A crazy idea

Owen DeLong owen at delong.com
Sun Aug 1 19:38:15 UTC 2021

> On Jul 29, 2021, at 14:06 , Joe Maimon <jmaimon at jmaimon.com> wrote:
> tim at pelican.org wrote:
>> On Monday, 19 July, 2021 14:04, "Stephen Satchell" <list at satchell.net> said:
>>> The allocation of IPv6 space with prefixes shorter than /64 is indeed a
>>> consideration for bigger administrative domains like country
>>> governments, but on the other end, SOHO customers would be happy with
>>> /96, /104 or even /112 allocations if they could get them.  (Just how
>>> many light bulbs, fridges, toasters, doorbells, phones, &c does SOHOs
>>> have?)  I would *not* like to see "us" make the same mistake with IPv6
>>> that was made with IPv4, handing out large blocks of space like so many
>>> pieces of M&M or Skittles candy.
>> Nay, nay, and thrice nay.  Don't think in terms of addresses for IPv6, think in terms of subnets.  I can't stress this enough, it's the big v4 to v6 paradigm shift - don't think about "how many hosts on this net", think about "how many nets".
> Think of how many large ISP's a /3 of ipv6 effectively holds, assuming that /48 per customer is the norm, and /24 up to /12 assignments for those ISP's is also.
> In those terms IPv6 isnt that much bigger.

Let’s say an average “large” ISP burns a /11 of IPv4 serving their ~2M customers with a single IPv4 address each.
IPv4 supports a maximum of 2,048 such ISPs without regard to space for multicast, class E, etc. (which reduce this number).

Let’s say that we give each of them enough space to issue 16M /48s (an IPv6 /24).

That means we have 2^21 IPv6 large ISPs serving 8x as many customers with /48s.

That’s 2 million large ISPs covered in the first /3.

Since each of them is serving around 2M customers, that’s 4,000,000,000,000 customers.
For comparison, the world population is less than                8,000,000,000.

Tell me again how IPv6 is not that much larger, Joe?


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