Re: But ...
When we get to the stage that every company and its uncle Freddy has a routable /29 (six usable, probably NATted at the gateway on one of them) because that's all they could afford, let's just see how long the core routers stay up with all that extra load.
I'll say it again, you cannot do this reliably with v4. The infrastructure just doesn't support this level of granularity in the address space -
we are almost at that stage already & the world hasn't broken. The biggest problems are when the IP's are used out of region, but even when reused in region between different IPS's from where the main block originated it causes a new global route entry, so the mere act of creating / having a /29 is most likely to have caused a new route entry anyway, doesn't matter where it is.