Private use of non-RFC1918 IP space (IPv6-MW)

Patrick W. Gilmore patrick at ianai.net
Wed Feb 4 18:02:56 CST 2009


On Feb 4, 2009, at 6:56 PM, Scott Howard wrote:
> On Mon, Feb 2, 2009 at 9:35 PM, Patrick W. Gilmore  
> <patrick at ianai.net>wrote:
>
>> Except the RIRs won't give you another /48 when you have only used  
>> one
>> trillion IP addresses.
>
> Of course they will!  A /48 is only the equivalent of 65536  
> "networks" (each
> network being a /64).  Presuming that ISPs allocate /64 networks to  
> each
> connected subscriber, then a /48 is only 65k subscribers, or say  
> around a
> maximum of 200k IP addresses in use at any one time (presuming no  
> NAT and an
> average of 3-4 IP-based devices per subscriber)
>
> IPv4-style utilization ratios do make some sense under IPv6, but not  
> at the
> address level - only at the network level.

First, it was (mostly) a joke.

Second, where did you get 4 users per /64?  Are you planning to hand  
each cable modem a /64?

-- 
TTFN,
patrick





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