In message <559db604.8060...@lugosys.com>, "Israel G. Lugo" writes: > > On 07/05/2015 06:26 PM, Owen DeLong wrote: > >> On Jul 4, 2015, at 23:51 , valdis.kletni...@vt.edu wrote: > >> > >> Put their IPv4 behind a NAT and a globally routed /56. > >> > >> There, FTFY. :) > > Or better yet globally routed /48. > > > > /56 is still a bad idea. > > > > Owen > I've read this many times and am aware it's the standard recommendation. > Makes perfect sense for the customer side, as it would be hard for him > to subnet properly otherwise. > > Doesn't seem to make sense at all for the ISP side, though. Standard > allocation /32. Giving out /48s. Even if we leave out proper subnet > organization and allocate fully densely, that's at most 65,536 subnets. > Not a very large ISP.
/32 is not the standard allocation. It is the *minimum* allocation for a ISP. ISPs are expected to ask for *more* addresses to meet their actual requirements. > You can say "get more blocks", or "get larger blocks". Sure, let's give > each ISP a /24. That lets them have up to 16M customers (and that's > still subnetting densely, which sucks rather a lot). Doesn't leave that > many allocation blocks for the RIRs to hand out, though. Which in part is why the minimum is a /32. > People usually look at IPv6 and focus on the vast numbers of individual > addresses. Naysayers usually get shot down with some quote mentioning > the number of atoms in the universe or some such. Personally, I think > that's a red herring; the real problem is subnets. At this rate I > believe subnets will become the scarce resource sooner or later. No. People look at /48's for sites. 35,184,372,088,832 /48 sites out of the 1/8th of the total IPv6 space currently in use. That is 35 trillion sites and if we use that up we can look at using a different default size in the next 1/8th. > Sure, in the LAN side we'll never have to worry about address scarcity. > But what's the point of having addresses to spare, if it just means > you've got to start worrying about subnet scarcity? If the goal was > never having to worry about counting anymore, I propose that 128 bits is > far too little. Should've gone a full 256 and be done with it. > > Regards, > Israel G. Lugo > > P.S.: I'm 100% for IPv6 and $dayjob has been fully dual stacked for 10 > years now. -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org
