who gets a /32 [Re: IPV6 renumbering painless?]

Fri Nov 19 23:53:36 UTC 2004

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