I had a very brief look at the document
draft-kim-bgp-community-site-multihoming-00:
Would it be possible to quote the full URL for drafts? That's much
easier than having to search for the all over the place.
An Application of the BGP Extended Community Attribute for
Distributed IPv6 Site Multihoming
.. however, it introduces a number of big problems:
Yes. I don't really understand the whole thing, but it does seem to
depend on propagating per-multihomed site information throughout the
network using BGP. If we could do this we wouldn't be here trying to
come up with all this complicated stuff in the first place. But we
can't because propagating this information doesn't scale, so we are.