3 Mar
2011
3 Mar
'11
2:36 p.m.
So IPv4 isn't that bad, even technically, if you think about it. But it turns out that the current IPv6 allocation practice prevents running with aggregated FIBs---there's a hole after each PA allocation. The hole is visible because you're expected to generated ICMP unreachables for packets target there, so you can't lump two PA prefixes together, even if they share the same next hop. This is yet another case of premature optimization gone wrong.
This would mean that one ISP de-aggregating their /32 won't cause many problems. Those could be auto-aggregated in the FIB. - Sander