On 23/07/2013 09:12, Mark ZZZ Smith wrote:
> Hi,
>
> Firstly, I support advancing this draft.
>
> Some suggested changes:
>
> " This has no known harmful effect as long as the
> replicated MAC addresses and IIDs are used on different layer 2
> links. If they are used on the same link, of course there will be a
> problem, to be detected by duplicate address detection [RFC4862], but
> such a problem can usually only be resolved by human intervention."
>
> I think it would be worth pointing out that the link layer is most likely to
> fail to operate with duplicate link layer addresses, before DAD has a chance
> to detect duplicate IPv6 addresses.
OK.
>
> " Also, there is
> evidence from the field that IEEE MAC addresses with "u" = 0 are
> sometime incorrectly assigned to multiple MAC interfaces. Firstly,
> there are recurrent reports of manufacturers assigning the same MAC
> address to multiple devices. Secondly, significant re-use of the
> same virtual MAC address is reported in virtual machine environments. "
>
> I found this text a bit confusing. The '"u" = 0' term read like it was
> referring to locally unique IEEE MAC addresses ("unique equals no"), and then
> the 2nd sentence is referring to globally unique (but duplicated and
> therefore not actually globally unique) MAC addresses, u = 1 in an IPv6 IID,
> the opposite of what the previous sentence was referring to. Then the third
> sentence seems to be describing to what the first sentence was referring to.
> I think the cause of the confusion might be that IEEE use the "locally
> assigned" bit to distinguish locally generated or not (i.e., "l" = 0 for
> globally unique), where as IPv6 IIDs have renamed it to "u" bit when the
> value is inverted. I'd suggest trying to ensure the IEEE terminology is used
> when IEEE addresses are discussed to make it clearer what the properties of
> the IEEE address are.
Yep. I remember complaining when the bit inversion was first proposed
that it would lead to years of confusion. Which IEEE standard is the
basic reference for their terminology?
Brian
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