In message <559DB604.8060901@lugosys.com>, "Israel G. Lugo" writes:
On 07/05/2015 06:26 PM, Owen DeLong wrote:
On Jul 4, 2015, at 23:51 , Valdis.Kletnieks@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: marka@isc.org