Re: I-D Action: draft-linkova-6man-default-addr-selection-update-00.txt

[Erik Kline <[e-mail]>]

On 7 April 2017 at 22:21, Jen Linkova <[e-mail]> wrote:

> On Fri, Apr 7, 2017 at 3:11 PM, Erik Kline <[e-mail]> wrote:
> >> I probably need to make the text a bit more clear but the use case
> >> I've observed has nothing to do with SLAAC, so neither
> >> RFC 7217 nor RFC8064 are applicable here. People do configure VRRP LLAs
> >> manually
> >> and it's understandable that they do not want to generate an unique
> >> LLA for each interface (LLAs are supposed to be unique within a link,
> >> right? so it's perfectly fine to have fe80::1 configured on each
> >> interface).
> >> It's operational reality, it does make sense (or we shall stop
> >> pretending that  LLAs have link scope...;( ) so I believe it would be
> >> nice to tweak the source address selection a bit to deal better with
> >> the real life..;)
>
> > It is a sad, but seemingly true, state of affairs that all of this blows
> up
> > the core DNAv6 working assumption:
> >
> >     https://tools.ietf.org/html/rfc6059#section-1.5
> >
> >    o  The combination of the link-layer address and the link-local IPv6
> >       address of a router is unique across links.
>
> Well, I'd expect that the combination of the L2 address AND LLA v6
> address would still be unique (unless
> people are explicitly configuring L2 addresses or MAC addresses are
> not unique - both cases do happen but from my limited experience,
> not so often as explicitly configured VRRP LLA Ipv6 addresses).


If people are using the VRRP MAC space, then I don't see a lot of room for
uniqueness:

    https://tools.ietf.org/html/rfc5798#section-7.3