Current Consensus on IPv6 Customer Allocation Size

Tim Densmore tdensmore at
Thu Aug 2 17:37:02 CEST 2012

On 8/2/2012 12:30 AM, Mikael Abrahamsson wrote:
> On Wed, 1 Aug 2012, Tim Densmore wrote:
>> trying to come up with a reasonable numbering plan that can 
>> accommodate /48 customer assignments from our /32.
> First of all, /32 is the default allocation you get without 
> justification, right. So if you justify, you will get more. Do a 
> proper justification now, not in 3 years, so you're on the right track 
> by trying to find out.
> If you want a big subnet, planning to hand out /48 to everybody will 
> give you a lot of addresses, increasing flexibility down the road. 

Hi Mikael,

Based on my conversations with ARIN, my understanding is this - 
currently ARIN usually only assigns two sizes of subnet which are /28 
and /32.  They will not allocate outside of a nibble boundary. They have 
a fee schedule for multiple sizes of ORGs, but in reality are only 
allocating "small" and "large."  In our case, we would qualify as a 
"medium" ORG so were offered the option of either allocation.  The /32 
came with no additional yearly dollar cost. The /28 would have been a 
substantial increase in our yearly ARIN fees (something like $6k, but 
that's based on memory, and might be inaccurate).  This was not on the 
table in my case.

Regardless of whether IPv6 is something that will be an absolute 
requirement down the road, currently it's not something that's going to 
generate any revenue (the majority of our agg gear and CPE don't have 
any notion at all of IPv6), and with multiple other projects waiting for 
funding which actually will be revenue generating, well, I'm guessing 
you get the picture.  I didn't push, but even personally, I'd rather 
spend the ARIN fees on new gear, upgrades to pipes, etc.

Either way, thank you very much for your POV.  Hopefully you understand 
my POV.  FWIW, I'm leaning towards the same sizes you (and a few others) 
have discussed - /48 for biz/big/requesting customers, and sparsely 
allocated /56 for residential.


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