From evaluation of the arithmetic, there is not a reasonable forecast model
On Wed, Dec 20, 2017 at 3:57 PM, Mark Andrews <marka@isc.org> wrote: [SNIP] 25B estimate for earth's carrying capacity for humans is likely on the high side, but sure: IPv6 should suffice until we have a few planets' worth of humans, and require an interstellar IP network with end-to-end comms between every remote device in our galaxy cluster --- and may have to fallback to planetary NAT or LISP for some applications. Something should probably go into some FAQ at some point..... "Q: IPv6 could still run out of addresses / Waste will kill ipv6 too / Etc." "A: No, although there is an occasional point of confusion regarding IPv6 that we will still run out of addresses: that is a highly-improbable event: please see list archives. that can be made that would start from realistic assumptions about network growth and could come to the conclusion that depletion of IPv6 would be a possibility under current regional registry allocation policies based on justified need, even allocating up to a couple dedicated /48s per person up to the expected maximum population capacities of earth.... -- -JH When the IETF decided on 128 bit addresses it was taking into consideration
/80 sized subnet. Prior to that it was looking at a 64 bit address size and allocating addresses the IPv4 way with lots of variable sized networks. This was changed to /64 subnets to accomodate 64 bit MAC. After that there was discussion about how many subnet should be enough for 99.99% of sites which gave /48 per site using /64 sized network. That 281474976710656 sites or 35184372088832 out of the /3 we are currently allocating from.
Now there are very few sites that need 65536 subnets and those that do can request additional /48’s.
Now if you assume the earth’s population will get to 25B, and every person is a site, that still leaves 35159372088832 sites. And if each of those people also has a home and a vehicle, that still leaves 35109372088832 sites.
Handing out /48’s to homes was never ever going to cause us to run out of IPv6 space. Even if the homes are are connected to multiple providers there isn’t a issue.
Mark
On 21 Dec 2017, at 7:57 am, William Herrin <bill@herrin.us> wrote:
On Wed, Dec 20, 2017 at 1:48 PM, Mel Beckman <mel@beckman.org> wrote:
I won’t do the math for you, but you’re circumcising the mosquito here. We didn’t just increase our usable space by 2 orders of magnitude. It’s increased more than 35 orders of magnitude.
Hi Mel,
The gain is just shy of 29 orders of magnitude. 2^128 / 2^32 = 7.9*10^28.
There are 2^128 = 3.4*10^38 IPv6 addresses, but that isn't 38 "orders of magnitude." Orders of magnitude describes a difference between one thing and another, in this case the IPv4 and IPv6 address spaces.
Using a /64 for P2P links is no problem, really. Worrying about that is
like a scuba diver worrying about how many air molecules are surrounding the boat on the way out to sea.
It's not a problem, exactly, but it cuts the gain vs. IPv4 from ~29 orders of magnitude to just 9 orders of magnitude. Your link which needed at most 2 bits of IPv4 address space now consumes 64 bits of IPv6 address space.
Then we do /48s from which the /64s are assigned and we lose another 3 or so orders of magnitude... Sparsely allocate those /48s for another order of magnitude. From sparsely allocated ISP blocks for another order of magnitude. It slips away faster than you might think.
Regards, Bill Herrin
-- William Herrin ................ herrin@dirtside.com bill@herrin.us Dirtside Systems ......... Web: <http://www.dirtside.com/>
-- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka@isc.org