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
assignment.


Regards,
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