Waste will kill ipv6 too

Mel Beckman mel at beckman.org
Wed Dec 20 21:38:51 CST 2017


You are correct.

As a double check, I divided 340282366920938463463374607431768211456 by 4294967296, getting  79228162514264<tel:79%20228%20162%20514%20264>337593543950336<tel:337%20593%20543%20950%20336>, which is 28.8 orders of magnitude :)


On Dec 20, 2017, at 12:58 PM, William Herrin <bill at herrin.us<mailto:bill at herrin.us>> wrote:

On Wed, Dec 20, 2017 at 1:48 PM, Mel Beckman <mel at beckman.org<mailto:mel at 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.

Bill Herrin

William Herrin ................ herrin at dirtside.com<mailto:herrin at dirtside.com>  bill at herrin.us<mailto:bill at herrin.us>
Dirtside Systems ......... Web: <http://www.dirtside.com/>

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