> The only way to do what you want is to effectively have a variable > length address. While there were a few crazy advocates of this many > years ago, they were shouted down. variable length addresses are a better idea than it appears at first glance. they do bring certain difficulties with them, especially when trying to do fiber-speed switching in hardware. it's hard to switch on arbitrary bit boundaries and it's harder to switch in hardware using prefixes of arbitrary length. but there are ways to deal with these problems. nobody should expect core routers to pay attention to less significant bits of a variable length address any more than they pay attention to the less significant bits of a fixed length address, and just because addresses are variable length doesn't mean that there cannot be a maximum length of a prefix advertised in BGP. overall it strikes me as a hell of a lot better than NAT. _______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf