> Will all due respect, even if you assume a "home" with ten > occupants, a few hundred subnets based on functions, and > enough sensor-type devices to estimate several thousand of > them per occupant and a few thousand more per room, 2**64 is still a > _lot_ of addresses. This is hyperbole. All IPv6 subnets have the same minimum number of addresses (2**64) regardless of where they are used. > But I don't think hyperbole > helps the discussion. I agree. In any case, it doesn't make sense to discuss IPv6 in terms of hostcounts. It makes more sense to discuss numbers of subnets or numbers of aggregation levels. If a private home with two occupants and one PC, builds out an in-law suite for one mother-in-law with one PC, then it still makes sense to have at least two subnets in that private home, i.e. at least one level of aggregation. Hostcount is irrelevant. Note that if both mother-in-law and homeowner install 4 or five home media devices, the subnetted architecture will work better than a /64 per home scenario. Now that we have shown subnetting is useful in a private home, it is clear that a /64 per home is not enough. It still leaves open the question of whether a /48 is too much, i.e. too many subnets and/or too many levels of aggregation. If a /48 is not too much, then the IETF should issue guidance that states that. If some prefix length between /48 and /64 is OK under certain circumstances then the IETF should issue guidance which states that. I still have not seen any clear indication that there is a negative technical impact of assigning a /56 per home. To date, the only clear technical issue I have seen mentioned for subnet prefixes longer than /48 is that if they are not on a 4-bit hex nibble boundary, it makes IPv6 PTR delegation more complex. --Michael Dillon _______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf