Re: what problem is solved by proscribing non-64 bit prefixes?

[Brian E Carpenter <brian.e.carpenter at gmail.com>]

On 2008-10-02 02:04, Dunn, Jeffrey H. wrote:
> More to the point, what would a individual household do with Avogadro's
> number worth of IPv6 addresses (2^80 = 1.2x10^24)?  This seems
> extremely wasteful.  Further, a reasonable sized ISP with a couple of
> million customers would require a /28 or more just for their
> residential customer base.  This sounds like a prescription for address
> exhaustion.

Not in the least. Please remember that we have raised the size of the
address space to the *fourth* power; we squared it and squared it again.
Even if we'd stuck to the original plan of assigning /48s everywhere,
that means we've *squared* the size of the subnet prefix space (/24 to /48).
Unless really stupid allocation mechanisms are allowed, that is enough
for any imaginable future. And all the evidence is that the RIRs are
being extremely conservative in their practices for allocation. So
I don't see even a remote cause for concern.

On the other hand I see enormous value in allowing any size of network
on any customer's premises. It's not for this generation of engineers
and ISPs to constrain what our great-grandchildren might invent.

    Brian
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