[Dagger2]

There's no particular reason to use the entire IP as the lookup key though; all customers will be numbered out of the ISP's single allocation and you don't need to keep track of the traffic of each individual host, just the overall traffic of each customer.

You'd end up needing a much smaller array for v6 -- small enough that you could fit it into the presumably-unused parts of those 2^32 arrays that correspond to the v4 class E space.