
> you've got to start worrying about subnet scarcity? If the goal was
> never having to worry about counting anymore, I propose that 128 bits is
> far too little. Should've gone a full 256 and be done with it.
>
> Regards,
> Israel G. Lugo
>
> P.S.: I'm 100% for IPv6 and $dayjob has been fully dual stacked for 10
> years now.
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka () isc org