> >> 6to4 is now widely deployed >> > > Is it? Can you cite any data? > Well, it ships with Windows, MacOS X, and Linux, and has for some time. Vista enables it by default if it doesn't see an RA for an IPv6 prefix. What more evidence do you want? Of course, widespread use can be expected to lag widespread deployment, but lack of visible widespread use is no excuse for breaking recently deployed code that appears to be useful. >> and ships with every major operating system. It's a bit late to >> change the length of its prefix. But now sites that deploy 6to4 >> will have some disincentive to move to native IPv6 (or to delay >> doing so) in that their pain in transition will be even greater than >> before. >> > > 6to4 is a transition technique that I would argue is not really > appropriate for a large site (i.e, one with _many_ subnets). Because relay routers don't work as well in practice as we'd like, a large site might find it advantageous or even necessary to support 6to4 in addition to a native prefix. Though I think this is probably irrelevant to the current discussion as large sites can presumably still get /48s. >> The /48 prefix length is not just some knob that RIRs or ISPs can turn >> at their will. It's a constant that's embedded into 6to4 protocol >> implementations in tens or hundreds of millions of computers. >> > > Give me a break. Use leading zeros for the first 8 bits of the subnet > part and everything else still works just fine. > So a router that automatically divides up that /48 according to requests from interior routers, should also assign zeros those bits? How many more things does this affect? >> That doesn't mean that /48 can't be reexamined, but it does mean >> that it's not the RIRs or ISPs business to be making that decision. >> > > Um, Keith, it _is_ the RIR's business. This is what they do. They did > it for IPv4 and they are doing it for IPv6. If you have an issue with > this, you are at least 5 years too late. > No, Thomas, this is part of the protocol design, not merely an assignment of addresses. We had that discussion when the /48 prefix was chosen, and the objection was raised at the time that this was the RIR's scope. It wasn't true then and it isn't true now. Just because the RIRs might think it is their business does not make it so. It really amazes me when people in IETF claim that we'd be stepping on toes by objecting to things done by others that contradict our protocol designs and/or do harm to the efficacy of our protocols. That's not stepping on toes, that's our job. >> I keep getting the impression that the biggest barrier to the success of >> IPv6 is that so many people have screwed with the design of IPv4 that >> they think they have the right to screw with IPv6 too. >> > > The biggest barrier to the success of IPv6 is the lack of a short-term > ROI. There just isn't a strong business case for anyone to invest in > deployment. It's really that simple. > That's a bit like saying that there's no strong case for hitting the brakes on a car just because the end of the road is in view and it appears to end at the top of a cliff. But really there's a short-term barrier and a long-term barrier. We might get past the short-term barrier only to find out that IPv6 is every bit as screwed up as IPv4 was, because people kept trying to impose brain-damage that was adopted in IPv4, onto IPv6. Keith _______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf