Re: [v6ops] Could IPv6 address be more than locator?//draft-jiang-v6ops-semantic-prefix-03

[Lorenzo Colitti <[e-mail]>]

On Fri, Jun 7, 2013 at 10:23 PM, Ted Lemon <[e-mail]> wrote:

>  Argh.   I don't think anybody ever said that there was no cost to these
> bits, and I agree that the cost should be discussed.   So I guess we've
> been arguing over a nonexistent disagreement!   :|
>

Yes, that happens. :-(

One thing to bear in mind is that it depends a lot on how much space you
already have. Examples:

1. Deutsche Telekom has a /19. That's over 500M /48s, and if they use it
only in Germany, that's 5 for every person in the country, with a fair bit
left over. So they can afford to use 2 bits for semantic prefixes.

2. Comcast only appears to have a /29 and a /28 (2001:558::/29, 2601::/28).
That's only 1.5M /48s, and they have about 10x that many customers. They
likely can't use /48 plus semantic prefixes, because if ARIN doesn't accept
"semantic prefixes" as using space efficiently (and word from ARIN on this
thread seems, well, negative on the matter), then they won't be able to get
more space from ARIN. That means that there is a fundamental tension
between using semantic prefixes and giving more address space to customers.

We need to be very careful not to create an incentive to give less address
space to customers, because IPv4 shows us very clearly how that ends up
complicating the whole network.

Cheers,
Lorenzo