I'm starting to be convinced (see recent NANOG discussions) that the operator community isn't all that impressed with the multi6 efforts to make multihoming possible with provider-derived addresses. It looks like the RIR address policy forums will soon face the question of whether to (de facto) allow provider independent address space for end-users.
It'll be coming up on ARIN PPML this week (sorry).
So _if_ IPv6 PI space is going to be a reality, we should do what we can to limit the damage. The only way to do this is to make it possible to filter out the PI prefixes at least in certain parts of the network without getting in the way of reachability.
That's not the only solution -- just the most obvious one. Clearly, if IPv6 PI space spirals out of control like many operators think will happen, we need to find a way to make BGP (and possibly forwarding) performance not dependent on the number of prefixes in the table. There's many ways to skin that cat, and maybe it's time we start looking at that in parallel to the work on multi6 and HIP.
Worst case is we'll end up eliminating IP addresses as locators and build another layer beneath IP (and thus transparent to TCP) that actually handles routing, at least in the DFZ. In some sense we already have a foundation for that with MPLS, but we'd need to hack/replace BGP to make the new layer scale across ASes. Or perhaps we'll find a way to route based on ASNs in the DFZ, and the mapping from destination IP to ASN will be made only at the edge of the DFZ.
S
Stephen Sprunk "God does not play dice." --Albert Einstein
CCIE #3723 "God is an inveterate gambler, and He throws the
K5SSS dice at every possible opportunity." --Stephen Hawking
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