IPv6 did not tackle the router-side problem with CIDR: huge routing tables. In 1994 CIDR was causing a lot of hurt in the then backbone because routers needed

IPv6 did not tackle the router-side problem with CIDR: huge routing tables. In 1994 CIDR was causing a lot of hurt in the then backbone because routers needed more and more memory to hold ever larger routing tables. Keeping routing the same except adding more bits to the address space merely made the problem worse except for the hope that the address space wouldn't be too fragmented, and that something like the DNS A6 RR type (failed) would resolve address portability concerns. IPv6 could have had a way to explicitly identify in the IPv6 header the route to the destination by AS number. I don't mean that applications should have been aware of AS numbers -- that could have been a system feature, or a first border gateway feature. This would have made routers cheaper by making their routing tables much smaller (2^16 routes max) and would have made number portability easier by making it more tolerable to have huge IP->AS lookup tables outside the core routers. Though on the flip side it might have led to more fragmentation of the address space, so maybe it's better the way it is.