>In your example, your ISP has allocated you well over half the bits in an address. The reason for that is because as of IPv6, DHCP is is no longer the standar

>In your example, your ISP has allocated you well over half the bits in an address. The reason for that is because as of IPv6, DHCP is is no longer the standard way of getting an address. With IPv6 autoconfig each device assigns its own /64 address (either based on MAC, or randomly generated), thus subnets smaller than /64 are simply not practical for most use cases. Having a /56 means you get 256 distinct subnets to assign as you please, just like you did with 192.168.0.0/16