[arin-discuss] IPv6 End User Assignments

[Garry Dolley]

On Thu, May 07, 2009 at 09:34:01AM -0500, Dan White wrote:
> 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!

But that 8192 possible customers is if you only give 1 IP per
customer (/32) and you have one huge subnet (the /20 itself); isn't
that a bit unrealistic?  I mean customers will want /29, /28's,
etc...  no?  Most of my customers request more than 1 IP. 

I see what you're saying mathematically, but still...

The 65536 /48's within your /32 is more realistic given that a /48
is probably enough for most customers.  They can subnet all they
like and still have a lot of addresses.  You could indeed sustain
65K customers in your /32 and give them all /48's.

-- 
Garry Dolley
ARP Networks, Inc. | http://www.arpnetworks.com | (818) 206-0181
Data center, VPS, and IP Transit solutions
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