Paul Vixie wrote:
either of these limitations...
o A maximum of two alternate networks (for a total of three networks) can be encoded on a single unicast address. o Renumbering when changing networks is not eliminated and is actually made worse because changing any of the networks requires renumbering. Worse yet, even changing the routing preference between the the networks requires renumbering.
...is fatal to this approach.
Fatal in that it does not address the needs of "major" multihomers like ISC. Certainly not fatal to the millions of small to mid sized networks that could benefit from multihoming to two or three providers. For those networks this method would be at least as good and easy as it is today with IPv4, plus the benefits of not polluting the global routing table, consuming unique AS numbers or requiring convoluted application or protocol tricks. In fact anyone could do simple multihoming. Just get a second connection and set your interface addresses accdordingly. Networks that need to multihome to more than three networks would likely qualify for IPv6 PI space anyway (as ISC did and still does). There is a range of large purely end site networks that would not qualify for PI space and would need more multihoming support than this method provides. In those cases it would be necessary to use more advanced (read: complicated) technology. As we have seen, the advanced methods come with their share of limitations too. I don't think we are going to find a "one size fits all" solution to IPv6 multihoming. As for renumbering, we all know that will be solved by some form of address translation (like it or not). -- Kevin Loch