On 13/11/2010 23:42, Romain Riviere wrote: > >> I can see IPV6 turning into another IPv4 style farce due to those in the know handing out very large allocations. The logic seems to be that routers today can handle at most something like /24 routing, so allocate large sub allocations to avoid routing problems exploding... Seems like the wrong design decision though..? >> >> Who knows, a /56 is a BIG space, yet if we start handing out /56 space to light switches then perhaps we are back at square one? > Except that there are 2^56 /56 prefixes, roughly 10 million times the world population. I don't see exhaustion looming over the 35-year horizon just quite yet :) Yeah, but it's way less than 2^128 which is how everyone is looking at IPV6 I don't know, but I wouldn't be surprised if larger prefixes are handed out to those who ask, eg larger ISPs who in turn are handing out /56s to customers. There is a risk of handing out too large a prefix here just like in the early days of IPV4 where they handed out /8s to anyone who asked... 10^7 just doesn't look like much of a safety margin when you can easily imagine reducing that by 10x - 1,000x in the near future? I think the point is that IPv6 /32s are way beyond current router capability, so really the standards backed up to something targeting more like some million or so times greater than current capacity from a pure router capability point of view. This is great, but it's way less than the 2^96 fold improvement you might naively expect. I guess router manufacturers can pull a 10^6 fold performance improvement out of somewhere in the next 35 years - question is whether demand for zillions of new routed devices will waste the large ipv6 block allocations rapidly... Ed W