Dave Reed on e2e notes a very interesting item – ARIN has announced that migration to IPv6 is now mandatory for allocation of contiguous IP address space. “I still remember debating variable length addressing and source routing in the 1970’s TCP design days, and being told that 4 Thousand Million addresses would be enough for the life of the Internet” Dave crows. But is this an accurate “read”? (I know Dave won’t mind the pun, as he’s heard it many times before).
As I commented on e2e, I remember that debate as well. But the whole genesis of why 32 bits was good enough was an (underjustified) view on the use of networks rather than an understanding of how sparse addresses were actually employed. Everybody knows hash tables work best mostly empty – the same may be true with address blocks because they are allocated in routable units. But how does this really work?