[ppml] IPv6>>32

Howard, W. Lee L.Howard at stanleyassociates.com
Tue May 10 18:02:51 EDT 2005

> -----Original Message-----
> From: owner-ppml at arin.net [mailto:owner-ppml at arin.net] On 
> Behalf Of Tony Hain
> Sent: Monday, May 09, 2005 6:57 PM
> To: 'Randy Bush'
> Cc: ppml at arin.net
> Subject: RE: [ppml] IPv6>>32
> Randy Bush wrote:
> > > IPv6 deployment is gated by lack of applications and/or a crisis. 
> > > The crisis is looming
> > 
> > shall we have a game to see who can list the crises which 
> were about 
> > to explode v6 deployment which have loomed in the last decade?
> > 
> > don't get me wrongly.  i will not be at all unhappy if ipv6 
> moves from 
> > k00la1d to reality.  but, for a decade, i have had this problem of 
> > seeing the emperor's attire, and i don't see it today. 
> perhaps it's my 
> > aging eyes.
> Those would be the same ones that claim to see that 8k times 
> the number of bits that got us 30 years (while arguably 
> loosely managed and including
> hosts) will be insufficient to get us past 100 years (by only 
> indicating the customer demarc). 45 bits is a very large space. 

I think that argument is a little misleading.  Extrapolating
(32 bits / 30 years) = (64 bits / 60 years) assumes that past
performance is a predictor of future allocation [1].

The problem, as I like to frame it, is that if we take the 
attitude that IPv6 is infinite, then addresses or subnets will
be assigned to consumables, consumed, and never reused.  I see
lots of engineers-cum-science-fiction-writers who talk about
potential uses for IPv6, all of which seem to me to argue against
themselves; they seem to say there will be such demand that we 
can't afford to be careful now.  Especially since produce-truck 
drivers, nanobots, and complex molecules, are not ISPs as 
currently defined by policy.  If these clusters are going to be 
sliding gracefully from network to network with their /48s, then 
the /32 aggregation goal is blown.  

The magic of a /64 is that it's a single routable entity.  If I
assume that layer 3 networks connect layer 2 networks, I still 
haven't seen any argument here about what a layer 2 network of 
2^64 devices would look like.  It's not only inconceivable, it's
inconceivable to (2^32) power or more, and then we say that we
have to assign this enormous set of numbers in groups of 2^16.

The /48 rule applied equally to every possible definition of 
end user is arbitrary and reckless.  I will concede that in 
IPv6 terms, a /48 is reasonable for the enterprise network,
but I just can't understand how it's more responsible to assign
this much to every node on the theory that in someone's wildest
dreams, any node could someday be a router.  If a node does
someday become a router, is renumbering one device (possibly to 
a /48) insurmountable?  Even if it is, is there any barrier to
the household (or cellular, or vehicular) router routing (or
switching) /96 subnets within the /64?  Presumably, my blinds
will never have a host address (EUI-64, MAC, or whatever) that
conflicts with my vacuum cleaner.

Oh, for the record, Geoff Huston's model said we'd consume a /1 
to a /4 in 60 years; at the rate of one /1 every 60 years, we 
run out of IPv6 space in 120 years.


[1] OK, technically it assumes an exponential progression, but a
predictable exponent.  And I don't think most people see that.

> You can drop the bubble-hype of 'it didn't happen in 6 months 
> so it isn't real'. We knew going in that it would take a 
> decade to make a massive change to the infrastructure, and 
> all hype aside we are not getting it done any quicker by 
> wasting time fighting nay-sayers. If you choose to slam into 
> the wall when the address pool runs out that is your choice. 
> Some of us want to enable others to avoid the problems that 
> will create.
> Tony

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