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by chippiewill 1599 days ago
IIRC /64s are ideally meant to address to individual subnets (the bottom 64 bits aren't intended for routing) so it's only really 64k addresses in the conventional sense.

/48 is actually a relatively standard allocation even for home connections, although /56 is more common.

3 comments

I think what Rogers in Canada does is reasonable. They issue a /64 by default and a /56 if you set an assignment hint.
This was key to me understanding IPv6 - you don't really do variable length subnets. You just get a /48 and break that up into /64's. Because the space is so vast, you can do inefficient things with no chance of running into allocation issues like v4 and you don't have to mentally try and subnet a 128 bit address which maybe some can handle but hurts my head.
The intent of the standard /48 end user size was to prevent residential ISP's from being stingy and only assigning one IP. They wanted homes to have as many publicly routable subnets as the would ever need or want.

This was later revised to "/56 by default, /48 if you ask with no justification needed"