[ppml] Those pesky EUI-64's causing a shortage of IPv6 space (Was: Those pesky ULAs again)

Paul_Vixie at isc.org Paul_Vixie at isc.org
Mon Jun 4 14:10:03 EDT 2007

> We are starting to get into an IETF thing here and not policy anymore ...

IETF and ARIN PPML is a lot of the same people.  and the relationship between
policy and technology is more of a feedback loop than producerish/consumerish.

> So I understand correctly here that you are afraid that IPv6 enabled sensors
> in your carpet will only be relying on a /64 RA to be available?

well, yes, but i'm more concerned about the fact that IETF killed off every
other IPv6 addressing paradigm that turned out badly, but didn't kill EUI64
(yet?).  i'm not so much bitter about the favouritism as i am concerned that
IETF has chosen the wrong (painful) things to have any spinal rigidity about.
so if EUI64 isn't going to be killed we all need to know that since a future
carpet sensor will need it and ARIN's policies have to assume /64 LANs even
though DHCPv6 is going to be more common and doesn't need /64's; or if EUI64
is going to be killed then can it please be killed quickly so that we don't
give home users /48's or /56's when /108's would have been quite enough?

> A possibly better way to solve that problem is to require the support
> for DHCPv6 in all nodes, or have at least a sticker on the box "DHCPv6
> supported" so that you know what to expect. The DHCPv6 request will go
> over a /64 LL of course. Also in case you come across such a device
> you can always special case that subnet and give it a /64 out of the
> 65k ones you get for a site.

i love the sound of that plan.  be sure to post the I-D URL here :-).

> A bigger question in this are actually is, what space do you save with it?

address bits on the CAM in wireless routers.

> IMHO using /64's is not a bad thing. If you don't want to use them,
> then, as said, don't.

this is probably the reason why IETF hasn't killed EUI64.  "since we're
going to have to use it for LL, and we've got way more bits than we could
ever route for, there's no reason not to waste this space in this way."

> My ISP for instance also gave me a an IPv6 IP for my DSL link out of a
> /80. This simply for management purposes. They did route a /48 to the
> endpoint and point DNS for the /48 it to my endpoint though:
> eth1      Link encap:Ethernet  HWaddr 08:00:2B:E7:02:B3
>           inet addr: Mask:
>           inet6 addr: 2001:7b8:5:10:74::2/80 Scope:Global
>           inet6 addr: fe80::a00:2bff:fee7:2b3/64 Scope:Link
> The LinkLocal is a /64 though, and that is used as the nexthop:

you raise the interesting possibility that rather than NAT, IPv6 will use
some kind of overlay scheme where only LL has broadcast, and everything
else uses some RARP-like thing on a /128 per endpoint out of /80 pools.

but while this is interesting for lab rats, i don't think it works at home.

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