Companies using public IP space owned by others for internal routing

Anthony Newman nanog at
Tue Dec 19 22:19:52 CST 2017

On 2017-12-19 12:18 PM, UpTide . wrote:
> If we allocate a /64 like we do single ipv4 addresses now the space gets 2^56 (16777216) times larger; but if we start doing something crazy like allocating a /48 or /56 that number plummets. (256 times larger, and 65536 times larger respectfully.)
> But then again I'm bad with math, maybe not?

You most certainly are. There are (2^32)*(2^32) in 2^64, meaning 
everyone who has a /32 of IPv4 would get about 4 billion /64s if we 
chopped it all up the same way. Or 65536 /48s, or 16777216 /56s.

I think the argument is not that there isn't enough address space to go 
around; more that profligate allocations to begin with may restrict 
future options on a century-scale timeline.

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