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List:       ipng
Subject:    (IPng 3710) Re:  indicating globicity
From:       Steve Deering <deering () cisco ! com>
Date:       1997-05-27 18:59:56
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Erik,

> The organization that owns the all-zeros OUI might very well decide to use
> its part of the EUI-64 space with the local bit set for some other purpose
> that might cause collisions with the all-zeros subnet anycast address.

There's no required relationship between the "interface ID" field of an
IPv6 anycast address and any MAC-layer address.

> I think there is a fundamental problem that IEEE owns the number space
> for IEEE 802 and EUI-64 addresses thus if we want to assign anything from
> this space (universal or local) we need to do it from a properly acquired
> part of the IEEE number space.

But we're talking about the IPv6 address space.  IPv6 addresses with the
global bit set (as proposed) take their interface IDs from the universal
EUI-64 space; IPv6 addresses with the global bit cleared do *not*
necessarily take their interface IDs from the non-universal EUI-64 space,
but rather from the space of the IPv6 subnet in which they are allocated.

> Assuming that nobody will be using IEEE addresses with the local bit set
> seems fragile to me.

I am not assuming that.  Rather, I am assuming that on a link that uses
non-universal IEEE 802 or EUI-64 MAC address with an all-zeroes OUI, IPv6
interface IDs are *not* autoconfigured from those MAC address.  At worst,
that may inconvenience whichever organization it is that owns the all-
zeroes OUI.  (I wonder if that organization is my previous employer? :-)

(Question: when IEEE assigns an OUI, is that understood to include both
the universal space and the local space containing that OUI, or is it an
assignment of some universal space only??  Or, in other words, is the
purpose of the IEEE registry solely to allocate the universal space?
Why would you need a global registry for local address space, given that
it its use is a local concern only?)

Steve


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