On Feb 22, 2013, at 1:11 PM, james woodyatt <[email protected]> wrote: > On Feb 22, 2013, at 06:16 , Michael Richardson <[email protected]> wrote: >> >> If the ISP with the longest prefix is alive first, then the routers >> pick subnet-id parts that fit into that. If that ISP has provided >> enough subnets, then even when another ISP comes along, the "xx23" >> part might remain stable for a long time. > > This problem is precisely why I campaigned bitterly and vigorously against > the adoption and V6OPS and later the publication of RFC 6177. > > When there was still a consensus that subscribers should always get a /48 > prefix, it was reasonable to expect that a randomly chosen 16-bit subnet > identifier would be unlikely to collide with another subnet in most > automatically numbered routing domains. We were also in a position to expect > that when a subscriber adds a new prefix from the same or a different > provider, that all the subnet identifiers in use on one prefix could be > mapped 1:1 into the new prefix. Now we have RFC 6177, which explodes all of > that, for basically no sensible reason that I can see, and we are all the > poorer for it. > > Well done, V6OPS, well done.
Two thoughts. One: the v6ops result reflects the operational result in the ARIN community: operators there would like to be able to allocate /56 prefixes to smaller customers and /48s to larger ones. If you want castigate someone, castigate them. Two: If randomization within the home is the issue, I'm not sure the difference between a /48 and a /56 is all that significant. We're discussing the ability to pick a half dozen at best out of a much larger field, and arguing against operators that can't see a reason for anything shorter than a /64. You've heard me argue before that prefix length should be an attribute of the service one purchases, much as capacity is: in the home, I suspect that a /60 would suffice for the vast majority of purposes, and I can imagine companies that would not be happy with a /56 but might be happy with a /52. I don't see a technical argument that everyone has to have precisely a /48. _______________________________________________ homenet mailing list [email protected] https://www.ietf.org/mailman/listinfo/homenet
