Re: There's begillions
Do you have to configure a /64 as a routed subnet?
Are you sure you can't be more granular than that?
That link you gave was too long for me to read (quickly) but from what I understand, you could * use a smaller subnet but it's definitely not recommended. The problem is that ipv6 lets you do some neat automatic configuration at the "single user end LAN" router but only if the address space it's managing is /64. If your LAN space is smaller than that then the Stateless
Address Auto Configuration (SLAAC). mechanism won't work. Basically you will want to use SLAAC even thought technically you don't have to.
* ipv6 routing tables aren't significantly different from ipv4. You can still, for example, put in arbitrary static routes, but it's not the "ipv6 way".
* edit: just to add another explanatory note, ipv6's natural subnet size is /64, while they define /56 as being for "Minimal end sites assignment". So (to keep things really simple) ignoring any special address spaces carved out of the global address space, there are up to 2**56 different "end sites", each of which can have 2 ** (64-56) = 256 subnets, each of which can have up to 2 ** (128 - 64) individual hosts.