[arin-discuss] IPv6 End User Assignments

[Dan White]

Joe Maimon wrote:
> michael.dillon at bt.com wrote:
>
>   
>> It is not a waste of space. Very large ISPs in Europe and
>> Asia already do assign /48s to each customer. ARIN policy
>> allows it in North America as well.
>>
>>     
>
> Only large ISP's can afford to do so with impunity. A /32 is not
> sufficient for a default allocation of /48 per customer. That makes it
> effectively only 16 times larger than an ipv4 /20, which suggests
> additional prefixes or renumbering pain.
>
> A /24 or /28 would be better if indeed /48 per customer is expected to
> be the norm.
>
> People are trying to carve up their allocated space now, in an
> intelligent manner as much as possible. Getting it right at this point
> could avoid pain later, so this is important.
>   

To me, the conservative approach is to assign a /48 to each customer. To 
do so means that they will never need to ask for more addresses again 
(in most cases), regardless of their size... and as their provider, it's 
doesn't make sense to me to suggest what their network should look like 
today, or what it likely will look like in 5, 10 or 20 years.

I tend to stay away from the approach of allocating small subnets today, 
and then allocate larger ones based on customer need. I prefer to do the 
heavy lifting up front - /48 via prefix delegation or routing protocol - 
which will save me the work of reconfiguration their allocation down the 
road.

 > A /32 is not sufficient for a default allocation of /48 per customer.
 > That makes it effectively only 16 times larger than an ipv4 /20

I have two /20 IPv4 allocations, which gives me 8192 possible customers 
(and I have many less than that). I have a /32 IPv6 allocation which 
gives me 65536 possible customers at /48, which should easily last me 30 
years to retirement!

- Dan