In message <4d4e1c5d.20...@brightok.net>, Jack Bates writes: > On 2/5/2011 8:40 PM, Mark Andrews wrote: > > A IPv4 /16 supports 64000 potential customers. A IPv6 /32 supports > > 64000 potential customers. Either you have changed the customer > > estimates or changed the growth space allowances or were using NAT > > or .... > > > > You don't suddenly need 256 times the amount of space overnight all > > other things being equal. About the only thing I can think of is > > you need to advertise 256 routes and you are asking for extra blocks > > to get around poorly thought out filtering policies. > > > What filtering policies? My allocation was based on customers per > terminating router, 1 route per terminating router. A /32 was nowhere > near enough. The reason a /16 works today is because I have a routing > table that looks like swiss cheese and a 95%+ utilization rate. 9 /40 > (equiv of 9 /24 IPv4 DHCP pools for residential DSL) networks don't fall > on a bit boundary. Nibble would make things even easier, but to say I > have to run multiple routes to a pop and squeeze things in as tight as > possible is insane. Justifications DO allow for some amount of > aggregation in numbering plans.
Rationalising to power of 2 allocations shouldn't result in requiring 256 times the space you were claiming with the 8 bits of shift on average. A couple of bits will allow that. > > If ISPs were being honest and matching IPv4 to IPv6 filtering the > > filters would be set a /40 not /32. By setting the filters to /32 > > you force the small ISP to ask for up to 256 times as much address > > space as they need with absolutely no benefits to anyone just to > > get a routing slot that won't be filtered. > > > Actually, many router policies, as discussed previously on the list, > support /48. Routing policies don't force the /32, and a current > proposal to ARIN even supports a small ISP getting a /36, hopefully at a > lower cost. > > > What's really needed is seperate the routing slot market from the > > address allocation market. > > > > I agree that inter-AS routing needs to change, though that still has > nothing to do with address allocation itself. Sizes of allocations were > chosen to allow for growth. The ISPs don't get near the wiggle room that > corporations and end users get in address assignment currently. > > When analyzing exhaustion rate of IPv6, like IPv4, you have to view it > at the RIR allocation level. In this case, across the board, we will see > a minimum of an 8 bit shift in allocations, and often 12-16 bits (what's > to the right of the allocation bits doesn't matter when we consider > exhaustion rates, so long as what's to the right is appropriately > utilized and justified by community standards before another request is > handled by the RIR). You need to look very closely at any ISP that only shifts 8 bits going from IPv4 to IPv6, something dodgy is probably going on. This is not to say it is deliberately dodgy. Mark -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org
