Dual stack IPv6 for IPv4 depletion

Wed Jul 15 20:34:34 UTC 2015

George Metz wrote:
> >  snip
> >  Split the difference, go with a /52
> >>
> >
> > That's not splitting the difference. :)  A /56 is half way between a
> > /48 and a /64. That's 256 /64s, for those keeping score at home.
> >
> 
> It's splitting the difference between a /56 and a /48. I can't imagine short of
> the Nanotech Revolution that anyone really needs eight thousand separate
> networks, and even then... Besides, I recall someone at some point being
> grumpy about oddly numbered masks, and a /51 is probably going to trip
> that. :)
> 
> I think folks are missing the point in part of the conservationists, and all the
> math in the world isn't going to change that. While the... let's call them IPv6
> Libertines... are arguing that there's no mathematically foreseeable way
> we're going to run out of addresses even at /48s for the proverbial soda
> cans, the conservationists are going, "Yes, you do math wonderfully.
> Meantime is it REALLY causing anguish for someone to only get
> 256 (or 1024, or 4096) networks as opposed to 65,536 of them? If not, why
> not go with the smaller one? It bulletproofs us against the unforeseen to an
> extent."

You are looking at this from the perspective of a network manager, and not considering the implications of implementing plug-n-play for consumers. A network manager can construct a very efficient topology with a small number of bits, but automation has to make "gross waste" trade-offs to "just work" when a consumer plugs things together without understanding the technology constraints. 

Essentially the conservationist argument is demanding waste, because the unallocated prefixes will still be sitting on the shelf in 400 years. It would be better to allocate them now and allow innovation at the cpe level, rather than make it too costly for cpe vendors to work around all the random allocation sizes in addition to the random ways people plug the devices together. 

> 
> As an aside, someone else has stated that for one reason or another IPv6 is
> unlikely to last more than a couple of decades, and so even if something
> crazy happened to deplete it, the replacement would be in place anyhow
> before it could. I would like to ask what about the last 20 years of IPv6
> adoption in the face of v4 exhaustion inspires someone to believe that just
> because it's better that people will be willing to make the change over?

TDM voice providers had 100 years of history on their side, but voip won, because cheaper always wins. 