IPv6 end user addressing

William Herrin bill at herrin.us
Wed Aug 10 20:43:20 CDT 2011

On Wed, Aug 10, 2011 at 2:17 PM, Jeff Wheeler <jsw at inconcepts.biz> wrote:
> On Wed, Aug 10, 2011 at 2:03 PM, Owen DeLong <owen at delong.com> wrote:
>> That said, /48 to the home should be what is happening, and /56 is
>> a better compromise than anything smaller.
> You don't really imagine that end-users will require
> more than 2^8 subnets, but that they will want several levels of very
> simple, nibble-aligned routers within their network?

Hi Jeff,

In Owen's world, the refrigerator, toaster and microwave each request
a /64 from the GE Home Appliance Controller, those /64's being
necessary to address each appliance's internal button, light and
sensor networks. To accommodate all of these appliances, the HAC has
acquired a /59 for all the home appliances from the Home Automation
System (HAS) which also has its own LAN and supplied a big block to
the furnace and a smaller block to the security system. So, the HAS
needed a /58 which it got from the Linksys Home Router.

The Sony Home Entertainment Network (HEN) Controller also needed a /58
from the Home Router to accommodate the Playstation 5's need for a /62
(one /64 for its internal network, another for the PSN VPN and a third
for the peripherals network). The Ultra-NES 512 only needed one /64,
but the amplifier insisted on a /60 so it could delegate /64's to the
cassette tape deck, cd player, mp3 player, etc.

The Ford Home Automotive Network (HAN) also grabbed a block from which
to delegate /62's to the three parked cars. Because you know: you need
separate networks in each car for the life safety systems, the
non-safety systems and the entertainment systems. I mean really, why
wouldn't the life safety system in a car dynamically acquire its
globally-addressable IPv6 addresses from the customer's cheap home
Internet equipment? So they'll each need their /64's which means the
car as a whole needs a /62. But the HAN only needed a /60 for for all
of it since there were only 3 cars.

Now, the Windows 9 PC sat on the /64 PC LAN directly connected to the
Home Router, but it needed an additional /64 for its virtual machine
network hosting the Windows XP VM needed to run older software. And
the wireless LAN only ended up consuming a single /64. But after the
two /58's, that meant the Home Router needed a full /56 from the
Internet Router.

Finally, the Internet Router connects two networks... the customer's
web server DMZ (/64) and the home router (/56). So after you figure in
the HAC, the HAN, the HAS, the HEN and all the other connections you
need at least a /55... which doesn't fit in a /56 but does fit in a
/48. Qed. *

Now, in Bill's world, the appliances don't expose their internals.
When they employ any form of IP networking inside, which they
generally don't, they use fe80 link-local addresses inside or maybe a
ULA prefix.  So even you have a Smart Fridge within the time span that
you care about for today's home user IPv6 assignments, it occupies a
single public address on your home's flat /64. Ditto the game consoles
and tape decks. With maybe two other /64's: one for servers and one
for the wireless LAN. And that /62 need easily fits in your /56

Bill Herrin

* I say this with trepidation. A quarter century ago I used a similar
reductio ad absurdum with a friend who suggested making every road a
toll road. "Back out of the driveway. Pay the toll. Turn on to main.
Pay the toll. Left on 15th. Pay the toll." Wouldn't you know, E-Z Pass
came along and brought it to the edge of possible. Then again,
possible doesn't necessarily mean advisable.

William D. Herrin ................ herrin at dirtside.com  bill at herrin.us
3005 Crane Dr. ...................... Web: <http://bill.herrin.us/>
Falls Church, VA 22042-3004

More information about the NANOG mailing list