William Herrin wrote: [..]
I'm not aware of any way of dynamically assigning an IPv6 subnet to a customer that's as well automated as IPv4 /32 dynamic assignment to a DSL router with an RFC1918 NATed interior, but that may just be my ignorance since I haven't needed to research it.
DHCP-PD (prefix delegation)
Static IP customer: /60
ARIN defines a /56 minimum. That is the reason that ISPs get a /32. RIPE defines a /48 at the moment. [..]
I recommend /60 as the customer default where most folks suggest /56 or /48. The IPv6 use profile looks a heck of a lot like the IPv4 use profile and /60 is 16 subnets. How many of your customers find a reason to use more than 3 IPv4 subnets, including their RFC1918 ones? Relatively few.
Think Future. And why bother with that anyway. If you as an ISP needs more address space just ring RIPE/ARIN/APNIC and ask for more, they will happily give it to you.
Giving every customer enough subnets by default to meet 90% of the typical usage profiles is not the worst idea in the world... IMHO it's a pretty bright idea. But there's no need to be damnfool wasteful about it.
I guess you ran the numbers on how to run out of IPv6 address space? You can always ask the US DoD for a few /32s, they have enough of them... Routing will become a problem before IPv6 address space will run out. Oh, and we are only allocating from 2000::/3 at the moment, can retry on the other 7 /8s.... Greets, Jeroen