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Using IPv6 with prefixes shorter than a /64 on a LAN



On 2/5/2011 6:47 AM, Mark Andrews wrote:
> So why the ~!#! are you insisting on comparing IPv4 allocations with IPv6
> alocations.
>
Because that is where the comparison must be made, at the RIR allocation 
size/rate level.

> There are two sizes. Those that fit into a /32 and those that don't.
> The latter ones have to justify their allocations.
>
Yeah, tell that to the fee schedules.

> No. You need to compare it to the number of customer sites. If you
> have 1 customer with wires going to two locations thats two /48's.

That's definitely the wrong way to look at it. Sure that's related to 
justification to an RIR to get an allocation, but ISPs will end up with 
much more flexible address space.

> Residential ISPs shift 16 bits (48-32=16). You shift less if you
> have less than 64000 customers sites and don't get address space
> from a larger ISP.  Commercial ISPs shift more as what was multiple
> address at one sites becomes 1 /48.
>

64,000 customer sites isn't required to receive more than a /32 (unless 
a single router makes up your entire network).

Well, I currently have a /30, which is a 14 bit shift right from my /16. 
(30-16=14). In the near future I expect to be somewhere between a /24 
and a /28, which is an 8 to 12 bit shift right from my IPv4 /16 allocation.

Still, that is a considerable number of bits we'll have left when the 
dust settles and the RIR allocation rate drastically slows.

Jack